Propliner Tutorial

[Tom/CalClassic]

Part of the CalClassic Archive Project



THE 2008 PROPLINER TUTORIAL

SIMULATING PROPLINER OPERATIONS USING MICROSOFT FLIGHT SIMULATOR


INTRODUCTION.

I claim copyright over the text component of this tutorial. I have authorised hosting of the text, in part or in whole, only at www.calclassic.com. I may publish parts of it elsewhere, or by other means, in the future. This tutorial is aimed explicitly at those who have no real world aircrew experience. The goal is to explain how to achieve realistic simulation of 'propliner' operations within Microsoft Flight Simulator 9 and why design errors within FSX must be fixed by flight simulation users seeking realism.

This tutorial is nominally divided into parts which explain phases of a simulated flight, but it should be read as a continuous narrative as each part assumes knowledge of all that has gone before. Key topics can be reviewed later using keyword and key phrase search from within any text reader. The tutorial is stored in plain ASCII format to minimise bandwidth. You may wish to vary font type and size after downloading and then save in your preferred format.

The tutorial may appear to have an odd sequence, but for good reasons it should be studied in the following order.

Part 1 - Flight Simulation Basics

Part 2A - En Route Phase (simulating historic infrastructure constraints)

Part 2B – En Route Phase (Radio Ranges – navigation gauge development)

Part 2C - En Route Phase (Procedures, Mach, ETA v ATA, Winds, 4D navigation)

Part 3 - Arrival Phase (including holding procedures)

Part 4 - Approach Phase

Part 5 - Departure Phase

Part 6 - Flight Planning in detail

Part 7 - Near runway operations

Part 8 - Managing thrust in propliners

Please download the freeware version of Adobe Acrobat and PRINT the included diagrams;


KIZG_NDB.pdf
3B1_NDB_14.pdf
KSFM_RR_25.pdf
KLEW_ILS_04.pdf

before studying Part 3. Always obtain the latest versions for real world flight, but use the versions included when flying the tutorial exercises. The file NE1TO.pdf need not be printed. The tutorial will explain when to view it on screen. You will be encouraged to make hand written notes on the other four documents during the tutorial.

The tutorial eventually proposes exercises to be flown in FS9. In order to explain those exercises with precision they must relate to a specific cockpit environment associated with specified flight dynamics. Many of the exercises should be flown in Bill Lyons’ freeware FS9 Grumman Goose. The necessary updates to the original release, needed to match tutorial content, are included in this tutorial zip. You can apply them to Bill’s Goose obtained from elsewhere now, but I will remind you again just before you need to fly the Goose to follow this tutorial.

Parts of this tutorial associated with the vintage phase of aviation history require you to download the Savoia Marchetti S.73 (v2) from Avsim.com. That download contains gauges, files and further pdf documents needed later in this tutorial.

Finally this tutorial has exercises involving the FS9 DZN L-049A Constellation (patched). The aircraft and the required patch can be downloaded from the Constellation page at www.calclassic.com. Please note that the DZN L-049A release package contains one of the few full function autopilots that is not plagued by bugs. That autopilot (and no other) will be required to carry out various exercises set later in this tutorial whether or not the aeroplane involved is the L-049A. Simply install the DZN gauge package in accordance with its release notes and then copy its gauge.cab to your FS9 gauges folder so that those gauges are available in other cockpit environments. You should do that now as I will not remind you again.

Questions about this propliner tutorial, (but not real, or modern flight operations please), can be asked in the relevant support forum.

www.calclassic.com/cgi-bin/yabb/YaBB.cgi?board=General

This forum belongs to, and is moderated by Tom Gibson. If he, or one of the 'resident' real world pilots, cannot answer your question I will probably turn up to answer it eventually. Please be patient.

This tutorial does not explain the basics of how to fly an aeroplane in real life or in a simulator. That may be learned by using the interactive lessons included within MSFS, together with the Microsoft tutorials in the 'Learning Center', which is installed during a full install of MSFS. This tutorial begins where the content of the 'Learning Center' ends and explains how to achieve realistic simulation of propliner operations from the dawn of commercial flying to the end of the classic era of aviation history around 1970 when radar control replaced procedural control. It has some relevance to analogous military and naval aircraft, including maritime patrol and bomber aircraft.

An ab initio student intending to acquire the knowledge and qualifications necessary to fly the procedures I am about to describe, in a real propliner, would undertake at least 12 months of full time ground school and would receive at least 150 hours of one to one flight tuition. By contrast this tutorial is intended to be compatible with several dedicated weekends of study and self tuition. It therefore omits a number of real world procedures and simplifies others.

Similar tutorials are available from other websites, but they are either aimed at real pilots about to upgrade their qualifications and take a great deal of prior knowledge for granted, or they are aimed at simulating IFR arrivals in conformity with present day rules and procedures. By contrast this tutorial deliberately blurs the difference between the Visual Flight Rules (VFR) and the Instrument Flight Rules (IFR). MSFS is not capable of replicating ATC implementation of either with any accuracy and they have anyway changed over time, and continue to change.

This tutorial therefore sets out a singular mode of propliner simulation that can be used, day or night, whatever the weather, and whatever the type of flight plan. If you feel the need to operate in complete conformity with the VFR or IFR you will need to purchase and study the relevant textbooks for your jurisdiction.

NOTHING THAT FOLLOWS IS FOR REAL WORLD USE. I will however attempt to place the tutorial into a real world context since many of the things that are done in the real world are done for reasons that are far from apparent when using MSFS. Since what follows is only a cut down approximation of the reality, aimed at non aircrew, there are of course alternative approximations which might emphasise other aspects of the simulation and omit some which I have chosen to emphasise.

This tutorial is not aimed at users of simulators who are still uncertain how to use avionics such as ADF, VOR and ILS to conduct basic radio navigation of aircraft. Tutorials concerning use of ADF, VOR and ILS are available within the 'Learning Center'. Explanations of modern approach lighting etc., are also available elsewhere. This tutorial explains how to use vintage and classic era avionics realistically within the context of commercial propliner operation in a non radar environment. Unless explicitly stated everything in this tutorial assumes the nil wind case.

In order to simulate the operation of propliners realistically, in any era, we need to undertake pre flight planning. To simulate some early phases of commercial aviation history we need only a good tourist map. For others we need to download and study the current real world departure, arrival and approach procedures for our point of departure and destination. Most are freely available on the web.


When simulating the operation of a propliner prior to the 21st century there is little point in 'filing an IFR plan'. The canned ATC will just try to impose unsafe radar vectors, unrealistic clearances and unrealistic rates of climb and descent that are not appropriate to the era being simulated or the aircraft in use. The canned procedures are never appropriate outside the U.S. anyway. Within MSFS ATC is more of a navigation cheat mode than a simulation of real ATC.

Creation of a hand written, or printed, 4D flight plan to follow is essential. It must be corrected as we fly along. The difference between estimated time of arrival (ETA) and actual time of arrival (ATA) is crucial. We must be able to update our plan as we execute it. If we fail to plan, then we plan to fail. The usual flight planning tools are not capable of doing that without error. Full guidance is available within Part 2C and Part 6 of this tutorial.

We must also learn to issue appropriate ATC clearances to ourselves. The tutorial will provide guidance as it progresses, but that level of detail can wait until later. First we need to cover the basics of propliner flying.


JETLINERS v PROPLINERS

The dynamics of jet engines and piston engines are not just dissimilar, they are totally different. Consequently many of the statements in this tutorial are false when applied to jets. Miles per gallon achieved in a jet depend on altitude. Any jet has double the fuel economy, and therefore double the range, at 41,000 feet. It must get up there as fast as possible, stay up there as long as possible and therefore plans to descend in a high drag, steep, power off, dive. This profile is not about saving money. Any jet will run out of fuel as little as half way to destination if it cruises too low or descends too soon. Regardless of the velocity it cruises at.

For a jet early climb and late descent are flight safety requirements. Jet aircraft require a radar based ATC environment to meet that requirement. Propliners did not and until commercial jets arrived ATC, navigation and flight planning was 'procedural'.

Piston engines have neither the benefits nor the problems of jet engines. They achieve about the same fuel economy (range) at any altitude. However even though fuel economy varies little the higher they fly the less air resistance propliners encounter and the higher the True Air Speed = TAS = velocity they achieve without any loss of range or economy of operation. So long as they do not exceed their current operational ceiling.


The time it takes a propliner to get from A to B depends mostly on altitude, but unlike a jet the fuel burned does not. Piston engined aircraft are therefore very inefficient for long range flying. However the only way to get from A to B in the minimum time in any aeroplane is to operate it at its operational ceiling. The operational ceiling depends on the current weight. We must climb to the initial operational ceiling and as weight reduces through the flight we must step climb to new higher operational ceilings.


OPERATIONAL CEILING.

The practical definition of operational ceiling when using a simulator is the maximum level to which the aircraft can climb, *using only climb MAP and rpm*, without the Vertical Speed Indicator (VSI) falling below 500 ft/min and without the Indicated Air Speed (IAS) falling below the mandated climb IAS.

During a short haul flight a propliner (or bomber etc) may never reach operational ceiling, and will never achieve the cruising velocity we see quoted in references. Cruising velocity can only be achieved at operational ceiling.

It may take a propliner more than thirty minutes to reach its initial operational ceiling and more than ten hours to reach final cruising level after several step climbs. Most MSFS users fail to understand that they will arrive at destination many hours later than necessary if they do not sustain operational ceiling throughout the flight.

In a propliner fuel consumption per mile will not vary significantly with altitude at constant power, but fuel consumption per hour will. Piston engined aircraft can cruise slowly at low level without significant fuel penalty if required to do so. Jets cannot.


DRAG.

The lower we fly, the slower we fly, in any aircraft. We are ramming more air molecules and they slow us down (a lot). Think about what a 34 KIAS wind, called a gale, does to a tree. The Air Speed Indicator (ASI) is just recording the number of molecules rammed per second, (collected in the pitot tube), and therefore displays our profile drag, not our velocity. Whenever we fly any aircraft we must work hard to maximise our velocity (TAS) whilst restraining our profile drag (IAS).

From the DC-6B handling notes.

****************************
Econ Cruise: (1000hp x 4)
Use only <= 89,000lbs
COWL FLAPS = CLOSED
MAP = 32 inches
RPM = 1850
Check CHT < 232C
Plan 1900 PPH
@ zero pitch climb 2000 ft & 500 VSI
Note - Yields 242 KTAS at FL220 @ 89000lbs
****************************

Econ cruise MAP and rpm delivers a profile drag of about 182 KIAS at any level but it depends on current weight and the weight of a DC-6B varies a lot over ten hours of flight. This is anyway a drag not a velocity. It is the most economical drag for cruising. The only altitude at which the drag and the velocity are equal is sea level. 182 KIAS = 182 KTAS at sea level but 182 KIAS = 258 KTAS at FL220.

At constant MAP the fuel burn per hour rises with altitude, but the fuel burn per mile does not. Piston engined aircraft therefore have much more endurance at low level, but have about the same range at any level up to their operational ceiling. Piston engined aircraft were therefore retained for extreme patrol endurance long after they were abandoned for long range operation, but if we fly low we can only fly slow.

With piston engines fuel consumption per mile (range) is nearly constant versus altitude. It is the velocity at which we can traverse that range that differs (a lot).

We can fly 1820 miles at low level in a DC-6B and take ten hours, or we can do it at FL220 and take seven. It is entirely our choice. We use the same amount of fuel either way, but our virtual airline does not pay us to arrive three hours late on every medium haul trip in a DC-6B. We are paid to fly the DC-6B with a drag of 182 KIAS at a velocity of 242 KTAS, in thin air, up at operational ceiling, not down at low level in thick air with a velocity of only 182 KTAS.

Nor are we paid to apply abusive power at low level to try to get the drag up to 242 KIAS. Abusive power forces an aircraft to fly noticeably nose down. Using the fuel to increase drag (IAS) is not a substitute for using it to increase velocity (TAS). Available excess power is used only to create climb power to reach the thinnest possible air.

The tail becomes stressed if we add too much drag. DC-6B Vno is 251 KIAS. If we push the drag on the tail beyond 251 KIAS it may suffer structural failure if we encounter turbulence. We should target a drag below 251 KIAS even in descent. To force the aircraft nose down enough in level flight to reach a drag of 251 KIAS we would have to apply very abusive power and we would run out of fuel half way to destination because we used fuel to increase drag (IAS) not velocity (TAS). The only way to fly fast is to fly high. Sure we can fly lower than the operational ceiling, but we are wasting huge amounts of time. It will take many extra hours to complete even a medium haul.

Air molecules exert great drag on aeroplanes. Gale force upon gale force of drag. We must keep the IAS down and the TAS high by flying as high as possible in the thinnest possible air.

Anyone using a flight simulator needs to understand that before they can use a flight simulator realistically, but most simulator users never quite grasp the difference between drag (IAS) and velocity (TAS). Consequently they end up trying to increase the wrong one, applying more and more power, at too low an altitude, achieving ever more nose down attitudes, as the gales of drag rise out of control due to the abusive power and abusive fuel burn.

That extra power is there only so that we can climb into thinner air. It is not there to increase drag (IAS) at low level.


ECONOMIC OPERATION of PROPLINERS.

The optimum en route drag in a DC-6B at mid cruise weight happens to be around 182 KIAS. The resulting velocity (TAS) varies with altitude but we must use the optimum MAP and rpm regardless.

The engine overhaul costs for piston engines outweigh consideration of fuel costs. We must operate a propliner to minimise engine wear and overhaul costs, not to minimise fuel costs. That is why propliner handling notes tell us to apply a particular MAP and a particular rpm and do not tell us to target a particular drag (IAS) in the cruise. The airframe and wing do indeed have one particular drag at which their efficiency maximises and miles per gallon maximise, but it is irrelevant. En route, fuel economy must be sacrificed to the needs of the hugely expensive, maintenance hungry, engines.

For jet aircraft with low maintenance, long life turbines the economics are reversed. If necessary they are cruised at variable power to achieve a Mach number target. Mach drag can be fearsome in more ways than one.

For a propliner when not en route, e.g. when holding, (or loitering / patrolling in military aircraft), it may be appropriate to vary the MAP to sustain a target drag. From the DC-6B handling notes again.

****************************
En route Holding:
FLAP = UP
COWL FLAPS = 1 degree
2000 RPM
Slowly REDUCE MAP
To obtain 160 KIAS
Check CHT < 232C
Plan 1450 PPH
*****************************

We reduce drag to hold because the operational goal has changed from covering a great distance quickly to using as little fuel as possible regardless of how slowly we travel around the holding pattern, but en route, including en route descent, the engine settings are more important to economic operation than sustaining a particular drag (IAS).


ACCELERATION and DECELERATION in aircraft.

Most MSFS users have never flown an aircraft, but have operated terrestrial vehicles. Everything they have ever learned about terrestrial vehicles leads them to believe that any vehicle is easier to accelerate going downhill than going uphill. The whole point about aircraft, and the only reason airliners exist, is that aircraft are incredibly easy to accelerate when going uphill and almost impossible to accelerate when going downhill.

If that sounds unlikely then you are bound to be flying unrealistically.

It takes simulator users, (and many real pilots), a long time to understand that if a fighter pilot power dives his fighter from 250 KIAS at 40,000 feet to 400 KIAS at low level he has decelerated from about 500 KTAS to about 400 KTAS. As the fighter pilot dives hard and watches the ASI needle proceed from 250 to 400 he is watching the drag rise, he hears the wind noise screaming ever louder as he decelerates a hundred knots in no time at all.

A drag of 400 KIAS at low level ensures that the fighter is much slower than it is with a drag of 250 KIAS at high level. It's just a lot more drag, so we hear much more wind noise. Wind noise isn't an indicator of velocity; it's just an indicator of drag. IAS isn't an indicator of velocity; it's just an indicator of drag.

Until MSFS users grasp that IAS is drag and TAS is velocity it is impossible to understand how to plan the climb and descent of aircraft. It is impossible to flight plan, and it is impossible to understand why aircraft must follow a 4D flight plan.

When flying an L-049A Constellation we must take care that the drag does not rise above 152 KIAS until we have finished accelerating the aircraft, which will be at least 30 minutes after take off. We must keep the drag low and point it up hill or it will not accelerate. So long as we keep going up hill it will accelerate so fast that we can reduce MAP whilst climbing. At very high altitude we must restrain our profile drag (KIAS) to even lower values to promote climb and acceleration. We cannot accelerate a Constellation by applying 35 inches of MAP and burning 3000 PPH at low level. We can only accelerate by performing a long, long hill climb. In an aeroplane climbing enables acceleration and diving promotes deceleration. When climbing we need less and less power to go faster and faster. The aeroplane is the exact opposite of a terrestrial vehicle. That's the whole point.

***********************************
Climb Power below FL90: (Stage2 = Low Blower)
MIXTURE - AUTO
COWL FLAPS = 30%
CHT < 260 C
MAP = 35 inches
RPM = 2300
152 KIAS
Plan 3000 PPH
***********************************
Climb Power FL90+: (Stage3 = High Blower)
MIXTURE - AUTO
COWL FLAPS = 30%
CHT < 260 C
MAP = 33 inches
RPM = 2300
Below FL210 = 152 KIAS
Above FL210 = 142 KIAS
Plan 3000 PPH
***********************************

Airliners cannot fly fast at low level. They do not have enough power. To fly fast an airliner must accelerate for as long as possible, and the only way to accelerate an aircraft, for more than a couple of minutes, is to point it uphill and keep on going uphill for as long as possible.

At sea level a profile drag of 152 KIAS delivers a velocity of 152 KTAS, but after going up hill in a Constellation with our profile drag pegged at 152 KIAS for 30 minutes, flying in ever thinner air, we will have accelerated to a velocity in excess of 200 KTAS. If we departed at max gross we will be around our current operational ceiling by then so we will reduce power further to 25 inches and allow the drag to rise to just over 170 KIAS allowing the aircraft to accelerate further to a velocity of around 230 KTAS.

****************************
Econ Cruise (about 980hp):
COWL FLAPS - CLOSED
MAP = 25 inches
RPM = 1800
Plan 2000 PPH
Yields 239 KTAS at FL250 at MCW
c28000lbs @ 2000 PPH = 14 hrs nominal
****************************

Early series aircraft tend to have very restricted gross weights. they climb exceptionally well, but can carry little fuel and payload. Over time the airlines demand more profitable versions with more payload, making more profit, and with much worse climb performance. The original intercontinental DC-6 could climb almost as well as the original L-049A, but the DC-6B was much heavier and much more profitable. When flying most propliners we must be very careful not to climb above our operational ceiling in economical cruise power. We could continue climb higher but when we reduced to economical power our cruising speed would be deficient and we would only be able to fly at substantial pitch angles with high induced drag.

During the initial climb of propliners we must monitor either decay of IAS or decay of VSI and reject climb for cruise at a critical value. Once the classic phase of aviation history was in place (see later) the minimum legal climb rate became 500 VSI. When climbing classic era propliners like the L-049A which climb at constant IAS (152 KIAS) we must monitor VSI. As it decays towards 500 VSI we know that we must soon reject climb for cruise. If we allow it to reach 500 VSI we have already climbed too high. We should initiate cruise at zero VSI (using only 25 inches MAP) before climb rate at 33 inches MAP falls to 500 VSI.

Heavier, more profitable, propliners with larger loads often used a climb technique as close to the cruise climb technique from the vintage era of aviation history as the laws of the classic era allowed. They were climbed at a constant 500 VSI (the legal minimum) and autopilots which had the ability to sustain a demanded VSI, (rather than a demanded pitch), were slowly introduced. When flying propliners like the DC-6B we use a constant VSI technique and monitor decay of IAS instead.

***********************************
Climb Power: (1400 hp x 4)
COWL FLAPS = 4 degrees
39 inches MAP
2400 RPM
VSI = 500
Check CHT < 232C
WHEN IAS < 170 KIAS enter initial cruise
****************************

That initial climb rejection trigger, whether cited as a VSI or as an IAS, does not relate to safety. In this case if we cannot sustain 170 KIAS using climb MAP (39 inches and 4 x 1400hp) at 500 VSI then our cruising velocity will be inadequate using economical MAP (34 inches and 4 x 1100hp) at zero VSI. We use either deteriorating rate of climb (VSI) at constant profile drag (IAS) or deteriorating IAS at constant VSI to judge when we must reject climb for economical cruising, even though we could climb higher.

****************************
High Weight/Speed Cruise: (1100hp x 4)
COWL FLAPS = CLOSED
MAP = 34 inches
RPM = 2100
Check CHT < 232C
Plan 2100 PPH
@ zero pitch climb 2000 ft & 500 VSI
Note - yields 251 KTAS at FL210 @ 89000lbs
****************************

After departing a DC-6B at max gross weight in most weather systems we will need to reject the initial climb phase at FL150 or FL160 and enter the initial cruise phase. To go faster (accelerate) in most propliners we must step climb again and again as weight reduces hour by hour. Many hours later we can cruise at 251 KTAS up at FL210, still with only around 182 KIAS of drag. We will have turned a ten hour flight into a seven hour flight by climbing and sustaining operational ceiling as weight reduces. Most of the time we will be flying above most of the weather in smooth air. Whether we can see the surface will be a matter of chance. How we navigate will be explained shortly.

We time each subsequent step climbs by monitoring our cruise pitch:

****************************
...........

@ zero pitch climb 2000 ft & 500 VSI

...........
****************************

Even to cruise a DC-6B at around 230 KTAS at low level we would need to apply abusive power to try to get the profile drag up to almost 230 KIAS. The aircraft would be forced nose down passing a profile drag of about 190 KIAS and the fuel burn would be horrendous. We would be trashing the engines at the same time confusing drag with velocity, confusing IAS with TAS.

Unless we need to battle headwinds we must never allow aircraft to cruise nose down. We must step climb instead. Exact measurement of zero pitch is not required, It is pilot error to induce negative pitch in the cruise unless battling headwinds. Once positive pitch approximates zero it is time to step climb. We will examine how to battle headwinds later in this tutorial.

Aeroplanes are not terrestrial vehicles. The closer they are to sea level the worse they perform. Their performance maximises at their current operational ceiling which changes throughout the flight with weight and weather. We must constantly seek that operational ceiling and should never be more than 2000 feet displaced from it unless battling headwinds. Of course manufacturers like Cessna provide aircraft like the C172 with an operational ceiling of a couple of thousand feet or the C182 whose operational ceiling is a few thousand higher. They are efficient at low levels and it is almost impossible fro amateur pilots of simple aeroplanes to be operating with more than few thousand feet of error in their selection of cruising level. propliners provide the possibility of huge pilot error in altitude selection throughout the flight and Part 2 of this tutorial will examine that in detail.


ENERGY STATE MANAGEMENT.

Unfortunately understanding energy state management of aircraft is tough. Fortunately in the real world it is only really a problem for air traffic controllers and combat pilots. In MSFS we must do the planning that ATC would do for us in real life.

When flying we also need to consider manoeuvrability.

Aircraft (kinetic) energy state = momentum = mass * TAS^2.

Energy state (momentum) has nothing to do with drag and hence nothing to do with IAS. Energy state controls manoeuvrability. Manoeuvrability depends on TAS and is nothing to do with IAS.

A jetliner descending from FL410 to sea level at a constant drag of 250 KIAS halves its velocity, from around 500 KTAS to 250 KTAS, and consequently loses three quarters of its energy state. The fuel burn per hour will not change and so the range will halve. It must descend as late as possible or it may crash.

Since radius of turn depends inversely on energy state that same jet quarters its turn radius at any applied bank angle.

Radius of turn = TAS^2 / G

In order to fly any approach procedures we must reduce our energy state. We must fly the turns at rate 1 (turn 180 degrees in 1 minute) = 3 deg / sec.

It is legal, and just about safe in most weather, to allow a DC-6B to reach a drag of 250 KIAS, but at approach altitudes a drag of 250 KIAS is also a velocity of about 250 KTAS. We would have about double the turn radius that we would have at 182 KTAS and we would have to apply massive bank angles to fly the mandatory rate 1 turns of the approach and holding procedures. Our classic era passengers would hate us.

258 squared is twice as much as 182 squared. At any given bank angle the radius of turn is doubled at 258 KTAS when compared to the same turn flown at 182 KIAS. To fly the same radius at 258 KTAS as at 182 KTAS we have to double the G load. 251 KIAS is when the tail will fail at 1G, not 2G or 3G. Turning hard at Vno is not an option.


AIR TRAFFIC CONTROL.

MSFS assumes that ATC are using radar in conjunction with modern era jetliner procedures, and so it assumes that ATC can construct the approach sequence using lateral separation. In the vintage and classic phases of commercial aviation they could not. Approach sequencing was entirely vertical. The first aircraft to badger a clearance out of ATC to the lowest level in the stack (sequence) landed first. All pilots bitched for early descent, but they got a descent clearance based on their number in the stack (approach) sequence anyway. There is always an approach sequence whether or not aircraft are actually stacking.

In real life ATC force aircraft to descend to control their energy state. Altitude controls energy state and therefore turn rate. In real life if ATC intend to start vectoring an aircraft they will force it to descend to kill its energy state first. The canned ATC in MSFS is too dumb to do this. Because it is too dumb to control aircraft energy state it vectors aircraft over huge distances at excessive velocities in huge radius turns.

Suppose in real life ATC instruct a DC-6B to maintain FL 220 and to reduce drag by ten knots from 190 KIAS to 180 KIAS. This decelerates the aircraft by 14 knots from 269 KTAS to 255 KTAS. But ATC can only tell an aircraft in the cruise to reduce profile drag (IAS) a fairly small amount before it might become unsafe. Reducing drag also potentially reduces lift.

Instructing the same DC-6B to increase (drag) to 200 KIAS and descend to FL150 reduces its velocity from 269 KTAS at FL220 to 252 KTAS at FL150. Increasing drag by 10 knots while power diving 7000 feet with increasing IAS slows the aircraft 17 KTAS. The higher the IAS in a dive, the more the drag, the steeper the dive, and the faster the deceleration.

On reaching FL150 the pilot can now be instructed to reduce (drag) 20 KIAS to 180 KIAS and TAS will fall by a further 25 KTAS to 227 KTAS. The aircraft will have decelerated 42 KTAS for the 10 KIAS drag reduction from the original 190 KIAS to 180 KIAS losing almost 16% of its velocity (TAS) and a quarter of its energy state. The 16% deceleration and 25% reduced energy state are mostly due to the ATC mandated descent.

At any bank angle its turn radius will now be 25% reduced when (RDF or radar) vectored. In real life ATC will force it much lower and kill its energy state much further before vectoring it hard for approach sequencing else it will exit the protected airspace of the airway or terminal area when turning. That's why terminal ATC airspace has to look like a series of inverted wedding cake tiers.

The sky is crowded. ATC cannot afford to do most of the early approach sequencing by dog legging high velocity aircraft all over the sky. Inbounds are selectively decelerated by instructing them to descend in the appropriate sequence. Telling a pilot to reduce altitude and drag at the same time is stupid. An aircraft can go down and slow down (reduce TAS) very easily, but it cannot easily go down and reduce drag (IAS) at the same time. A descent with drag lower than cruise drag would be very shallow. The pilot needs to target higher drag than econ cruise IAS to dive steeply to decelerate the aircraft quickly.

I realise that this is entirely counter intuitive to users of terrestrial vehicles, but to succeed in flight simulation it is absolutely necessary to understand that the more we need to decelerate the harder and further we must dive. It follows that the airliner that needed to dive hardest and farthest was Concorde. It had to decelerate faster and more than any other airliner.

For Concorde top of climb and top of descent were co-incident. They occurred at about FL600, Mach 2 and 1138 KTAS. Since it is unlawful to fly an airliner supersonically over land, as Concorde approached a land mass it always entered an exceptionally steep dive of more than 20,000 feet which rapidly increased the drag and allowed it to slow to just M0.9 and 515 KTAS at FL370 in just a few minutes. No other airliner could dive hard enough to shed 630 KTAS over not much more than 20,000 feet of descent. All other airliners have had tailplanes and tailplanes are too weak to allow long steep dives and the rapid deceleration they impose.

In real life a pilot can pregnant dog at ATC for descent in accordance with his or her airline's fuel saving policy all they like, but they get clearance according to their position in the approach sequence. At a busy airport today there are never fewer than thirty aircraft in the queue for each landing runway, often there are over fifty. In the classic era more like a dozen. Either way they are being approach sequenced by ATC before they get descent clearance from FL 220. When ATC have killed an aircraft's energy state to their satisfaction they will start to vector it hard in low radius turns that do not endanger other aircraft and don't take 2 minutes to turn 60 degrees.

The canned ATC provided by Microsoft is too dumb to implement this. We must impose these real world strategies upon ourselves in order to experience realism.

Given a free hand we will not choose to descend at more than 700 VSI in a propliner as it will quickly cause profile drag (IAS) to rise to unsafe values. Descending at more than 700 VSI we risk exceeding first Mno and then Vno. We will study those structural limits in detail later. Of course some propliners have higher drag co-efficients than others and some are stronger than others. Some run little risk of exceeding Mno, even when descending at more than 700 VSI, even in econ cruise power. Compared to a Cessna the DC-6B is pretty slippery and tends to have an energy state problem that we have to manage with both care and foresight in order to avoid structural failure. That's one of the things what makes it so much more interesting to operate than a jet.

Back in the classic phase of aviation history we would have been approach sequenced entirely by when we were given descent clearance, from cruising level, and to each successive level. Remember we are not entitled to descent clearance at all. As we fly towards our destination we do not have an approach clearance. In real life we may have to maintain cruising level into the stack and make all of our descent winding down in the hold, round and round until it is our turn to have approach clearance. For a DC-3 cruising down at FL100 this would happen frequently, but for a DC-6B up at FL220 hardly ever.

However inbound to a busy airfield we are always in the ATC approach sequence at least 20 minutes before we get an approach clearance and normally before top of descent. In real life, when and how much an airliner descends is not an aircrew problem, but they can always ask politely if ATC have forgotten them.

The canned ATC is too dumb to cope with any of this and we must issue a descent clearance to ourselves at the correct time. I do mean correct time not correct place. Think very hard about the difference. Aerial navigation is a 4D process and as we shall discover the most important instrument in most propliners is the clock. More detail in later parts of the tutorial.


MSFS - FLIGHT SIMULATOR OR GAME?

Flight simulation is the process of operating a virtual aeroplane in compliance with real world procedures, in a realistic atmosphere, all within a simulation environment fully compliant with the laws of geometry and dynamics. The skills learned and practiced are worth hundreds of dollars per hour in the real world. A game has only abstract rules and an abstract environment, designed for entertainment purposes. The knowledge and skills acquired in a video game are worth nothing in the real world, however entertaining they may be. It's a crucial difference.

Those who manage to understand and apply all parts of this tutorial, can start to use MSFS as a flight simulator rather than a role playing game. FS9 is a flight simulator, not a game. We can fly compliant 4D departures, compliant 4D flight plans, compliant arrivals and compliant approaches, appropriate to a particular aircraft type, at a particular date, and use the real procedures, in real weather, in real time, rather then making them up and just pretending. It takes a lot of effort, but there is no reward without effort. The difference between just pretending to fly an aeroplane and simulating the compliant operation of that aeroplane is huge. This tutorial is the key to progressing from one to the other.

You may need to read Part 1 of this tutorial several times and also practice the concepts it explains over and over again using MSFS before you understand it all and can relinquish misconceptions based on a lifetime of confinement to the 2D world of terrestrial vehicles. Aviation is all about thinking and operating a vehicle in 4D. There is much more that the MSFS user needs to know before they can even begin to comprehend what that means.

Part 2A of the tutorial explains the history of en route aerial navigation and how to simulate each contemporary reality within the constraints of MSFS. It also explains why FSX is not a flight simulator. Each subsequent part of this tutorial assumes an understanding of the preceding part so even if you think you already understand en route navigation (in nil wind) I strongly advise you to read part 2A before proceeding to later parts of the tutorial.



PROPLINER TUTORIAL PART 2A - EN ROUTE PHASE (SIMULATING INFRASTRUCTURE CONSTRAINTS)

Part 2 of the propliner tutorial now explains how to simulate propliner navigation in the pioneer, vintage and classic phases of aviation history.

However nothing in this tutorial is about how avionics work or how to use the knobs on a VOR or GPS. That is explained on various web pages and in many modern era tutorials aimed at modern era real pilots. This part of the Propliner Tutorial is about when to use them (or not) after becoming familiar with how they work and what the knobs do.


THE FOUR PHASES OF AVIATION HISTORY

Aviation history is about much more than aeroplanes because the things achieved by aeroplanes and those who fly them depend on a complex external infrastructure that is often ignored. During the pioneer phase of aviation airlines attempted scheduled passenger services without the infrastructure necessary to make it safe. An airline passenger in the Continental United States (CONUS) who chose to make a journey by air in 1929 was much more likely to be delayed and several hundred times more likely to be killed, than if he or she made the same journey by rail.

Microsoft's description of the Ford Trimotor ends, "During its years of regular service in the late 1920s and early 1930s, the Ford Tri-Motor helped popularize commercial flight and promote the safety of flying to travelers." No aeroplane could have done that in the pioneer phase of aviation. The necessary public sector infrastructure did not exist. Air mail planes and their pilots were being sacrificed monthly and as soon as the airlines attempted to carry passengers with the air mail in single crew aircraft like the Ford 4-AT-E Trimotor passengers began to perish too.

What each phase of aviation has in common in every country, whenever it arrives, is nearly identical public sector aviation infrastructure, (civilian or military), regardless of aircraft diversity or airline ownership and control. The infrastructure was created by federal governments to enable, impose and monitor private sector compliance with the increasing federal regulation imposed.

The pioneer phase of aviation in each nation, or sector of aviation, was characterised by irregularity of service and high death rates due to inadequate public sector infrastructure. Aircraft were operated by pilots who had no formal training or qualifications in wireless operation or navigation. They compared a road map to the scenery as it went by and often became fatally lost.

The vintage phase of aviation that followed was therefore characterised by large flight deck crews, including both a qualified wireless operator, and a qualified navigator. They used global positioning systems, (GPS), to navigate without reference to the scenery. Using GPS they attempted to fly direct from departure to destination. This was a terrible mistake, but in most nations it took a very long time for federal regulators to come to terms with the failure of vintage era GPS navigation techniques. Remember there were Global Positioning Systems in use long before the emitters were in geostationary satellites. SAT-NAV is just the latest form of GPS. All earlier forms of GPS were terrestrial.

The following classic phase of aviation history was characterised by mandatory procedural compliance with government regulation, using an infrastructure provided at public expense, to ensure both regularity of service and greatly enhanced public safety. In the classic phase of aviation history both the wireless operator and the navigator were banished from the flight deck and the remaining pilots were comprehensively retrained to tune and follow radio beams from radio beacon, to radio beacon, to radio beacon, using sequential point to point instrument navigation following simple text flight plans and federally published and mandated procedures. That third classic phase eventually gave way to the fourth and modern phase of aviation history.

For a single location such as California a passing phase is also an era. Aviation historians tend to talk about eras of aviation, but the truth is that aviation history has happened in phases. Different nations have gone through identical phases at different times and the military, naval and commercial aviation sectors within a single nation tend to progress into and through those phases at different times and at different rates. In what follows I may talk about eras, but they were really overlapping phases which happened at different times in different places. How we conduct a realistic propliner simulation must depend on four different things;

1) crew complement

2) the avionics being simulated

3) location

4) date



PHASE 1 - THE PIONEER ERA - NAVIGATION BY VISUAL REFERENCE TO THE SCENERY

When simulating flights from the pioneer era of aviation, or during simulation of flights in simple aircraft at a later date, we must navigate by visual reference to the scenery. Our goal is to recognise landmarks chosen from a tourist map, then track from them to intercept a line feature, shown on the map, but not yet in view. Tracking from a landmark to another landmark already in view in the far distance is good practice, but attempting to track directly to a landmark not yet in view should be avoided.

By default the aircraft is always flown to the right of the on course track. When we eventually locate the chosen line feature, we turn left, and follow it keeping it on our left. Other aircraft following the same line feature in the opposite direction will be doing the same and will pass 'port to port' as required by maritime law, which applies to all vessels in transit including aircraft. If we ever meet a head on confliction we must (both) turn right.

We follow the intercepted line feature to the next landmark which we chose as a waypoint when preparing our flight plan from a tourist map. Now we set off to intercept another line feature that we will be able to recognise when it looms into view. Repeat as often as necessary.

Once flight simulation is conducted in realistically restricted visibility attempts to locate landmarks directly will often fail because they pass by to one side, outside the restricted limit of visibility. We must cultivate the habit of navigating along line features to landmarks which we will use as waypoints (turning points). Then we turn for another line feature which we are certain to intercept and can follow to the next landmark (flight plan waypoint).


LINE FEATURES are the key.

Line features are rarely straight. Coasts, lake shores, rivers, canals, roads and railways are all line features and the landmarks chosen as waypoints will often be nothing more than the conjunction of two such recognisable line features. The landmark (waypoint) itself is located by turning left to follow the intercepted line feature upon which it lays, from somewhere / anywhere to the right of the landmark, to the landmark. Sometimes a landmark (turning point) is just a sharp and recognisable bend in the feature we are following

As soon as visibility is too poor to see one landmark from the last it is an error to set off directly to the next landmark, and therefore an error to choose landmarks during pioneer era flight planning that cannot be located by intercepting an extended line feature leading to the next landmark. Remember visibility may reduce during the flight.

The idea is to give ourselves an entire line feature to locate after setting of from any waypoint. We aim right of the next landmark, so that we know we must turn left when we locate the line feature that leads to it. Each pioneer era flight is a series of time wasting turn slightly right, turn hard left, zigzags.

We must practice intercepting all sorts of line features right of the target waypoint and turning left from the interception point (IP), following the line feature to the target, keeping the line feature on our left. Big rivers and big lake shores make excellent line features. Roads and railways are more common, which is good, but also bad, because they may be more difficult to differentiate from one another.


RECOGNISING TRUE TRACK VIA RELATIVE TRACK

A key skill as we cruise along is working out the track of every line feature we cross. We may be tracking north looking for a particular road or railway whose general track is SE to NW before turning NW to follow it. We must learn to recognise the magnetic track of line features not just when tracking 360, 090, 180 or 270 but when the plan calls for us to track say 140 to the line feature. We must always be thinking about the *relative* track of the feature we are trying to locate. We may cross several roads proceeding in the wrong direction before we locate and recognise the one we intend to follow. Its only recognisable feature may be its track relative to our track and we must hold that picture in our mind. The relative track may be the only thing recognisable about it in restricted visibility.

After we turn to follow what we believe to be the correct line feature, every few minutes we must check our compass heading against the magnetic track of the feature we are following. Is it compatible with the line feature we intended to follow? We will sometimes intercept the wrong line feature.


NAVIGATION IS A 4D PROCESS

For that reason we always start a stop watch when turning onto any leg of any flight plan. We must always know how long we have been flying in the wrong direction so that we can 180 and backtrack along the leg for the same amount of time to get back to where we made the error and then resume the flight plan track from roughly the position of the original mistake to the feature we really need to intercept. There may be nothing memorable or recognisable about the point on the river or road or railway where we intercepted it. We need to navigate by reference to time, not place.


SHORT SEA CROSSINGS

This technique also applies to short sea crossings, but commercial ocean crossings were not attempted until the vintage phase techniques described next were available. If we are tasked to fly from London to Antwerp in the pioneer era, or in any aircraft whose avionics are no better than were available to the pioneers, then we must be sure to intercept the coast of Europe to the right of the Schelde estuary so that we know that we must turn left on intercepting the coast. When the coast, whether French or Belgian, is located we cross the coast to fly just inland with the coastline left of the nose and follow it northward and then inland to Antwerp along the southern shore of the Schelde estuary. In the pioneer phase of aviation history we never attempt to fly direct to destination.


DIVERSION PLANNING

It may seem that departing London there is no need to have any waypoints before the French/Belgian coast. Wrong. Remember we must be able to divert back to our point of departure at any time before the point of no return. We must have a, (potentially second), flightplan with line features and landmarks to allow that. Think about how much harder that makes flight planning in the pioneer era versus turning round and just following the same radio beams back the way we came using classic era techniques to be described in detail later.


DRIFT

During pioneer era flight the cardinal sin is to fail to aim far enough to the right of the next landmark when seeking the line feature that leads to it. If we fail to aim far enough to the right we may not allow for an unexpected crosswind from the right on that leg. Such a crosswind could drift us left of the next landmark. In those circumstances we would be doomed to turn left away from the landmark when we reached the line feature. We would progress further and further away from the landmark, potentially flying into high unexpected terrain.

This was the fatal problem. During the pioneer era aircrew needed to aim well right of the next waypoint, whilst seeking the next line feature to follow. During that phase they sometimes drifted very far right of track and flew into high terrain when a cross wind developed from the left. But before adoption of the techniques that marked the arrival of the vintage phase of aviation history there was no safer choice.

Many pilots who attempted to fly direct to unseen landmarks never saw them go by, to left or right, beyond the limit of their current visibility, and became lost. Without the possibility of help from air traffic control they failed to find an airfield large enough to land on before they ran out of fuel. Others blundered into high terrain whilst 'square searching' for the landmark they eventually realised they had overshot


PASSING PORT TO PORT

Pilots are allowed to cut corners when following line features, but not to the extent that they might collide with an aircraft keeping the same line feature on its left coming in the opposite direction. Pilots must keep right of the median. Often a road and a railway will follow a river through a river valley. We must not become absorbed in following just one of the line features. A road may cross the median of the valley via a bridge. The aircraft must be flown to the right of the median.


SEEKING HIGH ANGLE INTERSECTION

During pioneer era planning common sense must however prevail. We must always fly right of track when *following* a line feature without exception. By default we will plan to fly right of track when *searching* for the next line feature, but not when that defies common sense. Suppose we are tasked to fly from Green Bay in Wisconsin eastwards across Lake Michigan to Grand Rapids in Michigan. It would be ludicrous to fly southward down the lake to intercept the east shore south (right) of Muskegon.

We would instead plan to fly directly east from Green Bay to intercept the east shore north (left) of Muskegon. When we locate the east shore we turn right keeping the shore on our left. We follow it to Muskegon. Over Muskegon we turn to locate the major road that runs from Muskegon to Grand Rapids and we simply follow it keeping it on our left. We could go down to Spring Lake and follow it to Grand Rapids, but we would have to keep it on our left; and the river that flows through Grand Rapids into Spring Lake is pretty small and may be more difficult to follow than the main road. Yes, the current main road is bigger and better than it was in the pioneer era of aviation, but there was a road to follow even before WW1. Anyway in this case we have a choice of two different line features to follow.


INTERCEPTION POINTS (IPs) AND TARGETS

During pioneer era navigation there are legs whilst searching for a line feature in limited visibility when we have only an approximate idea of where we are now, or where exactly we will encounter the next flight plan line feature, but we always know exactly what we are looking for through the windscreen, what the relative track of the line feature is, and which way we will turn when we locate it. In low visibility we may locate it very suddenly and may need to turn quickly to keep it in view on our left. In aeroplanes the captain's seat is on the left. When an aeroplane is flown solo it is the left hand seat that is occupied. If we need to fly a circuit pattern it will be left hand, looking left, by default. The runaway in use is a line feature and we keep it on our left.

The challenge of operating a pioneer era aircraft is navigating the aircraft lawfully and safely without any electronic aids, not flying it. Pioneer aircraft, and modern general aviation aircraft with no avionics, are easy to fly, but difficult to navigate. We should eventually learn to cope with navigation in 3 miles visibility at dawn and dusk with the sun in any direction. Then we should learn to do it with rain or snow showers from time to time. Employ the user defined weather menu to control the difficulty of the challenge as experience is gained. Don't start with 3 miles. Work down from say 10 or even 20 miles visibility flying the same route several times until it can be navigated safely in a visibility of 3 miles. Spend as much time as necessary training at 5 miles visibility before attempting 3 miles. Flight simulation is not about admiring the scenery in nice weather. Flight simulation is all about locating the right piece of scenery in bad weather. That skill is hard to acquire, but gives great satisfaction once mastered.

During pioneer era flight we are frequently uncertain of our position and progress. We must indoctrinate ourselves to avoid flight planning directly to each target. We must instead flight plan to intercept a line feature that we are certain to intercept somewhere at unknown offset from the target, but from which it is easy to locate the target by visual reference to the line feature. In the pioneer phase of aviation each waypoint is a target with an offset IP whether or not the flight is military.


HEIGHT KEEPING

One of the most important skills that real amateur pilots of the present day and pioneer era airline pilots need is the ability to judge height. Height is displacement from the local terrain. Altitude is displacement from sea level. An altimeter can only tell us our height if we are over the ocean.

In any visibility, when navigating by visual reference to the scenery, we must learn to maintain a more or less constant height of 1500 feet, varying altitude as required. In many jurisdictions, and across much of history, 1500 feet (or 500 metres) was the minimum height for overflying towns and cities, and in many cases, other than during departure and approach, it is the minimum legal height for overflying any obstacle at all.

We must learn to recognise when the height of the local cloud base is less than 1500 feet above the local obstacles. The altimeter is of no use in this task. It shows only altitude, not height. The only way to tell if the cloud base is at least 1500 feet above the obstacles is to learn how to keep that height during en route navigation, varying altitude as required. If we meet cloud we know its base is below 1500 feet.

If the cloud base is encountered whilst maintaining a height of 1500 feet our safety minima have been reached and it is time to divert. In this circumstance by turning 180 degrees and tracking back into the safer weather and higher cloud base known to exist in that direction. The aircraft is then landed at the last suitable airfield already passed. In theory this could be the point of departure, especially depending on the nationality and visas held by all aboard during an international flight through the airspace of diverse nations.

When flying in the pioneer era perfectly ordinary weather that we would not even notice as bad weather when driving a car to the airport becomes a potential killer. Even moderately low visibility can kill. Pioneer era navigation was conducted by reference to the scenery. We must fly low enough to see the terrain in enough detail to identify landmarks and to intercept and follow line features. However it is all too easy to become over absorbed in the task of maintaining contact with the scenery; flying lower and lower as visibility or the cloud base deteriorates.

Eventually this will kill you. On average it killed pioneer era aircrew after just a few hundred hours of flying and it still kills many real amateur pilots after the same time interval today. It is very important to be aware of our height, (not our altitude), so that we can recognise when a low cloud base, or locally reduced visibility might force us down to an illegal and unsafe height. When flying by visual reference to the surface the ability to judge height is essential. Flight simulation users must learn to maintain a height of 1500 feet above the terrain and any construction rising above the terrain as the terrain and construction upon it undulates. Above all we must be able to recognise when the weather is about to force descent to a height less than 1500 feet. We must divert when that happens.

Flight simulation is not about turning some knobs in a defined sequence. It is about navigation and it is about captaincy. Flight simulation is all about planning, recognising changes of circumstance that threaten the plan, then knowing when and how to change the plan.

The earlier the era of aviation history we attempt to simulate the less the simulation is about operating equipment and the more it is about careful planning and skilled captaincy. Without both, in the pioneer era of aviation history, we will soon die.


FLIGHT SIMULATORS HAVE ERRORS.

This tutorial is about simulating the operation of propliners within flight simulators. To achieve that goal it is necessary to understand not just how propliners work, but also how flight simulators work. I will now use less than 1% of this tutorial to explain why you must not ignore the second requirement.

Many flight simulation users impose a terrible burden upon themselves by using broken files which cause them endless confusion. Many of you are using broken flight simulator control interfaces (panels and VCs). FSX has made that problem worse. Before I can provide exercises for you to use during self training I need you to ensure that you are using a flight simulation control interface that is error free. Two tutorials explaining how to identify and fix (harmonise) broken simulation control interfaces are available from;

www.calclassic.com/tutorials

The main tutorial applies to both FS9 and FSX. The supplementary tutorial applies only to FSX. If you fail to read them and you fail to implement the fixes they explain you will not achieve flight simulation. You will be stuck in a role playing game with broken user interfaces.


SCENERY DISTORTION WITHIN MSFS.


Within MSFS many panels, including many Microsoft default panels, have been designed to misplace the scenery and mesh using fake values. In order to judge either height above obstacles, or distance to go to obstacles, flight simulator users need realistic scenery perspective and placement to control the parallax relationship between the cockpit environment displayed in the front window of the simulation and the scenery displayed in the rear window of the simulation.

Mesh and scenery perspective is controlled via the SIZE_Y projection variable in FS9 and also by view_window_rect within FSX. These variables are within the panel.cfg. Mesh height and scenery position is controlled via the ZOOM projection variable. Each version of MSFS and MSCFS has a single value of ZOOM which places the scenery at its real LAT/LON with real displayed mesh elevation.

Unfortunately many people who regard themselves as 'FS9 panel makers' or ‘FSX aircraft makers’ have failed to understand that Microsoft actually require them to project the simulation scenery. Many have failed to understand that they are the simulator scenery projectionist. Many either fail to write the scenery projection code at all or upload broken scenery projection code.

Those who only pretend to fly aeroplanes may be content with the resulting mesh and scenery distortion and displacement, but for flight simulation use it is unacceptable and we must take the necessary steps to avoid it, or fix it. All cockpit environments require users to ‘police’ the files they use to eliminate gross errors of scenery projection.


CORRECT MESH AND SCENERY *PERSPECTIVE*

During flight simulation we need to see the mesh and scenery in true perspective else it becomes difficult to judge glidepath. For this reason a flight simulator should never be projected into any window whose resolution is not supported by its options/graphics menu. Many of you distort perspective by using window (screen) resolutions which you know the flight simulator you are using does not support. Using a flight simulator with distorted perspective is a really bad idea.

Many / most ‘2D panels’ lack the necessary code anyway. CFS uses different rear simulation window SIZE_Y protocols to MSFS. It is nevertheless common to see those CFS protocols within panel.cfgs which claim FS9 or FSX compatibility, but that claim is then false with regard to delivering true scenery perspective in FS9 or FSX.


CORRECT MESH HEIGHT AND SCENERY *PLACEMENT*

FS9 is a flight simulator by default. FSX is just a video game by default. It delivers false scenery placement by design and by default. It requires substantial modification by users before it is safe to use FSX as a flight simulator. Those who cannot be bothered to convert FSX from video game to flight simulator should avoid using FSX.

Where scenery is displayed in a video game is of little consequence. Within a flight simulator scenery must be displayed at its real LAT/LON. The gauges always use real LAT/LON and never point to false scenery locations. When a gauge says that a runway threshold is down a 3 degree glideslope, 5 degrees left and at 4 miles that is where it must also be displayed in the outside window of the simulator. Randomly placing scenery at false LAT/LON quite different to that shown on the gauges is a gross error during flight simulator use, or during design of flight simulator components.

Many of you do just that every time you use a flight simulator!

Gross errors are present in all default FSX Cockpit Views (CV = 2D panel), and most third party CVs for use in FSX, probably because those who wrote the code did not understand how to control scenery placement; or even that they were responsible for placing it.

In FSX every aircraft and every start up flight must specify the correct ZOOM to place the scenery at its true LAT/LON. Every producer of every *aeroplane* converted or created for use in FSX is individually and personally responsible for placing the scenery in FSX! This design error has caused massive problems for FSX users because many / most third party FSX producers have not understood how FSX works and have failed to impose the required scenery projection code.

Zoom controls the LAT/LON at which scenery is projected in any flight simulator. False ZOOM distorts distance, but false ZOOM does not distort time. If ZOOM is incorrectly coded a ridge that is really 8 miles away may be displayed less than six miles away. At 60 knots we still take 8 minutes to reach it, not less than six minutes. We cannot judge the VSI required to climb over the ridge due to misplacement of the scenery. When descending to land that situation is reversed. It seems that we must descend steeply to a threshold displayed less than six miles away that is actually 8 miles away.

Those who use files which have false ZOOM encoded cannot judge distance or glidepath because glidepath is the Pythagorean consequence of the baseline distance. As retailed the CVs in FSX are badly broken and the gross errors within them have been almost universally copied by third party FSX producers who have also assigned the out of date FS9 required ZOOM = 1.0 whilst claiming compatibility with FSX.

In a flight simulator we need to be able to see where the ridge really is and how high the ridge really is. We need to judge the VSI required to climb above it. We need to be able to decide when to reduce from obstacle avoidance (Rated or METO) power to only climb power. On approach we need to see where the airfield really is and we need to see the real glidepath to the runway.

FSX cannot read ZOOM commands from a panel.cfg. FSX *requires* the producer of the *aircraft* to control scenery placement, aircraft by aircraft! Created or converted!

The vast majority of aircraft released or converted for use in FSX lack the code necessary to place the scenery correctly within FSX. Most have nothing more than random values. Consequently those who have used FSX have been subjected to random scenery placement, random displayed mesh height, randomised climb paths and randomised glideslopes! FSX cannot deliver flight simulation without substantial effort by users to fix all the aircraft they use. If you hope to achieve flight simulation and cannot be bothered to fix FSX then you should avoid it.


CORRECT *PARALLAX* AND EYEPOINT

Within the FS7 to FSX range of Microsoft products every Cockpit View (2D panel) must have the necessary VIEW_FORWARD_DIR command to control scenery parallax in elevation versus pilot eyepoint. The CFS range of Microsoft products have different protocols. CFS normally requires VIEW_DIR commands to be absent to allow CFS to impose its own default.

If the VIEW_FORWARD_DIR variable is absent or false it distorts scenery and mesh *parallax* in FS9 and FSX. The Cockpit View (2D panel) becomes functionally useless. In a flight simulator we need the angular elevation of the next ridge line in the projected scenery to be correctly above or below our eyeline in the cruise, not just a randomly encoded above/below event due to the ‘panel designer’ leaving it to be randomised, or not bothering to calculate the correct value that places the scenery parallax versus the project eyepoint.

Cockpit View design is all about the harmonisation of the two overlaid Microsoft windows on the screen. Many 'panel designers' still have no idea what they are supposed to be doing or how to do it. Many 2D panels are functionally useless because the panel designer in FS9 and the aircraft designer in FSX only bothered to design and encode the front window on the screen and could not be bothered to control the perspective, placement and parallax of the projected scenery in the window behind it at all.

Those who only pretend to fly aeroplanes in MSFS never notice that the mesh and scenery have false perspective, false placement, false parallax, false glidepaths, false eyelines, and false mesh heights.

*Even when they are obviously correct in the Virtual Cockpit View, but entirely different when the 2D panel is in use*

If you hope to achieve flight simulation you must personally take responsibility for fixing or discarding all the broken cockpit environments that you have purchased, or that you have downloaded as freeware. Using this tutorial with randomly projected scenery at the wrong LAT/LON displayed with random parallax and random perspective is a waste of time. You must make time to fix what is broken or avoid what is broken in both FS9 and in FSX. Using broken flight simulator files is potentially dangerous, especially for real aircrew, or anyone who may become a pilot later. You may fail to understand that the scenery is misplaced and develop dangerous patterns of behaviour based on that false placement. Many of you do. These issues are explained and illustrated in greater detail within the simulation control interface tutorials available from www.calclassic.com/tutorials.

In this updated Propliner Tutorial I have included two screen shots to demonstrate the display errors which are present by default within FSX. Now is the time to study FSXcv.jpg and FSXvc.jpg which demonstrate exactly how FSX distorts perspective, scenery placement and mesh height. This destroys the necessary relationship between time and distance and destroys the necessary relationship between where the gauges correctly show the scenery is in azimuth and elevation and where it is being projected in the rear window of the simulation. The example chosen is the FSX default Baron. The default Baron CV has uncorrected FS9 scenery projection variables. The ridge line is displayed several miles closer than it really is.

Now let’s turn that gross error of distance and climb slope around and think what it means for the approach case. During the approach the time and distance to go to the runway is much longer than it is displayed to be. FSX CV users see a zoomed ‘picture’ which causes them to descend far too soon or at a VSI which is excessive. Things that are 8 miles, and perhaps four minutes away, may be displayed as less than six miles and less than three minutes away. That may be ‘entertaining’ in a children’s video game, but it is useless for flight simulation.

*Using misprojected scenery is the worst mistake anyone interested in flight simulation can make.*

Attempts to use this tutorial with broken or randomly encoded simulation control interfaces are doomed to failure.

Not even real aircrew can learn how to use a flight simulator when scenery projection is just random and grossly wrong. If you allow yourself to fly with grossly misplaced scenery you will never be able to judge distance or glideslope or climb slope during flight simulation. You will never be able to judge when to descend or what VSI is required.

Both screen shots are from the FSX default Baron at the same departure threshold using the values encoded by Microsoft. In the cockpit view screen shot the zoom is 1.0 because Microsoft failed to encode the required FSX Pythagorean compliant ZOOM value. In FSX cockpit view we are given false cues. The runway is displayed as much shorter than real life and with false perspective cues to match that deception, the ridge line is falsely displayed much closer than real life and the mesh is falsely rendered to match that deception.

That alone would make FSX a product for those interested in flight simulation to avoid. However there are also errors in its VC views. Again the *aircraft* producer has to project the scenery from VC view using code in the aircraft.cfg. In many cases the producers and converters of FSX aircraft have failed to understand their responsibility and have failed to provide the necessary scenery projection code. Many aircraft said to be compatible with FSX will display in FSX, but they are not FSX compliant. The necessary scenery projection code is randomised or has never been converted from the values used by FS9.

It is important to understand that last point. This is not just a problem of huge errors in one FSX viewing mode and smaller errors in the other. Because scenery placement is coded by the *aircraft* creator in FSX most third party aircraft makers (and converters) have guessed and coded random values for the FSX scenery projection variables because the aircraft maker/converter never understood they were responsible for projecting the scenery correctly in FSX. Many have just made LAT/LON projection numbers up at random and they are all different.

Both viewing modes in FSX have errors. Both cause false scenery display according to what an individual aircraft designer randomly decided to encode. Not only do two viewing modes in a single aeroplane have entirely different scenery placement in FSX, each different aircraft in FSX has randomly different scenery placement and randomly different ways of displaying a 3 degree glidepath.

A flight simulator is not a variety of video game. Any simulator must be programmed to replicate reality. The rules of the simulation must be the laws of the real universe. In a simulator time and distance must match. In a flight simulator scenery placement must be real. In a flight simulator the azimuth and elevation of scenery as indicated by the gauges must match where the scenery is projected in the rear window of the simulation. None of those things is true in FSX until and unless the ZOOM has been encoded correctly by the *Aircraft Designer*.

You must personally take responsibility for fixing or deleting all the broken files within retail FSX and which you have subsequently downloaded for use in FSX, or which you download or purchase in the future. If you do not you will become terribly confused and will never be able to judge height, distance, and glideslope because scenery perspective, placement and mesh height will forever be randomised. Retail FS9 is not broken by default in the same way as FSX, but many of the ‘2D panels’ created by third parties are broken. FS9 Virtual Cockpits do not suffer from these design errors, though they may have functionally useless eyepoints. These issues are explained and illustrated in greater detail within the simulation control interface tutorials available from www.calclassic.com/tutorials.


Judging distance, relative height, speed, and time to go to the obstacle or touchdown point are what flight simulation is all about. I fear many of you are so used to being confused by false scenery projection that you cannot judge if scenery, whether runway or ridge line, is eight miles away or five miles away because one is displayed as the other every time you switch from CV to VC in FSX, or whenever you change aircraft, and many of you also allow scenery placement to vary randomly by choosing to fly with broken 2D panels in FS9.

If you have not acquired the ability to judge distance you cannot judge height. If you cannot judge relative height you cannot judge required glide slope or required climb slope. If you cannot control parallax you cannot control the angular relationship of the aeroplane to the scenery. Learning to judge those things, in order to respond skillfully with the correct simulation inputs, is what flight simulation is all about. With scenery displayed at false distances and heights we cannot plan. We need to be able to judge the glidepath to the runway, or the climb slope to the ridge line, or our distance from the runway when we need to join the circuit pattern.

Real pilots never have this ridiculous problem. Each time they fly scenery placement is real, perspective is real, and parallax is real. The correct spatial relationship of everything to everything else becomes implanted as a ‘reference picture’ that they recall and compare to what is outside the windscreen. It is impossible to fly an aeroplane head up without access to that ‘reference picture’ and it needs to be the real one, especially if you need to retain real world flying skills; or intend to acquire them one day.

Real pilots need the distance shown on the DME to match where the scenery is. Real pilots need the glidepath observed through the windscreen to be three degrees when the ILS says it is three degrees. Real pilots need the climb gradient to the next ridge line to be real.

So do we!

Think hard about whether you will remember to fix every aeroplane you have ever acquired, or ever will acquire for use in FSX. If you doubt that you will remember or bother to fix every broken aeroplane in FSX you should avoid using FSX altogether. There are fewer 2D panels with gross errors in FS9 because it is not broken by default, but the same warning applies to those produced by third parties.


REALISM IS MORE THAN REALISTIC FLIGHT DYNAMICS.

In a perfect world all the files available for purchase and download would be free from gross errors. Real life is not like that. In order to experience flight simulation you must be vigilant. You must police the files you use. This tutorial is useless to anyone who does not bother.

FS9 VC mode always imposes realistic scenery perspective and placement. With a realistic eyepoint FS9 VC mode imposes realistic parallax and a fully functional field of view. Only eyepoint is coded by third parties and may need correction in FS9 VC.

No updated propliner tutorial for release after the debut of FSX can be without the stringent warnings above. I know it takes a lot of effort to achieve flight simulation, but if you do not make the effort to use only files which impose realistic scenery placement you are doomed to confusion and failure. We will revisit the importance of scenery parallax again and in more detail in Part 7 (near runway operations).


TIME TO INSTALL THE ‘ENHANCED REALISM’ GOOSE.

Now that the need for great care in selection of cockpit environment, aircraft and simulation version has been explained we can begin practical training. The goal is to recognise a height (not altitude) of 1500 feet. This is the moment when you need to install first Bill Lyons’ Goose for FS9 followed by the Grumman Goose enhanced realism update package from Calclassic.com which is part of this Propliner Tutorial zip.

Alternatively if you prefer to practice metric height keeping at 500 metres the FS9 Savoia Marchetti S.73 propliner (V2) available from Avsim as s73_v20.zip may be used without amendment in the pioneer era tutorial missions that follow. You will need it anyway for the vintage era tutorial exercises. Don’t discard the Goose files they are required for the classic era exercises anyway.


FS9 TRAINING MISSION #1

We depart any airfield near a city which is situated on a plain or plateau where terrain elevation changes very little. We note the altitude of the runway. If it is 2000 feet altitude (QNH = altitude) then we climb to 3500 QNH so that our height is 1500 feet (QFE = height) above the airfield. Now we fly backwards and forwards across the airfield, the suburbs and the city centre. We must teach ourselves to recognise what the various autogen buildings and trees we have personally chosen to install look like from a height of 1500 feet.

During that early training we will be about 1500 feet above the ground. Once we are able to recognise that condition we must estimate the height of trees and buildings above the ground. Then we must teach ourselves to fly 1500 feet above the highest obstruction ahead. If we cannot do that due to poor visibility or low cloud we must divert.

It may take many such flights over several weeks before the ability to height keep becomes instinctive. The skill of height keeping must be practiced until it is instinctive. Altitude keeping was irrelevant in the pioneer phase of aviation history and consequently altimeters were only rudimentary.

We must be able to recognise when the cloud base or low visibility prevent us from maintaining a height of 1500 feet above the obstructions whilst identifying landmarks and following line features during navigation by reference to the scenery. As soon as we are forced below a height of 1500 feet the weather has become too dangerous to continue and we must divert. Potentially back to our point of departure. The ability to recognise and maintain a height of 1500 feet only comes with experience. Practice, practice, practice.

In order to learn the skill of height keeping we must use only cockpit environments that were designed correctly and that have all the necessary variables present and correctly encoded as explained above.

The next step is to repeat the training exercise above after employing the user defined weather menu to turn the visibility down to 3 miles. Notice that we can still locate and follow any rivers, roads and railway lines inside the limit of restricted visibility by looking through the windscreen. Practice following line features in low visibility. Practice, practice, practice.

Many / most 2D cockpit views released for use in MSFS are so badly designed that this simple task is impossible. That includes badly designed Microsoft default retail aircraft cockpits. Many are useless and confusing. There is much more to obtaining realism from a flight simulator than downloading realistic flight dynamics.

Unless in significant turbulence, the challenge of operating pioneer era aircraft should be navigating the aircraft lawfully and safely, without any electronic aids, not flying it. Eventually we must learn to cope with height keeping and navigation in 3 miles visibility at dawn and dusk with the sun in any direction. Then we must teach ourselves to do it with rain or snow showers from time to time, employing the user defined weather menu to control the difficulty of the challenge as experience is gained. We must not start with 3 miles. We must work our way down from say 10 or even 20 miles visibility flying the same route several times until we can navigate it safely in a visibility of 3 miles. We may need to spend a long time training at 5 miles before attempting 3. In any visibility we practice height keeping at 1500 feet, varying your altitude as required, and navigate solely by visual reference to the scenery.

You will notice that 3D scenery looks more and more realistic as the visibility reduces and blurs any imperfections. A visibility of 3 miles is, in some current jurisdictions, nothing more than the lower limit of visibility that newly qualified amateur pilots are expected to cope with, without access to any electronic aids. Pioneer era flight simulation, including modern era general aviation simulation, is all about developing that real world skill. Only after experiencing rising terrain or masts looming into view frighteningly close ahead in poor visibility is it possible to understand why early airliners had to be so slow and why no one bothered to streamline them to make them faster until an infrastructure existed to promote cruising at much greater heights. This is stuff that cannot be understood by reading a book. It has to be 'experienced'. That is what flight simulators are for.


MAPS FOR USE IN MSFS

Road maps that show coasts, lakes, rivers and roads are available for purchase everywhere. Many also show current public use airfields for the benefit of tourists who may need to locate them to access airline services. Older second hand maps are adequate for this purpose and are often very cheap. Road Atlases such as that prepared by Rand McNally are perfectly adequate for simulated pioneer era navigation right across the United States and in practice just about good enough for simulated pioneer era navigation across Puerto Rico, Canada and Mexico as well.

With modern maps we just have a few more roads to confuse us, or to follow, and there are more masts to threaten us in the modern world. Unfortunately Rand McNally does not show railways. Seek out similar volumes for other continents and unlimited world wide realistic challenges await. There is no need for third parties to create or define challenges for FS9 users, and to simulate pioneer era navigation we do not need current Sectional and Terminal charts. They should be employed when simulating modern general aviation or third level airline propliner flying in the current era and can be downloaded from Avsim.com.


FS9 TRAINING MISSIONS #2 and #3

I recommend that everyone fly the Green Bay to Grand Rapids and the London to Antwerp flights in both good and bad weather using the Goose for the first and the Savoia Marchetti S.73 fro the second. The goal is to master the techniques of flight planning for navigation by visual reference to the scenery using simple non aviation maps. Concentrate on the flight planning. Concentrate on the selection of landmarks and the line features that lead to them so that they can be located in any visibility. Plan your diversion back to point of departure and fly it from roughly the half way point at least once. Diverting back to ‘London’ presents the most interesting challenge.

Make the effort to seek out the real world or web resources needed to conduct a realistic flight simulation and learn to tailor the simulation to the resource available. A flight from London, (whichever airfield you deem that to be), to Antwerp in the pioneer era does not require a detailed or accurate map. The real pilot would not have had one either.

These techniques may be needed again during certain parts of propliner flights in the vintage era of aviation history.


THE END OF THE BEGINNING

The airline pilots of the pioneer era had to push their luck a lot further than flying in a visibility of three miles if they wanted to keep their jobs, often with fatal consequences for all aboard. Simulating what they had to do to keep their jobs is the only way to understand why the pioneer era of aviation killed so many aircrew and passengers and why the United States decided to impose classic era techniques via federal regulation.

I am aware that there was much more to learn before conducting navigation in the real pioneer era. This tutorial is intended to help those with no aircrew experience to grasp the main differences between pioneer, vintage and classic era commercial flying and why each had to be relinquished in favour of the other.

Of course if we have not yet learned to navigate by visual reference to the scenery in the visibility that is the legal minimum for some newly qualified amateur pilots we must establish what our personal limit of flying skill actually is and we must teach ourselves how to recognise that higher visibility, and we must indoctrinate ourselves to 180 and divert as soon as we encounter it. Flight simulation is all about the skills of captaincy because real flying is all about the skills of captaincy for most pilots, since most real world pilots fly alone.

Finally bear in mind that in the modern world there are all kinds of rules that did not exist in the pioneer era. This tutorial is not intended to replace VFR navigation techniques being taught to real aircrew today in accordance with current legal and safety requirements. Real aircrew must stick with the techniques they were taught and should make the maximum use of modern electronic aids and modern ATC to maximise safety at all times. This part of the tutorial was about how things worked (in general) before those possibilities existed.



PHASE 2 - THE VINTAGE PHASE - GLOBAL POSITIONING SYSTEMS

The vintage phase of aviation that followed, (everywhere except the Continental United States = CONUS), was characterised by large flight deck crews including a qualified wireless telegrapher (telegraphist) and a qualified navigator. They used global positioning systems (GPS) to navigate without reference to the scenery. Using GPS they flew direct from departure to destination. Those vintage era GPS techniques were never adopted over the CONUS which moved directly to the third and classic phase of aircraft navigation. On the other hand the European powers, and their associated world wide empires, progressed much sooner to the vintage phase of aircraft navigation.


How we should conduct a realistic propliner, maritime patrol, or bomber simulation within FS9 depends on;


1) crew complement

2) the avionics being simulated

3) location

4) date


By the time that the Savoia Marchetti S.73 entered service with SABENA in February 1935 most European empires, including the Belgian and Italian empires, had already entered the vintage phase of aircraft navigation. Airlines no longer relied on seeing any scenery to maintain an airline schedule, and no longer relied on primitive post medieval navigation devices such as sextants. They used GPS.

GPS does not require orbiting satellites to generate the necessary electronic signals. That is just a characteristic of the latest system. Earlier systems were terrestrial.

The vintage phase of aviation dawned with the arrival of highly trained and qualified wireless operators (wireless telegraphers/telegraphists), and highly trained and qualified navigators who joined the flight deck crew, and sometimes displaced pilots as captain of the aircraft.

When we use any flight simulator we must always act as both pilot flying and aircraft captain. Performing other crew roles is optional. This tutorial provides a framework for piloting and captaining aircraft in the vintage phase of aviation. If you wish to role play telegrapher or navigator you will need to obtain a different and additional tutorial, but you will still need to deploy the skills of pilot and captain concurrently!

Both Wireless Telegraphy (W/T = Morse) and Radio Telephony (R/T = Voice) pre date the powered aeroplane. Aircraft use of electronic global positioning for navigation dates from the Zeppelins of the Imperial German Navy. A Wireless Telegrapher or Radio Operator asked an operator on the surface to manually direction find (D/F) the aircraft's transmissions in the High Frequency H/F waveband. The surface operator, (on land or aboard ship), used a large rotating Adcock array to determine the bearing of the transmitter. The bearings supplied back to the qualified WTO or RO aboard the airship were then plotted on a chart by its navigator. Ideally three bearings from different D/F operators in sequence were used to triangulate present (actually recent) position. Just as in a surface ship the airship navigator then instructed the helmsman what heading to steer based on where the vessel was believed to have been a few minutes earlier.

By 1935 propliners always had a double barrel comparison compass. In some the upper barrel was just a wet magnetic compass, in others it was already a gyroscopic compass. In some airliners including the Savoia Marchetti S.73 these were already combined within a wing leveling autopilot which drove the rudder trim tab when activated. It is important to understand however that the assigned heading was always bugged whether or not an autopilot was going to be used. The heading assigned by the navigator or Pilot Not Flying (PNF) was dialed into the assigned heading monitor of the captain's comparison compass. The actual heading revolved above or below. As pilot flying (PF) we must always keep them superimposed.

Many vintage era aircraft, including the Savoia S.73 also have a course deviation compass (Askania Kompass) slaved to the comparison compass. After dialing current and assigned heading into the comparison compass we actually fly the assigned heading using the easier to read deviation compass.

Today in the 21st century pilot flying is assigned headings by qualified radar controllers looking at a radar plan position indicator. In the vintage era he was instead assigned headings by a navigator looking at a GPS display which he was updating manually. It makes no difference at all to us as pilot flying in MSFS, or to us as the aircraft captain in MSFS, who mandates the assigned heading, or whether they are aboard the aircraft. Actually it makes no difference in real life either.

Today a GPS can update the aircraft plot in less than a second. In 1915 or 1935 it took a few minutes to use GPS signals to update the GPS plot in an ocean liner, a battleship, or an aircraft with the relevant crew complement and H/F wireless transceiver. Using GPS to simulate the pioneer phase of aviation symbolised by the FS9 default single crew Ford 4-AT-E Trimotor is cheating and is pointless. Using GPS to simulate the vintage phase of aviation which followed is entirely realistic. Most simulation users fail to differentiate between the two phases and therefore fail to deploy GPS correctly during propliner, (and military or naval), simulation of the vintage phase of aviation.

Remember the pioneer and vintage eras of aviation overlapped in different places, and in military v naval v commercial aviation infrastructure at the same time.


THE NEED FOR Radio Direction Finding (RDF)

Nobody believed that aeroplanes could achieve scheduled operation using sextants for astronavigation. Attempts often ended in death, but even when hampered by the critically low endurance of aeroplanes a qualified navigator could get lucky a few times with a sextant and live to tell the tale.

Think about how useful a sextant is when the entire flight has to be conducted in or below cloud, or in limited visibility. Sextants only work well enough to be useful in vessels that can afford to have little idea where they are for days on end. That sometimes included airships, but never aeroplanes. Of course sextants were installed in some aeroplanes. They were just useless weight much of the time in any aircraft that had to maintain a schedule.

Sextants were much used by military and naval aviators, because their command structure could just postpone missions for days on end until the weather was good enough to navigate using post medieval means of navigation. Under combat conditions radio silence may be necessary. Post medieval means of navigation were sometimes all that were available during 20th Century combat missions, or during training for combat in radio silence, but airlines were not constrained to radio silence, except in a very few places during WW2.

Radio Direction Finding = RDF, (in the HF band = HFDF pronounced Huff Duff), began to replace sextants for oceanic navigation world wide from 1909. The RMS Titanic was being navigated by RDF when she struck an iceberg in 1912. Aircraft were simply no different. By 1912 few vessels in the developed world attempted scheduled ocean crossings without both a qualified wireless operator and a qualified navigator aboard. It soon occurred to the Imperial powers that the Sahara, the Arabian Deserts and the equatorial jungles of Africa were just another kind of ocean. Then the Imperial powers decided to treat the entire planet as an ocean whose mountains were just another kind of reef. The entire planet could be navigated using GPS, not just the oceans, and it was.

By 1929 RDF was possible using HF stations 1200 miles away, *in any direction*. HFDF provided wide source infrastructure to vessels in transit, whether on the sea or in the air. When using wide source infrastructure, however the GPS signal is delivered and decoded, the vessel does not navigate from GPS transmitter to GPS transmitter. It receives the GPS data anywhere and everywhere. GPS is wide source, not point source. Consequently the vessel attempts to navigate directly from point of departure to its destination without zigzagging across the planet from one radio beacon to another.


AIRCREW COMPLEMENT CONSEQUENCE

Across the British Empire RDF was a viable global positioning system (GPS) before WW1 never mind WW2.

Aircraft with significant useful loads had large crews, whether military or commercial, precisely because they used the form of GPS known as RDF to navigate. That is why a Martin M130, or a Savoia S73 could not have a DC3 flight deck complement of just two pilots, who only knew how to find and follow a series of radio beams from one point source beacon to the next.


FLIGHT BY U.S. AIRCRAFT OUTSIDE THE CONTINENTAL UNITED STATES

Following the lead of Britain and Germany, the U.S. Navy deployed RDF from 1918 onwards, but they did not share it with anyone else, (unless for one off propaganda purposes). The early US airlines had neither point source navigation infrastructure, nor wide source navigation infrastructure. Their fatality rate was dreadful. Over the CONUS the federally imposed detailed procedures that gave rise to the third and classic phase of navigation were introduced from 1932. Outside the CONUS all US aviation slowly caught up with the USN, the European powers, and everybody else, by introducing RDF.

When using flight simulators we must never forget that for aircraft with large useful loads, everywhere except over the CONUS, GPS in the form of airborne Marconi transmitters plus Adcock RDF surface aerials was the primary commercial, military and naval navigation system in use from WW1 onwards. During and after WW2 it was gradually replaced by LORAN, GEE, Decca Navigator and OMEGA, but from our perspective of both pilot flying and the aircraft captain each is just a slightly longer ranged, or faster decoding, or slightly more accurate GPS. Somebody else in the aeroplane operated each avionic system to create the GPS plot.

How the GPS signals were decoded at a particular date is not the point. The point is that with a large enough crew of specialists the captain of a Savoia S.73, and pilot flying if a different individual, both had access to GPS in 1935 whilst the instrument rated crew of a DC-2 flying over the CONUS in 1935 navigating along the audio beams generated by point source radio ranges did not.

The Savoia S.73 did not use point source radio navigation in the en route phase. It used wide source radio navigation (GPS). Just because two aircraft existed at the same time on different continents does not mean that their operation and navigation was similar. They were not. The tiny crew complement of land based US airliners required very expensive point source public sector infrastructure.


Each of the hundreds of Radio Ranges required a power supply from a nearby power plant. By the 1930s that was possible within the CONUS, but it was totally impossible in the middle of the Sahara desert, or the middle of the vast African rain forests. Everywhere outside the CONUS wide source infrastructure was already in use and vessels in transit, whether on the surface or in the air, had the necessary crew complement to use it to create their GPS plot.


REGULATORY CONSEQUENCES

RDF provided a wide source infrastructure. Unlike Radio Ranges and the hardly different VHF Omni Ranges (VORs) that replaced them it was not associated with federal regulations, airways, en route air traffic control, or mandatory procedures.

Everywhere except over the CONUS Huff Duff was widely available allowing multi crew aircraft to navigate above cloud without visual reference to the surface, and just as easily within cloud, or below cloud, without visual reference to heavenly bodies for astronavigation, on a scheduled basis, even in really bad weather.

Every government except that of the United States wanted wide source navigation systems (GPS) to be the basis of post WW2 international aerial navigation, despite their short comings, since they had to be maintained for use by all kinds of marine vessels anyway. The shortcomings of all the early GPS systems were complex radio encoding requiring a dedicated wireless operator, whilst manual plotting of the position decoded was deemed by some regulatory authorities to also require a qualified navigator. Not much problem in a ship, but for the US domestic airlines, already accustomed to two crew IFR operation using point source radio beams over the CONUS, a huge commercial problem in an airliner.

The US view prevailed and GPS is still fighting for acceptance as a primary aerial navigation system despite automatic real time decoding and plotting. Both real time decoding and plotting have been available in British GPS moving map systems such as Decca Navigator since the early 1950s.


SIMULATION OF RDF GPS IN MSFS

In theory the MSFS GPS code could be made to behave exactly like a human navigator waiting for decodes from a human WTO before plotting the symbol on the map with suitable inaccuracy and delay, but this is not really necessary.

The rules for conducting a GPS navigated flight using Marconi + Adcock technology during the vintage phase of aviation history only requires self disciplined use of the default MSFS GPS.

1) The aircraft, (whether civil, military or naval), must have at least a qualified WTO.

2) The GPS window must be 'popped up' only at substantial intervals during cruise; perhaps every 10th minute for a short haul flight, or every 30th minute for a long haul flight.

3) Once every such position update interval, a course correction not exceeding five degrees, and always rounded to five degrees, is made after using the GPS to establish whether the flight is currently left or right of flight plan track due to wind drift and any other cumulative navigation errors, (that we have perpetrated).

What we will be simulating using intermittent course changes and headings, which will be wrong by up to four degrees 80% of the time, is the error that arose from the manual plotting delay and the bearing errors inherent in using HFDF as the contemporary GPS system at extended range.


CREW RESOURCE IS THE KEY

Multi crew aircraft outside the CONUS knew roughly where they were all of the time, in any weather, using RDF as a slow to update and slightly inaccurate GPS. Aircraft like the Ford 4-AT-E Trimotor with inadequate crew resource could still only fly the pioneer way by visual reference to the scenery.

Classic era airliners like the B247, DC2 or DC3 had two pilots, neither of whom was a trained navigator, and neither of whom was a trained telegrapher. They used point source navigation and followed beams, zig-zagging from beacon to beacon. That classic phase method of navigation did not exist outside the CONUS and some parts of the Lufthansa network.

So during the vintage phase of aviation, everywhere except over the CONUS, and some parts of the Lufthansa network, a flight in an aircraft with adequate crew resource for GPS navigation begins with a visual departure flown by visual reference to the surface until clear of all potential obstructions. This is followed by a climb to design cruising level, whether or not design cruising level is in cloud, below cloud, or above cloud, directly on track to destination. Then every ten to thirty minutes, the MSFS GPS is used to adjust heading left or right five degrees in units of five degrees until the flight reaches a position where it is deemed to be safe to descend again near to destination.

Of course any aircraft may need to climb above design cruising level to clear a mountain range, or descend below design cruising level to clear ice, in the absence of de-icing equipment. Before WW2 very few aircraft had any de-icing equipment beyond carb heat and pitot heat. Equally some stages may be so short that it is not possible to reach design cruising level.

Note especially that no RDF signal is needed from destination, or anywhere en route to destination. The GPS stations in the 1930s were up to 1200 miles away from both the aircraft and its destination.


LIMITATION OF UTILITY OF RDF

The slowly updating and somewhat inaccurate GPS used by the navigator of the Titanic in 1912 was not adequate to enter a harbour blindly in fog without reference to the local scenery. Nor was it good enough to allow an aircraft navigator to find a particular runway without visual reference to the local scenery. However, the GPS of 1912 was good enough to navigate from somewhere close to Ireland to somewhere close to New York, whether by a ship, or by aircraft. With sufficient training and skill, both undersea motionless reefs, and continental mountains, marked on a (GPS) chart could be avoided. Moving icebergs could not.

Just because the GPS systems used from 1909 to the 1990s were too poor to be used as approach aids, or could not be used to avoid collision with other moving objects, does not mean that they could not be used, or were not used, for en route navigation. Of course they were. Unless radio silence was required for combat operations GPS was the primary means of en route navigation in any vessel with a qualified crew complement and save for the CONUS continental land masses were just treated as another kind of ocean with bigger rocks and reefs projecting above their surface.

Most flight simulator users never quite grasp this. Sextants are occasionally useful in aircraft with enough power to climb above all cloud, but vintage airliners needed to maintain a schedule. On many days, and on many legs, a sextant would have been as useful as a chocolate coffee pot.

Aircraft like the Martin M-130 might need to delay scheduled departure for days on end until a headwind abated. They could not afford to delay again until the sky was visible to permit astro navigation.

Now notice that the Savoia S.73 does not have an astrodome. One of the pilots of an S.73 might also be a qualified navigator, qualified to use a sextant, but there is nowhere for him to stand to use a sextant. There was no sextant. The S.73 was navigated using GPS, operated by the WTO, not astronavigation equipment operated by a NAV. Now think about all the other airliners and aircrew flying schedules, whatever the weather, who could not rely on post medieval navigation techniques and who had no reason at all to maintain radio silence. Most of the airliners they were flying also had no astrodome and no sextant. When flying boats were used as airliners they often did, but they also tended to lack the power required to climb above cloud to take astro shots, so they too were heavily reliant on GPS.


TYPES OF COMPASS and EARLY AUTOPILOTS

Vintage phase navigation required a double barrel comparison compass within a blind flying unit (BFU). Many flight simulator users confuse the (Sperry) BFU with an autopilot. It is not an autopilot, but it can be associated with one. The operation of BFUs and their sometimes related APs has been explained correctly in some flight simulation releases, but others have been 'faked' and released with operating instructions that do not match reality.

At this point everyone should load the S.73 VC into FS9, study it, and use its four compasses whilst reading on. The magnetic compass is top centre. Now locate the gyro comparison compass between the altimeter and the artificial horizon. It has two rotating drums, one above the other. The lower drum is controlled with the left hand knob. It must be set equal to the magnetic compass as frequently as may be necessary so that it displays current magnetic heading. Do that now.

The upper drum of the gyro comparison compass (in front of the captain) is set with the right hand knob. It must be set to the assigned heading. That heading is derived using GPS as explained earlier. Pick a heading ten degrees different to the current heading and do that now.

The internal gyroscopes of the captain's comparison compass then compare the two headings and drive the (Askania) deviation compass situated above the comparison compass. Every time our assigned heading changes (perhaps only every ten or thirty minutes) whilst en route we must make fine adjustments of the difficult to read gyro comparison compass, but in between we use the easy to read and interpret 'deviation compass' above to operate the aircraft.

None of that has anything to do with whether the aircraft even has an autopilot (AP) or whether the AP fitted will cope with what we are trying to achieve by way of 4D navigation. None of those instruments is an AP or even part of an AP.

The S.73 does have an automatic pilot (AP) of sorts. The 'Corretore Autodirezionale' is a primitive device of limited capability. It can hold assigned headings and little more. To do this it senses the gyroscopes of the captain's gyro comparison compass and if the actual heading deviates even a little from assigned heading it uses the rudder to maintain course with many 'very little and often changes'. It can be used to make *small* heading changes, by slight variation of the assigned heading on the upper drum of the captain's comparison compass, but since it has no control over pitch status changes of pitch may be induced as the rudder attempts to roll the aircraft to a new assigned heading.

The 'Corretore Autodirezionale' master switch is bottom right of the captain's panel. The normal procedure is that we first set the magnetic heading on the lower drum, then the assigned heading on the upper drum of the captain's gyro comparison compass, then we manually achieve zero deviation on the deviation compass above, then (maybe) we turn on the 'Corretore Autodirezionale' if the assigned heading is expected to endure long enough to make using the AP worthwhile.

The 'AP' has no control over pitch. The aircraft can be pitched with elevator or power whilst the AP is engaged. In real life it could be rolled with aileron against the rudder inputs of the AP, but FS9 will not allow that. There is an AP connected warning light above the deviation compass.

Be warned this system has been misrepresented in some FS releases and you may need to relearn its usage before operating the S.73.

In the real Savoia Marchetti S.73 the WTO maintained the GPS plot. Each time he managed to update it he handed it to Pilot Not Flying (PNF). He glanced at it only to work out whether the airliner was left or right of flight plan track and if necessary assigned a different heading to pilot flying (PF). In many vintage airliners the comparison compass was placed centrally between the two pilots so that whoever was PNF at the time could update the assigned heading for PF.

Simulation users may have come to think of the comparison compass as part of a vintage era autopilot, and it may be, but that is not its primary use. The assigned heading is always bugged, (usually by PNF), and equality maintained by PF. In MSFS we must play both roles. Only every ten or thirty minutes we must pop up the GPS window to simulate the WTO handing the latest GPS plot to PNF and determine whether we are converging with flight plan track. If not we bug a heading five degrees more convergent with flight plan track and then we fly it; whether or not we intend to use an autopilot to maintain the assigned heading. An AP is a luxury in any vintage airliner. A deviation compass is a luxury in any vintage propliner. A comparison compass is not.

We never bug a heading that is not divisible by five and we never attempt to navigate direct to anywhere many miles ahead. We always bug and then fly a heading that converges with our flight plan track. Unless of course our current bugged heading is holding flight plan track exactly in the current crosswind. If we are using real weather, that happy co-incidence will never last for long.

Although this is a propliner tutorial we may as well grasp that aircraft like carrier based torpedo bombers and most other multi crew combat aircraft were designed to operate in the same way. WTO ran the GPS plot and in a torpedo bomber he handed it to PF. A few combat aircraft had a navigator trained to use a sextant and somewhere to use it.


D/F LOOPS and GONIOMETERS

A goniometer is part of the equipment used to direction find (D/F) any signal. It is the device to which the aerial array passes the signal which it detects. Surface operators, whether in ships or ashore, had large and potentially complex aerial arrays which allowed them to D/F weak signals at great range. It was only possible to fit very small and simple aerials to aeroplanes. In the vintage era, if present, these were always small simple loop aerials. These simple loop aerials could feed the detected signal to an on board goniometer operated by the on board WTO. This could only detect strong signals at close range. These tiny loop aerials potentially had less than 5% of the D/F capability of a large surface array.

Nevertheless as powerful government funded radio beacons proliferated, (from 1908 and mostly for use by ships), the number of always emitting (broadcast) beacons of known location which might be within range of a simple D/F loop proliferated. The DF loop is there mostly for use by our virtual telegrapher during the en route phase, provided the en route phase takes place in the highly developed world where power stations and the navigation beacons they powered were eventually closely spaced and within range of tiny D/F loops.

Whether or not it was the actual mechanism we may think of the loop as mounted on a periscope stand and operated just like a periscope in a submarine. The telegrapher turns the periscope loop until the signal minimises. Then he notes the bearing from the base of the periscope stand just like a submarine captain taking a bearing on a ship. Our WTO knows that the radio beacon he has detected is at 90 degrees to the null signal. In commercial aviation our WTO takes care to tune the frequency only of beacons whose orientation he knows before he uses the loop. During military service it may not be clear whether the enemy fleet is 90 right or 90 left and then aircrew crew had to orient the hostile emitter via complex navigation procedures. Once our aircraft has a D/F loop we can D/F nearby powerful signals so long as we have a receiver which can tune the relevant waveband.

Now remember all of this was being done by ear. The WTO was listening to the powerful and nearby signal through his headphones and trying to judge when it minimised. That was a big problem because aeroplanes were getting more powerful and noisier. There was in reality a whole band of bearings over which the WTO heard nothing above the ambient noise in the aeroplane. The problem was detecting silence inside a noisy aeroplane, and in fact many WTOs were in the process of going high tone deaf due to the noise of their work environment. It was obvious that an electronic solution would be superior to an aural solution. What was needed was an electronic device with a needle which would show minimum and maximum signal strength as the on board WTO manually rotated his D/F loop.


SIGNAL CORPS RECEIVER (SCR) is a PILOT RADIO GONIOMETER

The U.S. Army Air Corps were especially excited by that prospect and soon funded relevant research by their Signal Corps. They quickly developed the U.S. Army Aviation Section Signal Corps Receiver (SCR) which is a default gauge in the FS9 Lockheed Vega and which is generically called a pilot (radio) goniometer (gauge) in MSFS. Its electronics allowed sensitive sensing of the max signal and pointed a needle at the emitter; any emitter that the aircraft had a receiver for.

When this gauge is mounted with a 360 degree dial it is called a radio compass instead. The radio compass soon proliferated too, but during the vintage phase of aviation history a radio compass was mounted only at the WTO station or at the NAV station, not on the pilot’s panel.

When the gauge is mounted with an obscured arc so that the needle is off scale unless the loop is pointing at the emitter it is called a pilot radio goniometer (gauge). This was only for use by pilots and the SCR in the FS9 default Lockheed Vega is a radio goniometer gauge. The Savoia S.73 also has a pilot radio goniometer gauge of different appearance located under the captain’s ASI. Make sure you can identify it and will never confuse it with the deviation compass. Note that both the captain and the co-pilot of the S.73 have a deviation compass and that either can maintain the assigned heading using only their deviation compass, but that only the captain has a pilot radio goniometer gauge.


FIXED LOOP and OCCLUDED ARC.

Pilots are not masters of all trades. A pilot may also be qualified as a navigator, or not. A pilot may be qualified as a telegrapher, or not. Most vintage era pilots were qualified as neither. They were helmsmen steering a course assigned by the vessel's NAV or WTO derived from data provided by the radio room.

However once the goniometer gauge (SCR) had been invented it was within the capability and remit of mere pilots to tune the frequency of a powerful and nearby government beacon at a known location relevant to the flight plan. However since pilots were not by default qualified in navigation or telegraphy they were not allowed to play at those roles without the relevant qualifications. Some aircraft were fitted with fixed loop aerials which could detect a strong nearby signal dead ahead. Pilots were not allowed to rotate the aerial, but they were qualified to rotate the aeroplane!

So a Lockheed Vega pilot was allowed to use an occluded arc goniometer taking its signal feed from a fixed loop aerial. He was not allowed a radio compass showing 360 degrees of arc, because he was not qualified to use one. He was not allowed to train an aerial to detect emissions, because he was not qualified to use one. Pilots were allowed to tune powerful nearby emitters of known location and then to turn an entire aeroplane until it was pointing at the emitter. Provided they monitored drift by other means they could then home to any powerful emitter for which the aeroplane had a receiver, just by following the needle on the occluded arc goniometer (called an SCR in the US).

This soon became the primary means of navigating expensive single crew aircraft.

Amateur pilots sometimes pretended that all of this was unnecessary government regulation and tried to exercise skills for which they had neither training nor qualification, but they were soon dead. The amateur pilot Amelia Earhart refused to train as a telegrapher and relied upon a professional navigator with a sextant. He also had no qualifications relating to the navigation requirements of the flight being undertaken. The only means by which the fatal flight could have been achieved was RDF. The U.S. taxpayer had funded a USN RDF presence, but no one on the aeroplane could be bothered to train or qualify to use that capability. There has never been the slightest mystery why that particular vintage era flight ended in death. It was being navigated only by post medieval means which were inadequate for the purpose.

What we must all learn from the death of Earhart and Noonan is that reducing the huge crew complement of trans oceanic flying boats, or any other navigation not conducted by reference to passing identifiable scenery in nice weather, was not a simple process. Those huge crews were not just mandatory, (for professional commercial / military / naval aviation); they were actually necessary to avoid death. Neither pilots nor navigators were qualified WTOs and the regulations had to match that reality. Hence fixed loop aerials and occluded arc goniometers in aeroplanes with no WTO. At least until an entire new external infrastructure was in place and the classic phase of aviation history could begin. We shall examine that transition shortly

The occluded arc goniometer is mounted to the left of the altimeter in the FS9 Lockheed Vega VC and immediately above the all important gyro comparison compass. In the Savoia S.73 the European pattern goniometer is underneath the Air Speed Indicator. It works just like the FS9 default goniometer, but I have a nasty suspicion that most flight simulation users have never bothered to learn how to use a fixed loop occluded arc goniometer. Shame on you! Now you have another chance, and the tutorial that Microsoft could not be bothered to supply. That tutorial is within the Savoia Marchetti S.73 (V2) release available from Avsim and is not repeated here. Readers should actually finish Part 4 of this tutorial before flying the more difficult fixed loop goniometer exercises in the S.73 tutorial.

Of course the S.73 had a dedicated WTO and a loop on a periscope stand which he could rotate. In Europe there were eventually many powerful government radio navigation beacons so he might actually do just that, but in Africa where the S.73 did most of its flying such beacons were too far apart to be useful during en route navigation. The S.73 WTO used the H/F long wire aerial(s) to emit signals which surface stations used their large array to D/F and then tell the WTO his bearing from them. He also received that reply through the long wire H/F aerial(s). Many aircraft could reel out and reel in a very long trailing wire aerial to improve the range of HFDF. So even though the S.73 had a rotating loop, most of the time and in most places, the WTO just locked it as a fixed loop. He tuned it for PF who could then use it to drive his occluded arc goniometer during the arrival, approach and departure phases, which we shall study in detail in parts 3 to 5 of this tutorial.

So over developed nations the WTO may swing the loop aerial manually during the en route phase. However just before time of descent he always locks the loop as a fixed loop and tunes the beacon defined as the initial approach fix (IAF) for destination. Then he informs PF that the blind flying panel occluded arc goniometer is tuned. In MSFS we must tune occluded arc goniometers ourselves by popping up the avionics window. We will revisit the relevance and usage of these loop aerials and occluded arc goniometers more than once in this tutorial.


LOCAL INFRASTRUCTURE CONSTRAINT

O.K. let's consider the rules of conduct for flight simulation of a SABENA Savoia Marchetti S.73 flying the London to Oostende schedule in the winter of 1939. On this flight we can use Belgian and British commercial aviation infrastructure which includes GPS wide source signals, but not point source Radio Range signals of the kind that were in use in the United States. It will be cloudy and raining a lot of the time. We do not wait for clear blue sky because we do not need to climb above cloud to take sun shots or star shots. It will be dark by 4 PM (1600 local = GMT). We have nowhere to stand to take astro shots with a sextant anyway. We do not wait for high visibility at low level because we do not intend to navigate en route by reference to the scenery.

We could use ancient pioneer era flight by visual reference to the scenery navigation techniques to locate Oostende, but our track mileage will be less if we use GPS to proceed in a straight line. SABENA are not paying the other three aircrew in our virtual cockpit for nothing. We will also enjoy a much faster cruising velocity up at 4000 metres in nice thin, low drag, air.

If we have not installed a third party scenery of Croydon we will use nearby Redhill (EGKR) in FS9 instead. We must climb out over the local terrain to somewhere safe, by reference to the scenery, potentially using a tourist map, before climbing into or above cloud. Climbing out of Croydon or nearby Redhill that will be no problem, but in Africa which was the natural home of the Savoia S.73 it may be a significant problem due to high mountain ranges.

Once in the cruise at an altitude of four thousand metres, potentially above, or quite often within cloud, cruising fast at high TAS in nice thin air, the goal is to transition from the en route phase to the arrival phase using GPS to decide when it is safe and appropriate to descend. This is a short haul schedule, so we pop up the GPS window only once every ten minutes and make course changes of no more than five degrees in units of rounded five degrees until on one of those updates we decide it is time (safe) to descend. This is the key captaincy decision when navigating using GPS in the vintage phase of aviation history. It is the descent through cloud that may kill us all.

We shall examine planning of Time of Descent (TOD) in detail shortly.

Sometimes only the middle third of a short haul flight undertaken in the vintage phase of aviation outside the CONUS will be conducted using GPS, but San Francisco to Honolulu would be RDF = GPS more than 95% of the way. In real life the way an aircraft is operated has nothing to do with the aircraft type or its date of manufacture. It depends on the current technology phase of the local aviation infrastructure. That is what we must seek to replicate and simulate during flight simulation.

By 1939 the R.A.F. already had fourth generation modern phase infrastructure within Britain, but British commercial aviation which spanned an empire was stranded in the second generation vintage phase. This constrained the operation of commercial aviation over and near Britain whether the airline was British, Belgian, Dutch, Danish or German.


MANDATORY USE OF RDF=GPS ABOVE CLOUD

In the examples above we use GPS to ensure that we descend through cloud plenty early enough to avoid terrain. On the other hand if simulating a British South American Airways (BSAA) Lancastrian schedule from Buenos Aires to Santiago in 1947 aboard the ‘Star Dust’, unlike the real captain, we must ensure that the WTO uses RDF GPS to instead ensure that we descend plenty late enough to have crossed the Andes before initiating descent.

What most commentators on these issues and most flight simulation users fail to comprehend is that the headwind encountered is irrelevant and the cloud base is equally irrelevant. Flight by visual reference to the surface scenery is irrelevant. The flight must be conducted using RDF=GPS else we are all doomed to die on a glacier on the wrong side of the Andes. The telegrapher on the ground in Santiago can use his Adcock array to D/F our normal wireless traffic (COM not NAV) signal and tell us when we are due north of Santiago, and until then we must not descend. Above all we must never pretend that sextants and 'dead reckoning' can be used to navigate aeroplanes safely. By 1947 thousands of aircrew had already died trying, and even in the U.K. it was almost time to end the pretence. The 'Star Dust' disaster would just hasten the end of that long standing pretence.

However in 1947 there existed many (British) aircrew who had been so extensively indoctrinated in maintaining radio silence during combat missions that they neglected to obtain the necessary RDF bearings to create the GPS plot when they became airline aircrew after WW2. BSAA propliner, after BSAA propliner, manned almost entirely by ex RAF Bomber Command aircrew, became lost with fatal consequences. None of these losses was mysterious. The aircrew did not obtain the necessary RDF bearings to create the necessary, but not always mandatory, GPS plot.

The vintage phase of aviation history was the era of make it up as you go along aerial navigation. No mandatory flight planning procedures, often no worthwhile flight plan at all. The crew just glanced at the GPS plot and decided what to do next. The flight meandered backwards and forwards across the flight plan track turning five right and five left depending on which way the mid course line was. Only TOD was ever really planned and checked at all, and some captains and some navigators just guessed (dead reckoned) that too. They soon reckoned wrongly and were soon dead.

We should always plan TOD correctly. During vintage era navigation Time of Descent has nothing to do with the runway location. It has everything to do with where the obstructions are and where the line feature we are descending to follow visually is located. We must use GPS to ensure that we descend clear of all obstructions and we must discover the elevation of the terrain underneath the current GPS plot and underneath the area we are descending into by planning these things before we ever fire up a flight simulator.

We must flight plan.



Figuring out surface elevation may present some difficulty if the terrain is not the sea. That was the problem in real life too. It is one reason that these techniques killed so many aircrew and passengers.

Towards the end of the vintage era significant airports had classic era terminal guidance infrastructure (radio approach aids), even though there were no en route beacons. In Europe by the late 1930s and in South America by the late 1940s no one should have been descending using GPS. They should have been using the classic era arrival techniques which we will study in Part 3 of this tutorial. Those who survived actually did. Those who did not and continued to believe in ‘dead reckoning’ were soon dead on the side of a mountain, whether they were flying a Martin M-130 or a Lancastrian.


MANDATORY USE OF RDF=GPS OVER OCEANS

If when simulating operation of a BSAA Lancastrian setting off from the Azores to Bermuda in the late 1940s, we use dead reckoning, or better still a sextant, then we can personally simulate adding to the Bermuda Triangle myth because we have no chance of finding Bermuda in bad visibility. Bermuda is a landmark, not a line feature. It could not be reliably located without RDF in the late 1940s any more than Howlett Island could be found by a Lockheed Electra with no trained or qualified telegrapher aboard a decade earlier.

There has never been the slightest mystery why all such aircraft disappeared 'without a trace'.

The 'trace' in question is the line on the ground or ship based D/F operator’s oscilloscope that shows the bearing of the transmitting vessel. He tells the on board telegrapher what that bearing is using Morse code, The WTO decodes it and creates the GPS plot, else he tells the navigator and the navigator updates the GPS plot and nobody dies. If the vessel had no trained WTO everybody died sooner or later. If the qualified WTO, (who was rarely the captain of the vessel), was never ordered by the captain, to obtain a radio bearing everybody died.

In the vintage era the key to survival was a large crew complement, professionally trained and qualified in diverse but essential skills, and above all who were sufficiently well trained and indoctrinated in the use of RDF based GPS. Those with the wrong training and the wrong indoctrination had ‘the right stuff’ for combat flying, but ‘the wrong stuff’ for airline flying.

Some British airlines like BSAA were still stranded in the Zeppelin phase of aviation history, even in the late 1940s. BOAC were still reliant on wide source infrastructure (RDF based GPS) and still not subject to adequate safety regulation of the type that had been introduced over the CONUS from 1932. Both British airlines still had the fatal accident record to match.


VINTAGE PHASE NAVIGATION OUTSIDE THE CONUS

From about 1923 onwards the general picture across the planet was not that of single aircrew mailplanes like the Ford 4-AT-E Trimotor, maybe with a few passengers too, navigating by visual reference to the surface. That was peculiar to the CONUS. From about 1923 onwards multi engine propliners in the rest of the world progressively used the original British form of Marconi (airborne component) + Adcock (surface component) GPS known as RDF. Some nations arguably made better use of it than the British.


TRANSITION TO THE CLASSIC PHASE OUTSIDE THE CONUS

Most nations and therefore most airlines and most air arms transitioned to the 'American Way' when they ratified the Treaty of Chicago (Chicago Convention) in the very late 1940s or during the 1950s. The Soviet Bloc, Communist China and North Korea did not ratify the Treaty of Chicago but the USSR soon developed superior GPS alternatives to simple RDF and these proliferated within the communist bloc.

By the late 1950s the 'west' had adopted either Radio Ranges or VORs or TACAN point source infrastructure as the primary means of navigating airliners and combat aircraft within a mandatory, expensive, heavily regulated, safe, air traffic controlled environment that constitutes the classic phase of aviation, but the transition from vintage to classic techniques took place before or after WW2 depending on both location and national doctrine.


WHICH NATIONS HAD WHICH TECHNOLOGY AT WHAT DATE?

Suppose we wish to simulate a flight from Copenhagen to Berlin in mid 1939. In Germany the classic phase of aviation began in 1934 quite uniformly for both commercial and military aviation because both were fully under state control. In 1939 Germany has already entered the classic phase, but Denmark has not.

By 1936 there were comprehensive radio navigation aids in Berlin including a Radio Range which any DLH flight will use to the full. By 1939 every multi engine DLH airliner had the ability to use Radio Ranges. DLH aircrew had the German government code books and the radio navigation charts. They knew the frequencies to tune and where all the beams pointed. The aircrew of the Danish airline DDL did not have the German government code books or German radio navigation charts. They could not use the more advanced German infrastructure. Nor could any British, French, Dutch, etc, etc, airline.

Prior to each nation ratifying the Treaty of Chicago, which only became available for ratification in the late 1940s, aviation was intensely nationalistic. Furthermore facilities that had been paid for from the public purse might be owned and operated by an airline nominated as the 'chosen instrument' of the national government who would deny that infrastructure even to their national competitors. Historians writing a book for general consumption can talk about German or US aviation infrastructure developments as though they were openly and widely available, but flight simulation users need to think harder about who had access to the aviation infrastructure that defines how the flight will be operated.

The crew of an airliner may lack access to classic phase aviation infrastructure for several reasons. The relevant transmitters may not be within range in their current location. Less obviously the crew may not have the relevant receivers in that aircraft, or the airline concerned may not employ aircrew with the necessary qualifications to use the infrastructure.


WHICH AIRCRAFT HAVE WHICH TECHNOLOGY?

For instance the Ford 4-AT-E Trimotor included by default within FS9 had engines rated at sea level and was optimised for flight at low altitude whilst height keeping at 1500 feet. It could not be fitted with an autopilot and had no blind flying unit (BFU). If a BFU was retrofitted the airline had to hire a co-pilot. He had to be someone who was both an instrument rated airline pilot and a trained mechanic. In practice even after the CONUS had an extensive point source infrastructure, complete with mandatory departure arrival and approach procedures imposed by federal ATC clearance, a Ford 4-AT-E could not access them. It was from the pioneer phase of US commercial aviation and was not worth updating to work in the classic phase. Better equipped and more powerful 5-AT series Trimotors flourished briefly, but all the Trimotors disappeared from the schedules quickly. They survived to fly ad hoc charters using pioneer navigation techniques. That situation must be read across to airliners with inadequate crew complement everywhere.


INTERNATIONAL FLIGHTS

Remember aviation over and within the CONUS went directly from the Pioneer phase to the Classic phase. Everywhere else there was a prolonged Vintage phase in between involving large flight deck crews and RDF based GPS. Outside the CONUS most airline schedules passed over diverse nations in very different phases of aviation infrastructure development. There were many decades during which an international flight was forced to access, and was limited by, pioneer, vintage and classic phase infrastructure in a single international flight.

The turning point was the post WW2 formation of the International Civil Aviation Organisation within the United Nations to promote international standards. The mechanism was the post war Treaty of Chicago. As each nation in turn ratified the Chicago Convention the classic phase became global. Historians outside the US usually consider the classic era of aviation to begin only when the rest of the planet caught up with the CONUS after WW2 and from widespread ratification of the Treaty of Chicago.


THE CRUCIAL QUESTIONS

Before attempting simulation of historic airline schedules, (or ad hoc charters), we need to answer the following questions to our own satisfaction.

Could the crew of the real flight about to be simulated have accessed classic era infrastructure all along the chosen route, in the chosen aircraft, at the chosen date? If not was the crew large enough and qualified to access wide area (RDF based GPS) infrastructure even if it was available.

These questions may lead us to the conclusion that the entire flight should be conducted using just one technique from one phase of aviation history. However more often we will be uncertain what the answer should be and then we must flight plan using a mixture of up to three navigation techniques and execute the plan accordingly. Examples later.


HORSES FOR COURSES.

The S.73 and all analogous propliners were carefully designed to utilise vintage phase en route navigation techniques and, as soon as they were available, location by location, also classic phase terminal guidance techniques. On some flights, if the weather permitted, the crew could just follow a coastline in the en route phase, but there was no coastline, river, or railway for SABENA aircrew to follow crossing the Sahara or the vast equatorial rain forests of the Belgian Empire where SABENA Savoia S.73s did most of their flying. Do not confuse the wide source GPS signals used by the WTO in the S.73 with the point source radio beams used by the two pilots of a DC-2 to navigate over the Continental United States (CONUS) in the same timeframe. En route vintage era navigation made limited use of broadcast beacons, but made no use of beams at all.

The S.73 did not zig zag from one beacon to another beacon following beams. It used radio signals from a Global Positioning System whose radio source was up to 1200 miles away in any direction. Huge vintage era propliners like the Martin M-130 had a dedicated navigator as well as a WTO. However WTO was qualified to plot a series of three bearings that he had obtained from surface D/F operators on a chart. Those three lines crossed to create a triangle of uncertainty within which the aircraft had been in the preceding few minutes. It was a somewhat inaccurate, slowly updated, GPS plot.

WTO presented that chart to PNF (or PF in an aeroplane with no PNF). PNF used it to decide whether the aircraft was left or right of flight plan course and then decided whether the heading assigned to PF should alter, and if so in which direction. Once that decision had been made PNF just reached across to set the revised assigned heading on the comparison compass. If a deviation compass was present, driven by a gyroscopic comparison compass, it was automatically updated by the comparison compass gyro.

In the vintage era PNF vectored PF just like a radar controller who looks at where a blip is on a radar screen and roughly estimates the heading required to get to somewhere else on the same radar map. PNF looked at the GPS plot handed to him by WTO in lieu of that radar screen or moving map display. The course correction would be in steps of five degrees. There was no beacon and no beam pointing to anywhere. The destination might be a desert strip in the Sahara, a tiny clearing in the vast rain forests of the Congo, or a tiny island in the Pacific. Many days it was possible to locate it only by using HFDF to update the GPS. There was often no emitter anywhere near that remote place, because that remote place had no power station to drive one!

In the 1930s point source navigation (Radio Ranges creating beams) existed only over the CONUS and along some parts of the Lufthansa network. No precision is required or involved when navigating propliners en route in the vintage era. Once every ten minutes we pop up the GPS window and turn five degrees right, or five degrees left, depending on which side of the desired track we seem to be. That is all. Nothing more. Nothing less.

The key captaincy decision is Time of Descent (TOD). We must descend through cloud somewhere safe. This may be well before the coast, or well after the mountain range. It just depends on the current leg and the nature of the obstacles that may kill us on that leg.

Of course GPS is still available in a Martin M-130 or Savoia S.73 below cloud and at low level because they have the crew complement of specialised air crew needed to make use of vintage phase GPS. HF signals can be received at low level. Vintage era HF band GPS was very long range, but it was slow to update. We should look at the GPS picture only once every ten minutes, then roughly adjust our heading based on what we see, then close the GPS until we are due another update in ten minutes time. After using GPS to descend safely through cloud, at a safe location, on a safe bearing towards the Initial Approach Fix, then we transition to using classic era terminal guidance with the occluded arc goniometer and at major airports the LBA receiver, which may or may not be able to provide DME as well as LOC data. Like everything else in aviation, that depends on the local infrastructure outside the aeroplane. We shall study terminal guidance in detail in parts 3 to 5 of this tutorial.

We use the panel clock to time our GPS updates. Updating late is OK, but allowing ourselves to update at intervals of less than 10 minutes, or allowing continuous display of the GPS is cheating. Vintage phase GPS did not have that continuous and instant update capability. It could not be used as an approach aid.

Remember during flight simulation we are always PF, PNF, WTO and CAPT. PF is just the helmsman. He just watches a comparison compass, or in continental European Askania deviation compass, slaved to the gyro comparison compass, whose assigned heading was dialed in by PNF. PF just uses aileron to hold two lines on two drums against one another inside the comparison compass, or he centres a needle in a deviation compass.

Continental European airlines had already invented the future for PF which would increasingly consist of centring needles on occluded arc goniometer gauges of one kind or another. Now is a good time to notice that an Askania deviation compass gauge, modern ILS gauges, VOR1 gauges, VOR2 gauges and TACAN gauges, just like the original SCR, are all occluded arc goniometers, all very carefully designed to prevent pilots from ever playing at navigator or WTO.

Now is a good time to notice that in the vintage era pilots are only allowed a rotating 'barrel' magnetic compass and one or many rotating 'barrel' gyro compasses. They are allowed neither a 360 degree circular gyro compass gauge, nor a 360 degree radio compass gauge *by design*. They were neither navigators nor telegraphers. They were neither trained nor qualified to use unoccluded direction finding gauges of any kind.

Having grasped how prolific obscured arc goniometers became, we must come to terms with the way they dominated en route navigation during the following classic phase of aviation history for several decades. We must try to grasp the aviation ‘culture’ and aviation ‘politics’ of the classic era.


ANOTHER TRANSITION

Vintage era flying was all about conducting the en route phase safely, at high level, at high velocity (TAS), with a huge expensive crew of many specialists. That same huge crew could run a GPS plot to determine when it was safe to descend. Cloud and visibility were irrelevant during the en route phase provided the huge expensive crew was properly trained and properly captained.

On the other hand the subsequent classic phase of aviation was all about avionics on a single panel operated only by pilots in an aeroplane with no WTO and no NAV, following simplistic detailed step by step mandatory federal procedures, imposed by federal ATC. Those new skills were acquired whilst qualifying for the new Instrument Rating, first introduced in the United States in 1932, and that slowly and steadily became a de facto or federal employment requirement for airline pilots everywhere.

Military and naval air arms everywhere were very slow to adopt these safer procedures and like the British airlines they had the fatal accident rate to prove it.


PHASE 3 - THE CLASSIC ERA

The newspaper announcement of the crash of yet another mail plane in the CONUS was soon relegated from the front page. The death of some passengers who chose to ride with the mail in a Trimotor mail plane was easily tolerated, but when celebrities started to perish it was all over the front pages for days on end. Governments had to appease an angry electorate, and the unregulated phase of commercial aviation gave way to the regulated phase of commercial aviation. This happened in different places at different times.

The Federal airways system established within the United States from 1932 onwards was very similar to the modern system, but of course there were no J (jet) routes. The Victor airways of today are pretty much where they were in 1939; there are just more of them now. One way airways in the present system were two way back then. Odd levels eastbound and even levels westbound, based on course not heading, just as today.

During the classic era pilots were required to intercept and track beams from take off to touchdown. The nature of the beams has varied over time and the gauges used have varied, but neither the intention, nor concepts, nor culture, nor politics, have changed.

Wide source GPS navigation using HFDF / MFDF / ADF was an un-American activity. It caused the high death rates in non American commercial aviation.

The whole idea behind the US Federal Airways was to preclude area navigation and to force airlines to follow exact routes along defined courses, with promulgated minimum enroute altitudes (MEAs), which guaranteed terrain clearance. Three aircrew were needed for IFR area navigation using HFDF, but safe airways navigation required only two crew. The savings in aircrew salaries compensated for the loss of more direct routing, but the objective was safety.


MANDATORY PROCEDURES

To ensure safety it wasn't only necessary to banish navigators, banish telegraphers, banish maps, and banish GPS, it was necessary to prevent pilots trying to recreate what had been banished.

Most flight simulation users don't get that at all! They think that maps and ground speed and other 'navigator' paraphernalia are relevant to classic era propliner simulation. They are not relevant. They were forbidden. That was the whole point. Those were the things that were killing all the British passengers in all the British propliners until the British and everyone else gave in, ratified the Treaty of Chicago and forced their commercial aircrew to follow mandatory federal step by step beam following procedures too.


BEFORE DME.

An airway may proceed from one beacon to another, but if there is an airspace obstruction in between the airway will dog leg around the obstruction. There is no need to place a beacon at the dog leg. Two beams meet at an intersection where we must alter course. Instead of flying down a radial or course FROM beacon 1 we must suddenly fly down a radial or course TO beacon 2. We use VOR 1 and VOR 2 gauges to sense and follow those radials, or we can use a Radio Magnetic Indicator with several needles on a single dial.


THE DME ERA

There were effectively no long range DME signals for civilian use until after 1955 so if simulating an earlier date we should turn all digital DME receivers OFF, or if they have no off switch remove them from the panel.cfg. If a modern airways procedure requires us to change course at a fix based on a DME range we will ignore that fix and assume that it did not exist in the 1932-55 era. We will flight plan and navigate via the next intersection or beacon instead.

Think hard about the difference between an INTERSECTION defined by two crossing CRS radials and a FIX defined by DME along a single radial. In the 1932-55 timeframe of the classic phase of aviation history intersections were widely used during navigation, but fixes were not.

We should treat DME as 'arriving' in 1955. From then on until the end of the classic era in 1970 we fly propliners using modern airway procedures including radial and DME fixes, but we reject radar vectors which 'belong' to the modern era.


FLIGHT PLANNING

During classic era flight planning we will always need to create a detailed flight plan. The flight plan replaced the map of the pioneer era, and the GPS plot of the vintage era.

Any good flight planner will auto-generate an airways plan from A to B. The trick when simulating 1932-55 is to ensure that the flight plan is based solely on VORs, intersections, and not at all on NDBs or DME fixes. I will delve deeper into the flight planning aspects of realistic propliner simulation in later parts of this tutorial.

Only the USA and Germany funded and adopted classic era infrastructure before WW2. By 1939 the German beacons delineated airways whose beams extending all the way from Amsterdam to Moscow, and all at the expense of the German tax payer. Of course the German government already had an ulterior motive for installing those beams.


IN FLIGHT

Once airborne we will use VOR1 to track the airways. We will use VOR 2 to locate the intersections. We set CRS on VOR2 to the second airway centreline radial which defines that intersection and tune NAV2 to FREQ2. When both needles on both receivers centre we are over the intersection. If this is defined as a turning point on our flight plan we will cease tracking the airway centreline FROM VOR 1 and begin tracking the centreline TO VOR 2. Of course just like intercepting an ILS we begin the turn before we reach the centreline to intercept the new mandated course.

We will only use a fix defined by DME when simulating 1955 to the present day and only when flying over ‘advanced nations’ with classic era infrastructure prior to 1970. Over ‘undeveloped’ nations we will use only pioneer and vintage phase navigation techniques right through to 1970.


HEADWIND COMPONENT.

Another important use of VOR2 is to check our progress along the flight plan route to locate all relevant airways intersections. As we fly through the intersections whilst tracking to the station tuned on VOR1 we use the intersections created by VOR2 to monitor headwind vector. We compare the Actual Time of Arrival (ATA) over the intersection to the Estimated Time of Arrival in our nil wind flight plan to calculate per cent headwind. If a leg that was planned to take 20 minutes with nil wind actually takes 23 minutes we know that have encountered a 15% headwind and we must treat that as significant. We will study shortly why *per cent* headwind is important information upon which we must act.


RULES OF THE AIR.

International Air Law is just a slightly modified version of International Maritime Law. Aircraft are just vessels in transit. All vessels in transit are required to navigate to pass one another 'port to port'. Just like any other vessel an aircraft must turn right (to starboard) upon encountering a head on confliction. Therefore whenever we fly an aircraft along the aerial equivalent of a shipping lane, known as an Airway, we always aim to be right of course, especially when climbing or descending.

We will only ever be left of course as a very deliberate act. Even if we do not know how many miles off course we are we must always be aware which side of the flight plan track we are, and by default we intend to be right of it to help us to be sure which side we are.

Maritime law requires vessels in transit to overtake on the right. Aircraft are no exception. There is no verge or kerb to avoid. If we overtook on the left we would move to 'the wrong side of the airway'. This means that the rules of the air do not match the rules of the road anywhere. Again expectation based on experience with road vehicles is misleading.


SAFETY FIRST, PRODUCTIVY TOO.

By 1936, in the United States and in Germany it was forbidden to navigate to the next beacon until after the propliner had intercepted the airway centreline. This allowed the airline passenger death rate over the CONUS to fall to zero in 1939. Federal ATC and the federally funded Airway infrastructure they delineated were what allowed the US airline industry to rapidly overtake the rest of the world with Germany not far behind until 1939. Only over the CONUS, or within the equivalent German infrastructure could aircraft fly across country in and above cloud, at night, and in all kinds of weather, IN SAFETY.

The classic phase of aviation history was the one in which employers lost the right to make the rules. Like their aircrew they came under strict government regulation. The aircrew no longer had an employer’s manual listing things they must not do when making up an arrival or approach procedure on the spur of the moment. Instead they had federal, mandatory, published procedures (with diagrams) depicting exactly what they must do and federal agents, (air traffic controllers), who they had to ask for permission to proceed, step by step, along those federally mandated procedures. Those same federal agents monitored compliance.

The new classic phase way of flying also increased cruising airspeeds by 15 to 25% over the CONUS simply by allowing airliners to always fly in thin air at medium or high level. Knowing they could always fly high and fast in thin air, whatever the weather, allowed the airlines to timetable shorter journey times on a scheduled basis increasing productivity by the same percentage.

Classic era flying was all about flying safely at high level using avionics, time based flight plans, detailed instrument flight procedures imposed by ATC and *no map or GPS at all*. Those new skills were acquired whilst qualifying for the new Instrument Rating, first introduced in 1932, and that eventually became a de facto or federal employment requirement for airline pilots everywhere.


THEN BLIND BOMBING.

Of course what worked best for airliners also worked best for bombers. In Germany the airways beacons were also the basis of the earliest blind bombing systems that were much used by the Luftwaffe from the blind bombing of Warsaw from September 1939 onwards.

By 1939 the German federal airways network generated beams and intersections (colloquial German = knickebein) over many European cities from Amsterdam to Moscow. The frequencies of the German network were secret, the direction of the beams, and the knickebein they created were secret. Only Lufthansa and the Luftwaffe could navigate the beacons of the German airways system and locate their knickebein. The western most German beacon secretly projected a beam over Rotterdam. Once Belgium and France were in German hands newly constructed beacons soon created knickebein over England too. The second London Blitz could begin late in 1940. From then on the capability of radio beacons and receivers developed ever more rapidly along with the electronic intelligence gathering (ELINT) and electronic warfare (EW) means to defeat them.


PHASE 4 - THE MODERN ERA - IN PATCHES

The classic era of en route navigation was based on the propagation of radio beams (radials) to *prevent* wide source (area) navigation (Global Positioning Systems) and to promote or mandate highly accurate point to point navigation flying only along radio beams instead. Over the CONUS and over carefully selected parts of Europe, before and during WW2, this system replaced the earlier GPS systems that continued in use everywhere else.

Germany aside, military and naval aviation made little use of classic era navigation techniques until TACAN (VOR with co-located DME transmitting in the UHF band to create a UHF Omni Range or UOR) was introduced during the fifties. The military continued to use huge flight deck crews and less accurate GPS navigation.


However after WW2 the classic era system of en route navigation via airways delineated by radials, without need for radio operators or navigators, was gradually adopted for commercial use everywhere due to the exceptional levels of passenger safety it enables, its lower salary costs, and its increased productivity.

Within commercial aviation the classic era is yielding to the modern era only very slowly. The modern era incorporates some radar navigation of en route airliners by air traffic controllers and also incorporates the use of navigation fixes based on DME. Otherwise en route navigation by airliners in 2008 hardly differs from the classic era, which grew from small beginnings in 1932.

Military and naval aviators moved back to GPS systems and abandoned classic era TACAN (UOR+DME) as fast as they could. They were short ranged and too easy to locate, jam or destroy. Adoption of classic era techniques by military and naval aviators may be regarded as an aberration, but TACAN is nevertheless still in place. However assorted types of GPS are increasingly the norm once again for en route navigation during modern combat operations.

In aircraft with huge crews, especially in military and naval service, navigators still existed. In those aircraft navigators continued to navigate. Even into the 1950s military and naval navigators continued to use vintage era techniques. The navigator still assigned headings to pilot flying whether or not the navigator was using electronic equipment of varying complexity to track a beam. Do not confuse the way things were done with huge crews and the way they were done in a cockpit with only two pilots (and potentially a flight engineer).


EN ROUTE BASICS - SUMMARY

Hopefully by this point in the tutorial several very widely held misconceptions have been set aside, the phased, but overlapping, development of commercial aviation is better understood, and the need to avoid false scenery and mesh projection has become obvious. Cockpit environments that misplace all the scenery are useless for flight simulation and must be fixed or avoided.

During the pioneer era of aviation no attempt was made to operate aircraft efficiently. Consequently no attempt was made to design aircraft efficiently. The primary goals were navigation by visual reference to the passing scenery using a simple map, and accurate height keeping. All flight was low, slow and inefficient. Entering cloud had to be avoided. Flying above cloud had to be avoided. With sufficient practice and skill low visibility below cloud could be overcome, but each pilot had to be able to recognise his personal safety minima, and divert if they could not be maintained.

We can use MSFS to practice those skills provided we take care to employ a cockpit environment that does not distort perspective, distance, height or glideslope / climbslope to the obstacle we need to avoid or the landmark we need to find. Even in later eras all propliner flights eventually end with flight by visual reference to the scenery. We will study the importance of parallax again and in more detail within Part 7 of this tutorial (Near Runway Operations).

In the vintage era huge flight deck crews operating whatever GPS system was locally available at the time allowed the en route phase of propliner flight to take place in cloud, above cloud, or below cloud in zero visibility. None of the relevant GPS systems were accurate enough to be used during the departure and approach phases however. At first those stages of each schedule were flown the way the pioneers had always flown them and so we need correctly configured cockpit environments and software for vintage era flight too. As the vintage phase of aviation history gave way to the classic era outside the CONUS departure and arrival progressed first to using classic era techniques of homing using the Goniometer or the Lorenz Beam Receiver, but we shall study those techniques later.

The classic era introduced the means to fly instrument departures and instrument approaches in cloud, above cloud, or in poor visibility below cloud, but at some point we still need to see the airfield. For flight simulation we need the scenery to be projected realistically in any phase of aviation.

Having recapped the basics it is time to examine simulation of the vintage and classic era enroute phases in more detail. We shall begin with the Radio Range phase of propliner history, but we must remember that Radio Ranges were little used outside the CONUS. They were largely a side show whilst the vintage phase of aviation history continued elsewhere.



PROPLINER TUTORIAL PART 2B (RADIO RANGE NAVIGATION)

INTRODUCTION.

This part of the Propliner Tutorial may help those with no aircrew training to understand how to use different navigation gauges and why they work the way they do. How to simulate navigation of aircraft using Radio Ranges using VOR1 and VOR2 gauges has already been explained. This part of the tutorial examines the history and development of Radio Range navigation and how that influenced gauge design for decades afterwards.


RADIO RANGES and OMNI RANGES.

If we fly between the major airfields that existed in the thirties and forties then the current Vhf Omni Ranges (VORs) will be pretty much where the four course Radio Ranges were back then. No fewer than 231 Radio Ranges defined the 1939 airways system over the CONUS.

The main difference between an Omni Range and a Radio Range is the number of radials generated, 360 from a VOR but only four from a Radio Range.

Over the CONUS the Radio Ranges used Morse code to transmit the two letters A and N. Four masts in a diamond shape delivered roughly 90 degree quadrants into which they transmitted A or N, alternating quadrant by quadrant A – N – A - N. At the edge of each quadrant both A and N could be heard together. When the dots and dashes of A and N merge in Morse code they form a continuous tone. This continuous tone was the ‘on course signal’ which marked the airway centreline. By this means each range generated four invisible beams (radials) that could be intercepted and followed.

The German Radio range network transmitted T and E in place of A and N. T and E also produce a continuous tone when merged.


CULTURE and POLITICS.

The purpose of the Radio Ranges, and therefore the purpose of the classic phase of aviation history, was not just to banish navigators and telegraphers from aviation, it was to banish navigation itself. The helmsman had never been a qualified navigator. He just matched current heading to an assigned heading using a comparison or deviation compass. From now on the federal government would assign courses and nobody else.

The government would establish emitters to create radio signals and a new training syllabus would teach mere pilots to use those signals. No navigator, no on board telegrapher, and no surface telegrapher would be involved. The new methods would work with tiny aerials in aeroplanes. The new qualification airline pilots were required to obtain before they were allowed to use those tiny aerials and any gauges they drove was an Instrument Rating.

The new Instrument Rating worked just like this tutorial. It taught pilots how to operate the aircraft en route and how differently to operate it during the arrival, approach and departure phases. During the arrival, approach and departure phases airline pilots were taught to use the occluded arc pilot goniometer. They were taught to centre needles and keep them centred. This was not new. Helmsmen had been centring the needles of their comparison compass and / or their deviation compass for many years.

Over the CONUS and along some parts of the Lufthansa network the en route phase now became a process of locating and following beams, because that became mandatory. At first the beams were located aurally. This required two crew. Now that the federal government had taken over course assignment one member of the crew (Pilot Flying = PF) was required to obtain permissions from a federal agent known as an air traffic controller. Aircrew now needed a permission known as an ATC clearance to do anything at all. PF had to monitor COM1 and proceed as cleared by ATC via COM1.

Meanwhile Pilot Not Flying = PNF listened to audio signals on NAV1. He used mandatory procedures to orient the four aural beams from the Radio Ranges. During that process he assigned headings to PF in the usual way; before and after he located the aural beam. Whether in a vintage era cockpit or a classic era cockpit PF just centred needles. The needles of the (Sperry) gyro comparison compass and / or the needle of the (Askania) deviation compass. It made no difference at all to PF how the heading he was assigned was calculated, or by whom. For PF the vintage and classic era had no difference at all. As we shall see in Part 2C of this tutorial the captain’s role hardly changed either.

It was PNF whose role changed.


FEDERAL REGULATION

The classic era method of navigation along beams with minimum en route altitudes (MEAs), installed and mandated by government decree, was the conceptual opposite of the wide source RDF method which allowed aircrew to plan any 4D flight plan profile they chose, however unsafe. First the aircrew, and then their employers the airlines, lost the right to plan flights to their own criteria. In the classic phase of aviation history everyone had to follow procedures issued by a federal agency and aircrew needed permission from federal agents (air traffic controllers) to proceed.

Aircrew now had to obtain a clearance that mandated the *procedures* to be followed. During the Instrument Rating course introduced in the United States from 1932, and made mandatory for airline pilots a few years later, pilots were indoctrinated to fly only along designated airways following mandatory courses at altitudes assigned by federal agents. This ‘procedural’ way of airline flying also included the departure, arrival and approach phases which we shall study in later parts of this tutorial.


ON BOARD D/F – THE FIXED LOOP AERIAL - again

You will recall that using aural navigation inside increasingly noisy cockpits was a problem. Giving that problem to PNF after sacking WTO did not solve the problem. Solving that problem required sensitive electronics driving needles.
Those electronics allowed sensitive sensing of the min and max signal and pointed a needle at the emitter; any emitter that the aircraft had a receiver for. When the gauge is mounted with an obscured arc so that the needle is off scale unless the loop is pointing at the emitter it is called an obscured arc pilot radio goniometer gauge.

So what does that have to do with Radio Ranges and the new US Instrument Rating? In reality quite a lot!

By the mid thirties any propliner, including primitive propliners like the Lockheed Vega), equipped with a fixed (straight ahead) loop aerial could also be fitted with a pilot goniometer whose needle would point to an emitter ahead of the nose. No WTO was required. Even PF could tune the frequency of the emitter and then PF could turn the whole aeroplane until the needle on his obscured arc goniometer centred. The nose was then pointing at the emitter.


POSSIBLE BUT FORBIDDEN

Now we must grasp that this was possible from anywhere, but unless the aircraft was already established on the beam it was *forbidden* over the CONUS. The classic era of propliner flying was all about compliance with government (ATC) regulation even though many other more dangerous possibilities existed. They were possible but forbidden.

The whole point of the classic phase of aviation history, (invented in the United States), was not just to avoid the need for huge flight deck crews, including both a WTO and a NAV, but also to prevent pilots from ever playing at WTO or NAV once they had been banished from commercial aviation. We shall examine that in greater detail in part 2C.

For the time being we must notice that in the 1930s US airline pilots, (and even military / naval pilots), were allowed only obscured arc pilot goniometers. They were not allowed 360 degree unobscured arc radio compasses. They were not even allowed 360 degree gyro compasses. They were restricted to barrel compasses. They were mere pilots, not navigators. They were trained and employed to fly assigned headings. Once upon a time those headings had been assigned by navigators, now they were assigned by mandatory published government procedure, or by federal agents in air traffic control facilities of many kinds.

Banishing navigators, *and navigation itself*, massively reduced death rates in aviation. It increased public confidence in commercial aviation. It increased demand for commercial aviation. It allowed bigger and bigger propliners to be designed and filled. It created the possibility of airliners and airlines that needed no tax subsidy other than the cost of the airways system and the air traffic controllers to run it. No airline had an unfair advantage. No airline had more subsidy than any other. Over the CONUS the huge tax subsidy was equally available to all, but over the Lufthansa network only to German government owned aircraft; commercial or military.

The classic phase of aviation history was a huge change of culture and politics. It worked. It worked far better than anyone had imagined it might. Consequently as the 1940s gave way to the 1950s the US government would fight against GPS navigation and would mandate VOR navigation. The US government would attempt to enforce a standardised form of VOR receiver which is just a slightly different obscured arc goniometer. They would subsidise that concept to any extent necessary to prevent the possibility of GPS being used instead.

Even in 2008 many cockpits still have obscured arc pilot goniometers. In order to understand the history of commercial aviation we must understand why. Then we must understand why some cockpits instead have 360 degree unobscured gyro compasses and 360 degree unobscured radio compasses. We must understand why the US government fought for decades to prevent their installation anywhere mere pilots could see them and use them, and why the US government lost that battle.

Which takes us right back to the difference between how Radio Ranges worked in theory, (how aircrew trainees were taught to use them to pass examinations), versus what was possible, and how they worked in practice.


COST to the TAXPAYER

Two things would cause the US government to lose their battle to prevent pilots having access to unobscured 360 degree navigation gauges. The one that really mattered was money. The Radio Range system was based on the concept that no pilot would change course unless he was in the cone of silence over a government Range. He would track from Range overhead to Range overhead. Everywhere the government would ever allow a commercial pilot to change course the taxpayer would fund a Radio Range and if necessary a power station or powerlines to energise it every hour of the year.

This was hugely expensive. The airlines loved it. The aircraft manufacturers loved it even more, but pilots hated it, and representatives of tax payers soon started to query it. What was needed was the ability to define waypoints somewhere other than overhead Ranges.


FAN MARKERS

At first this was achieved by locating audio MKRs at potential waypoints. MKR lights and tones were used to note the arrival of a waypoint, not only en route, but also during the arrival, approach and departure phases. The power needed by the short range MKR was less than that required by a Range, but the cost of running power lines to it was identical. There was an obvious alternative solution. That alternative solution was to use the intersection of Range courses as waypoints. That solution had no capital cost and no running cost. Each Range course could intersect with others to create at least four intersections and a minimum of five waypoints for the cost of one Range. It was a financial logic that could not be resisted for long.


INTERSECTIONS

Intersections were a huge money saver for the US taxpayer. Intersections not only allowed a cheaper airways system, they also allowed abbreviated routes. The problem was that most US propliners had only two crew. One had to monitor ATC on COM1 and the other was monitoring Range 1 audio on NAV1. Neither could monitor the audio signal from Range 2. The US government hated the idea of mere pilots playing at WTO or NAV, but if the federal government were to provide a cost efficient airways system they needed more and more intersections. They had to relent, at least little by little.

The advantage of intersections was that they required no MKR; provided the crew could locate the intersection by other means. That means already existed. Its use was simply forbidden. The fixed loop goniometer could D/F any emitter for which the aircraft had a receiver, provided the emitter was almost dead ahead of the nose.

It occurred to the federal authorities that allowing PF to use his goniometer to home the range after locating the Range course aurally did not negate the culture and politics of the Ranges. So that is what happened. PF tuned COM1 and listen to COM1. PNF tuned PF’s goniometer to the Range, *but only after the range course had been intercepted aurally*. Then PF centred the goniometer needle and by that means he homed to Range 1 visually. PNF now tuned Range 2 on NAV2 and listened for A + N = monotone. By that means the crew found the intersection and could change course over the intersection without the taxpayer funding either a Range, or a MKR, or a power supply to either.

In the earliest days of the Radio Ranges PF centred the needle of the (Sperry) Gyro comparison compass (or Askania deviation compass), but once intersections were introduced he centred the needle of his occluded arc goniometer instead. What had been forbidden became part of the Instrument Rating syllabus. Pilots were allowed to home Ranges using a goniometer *so long as they only did so along the Range course*.

Remember the classic era of aviation history was all about being confined to using government approved procedures even though other more dangerous possibilities existed. It was possible to D/F the Range (which was just another signal emitter) from anywhere. It was just forbidden until the on course signal had been located and intercepted by audio means.


PROBLEMS ARISING FROM TWO CREW AUDIO NAVIGATION

Now let’s remember that audio navigation was always a bad idea due to ambient noise in the cockpit. It was tedious and stressful at the same time. It was distracting. It was inaccurate. Pilots hated it.

Pilots wanted four different things.

1) PNF wanted PF to be qualified to track beams using needles which gave an analogue picture of angular deviation just like the (Sperry) gyro comparison compass in the BFU or the (Askania) deviation compass. Audio did not give an easy to interpret angular deviation cue to either pilot.

2) PNF wanted his qualification to allow him to turn the loop aerial just like WTO.

3) PNF then wanted his qualification to allow him to locate intersections using the loop and a goniometer just like WTO.

4) Meanwhile PF wanted his qualification to allow use of gyro and radio compasses with an unobscured 360 degree arc just like NAV.

This was not about altering the privileges of an airline pilot license. This was all about altering the syllabus and privileges of the Instrument Rating. This opened the way for government to have very restrictive legislation for mere pilots whilst allowing greater privileges to the few pilots who obtained an additional instrument qualification. That qualification now became mandatory for airline pilots and little by little pilots who had tenure were granted the four wishes above.

What we must grasp is that this happened during the era of the Radio Ranges.


TRAINABLE LOOPS and OMNI BEARING SELECTION (OBS)

The next step was to allow Instrument Rated pilots to train loop aerials using an omni bearing selector (OBS crank or OBS knob). PNF could now point the loop down any bearing, not just straight ahead. Now CAPTAIN had access to superior crew resource management (CRM). He could share workload in the two crew cockpit more evenly between PF and PNF. He could order PF to use audio to home range 1 and PNF to use the loop to locate the course from Range 2 if that shared workload better.

Under those circumstances PNF used the OBS to turn the loop to match the bearing of the Range course which formed the intersection. The pilot goniometer began to deflect as the intersection approached and would centre (more or less) as the aircraft crossed the monotone aural beam from Range 2. If the crew were going to turn down the beam to Range 2 they could turn early and knew when to turn early. They now had an analogue angular deviation display. Once the instrument rating qualified PNF to train a loop aerial the crew could intercept a range course the same way that a VOR radial or an ILS course is intercepted using the varieties of pilot occluded arc goniometers known as VOR 2 and ILS receivers which are still in use today.

Of course pointing the trainable loop dead ahead to allow PF to just home a signal was still possible.

The next step was to allow each instrument rated pilot to have his own occluded arc goniometer, one tuned to NAV 1 and the other to NAV2. Now both could use visual tracking.


PRIMARY and SECONDARY means.

Do not become confused. Audio continued to be the ‘primary’ means of locating and homing Ranges. The monotone signal it created as a beam was a COURSE. It never drifted with the wind. Before PNF was allowed to connect PF’s goniometer to the Range signal to home the beam using a goniometer PNF had to use audio to confirm that he was in the beam. Just because PF continued to point the nose at the Range with the goniometer thereafter did not mean that the aeroplane had not drifted off the beam.

Every ten minutes PNF had to turn up the audio signal for NAV1 to ensure that the aircraft was still in the NAV 1 beam. If it was not he assigned a new heading to PF via the comparison compass and disconnected PF’s goniometer from the loop. This procedure was identical to vintage era navigation. PNF knew whether the 5 degree course correction needed to be right or left according to whether he heard A or N when he *very briefly* turned up the audio. PF just centred needles either way.

Do not become confused. A primary means of navigation is more accurate than a secondary means of navigation. If the sources differ the crew must trust the primary source. This does not mean that the primary means of navigation is the usual means. It is the master source of data. The distance that an aircraft could drift off course in ten minutes whilst homing with a goniometer was not enough to matter, so long as it was corrected by reference to the primary means of navigation every ten minutes.


THE ‘1 in 60’ RULE

Everything in aviation is to base 60. Everything is about TIME, but of course time is about how long a planet with a circumference of 360 degrees takes to rotate.

At 60 KTS an aircraft travelling north moves one second of latitude every second of TIME and one minute of latitude every minute of time. In 60 minutes of time it traverses 60 minutes = one degree of latitude. Minutes of time and latitude are transferable and at 60 KTS they are equal. The 360 degree circumference of the planet is part of the same 4D system of navigation to base 60.

Consequently when an aeroplane is off course by 60 degrees it will be 60 (nautical) miles off course after 60 minutes. An aeroplane that is five degrees off course will be five miles off course after 60 minutes. After 10 minutes (1/6th of an hour) it will be less than a mile off course.

This is not a ‘rough rule of thumb’. It is the whole point of the 4D navigation system. It is ‘designed’ to be true. After each nation ratified the Chicago Convention after WW2 all aerial navigation was done in knots and all aircraft which hoped to obtain an IFR clearance from ATC had to be equipped with an ASI that displayed KIAS, not MIAS or KmIAS. Mph and Kmph just hinder navigation.


CENTRE THE NEEDLE

The reality of Radio Range navigation was hardly different to vintage phase navigation. PF might or might not be assigned a new heading every ten minutes by somebody else. Once audio confirmed that an aircraft which had drifted off the beam, was back on the beam, PNF did *not* reconnect the loop to PF’s goniometer. He now had a good idea how bad the drift was on that range course and dialed an appropriate assigned heading to negate that drift into PF’s comparison compass. PF then centred a different needle. He was listening to COM 1 throughout whilst PNF listened to NAV1 every so often to confirm, using the primary source of navigation, that the more convenient secondary source was not causing significant navigation error.

*Pilots did not listen to NAV audio continuously*.

There was no reason to. Whether drift had developed only needed to be checked briefly using audio every ten minutes. Whether drift was developing was easy to monitor. With no drift when PF centred the goniometer needle the current heading would be the Range course. If the heading required to point the nose at the Range was not the Range course then drift was developing and both PF and PNF could determine in which direction the crosswind was drifting the aeroplane. The comparison compass is at the heart of both vintage and classic phase aerial navigation.

The helmsman (PF) still just centred whichever needle NAV or PNF had ordered him to centre. PNF needed to monitor audio for drift regularly, but infrequently, and then decide whether to order PF to use the goniometer (no significant drift), or the comparison compass (significant drift). The text flight plan (see part 2C) allowed PNF to forecast when he needed to listen to audio to detect the cone of silence over the Range, but this could anyway be detected by PF with the goniometer which would suddenly go off scale as it lost the D/F signal upon entering the cone of silence.

Intersections existed in very large numbers for most of the Radio Range era. In MSFS we turn our loop aerial manually with the OBS knob of our VOR1 or VOR2 gauges. The Signal Corps Receiver in the default Lockheed Vega and the VOR receiver in the default Cessna 182 are both obscured arc pilot goniometers whose needle only moves when the loop aerial is pointing at the emitter.

The version of the SCR (goniometer) in the default FS9 Lockheed Vega dates from the era of fixed loops. It has no crank handle to use as a bearing selector. It has the appropriate period look, but it only ‘works’ if we are simulating roughly 1932 – 1939, before we need to locate intersections. In FS9 we need to use the modern varieties of obscured arc pilot goniometers known as a VOR1/2 receivers because they have a crank handle = OBS knob which allows us to train the aerial to the (Omni or Radio) Range Course we must locate as an intersection. We have no choice. The MKR tones and lights that marked the many intersections we need to locate are not present in FS9; whether or not we import single channel audio from a single tuned Radio Range into FS9 via a Radio Range audio add on.


DISATISFACTION

Remember all pilots and all governments outside Germany and the USA hated all this so much that they refused to adopt any of it and the dangerous vintage era techniques described earlier persisted for decades. Pilots in Germany and the USA were not given a choice, but American commercial pilots unionised and bitched about the situation and slowly obtained the concessions they desired.

It is perfectly possible to fly Ranges using only audio, but even then there is no reason to listen continuously. US pilots hated it and demanded fixed loops and Signal Corp Receivers with a needle to follow. These were soon fitted, but were of limited use. They were soon followed by trainable loops to make it possible to locate intersections without a MKR. Audio remained the primary means of navigation, but increasingly not the usual means of navigation.


FIVE MAST RANGES

From 1935 US Radio Ranges increasingly had a fifth mast in the middle which was a broadcast beacon used to transmit the weather and other aviation information by W/T and later R/T. The NAV signals were no longer interrupted to allow this. This fifth beacon broadcast the Range ident when not being used for ATIS. It could be tuned as a D/F signal. It was an NDB sitting in the middle of the Radio Range. No one was allowed to home to Ranges other than along their four courses, but audio played a smaller and smaller part in practice.

Once instrument rated pilots could train their loop they could create an intersection anywhere they wished. Intersections not associated with a course change could be used to determine variation between Estimated Time of Arrival (ETA) and Actual Time of Arrival (ATA) and thus to determine head wind vector. They could be promulgated by ATC to separate traffic by obtaining intersection passing reports. During arrival and approach procedures intersections increasingly allowed descent to a lower altitude since they confirmed that high ground or masts had already been avoided.

Published intersections, and unpublished intersections, located with trainable D/F loops became ever more important in those few places with classic era public sector infrastructure; precisely because both ATC and aircrew could create one as a way point anywhere they needed one.

Most flight simulation users don't grasp the culture or the politics of the classic phase of aviation history. They think that maps and ground speed and other 'navigator' paraphernalia are relevant to classic era propliner simulation. They are not relevant. They were forbidden. That was the whole point. Those were the things that were killing all the British passengers in all the British propliners until the British gave in, ratified the Treaty of Chicago and forced their commercial aircrew to follow mandatory federal step by step beam (radial) following and beam (radial) locating procedures too.


COMPROMISE

Outside Germany and the CONUS few governments were interested in imposing occluded arc gauges on pilots because there were no mandatory beams to locate and home. Airlines created procedures for their employees to follow, not governments. As soon as manual loops could be replaced with Automatic Direction Finding (ADF) they were. No one outside Germany and the CONUS minded if an airline added a 360 degree unobscured arc radio compass driven by an ADF to a pilot panel. Governments elsewhere refused to believe it was their business and refused to fund ‘beams’.

As soon as ADF was available and radio compasses, together with matching 360 degree unobscured arc gyro compasses were made available to pilots outside Germany and the CONUS it was obvious that they increased pilot situational awareness. It was obvious that the smaller the crew the more pilots needed them in an environment where there were no beams to follow. In particular unobscured 360 degree compass gauges of all kinds made intersections easy to promulgate and locate. This allowed MKR fans associated with arrival, approach and departure procedures to be deleted with considerable cost savings.

Soon there were unobscured arc radio compasses with more than one needle known as radio magnetic indicators (RMI) to aid that process of bearing comparison. Easier to interpret gauges allowed more complex, shorter, arrival, approach, missed approach and departure procedures saving engine hours and fuel.


HEADING BUGS

Once the 360 degree unobscured arc gyro compass was available the assigned heading tool became a bug rotating around the circle. That bugged heading was still assigned by PNF or NAV. That heading bug is an absolute necessity regardless of the presence or operation of any autopilot. We still need a gyro comparison compass. In the circumstances under discussion we bug the airway course as our assigned heading on the gyro comparison compass. We also select the airway course with the OBS knob making sure that we have a TO flag. Then we keep the needle of the obscured arc goniometer centred or the needle of the RMI pointing at the Range course. Now we note the difference between our current heading and the assigned heading. That difference is our drift. Once we have radials to follow we never need drift meters or any of the other navigator guesswork paraphernalia that had killed so many aircrew and passengers. They have no place in the classic phase of aviation history.

It was a trend that the US federal authorities could not resist. They fought hard. They tried to ensure that all pilot navigation gauges would continue to be occluded arc goniometers forever. In the case of aircraft likely to be operated by amateurs they managed to prevent RMIs from appearing to a large extent, imposing only occluded arc VOR receivers with omni bearing selectors. However instrument rated pilots increasingly achieved their fourth demand and acquired all sorts of unobscured 360 degree gauges to increase their situational awareness. These needed no OBS knob to train a loop. The loop trained itself whether the signal came from a Radio Range, a Vhf Omni Range, or an NDB.



THE VISUAL AUDIO RANGE (VAR)

From 1940 the U.S. Government began to establish a new type of Radio Range and a new type of occluded ARC goniometer for use with it. These new ranges still only had four courses (radials), but they emitted in the VHF waveband and were more accurate. The VAR receiver looked much like a VOR2 receiver. The VARs allowed the primary means of navigation to become visual with audio as back up.

Some sources say that these were installed only on a limited basis because the funds were soon diverted to the war effort, but that lacks logic. What was good for transport operations was good for bomber operations and WW2 provided an added incentive to develop new means of electronic navigation.

From 1940 when and wherever new ranges were installed they tended to be VARS, especially in Australia, but there was no need to replace all the existing LF ranges across the CONUS and extending into Canada. The reality was that they were already being navigated with needles. U.S. pilots were content to retain LF ranges provided they were allowed 360 degree unobscured arc radio compasses and 360 degree gyro compasses to increase their situational awareness. Deployment of the twin needle RMI made the need for occluded arc VARs even less important.

Both VAR receivers and VOR receivers were obscured arc goniometers being promoted by the U.S. government. What instrument rated pilots wanted were 360 degree unobscured arc gauges. From 1940 onwards they very slowly got their wish, but always fighting against the culture and policy of point source navigation and beam following using occluded arc gauges being promoted by the U.S. government. The classic phase of aviation history was all about preventing pilots playing at WTO or NAV.


COMMON SENSE PREVAILS

As time passed it became obvious that in practice the Ranges were being used as powerful NDBs. By the early 1950s the U.S. Government had published hundreds of arrival, approach and departure procedures that required instrument rated pilots to locate Range course intersections during those procedures. By then in reality these were being located using ADF treating the Range as a powerful NDB. If MKR fans were ever / still present at the intersection they had become a secondary confirmation of what the ADF or RMI needle already indicated. Many / most Ranges were now five mast Ranges with an NDB in the centre anyway.

First the U.S. government stopped funding the MKRs and their power supplies. Then once VORs became available in the mid fifties and were placed close to the old Range they removed the four outer aerials of the Radio Range. They could not remove the NDB in the middle. For a long time it had been at the heart of the arrival, approach and departure procedures. In many cases it is still there and in use in 2008 fifty years after the Radio Range of which it was supposed to be the least important part was torn down.

For instance at KDCA we see that the NDB which was at the heart of the DCA range and was then the DCA NDB has become the DC NDB today, but it is still transmitting on its original 1930s/40s/50s frequency. It is still part of the KDCA approach procedures in 2008.

Finally we must remember that none of the relevant MKRs are present in MSFS anyway. To find the intersections over which we must alter course and change altitude in MSFS we must use VOR1 and VOR2 as described in the previous part of this tutorial.


FLIGHT PLAN

During classic era flight planning we will always need to create a detailed flight plan. The flight plan replaced the map of the pioneer era, and the GPS plot of the vintage era. Any good flight planner will auto-generate an airways plan from A to B. The trick when simulating 1932-55 is to ensure that the flight plan is based solely on VORs and their intersections, and not at all on DME fixes.

Some military aircraft and commercial flying boats with huge crews, including wireless operators and navigators, continued to use audio as the usual means of Radio Range reception long after it ceased to be the usual means in the two crew propliner cockpit. The only other nation with Radio Ranges before WW2 was Germany where I believe audio beam following continued to be the usual means of navigation. However in MSFS VOR1 + VOR2 must be used to fly the German Radio Ranges whose beams extended all the way from Amsterdam to Moscow, all at the expense of the German tax payer. As stated earlier, the German government had an ulterior motive for installing those beams.

From the late thirties onwards during two crew commercial operations over the CONUS airway centrelines were increasingly tracked by instrument rated pilots using gauges, rather than headphones.

When simulating 1932-55 over the limited part of the planet which already has classic era infrastructure, in an aircraft that has the necessary crew, equipment and code books, we will mostly use VOR1 as a goniometer to *follow* the airways. However if an intersection, in the current airways system, is defined by two intersecting radials from two modern VORs we will assume that it also existed as a Radio Range intersection. We can then turn our loop aerial using the OBS knob on VOR2 to the second airway centreline radial which defines that intersection and only then tune NAV2 to FREQ2. When both needles on both receivers centre we are over the intersection. If this is defined as a turning point on our flight plan we will cease tracking the airway centreline FROM VOR 1 and begin tracking the centreline TO VOR 2. Prior to 1956 we should use only VOR 1 and VOR 2 obscured arc goniometer gauges with vertical needles to simulate the Radio Range era.

We will only use a fix defined by DME when simulating 1955 to the present day and only when flying over advanced nations with classic era infrastructure. If we do not intend to simulate ‘orienting’ Radio Ranges in any detail flying airways using Radio Ranges or VORs hardly differs within MSFS, because from the late thirties it slowly ceased to differ in real life. Once their airline installed a loop and a goniometer, and later an ADF and a radio compass or RMI, commercial aircrew increasingly treated the Range as a powerful NDB.

During use of MSFS simulating the roles of PF and Captain must take precedence over simulating the supporting and limited 2D navigation role of PNF. Aerial navigation is not a 2D process. Most FS9 users become bogged down in 2D navigation. In an aeroplane the third and fourth dimensions must not be neglected and the relevant skills of captaincy are what we must study next.


PROPLINER TUTORIAL - PART 2C (ENROUTE PHASE IN DETAIL)


PROPLINERS LACKING PRESSURISATION.

During the pioneer phase we intend to height keep at 1500 feet. Propliners from the vintage phase of aviation history lacked pressurisation and they normally have a public transport certification ceiling of 12,000 feet or 4,000 metres, but across the British Empire and Dominions if the crew lacked a liquid oxygen supply the limit was 10,000 feet by day, and only 8,000 feet by night.

Most, but not all, unpressurised propliners had a limited liquid oxygen supply that allowed passengers to don oxygen masks for no more than 30 minutes per flight to allow an unpressurised propliner to climb briefly higher over bad weather or a mountain range. We must observe these restrictions when operating an unpressurised propliner. The handling notes always provide a suitable warning. Some vintage era propliners had a copious supply of oxygen to allow flight at high altitude with everyone wearing oxygen masks above 4000 metres. Those propliners have a 'design cruising altitude' specified in their handling notes.

In the vintage era propliners could usually climb directly to design cruising level. If they needed an extra engine to achieve that, one was provided. In the classic era propliners were expected to haul huge loads and were expected to make a profit. The huge federal subsidies of the vintage era had gone forever.

Classic era propliners were often critically short of power. They had a variable operational ceiling. As fuel burns off any propliner accelerates in cruise power. In the classic era having slowly accelerated to zero pitch it is time to step climb.

All the data in my handling notes, and in this tutorial, relates to the International Standard Atmosphere (ISA), which only exists in MSFS if we select the clear all weather option. This is the basis on which all aircraft performance is measured in the real world. Real weather differs and the performance experienced differs correctly in MSFS. We must begin to examine how we allow for real weather when using a flight simulator.


OPERATIONAL CEILING and STEP CLIMBS in detail.

Real world operations manuals have tables for a series of weather conditions (especially temperature) above and below ISA. These cannot possibly be replicated for all the propliners available for use within MSFS so we must use a generic procedure that will work for all.

In the cruise we want the aircraft to present the minimum frontal area. It does that at zero pitch. We accelerate it to zero pitch and the profile drag co-efficient minimises. We work hard to keep it minimised by climbing while that is an option, and by reducing speed to stop the reducing wing AoA rotating the fuselage nose down when it isn't.

We repeat this step climb process until we reach certification ceiling or the highest level that ATC will allocate for the trip. At that point we can go no higher. The next time the aircraft accelerates to zero pitch we must reduce power instead of step climbing.

Each acceleration phase to zero pitch at each subsequent level may take an hour or more. It is not a short term level off manoeuvre. It might take a DC-6B nine hours to step climb to its certification ceiling and accelerate to zero pitch for the last time. From then on we stop managing the acceleration and begin to manage the deceleration. This phase may last longer than the acceleration phase.

Suppose we depart a DC-6B westbound at max gross in real weather. In today's weather system maintaining 500 VSI in climb power we are struggling to maintain 170 KIAS passing FL150 and so we level off at FL160 as our initial cruising level.

***********************************
Climb Power: (1400 hp x 4)
COWL FLAPS = 4 degrees
39 inches MAP
2400 RPM
VSI = 500
Check CHT < 232C
WHEN IAS < 170 KIAS enter initial cruise
****************************

We have reached our initial operational ceiling. We reduce to high weight econ cruise power.

****************************
High Weight/Speed Cruise: (1100hp x 4)
COWL FLAPS = CLOSED
MAP = 34 inches
RPM = 2100
Check CHT < 232C
Plan 2100 PPH
@ zero pitch climb 2000 ft & 500 VSI
Note - yields 251 KTAS at FL210 @ 89000lbs
****************************

After take off we will attempt to exceed FL160 only if weight and weather permit us to sustain > 170 KIAS at 500 VSI in climb power. Our eventual goal when our weight has reduced to 89,000lbs is to achieve 242 KTAS at FL220 using only economy power. We fly propliners because we are interested in learning the skills of profit maximisation. Only certain types of combat flying are about performance maximisiation.

****************************
Econ Cruise: (1000hp x 4)
Use only <= 89,000lbs
COWL FLAPS = CLOSED
MAP = 32 inches
RPM = 1850
Check CHT < 232C
Plan 1900 PPH
@ zero pitch climb 2000 ft & 500 VSI
Note - Yields 242 KTAS at FL220 @ 89000lbs
****************************

89,000lbs is mid cruise weight if we depart with maximum fuel and maximum related payload. On a maximum range flight we will reach FL220 half way to destination. The first half of the cruise will be at 2100 PPH and the second half at 1900PPH. The mean will be close to 2000 PPH. We start with 29,600lbs of AVGAS.

***************************
Maximum fuel load is 29,600 pounds. All fuel burn figures are for planning purposes and will vary slightly with altitude. Adjust fuel and payload using the fuel and payload menu in FS9.
***************************

Our endurance is almost 15 hours. In average weather, if we departed at max gross, we must attempt to cruise a DC-6B at FL220 until we have spent 7.5 hours burning off fuel. Our operational ceiling will only become FL220 when we are down to 89,000lbs. If we meet significant headwinds (see shortly) we will not climb that high. Seven and half hours into the flight our operational ceiling is still 3000 feet below our certification ceiling of FL250. It will be many more hours before our operational ceiling is as high as our certification ceiling.

Of course we reach 89,000lbs much sooner following a light weight departure.

At each intermediate cruising level, as the fuel slowly burns off, the wing adopts a lower angle of attack. It slowly rotates the whole aircraft more nose down in level flight. The aircraft will very slowly accelerate as the induced drag diminishes. We have constant power applied so surplus power is growing as weight diminishes. Our current operational ceiling is slowly increasing, but ATC will only allow us to climb in steps of 2000 feet, (odd levels eastbound and even westbound), so we must await the moment when our surplus power is enough to raise the operational ceiling 2000 feet.

In real life we would use the tables in the ops manual. In MSFS we must respond to the changing aircraft pitch. As soon as the pitch, (observed on the artificial horizon), reduces to (almost) zero we should have enough surplus power to climb 2000 feet at 500 VSI using the relevant climb power. By now the profile drag in a DC-6B may have risen to > 190 KIAS. We can allow it to bleed down to 160 KIAS in the next step climb during which we will use 2400 rpm. We will be using full throttle to step climb because we will already be above the level at which our superchargers can generate 39 inches of MAP.

In a DC-6B we can allow our IAS to bleed down to 160 KIAS in the next step climb. The METO section of the handling notes tells us our minimum safe IAS during step climb, but we will use climb RPM and climb cowl (drag) settings to step climb (not METO).

**********************************
METO Power (1800hp x 4)
COWL FLAPS = 4 degrees
48 inches MAP
2600 RPM
160 KIAS
Check CHT < 260C
Above all obstacles
VSI = 500
ACCELERATE > 180 KIAS
CALL for climb power
***********************************

Having very slowly accelerated to (almost) zero pitch in econ power at our original operational ceiling of FL160 we give ourselves ATC clearance to FL180, apply climb power and climb 2000 feet at 500 VSI, or for a slightly more rapid climb pull the nose up to reduce drag immediately to 160 KIAS and 'zoom climb' those 2000 feet. The passengers would prefer the former even if the latter is more efficient. We will repeat this procedure twice more until we are at FL220 some hours and several tons of fuel later.

Using this technique we will never be applying abusive power to the airframe, and we will never reach the next higher ATC cleared level with insufficient power to sustain a higher cruising velocity (TAS) than we had at the lower level. The technique is self correcting for all weather conditions, and takes into account ice accumulated on the airframe, on the props, and in the engine. It is just another form of energy state management. We shall keep the weight down and the thrust up by removing any ice from the wings and props of course. MSFS simulates all types of icing except carb icing. Provided we *remember to enable icing in the advanced weather* menu of course.

In the cruise if we are pitched significantly nose up we have climbed too high for our current weight. Conversely if we are pitched nose down we have applied too much power, or we are too low for our current weight. We should adjust one or the other, but all things being equal we should adjust our altitude and run the engines at optimal MAP and rpm. Mountains, ATC, turbulence, icing, etc, mean that sometimes we have to adjust power instead.

Aeroplanes never cruise nose down. Only pilots do that. Most of the time we should avoid doing so.


PIMPED RIDES

There are aircraft whose wing was designed for one power plant, but which later in life have much more powerful engines installed. When we apply optimal power from that much more powerful engine it will tend to pitch the aircraft nose down and stress the tail. Aircraft like that have significant energy state management problems because they are in danger of exceeding their safe drag limits in shallow descent or even in the cruise.

The DC-6 family re-use the wing from the much less powerful DC-4. If their additional power were applied at low altitude for more than a couple of minutes it might rip the tail off. With much more installed power to allow a much bigger load to be lifted by the same wing the DC-6 family must climb to an altitude where their engines are starved of oxygen before the same % throttle opening can be applied safely. It is the extra installed power (to lift bigger loads) that makes pressurisation essential. We must cruise in thinner air to avoid structural failure.

If we try to operate a DC-6 low down in thick air, at DC-4 altitudes and weights, even with econ power applied, it will tend to be nose down in the cruise because the wing was designed to be propelled by much less power. The extra power is a benefit, not a problem, so long as we use all the surplus power to reach its higher operational ceiling where it can cruise at a much higher velocity (TAS) than a DC-4.

Because the DC-6B is a pimped ride it has significant energy state management problems. At modest altitudes, in nice warm air, we can allow the drag to reach 250 KIAS without fear of ripping the tail off, but as we step climb higher and higher, into colder and colder air, transonic (Mach) shock will be induced. Whenever we are above FL170 we must take care to keep the profile drag below 220 KIAS to allow for the transonic drag which we cannot measure because we have no Machmeter. This may, or may not, be a problem in the cruise, but it will be a problem when we reach TOD (Time of Descent).

****************************
Descent:
ABOVE FL170 DO NOT EXCEED Mno = 220 KIAS
DO NOT EXCEED Vno = 250 KIAS
****************************

Pilot error can easily cause a DC-6B to depart controlled flight, leading to structural failure, during an incautious descent from levels well above FL170. Transonic drag, caused by transonic shock, is a big problem in many classic era propliners. Let’s examine that in more detail.


INTRODUCTION TO MACH.

It may seem that transonic flight has little relevance to propliners, but that is not true. Transonic shock develops well below the local speed of sound (Mach=1). Around an aeroplane air flow may be squeezed and accelerated to greater speeds than the surrounding general air flow. Think about what happens to a flow of water squeezed between two rocks. It speeds up and it becomes turbulent. Drag on the rocks is higher due to the greater local velocity and locally induced turbulence. Now imagine what would happen to one of the rocks if it were very finely balanced and needed to remain very finely balanced. The increased drag is a threat and the turbulence is a bigger threat to the stability of the finely balanced object. In an aeroplane that locally induced turbulence when the aeroplane is flying at much less than Mach=1 is transonic shock. Supersonic shock and drag kick in later and are not relevant to propliners. Transonic shock begins at small fractions of Mach 1.

In the very earliest part of this tutorial we discovered that an aeroplane may suffer structural failure in turbulence if the drag is allowed to exceed Vno. It may also suffer structural failure in turbulence if it is allowed to exceed Mno. This part of the propliner tutorial explains how to identify Mno, how to avoid Mno, and why Mno is the factor that restricts the maximum velocity of most classic era propliners, whether piston engined or turboprops.


MACH and COLD

The speed of sound in air depends only on temperature and nothing else at all. As we climb the air gets colder whatever temperature we start from at ground level. The colder it gets the more likely we are to induce transonic shock. The colder the place we start from the more likely we are to induce transonic shock.


MACH and TURBULENCE

We may or may not be able to avoid natural air turbulence ahead of the aircraft. Turbulence can occur in clear air as well as in cloud. Importantly clear air turbulence is more common in MSFS than in real life due to bugs in its weather model. If we exceed Vno or Mno in MSFS we are at considerable risk of structural failure. Either constitutes ‘Overspeed’ and the relevant warning will show. Some modern aircraft have overspeed warning horns, but as far as I know no classic era propliner had such a horn.


MACH and STRUCTURAL FAILURE

Some aerodynamic shapes and structures are more likely than others to cause transonic shock. Some aerodynamic shapes and structures are more likely than others to suffer a critical event during that transonic shock. That critical event will often be departure from controlled flight rather than immediate structural failure. However departure from controlled flight following a transonic shock event tends to be followed quickly by structural failure anyway.

If structural failure were not encoded the propliners we download could attain highly unrealistic drag and highly unrealistic velocities. Neither the maximum profile drag (IAS), nor the maximum velocity (TAS) of complex aircraft is limited by the power available. Both are instead limited by the fragility of their structure. When we fly a complex propliner we must constrain both profile drag (IAS) and transonic drag (Mach) to safe values. The maximum velocity (TAS) achievable is constrained by both types of drag and by the turbulent Mach flows caused by ‘squeezing’ of air flows well below Mach 1.

When the air is warm our safety limit is the dynamic drag = Vno (measured in IAS). When the air is cold the safety limit is instead the transonic drag = Mno (measured in Mach). Think hard about that before reading on. Both the maximum safe drag and the maximum safe velocity of a propliner are severely limited by how cold the outside air is. However when the classic propliners were being designed this was very poorly understood by real flight dynamics specialists. Consequently only a few propliners ever had Machmeters so that pilot flying could monitor Mach directly and thus avoid all possibility of sudden structural failure or sudden loss of control due to localised turbulence induced by abusive Mach.

In the early 1950s there were still people who believed that all that was necessary to make an aeroplane go faster was to install more power. Some of them actually designed real aircraft. As always this is all about understanding the difference between drag and velocity.


DRAG is not VELOCITY

Magazines and the Boys Bumper Book of Aircraft may claim that an aircraft has a maximum level speed (Vmax) of xyz, but the information is almost meaningless, especially if it does not specify the only altitude and temperature at which it could very theoretically be true.

In real life, for complex aircraft, there is a significant probability of structural failure long before Vmax. Only very simple and underpowered aircraft like Cessnas have Vmax limited by the power available. Most aircraft are instead limited by the fragility of their structure. The later triple tail Lockheeds were guaranteed to survive a drag of 260 KIAS, but only in modest turbulence, and only if they stayed in nice warm air. The numbers quoted in the Boys Book of Bumper aircraft are always for sufficiently warm air. The speed and velocity achievable in cold air were lower and often much lower.

Propensity to generate transonic shock increases as temperature falls, and as we climb temperature tends to fall at about two degrees Centigrade for every thousand feet that we climb. The higher we climb the more likely transonic shock followed by structural failure becomes.


TOTAL DRAG

As Part 1 of this tutorial explained we need to fly as high as possible to achieve high cruising velocity, but the higher we fly, and the higher that allows our velocity to become, the greater the danger from transonic shock. Eventually we create turbulent and localised transonic shock which is a fluctuating chaotic drag. It is no longer safe to allow our profile drag to reach Vno in cold air. We must allow for the growing chaotic transonic drag.

Those of you who have flown the DZN L-049A Constellation will have been observing the following two injunctions very carefully.

Above FL200 NEVER EXCEED 210 KIAS (Mno)

DO NOT EXCEED 236 KIAS (Vno)

The earliest incarnation of the Constellation could safely encounter a profile drag of 236 KIAS, even in modest turbulence, provided it never encountered air colder than minus seventeen Centigrade. Colder than that and dynamic drag (IAS) must be reduced progressively and substantially to survive.

In the L-049A aircraft.cfg we find,

[Reference Speeds]

flaps_up_stall_speed=88
full_flaps_stall_speed=70
cruise_speed=239
max_indicated_speed=236 ;Vno below FL160 - lower limits above due transonic shock
max_mach=0.48 ;Equal to 210 KIAS at FL225 in ISA


Those injunctions within the released handling notes and aircraft.cfg are a simplification of the real data table. It makes not the slightest difference what type of engine is used to create the abusive drag. The weak triple tail fails regardless. More powerful engines just allow pilot flying to rip the tail off more easily. They do not allow the aircraft to go faster.

Lockheed failed to supply any kind of gauge to indicate Mach in the L-049. Pilot flying had to limit IAS to allow for the growing transonic shock in cold air above FL200. Below FL200 an L-049A would have a high probability of surviving profile drag = 236 KIAS, but at any high altitude the maximum profile drag had to be limited to just 210 KIAS to ensure an equal chance of survival. The total drag including the unmeasured and unknown turbulent Mach shock would then always be below 236.

Avoiding 210 KIAS whilst climbing or even cruising an L-049A above FL200 is not especially difficult. The problem comes when it is time to descend. MAP must be reduced very slowly to prevent shock cooling of the incredibly expensive and fragile R-3350 engines and so VSI must be restrained to the legal minimum of just minus 500 until below FL200 when the drag can be allowed to rise and minus 700 VSI can be targeted with adequate safety.

Lockheed worked hard to make the later versions of the triple tail stronger and in the L-749 / C-121 / L-1049 the triple tail could withstand a drag of 260 KIAS, (10% more than the safe structural limit in the L-049). Mno rose to Mach 0.52. The power generated by the engines was always irrelevant to going faster in any of these triple tail aircraft. They already had enough power to rip their own tail off in cold air, with the power from piston engines.

The only place any type of aeroplane can ever achieve high velocity was in high cold air. Adding more powerful engines to a Constellation could not increase Vmax because Vmax was already limited by the weak triple tail.

[Reference Speeds] //L749 / C-121 / L1049

max_indicated_speed =260
max_mach=0.52

The triple tail family culminated with the fastest of all which was the L-1649A Starliner. The aircraft was hardly any stronger but Vno was re-assessed as 261 KIAS whilst Mno was re-assessed at M0.55. I doubt the tail was actually any stronger. I think that greater understanding of transonic shock eventually allowed the regulatory authority to take a very slightly more lenient view of the combined dynamic drag and transonic shock which the same tail could withstand in adequate safety.

[Reference Speeds] //L1649A

max_indicated_speed =261
max_mach=0.55

The more powerful propliners became the greater the complication arising from the need to avoid transonic shock. So in the Calclassic.com handling notes for the L-1649A we see;

***********************************
Normal Cruise:

COWL FLAPS = CLOSED
MIXTURE = AUTO LEAN
RPM = 2200
MAP = 37 inches

On reaching ZERO PITCH - STEP CLIMB
see www.calclassic.com/tutorials.htm

CAUTION - No Machmeter
!WARNING - AVOID Mno = M0.55!
= FL200 NEVER EXCEED 254 KIAS
= FL210 NEVER EXCEED 248 KIAS
= FL220 NEVER EXCEED 242 KIAS
= FL230 NEVER EXCEED 236 KIAS
= FL240 NEVER EXCEED 230 KIAS
= FL250 NEVER EXCEED 224 KIAS

WARNING - NEVER EXCEED FL250

PLAN 3200 PPH
Note: - Yields 290 KTAS at FL220
***********************************

The more powerful an aeroplane becomes the more its operation depends on seeking the most appropriate (temperature) thermocline in the current weather. High air is cold air. We can climb into that colder air, but we must reduce our profile drag if we do. The consequence may be loss of velocity. If the mountains are high enough, or we need to climb out of icing into clear air above high cloud, we may need to do just that.

In most propliners operational ceiling is limited by available climb power, but in powerful propliners operational ceiling may be limited instead by transonic shock and therefore by outside air temperature. In the absence of mountains and icing we may decide to operate where normal power delivers maximum cruising velocity (TAS). For that to be true the air must be warm enough to ensure our survival.

As fuel burns off the aeroplane becomes lighter. At constant power it rotates nose down, reduces induced drag, and increases cruising velocity (TAS). The lighter we become the greater the danger of transonic shock. We step climb instead, but eventually the air above will be so cold that doing so would be dangerous. When this happens we must trickle reduce power at our current level to ensure that the aircraft neither goes nose down, nor exceeds the reduced IAS (profile drag) safety limit for the chaotic transonic shock we are already inducing.

The Constellation family could barely tolerate the power produced by the final generation of piston engines in safety. They could not cope with turbine power. They already had almost too much.


MORE POWER = MORE USEFUL LOAD

Propliners are not terrestrial vehicles. They cannot be made to go faster just by adding more powerful engines. To go faster they must be made stronger *in cold air*. It is not enough to make them stronger in warm air. For much of the classic propliner era no one knew how to make aeroplanes more resistant to transonic shock even after they figured out how to slow down the onset of transonic shock.

The purpose of more powerful engines in propliners is therefore to lift bigger loads from the same runway. The mooted and tested Turbine Constellation could lift a bigger payload, or more fuel to carry the same payload over a longer range than the L-1649A, but it could not have a higher Mno in commercial service, and it could not have cruised any faster than the L-1649A. It was no stronger in cold air and that made it the ideal aeroplane to explore and document all the problems Lockheed, the USAF and the USN, needed to solve before they could introduced the C-130 Hercules to service.

To go faster the weak triple tail on the Constellation family had to be abandoned, first in the C-130 Hercules which could cruise safely at Mach 0.56, and then as Lockheed commercial employees (working outside the skunk works) gradually came to understand transonic shock, in the much stronger L188 Electra whose single tail allowed Mno = 0.615.


MACH measures COLD and limits VELOCITY

To achieve high velocity (TAS) we must restrain profile drag (IAS). To restrain profile drag we must climb high into thin air to ram fewer molecules. An aircraft can only be accelerated significantly by constantly climbing. High air is cold air. Cold air promotes transonic shock. Consequently the real maximum speed of high flying propliners is governed only by their ability to withstand cold. This is measured using Mach, not IAS (drag), or TAS (velocity).

If a propliner can tolerate a high Mach number it can fly colder. Consequently it can fly higher, and so can continue to accelerate for longer by climbing uphill for longer to a higher TAS (velocity) at constant IAS (profile drag) in ever thinner and colder air. The airliner that can climb highest, can accelerate for longest, and can go fastest. In any aircraft acceleration is all about climbing uphill for as long as possible. Concorde could climb (accelerate) continuously until TOD (Time of Descent), eventually reaching around FL600 and M2.02, but no propliner could reach anything like that altitude and thus could not reach anything like the 1138 KTAS which Concorde crews targeted at TOD.

Concorde could not have a tailplane at all!

Under normal operating conditions the L049 was increasingly likely to depart controlled flight if it exceeded M0.48. The L1049 was safe to M0.52. The L1649A was safe to M0.55. The L382 Hercules can sustain M0.56 in normal operation and by 1959 enough reality had leaked out of the skunk works that the L188 Electra could sustain M0.615. The real maximum velocities that could be attained by the aircraft above were in proportion to those maximum normal operating Mach numbers (Mno).

It was the failure of the Turbine Constellation, due to its critically weak tail, that drove the design goals for the Electra a decade after the Turbine Constellation was first mooted, and quickly abandoned as anything other than a research platform for studying the terrible problems of propliner flight in cold air.



BRITISH TECHNOLOGY LEAD

In Britain turbine engines had been around for longer and the related science was better understood. The BR10 Britannia which began route proving with BOAC in 1954 was good for Mach 0.57. The BR30 Britannia which entered commercial service with BOAC in 1957 was much stronger and good for Mach 0.6 whilst the VC9 Vanguard which entered commercial service with BEA in 1960 was a brute of a propliner strong enough to fly at M0.64 in normal use.


SOVIET TECHNOLOGY LEAD

During the classic era the Soviet Union were years ahead of everybody else in turbopropliner development. In 1961 they introduced the vastly superior Tupolev Tu-114 whose Mno exactly matched the contemporary British turbojet Comet 4C which could also tolerate M0.79 in normal use. All these aircraft could fly a little faster under carefully specified atypical circumstances, but by the mid 1960s only Soviet turbopropliners were truly competitive for long haul operations.

Piston engined propliners were dinosaurs by 1961. They could no longer compete in the long haul market and turbopropliners without swept wings and swept tailplanes would fare little better. They could neither minimise transonic drag, nor tolerate transonic drag. They would survive for a while in the medium haul market until they were overwhelmed there too by jetliners with turbofan engines and swept wings just a decade later.

Really high velocity (TAS) is only possible at low profile drag (IAS) in high, thin, cold air and that requires very high Mach tolerance. By the early 1960s the future for commercial propliners was confined to short hauling, only the military would go on using them to long haul due to their superior STOL performance which may be crucial during tactical deployments.




UNITED STATES SLOWLY CATCHES UP

To compete with European classic era turbopropliners like the Viscount and Friendship that captured all the relevant orders in the 1950s, conversion of old Convair airframes to turbine power and CV58 configuration using Allison 501 engines (designed for the Hercules) began in the mid sixties. The CV58 is a heavily pimped ride.

Although Pacific Airmotive did all that they could to strengthen the original Convair tailplane, it was still prone to fail at only M0.485. Consequently the CV58 achieves maximum safe velocity around FL200 when the air at the surface is at 15C. The air above FL200 is usually too cold for safe operation at the same velocity. We can easily climb a CV58 above FL200, but in most places it will be so cold up there that we will have to slow down or risk sudden death.

If we only ever fly over California we will enjoy warmer than average air. It is possible to fly a CV58 without worrying too much about the temperature over California, but we must not expect to survive if we take the same liberties over Alaska, (with real weather in use).


REALITY CHECK

The maximum safe level flight velocity (Vmax) of a complex aircraft is not a fixed number as books and magazines pretend. It is a complex variable. It depends where the aeroplane is and it depends on the weather. In warm places it is limited by drag, but in cold places it is limited by temperature. In a powerful propliner it is hardly ever limited by available power.

The higher we go the worse this problem gets, so pimped rides are trapped at altitudes where 'normal power' is 'abusive power' and they do therefore cruise nose down. In most places, in most weather patterns, if we climb a CV580 to its operational ceiling we are in danger of exceeding its safe drag limit because we are in danger of adding transonic drag (Mach) to the profile drag (IAS) displayed on the ASI.

The colder the outside air, the higher the risk becomes.

The CV340 it was converted from needs to have step climb managed as explained above, but the CV580 has so much extra power that it tends to be operated nose down at altitudes below its operational ceiling, in warmer air, where it has little risk of exceeding its transonic limit due to the addition of transonic shock.

If when simulating the operation of a CV-580 we exceed either its profile drag limit (Vno=260 KIAS) or its cold limit (Mno=M0.485) we will be overspeeding and the chances of structural failure rise swiftly. When we exceed either the normal profile drag operating limit (Vno), or the normal cold temperature operating limit (Mno), MSFS displays an overspeed warning and calculates our chances of survival second by second. Survival depends on whether we are turning, or pitching, both of which apply G to the structure. Most likely however it is a gust of wind from the weather model that will apply a fraction too much G and will cause structural failure as a result of our loss of control of the aircraft energy state.

Structural failure has almost nothing to do with velocity (TAS), but since we will perish if we apply abusive drag in pursuit of high velocity, or enter abusively cold air whilst accelerating for too long uphill in pursuit of high velocity, our velocity (TAS) will be limited realistically anyway provided we use realistic flight dynamics with both Vno and Mno limits encoded.


MONITORING Mno

By the time that the B377 Stratocruiser was submitted for certification it had finally dawned on U.S. regulatory authorities that commercial aircrew needed a means to predict structural failure, whether induced by excess profile drag, or by excess cold. The B377 was equipped with an ASI that not only provided very accurate drag readings in KIAS, but that also had a Mach bug to indicate when transonic shock (abusively cold air) might cause the aircraft to depart controlled flight and suffer structural failure soon after (Mach 0.52). When we simulate operation of the B377 we must pay careful attention to the Mach bug as well as the ASI needle else we may perish in abusively cold air.

The Mach bug provided on the B377 eventually developed into the ‘Barber Pole’ seen in the DC-7 or CV58 ASI which serves the same purpose. Both will converge with the ASI needle as soon as structural failure (for whatever reason) becomes an increasing probability. We must always keep a close eye on the barber pole within the ASI when flying such aircraft. We must never let the airspeed needle reach the barber pole, (or Mach bug), else MSFS will start to calculate our demise.

Powerful piston engined aircraft with low drag airframes like the L-1649A impose the same problems upon us even without using turbine engines and not all aircraft which impose this problem upon us have a barber pole to help us monitor Mno as the maximum safe profile drag (IAS) reduces with cold.

Almost all turbine powered aircraft have enough power to achieve structural failure in level flight. Some like the Fairchild built version of the Fokker Friendship known as the F-27A, equipped with very powerful engines to allow operation from short runways in the California, New Mexico and Nevada deserts, can achieve structural failure in level flight, even in really warm air. Because the F-27A will suffer structural failure at any temperature if we lose control of the energy state in the cruise, it needs neither a barber pole nor a Mach bug. Machmeters, Mach bugs and Barber Poles exist to warn us that we compromise safety by entering abusively cold air.

Consequently in the Fairchild F-27A Friendship handling notes we see;

***********************************
Max Cruise:

THROTTLE = 800 PPH/E
TGT < 760 C

NEVER EXCEED 224 KIAS

Note - Yields 264 KTAS @ FL160
****************************

The F-27A safety limit is always a profile drag limit of 224 KIAS and cold plays no part in the equation. No barber pole is required.



GETTING THE MAXIMUM FROM FLIGHT SIMULATION

Flight simulation is by far the best way to understand how aviation really works. Short of learning to fly real complex aircraft it is the only way to understand the dynamic nature of aviation; how one thing trades off against another, or how things are really limited and why. The numbers bandied about in books and magazines mean little in the real world. Some could be true under very peculiar circumstances, but many are just journalistic invention.

No variety of Constellation could have a Mach limit higher than the L-1649A whatever over powerful turboprop engines were installed. The only way for aviation enthusiasts to understand what aeroplanes can really do is to fly them in MSFS using realistic flight dynamics and matching handling notes. We must ensure we have the 'aircraft stress causes damage' realism option enabled else we will inhabit the poorly informed and imaginary world of journalists and magazine publishers where propliners can achieve warp speeds.


TURBOCHARGERS ARE DIFFERENT

The Boeing B377 Stratocruiser was a very unusual (and unsuccessful) airliner with turbocharged engines whose rated altitude was above the operational ceiling of the aircraft for most of the flight. That situation made management of the step climb particularly tricky and protracted. Handling notes and a separate set of handling hints specific to the Stratocruiser are incorporated within the relevant download.


EN ROUTE FLIGHT PLANNING IN DETAIL

We now know enough to study in detail the flight planning of any propliner en route cruise phase, but if you are uncertain about any of the topics already covered now would be a good time to go back and review them.

During flight simulation we must always combine and perform the roles of pilot flying and captain. Due to many deficiencies in the canned Microsoft ATC we must also be our own air traffic controller. We must do the necessary planning done by everyone wherever they are in the aviation infrastructure. The more modern the date, the greater the role of ATC in the planning and execution of the flight, but it hardly matters since Microsoft ATC is too dumb to plan correctly. We must do the ATC planning and then implement everything that they do in the real world too.

What we will not be doing in MSFS is playing navigator, unless we are simulating the vintage era when we will simulate the role of navigator using the GPS means already described. The fact that we will not be playing navigator in any other phase of aviation history makes flight planning much simpler than it would otherwise need to be.

This allows us to concentrate on what really matters which is navigation of the aircraft in 3D and 4D. Navigating the aircraft in 2D is very simple after the pioneer era. In the pioneer era 2D navigation was so difficult that there was no time for 3D or 4D planning or execution. In the vintage era 3D planning must take place. We must plan the flight at design cruising level when flying a Savoia Marchetti S.73 from Rome to Marseilles in 1939 or an Avro Lancastrian from the Azores to Bermuda in 1947. Once the external aviation infrastructure reaches the classic phase of aviation history we must plan in 4D not just 3D. Remember early US propliners like the Boeing 247D delivered from 1934 were designed and optimised for use in the classic era infrastructure which had been deployed from 1932 and was already in place over the CONUS.


PLANNED CRUISING LEVEL and TAS (WITHOUT PRESSURISATION)

There is no way that developers can provide all the tables necessary to predict operational ceiling for all weights, temperatures and air pressures. During pre flight planning we will always create our flight plan for a ‘default’ cruising level and nil wind.

Default, but not random.

We must consult the aircraftname_ref.txt handling notes to determine the flight level to use during pre-flight planning. For unpressurised aircraft we will use the highest level mentioned anywhere in the cruise stages of the handling notes. So for the Boeing 247D we would use FL120.

****************************
Max Cruise:
NEVER EXCEED 156 KIAS
RPM = 2000
MAP = 30 inches

Plan 75 USG per hour (2 x 440hp)
Mixture - lean as required
Note: Best cruise is full throttle & 2000 rpm at FL120 = 165 KTAS

Fast Cruise:
RPM = 1900
MAP = 28 inches
Plan 65 USG per hour (2 x 400hp)
Mixture - lean as required

Econ Cruise:
RPM = 1800
MAP = 25 inches
Plan 55 USG per hour (2 x 330hp)
Mixture - lean as required
****************************

The Boeing 247 dates from a time when aircraft design was only partly scientific and often mostly guesswork. Aircraft of that era were structurally weak even if they were powerful. Note the caution that we may rip the tail off if we ever allow profile drag to exceed 156 KIAS, even in level flight. Note that this is possible in level flight using only max cruise power!

Note however that we will be targeting (and therefore flight planning) a cruising velocity of 165 KTAS at FL120 where in the thin air the profile drag will always be less than 156 KIAS even at full throttle.

If that paragraph did not make much sense, or the drag limit, or target TAS, or the design cruising level were not evident from the handling notes then you need to go back and review the difference between drag (IAS) and velocity (TAS).

The Boeing 247D was unusual. It was designed to max cruise at medium level, so that UAL could obtain maximum advantage from the new massive tax subsidies that were being poured into the emerging U.S. federal airways system, but it could not max cruise at low level because its structure was too weak. This is still commonplace in general aviation aircraft, but soon became rare in propliners once the huge air mail subsidies of the original B247/B247A era had been withdrawn. By the classic era propliners everywhere were being designed to econ cruise at high level and max cruise at much lower levels.

We must always remember that max cruise and econ cruise are two power settings, not two drag values, or two velocity values, even if the ‘Boys Book of Wonderplanes’ gives the opposite impression by quoting often random examples of a cruising velocity that could theoretically be attained using one of those power settings.


PLANNED CRUISING LEVEL and TAS (WITH PRESSURISATION)

With pressurisation the default level and TAS to be used for pre flight planning becomes the level cited in the highest economical cruising level band. For the DC6B this will be FL220 and 258 KTAS.

****************************
Econ Cruise (FL155 and below):
COWL FLAPS - CLOSED
GEAR = LOW
MAP = 31
RPM = 2000
CHT < 232C
Plan 370 USG per hour
****************************

Econ Cruise (FL160 to FL225):
COWL FLAPS = CLOSED
GEAR = HIGH
MAP = 31
RPM = 1800
CHT < 232C
Plan 370 USG per hour
Note - yields 258 KTAS at FL220 @ 83000lbs
****************************

Accordingly we will use our flight planning utility to create a flight plan showing cruise at a default level of FL220 throughout the flight at 258 KTAS.

FL220 will normally be above our operational ceiling for many hours and we may climb a little higher by the end of the flight, probably with the power back to long range cruise, but we plan for FL220 at 258 KTAS even though that won’t be possible until weight reduces to 83,000lbs.

This tutorial explains how to simulate propliner operations using a flight simulator. Because we cannot obtain forecast winds aloft whilst using MSFS we will always plan for nil wind. By this means we make our planned speed (KTS) match our planned velocity (KTAS). This will make it very easy for us to monitor headwind component and to react correctly to varying headwind component. Before I explain that process in detail let me digress to discuss the concept of long range cruise.


LONG RANGE CRUISE - MAXIMISING RANGE

Let’s remind ourselves that this is a power setting not a velocity. The way an aircraft must be operated to maximise economy (profit) and the way it must be operated to maximise range are very different.

Under certain circumstances we may need to maximise range, not profit, throughout a flight, though usually only for propaganda purposes. From time to time we may wish to simulate a propaganda flight. We would then need to employ long range cruise power for as much of the flight as possible. Since that is very little power, it will greatly restrict our operational ceiling and the altitude we can reach, which in turn will greatly restrict the velocity we can accelerate to. During long range cruise we will be stranded in thick air at low velocity. If we attempt a propaganda flight we must plan accordingly.

Let’s see how that works in the L-049A Constellation.

****************************
Econ Cruise (about 980hp):

COWL FLAPS - CLOSED
MAP = 25 inches
RPM = 1800
Plan 2000 PPH
Yields 239 KTAS at FL250 at MCW
c28000lbs @ 2000 PPH = 14 hrs nominal

****************************
Max Range Cruise (about 700hp):

COWL FLAPS - CLOSED
MAP = 22 inches
RPM = 1600
Plan 1400 PPH

Yields 185 KTAS at FL150 at MCW
c28000lbs @ 1400 PPH = 20 hours nominal
****************************

During commercial operations we will target Econ cruise to minimise cost and maximise profit. During flight planning for an L049A we will create a plan with en route cruise entirely at FL250 and 239 KTAS even though FL250 may be above our operational ceiling for a protracted period.

However if we are tasked to make a long range propaganda flight we must apply far too little power to be efficient or profitable. We must strand the Constellation in thick air because we must use less power (fuel burn) to maximise range, but low power (fuel burn) cannot sustain efficient flight at high altitude in thin air.

We discovered in Part 1 of this tutorial that propliners have almost invariant range versus altitude, however range varies with profile drag. To achieve maximum range we must limit profile drag. To do that we must limit power, and when we limit power we cannot climb to high altitude.

To maximise range we will flight plan at FL150 and only 185 KTAS. We will never allow the Constellation to exceed either of those numbers and to do that we must restrain profile drag (IAS) to an extraordinarily low and efficient aerodynamic value that is nevertheless horribly inefficient and expensive in terms of the engine hours wasted over the distance. Flying a propliner economically is never about saving fuel. It is all about conserving engine hours.


FLIGHT PLANNING REQUIRES CHOICES

During flight simulation we must always be clear which aspect of the aircraft performance envelope we are attempting to maximise with our careful flight planning and subsequent targeting during execution of the plan.

The ‘Boys Book of Wonderplanes’ will report the maximum range and economical cruising velocity of L049A as though they were compatible, but we must grasp that it cannot possibly do both at the same time. They are incompatible targets. There is a correct combination of MAP and rpm to maximise efficient flight (econ cruise power) and a very different MAP and rpm to maximise range (long range cruise power). Very different cruising level, velocity, speed and drag must be *planned*.

We are the ones who have to plan it! Flight planning is about our intention. Before we begin simulation we must ask ourselves; ‘what do I intend to maximise during this simulated flight’? How we plan the flight and the numbers we must use in the plan depend on the answer to that question.

During either maritime patrol or combat air patrol operations we will most usually plan for maximum endurance, but during airliner operations we will most usually plan for maximum economy and profit. During certain types of military operation we might instead plan for corner drag at combat ceiling. If the handling notes were properly prepared they will contain the most relevant flight planning data.

No automated flight planning software can make that decision for us. We must answer that question and plan accordingly. We must extract the *correct* flight planning data from the on screen _ref.txt handling notes.


CERTIFICATION CEILING - CRUISE TECHNIQUE

During commercial flights we will never plan anything less than econ cruise criteria. However every propliner has a certification ceiling. If the aircraft is pressurised it is usually stated in the general section of the handling notes. So for the DC-6B;


****************************
General:
AEROBATICS are PROHIBITED
NEVER EXCEED FL250
DO NOT EXCEED Vno = 251 KIAS
Above FL170 DO NOT EXCEED Mno = 220 KIAS
AP in use never exceed 217 KIAS
FLAP 1 never exceed 174 KIAS
GEAR DOWN never exceed 174 KIAS
FULL FLAP never exceed 152 KIAS
CLEAN STALL 105 KIAS
Vmc 83 KIAS
STALL with FULL FLAP 81 KIAS
******************************

When we reach the certification ceiling of FL250 we must not climb any higher and we must not allow econ cruise power to pitch the aircraft nose down. Cruise pitch must be moderated with power.

We will target operational ceiling throughout the flight. Eventually however we will reach public transport certification ceiling and we must not step climb again even if the operational ceiling is higher. After achieving certification ceiling, if we reach zero pitch with any power applied then every few minutes we will trickle reduce rpm, to reduce thrust, to prevent nose down pitch. When this will happen will depend on current payload and current weather. On some flights it won’t happen at all. Some engines have rpm ranges that must be avoided in flight and must trickle reduce MAP instead.

This does not form part of the flight planning process. It does not need to. We simply plan (intend) to eventually sustain cruise at zero pitch at certification ceiling which will sustain the flight plan velocity (TAS).

It is never the FDE author who has to prevent aircraft cruising nose down. Pilots do that. During flight simulation we have to do that. We must initial climb, and then step climb, to operational ceiling, until operational ceiling equals certification ceiling, and then to prevent nose down cruise we have to moderate pitch by trickle reducing engine rpm or MAP.

Remember for some propliners, serving in some airlines, certification ceiling may be as low as FL80 at night and for unpressurised propliners it is generically FL120 by day plus any exceptions stated in the handling notes.


Continued in next post...

[Tom/CalClassic]

EN ROUTE FLIGHT PLANNING IN THE CLASSIC ERA

Deciding where in the tutorial to explain flight planning was not easy and in this revised tutorial I have decided to explain it in steps spread through the tutorial.

Flight planning was different, and needed to be different, in each phase of aviation history as aviation infrastructure slowly developed. Flight planning and associated dependent navigation techniques must therefore be explained aviation infrastructure phase by aviation infrastructure phase. We have already studied the process for pioneer and vintage phase flights in Part 2A of this tutorial.

There is probably no aspect of flight simulation that flight simulation users fail to grasp as badly as they fail to grasp en route flight planning and navigation in the classic phase of aviation history. Be prepared for your misconceptions to be severely challenged as you read on.

Flight planning for pioneer and vintage era navigation within MSFS can replicate the real process undertaken by the contemporary aircraft captain quite closely, but flight planning for the classic and modern eras cannot. In the real world classic and modern era navigation uses forecast winds aloft, leg by leg of the flight plan, at the flight planning stage. These are simply not available in MSFS. They may be present, but we have no practical means to extract them. If we could it would actually make our task more difficult. Real world techniques use them, but do not require them, so I don't think the compromises imposed on us by Microsoft matter much.

When intending to simulate classic or modern era en route navigation we *must* prepare a flight plan containing estimated times of arrival (ETAs) for every waypoint based on nil wind conditions. We must *print* that flight plan. During the flight we will compare each ETA to the actual time of arrival (ATA) over each beacon, intersection, or fix, and we will correct the times on the printed flight plan using a pen or pencil.


AERIAL NAVIGATION IS BASED ON TIME NOT DISTANCE

Aerial navigation is a 4D process. It revolves around time not distance. Most flight simulation users never come to terms with that and consequently involve themselves in all kinds of unnecessary complexity. Navigating a propliner within a classic or modern era aviation infrastructure is so simple that even pilots can do it. They must not play at navigator. They are not trained or qualified to play navigator. The trained and qualified navigators had to be banished from the airliner cockpit to achieve classic and modern era levels of air safety. The worst possible consequence of their banishment is for a real pilot or a flight simulation user to pretend that this was an error and begin playing at navigator.

RDF navigation was conducted by qualified wireless operators and qualified navigators who attempted to fly great circle tracks direct from departure to destination by plotting fixes on charts and maps whilst making impossibly difficult mathematical calculations, all too often leading to gross human error. The whole point of the classic phase of aviation was to make them, their maps, their complicated mathematics, their slide rules, and their 'drift computers' wholly redundant.

The classic and modern era cockpit has no wireless operator, no navigator, no maps, and no navigation paraphernalia. The classic phase of aviation was the one in which aircraft were navigated in 4D by mere pilots using nothing more than a text flight plan and a clock. They were and still are required to use instruments to fly directly from one radio beacon to another, following mandated radio beams (radials), leg by leg of the printed text flight plan.

Most flight simulation users confuse vintage era navigation with classic and modern era navigation. Consequently they fail to understand why there is no gauge that can tell them current KTAS (velocity), no gauge that can tell them current KTS (ground) speed. Most flight simulation users notice that the turn indicator is calibrated in minutes, and that the VSI is calibrated in minutes, and that the ASI is calibrated in hours, but for some reason suppose that all of this might be a ghastly error and that they must somehow calculate things like TAS or ground speed. We must not.

It's not a ghastly error. It's the whole point. In the classic and modern era cockpit aerial navigation is based on time not distance. The information that navigators craved is deliberately withheld and it is an error to seek it, calculate it, or use it. Its usage was always too complex. Its usage killed too many aircrew and too many passengers. When we are simulating the classic or modern eras of commercial aviation we must stop pretending that there is still a navigator in the cockpit and we must stop playing at navigator.

Let's pause briefly to remember that the Ford 4_AT-E Trimotor of 1929 belongs to the pioneer phase of aviation and was developed too early to have a navigator and conversely that the Douglas DC-3 of 1936 belongs to the classic era of aviation and was developed too late to have a navigator. California and the rest of the CONUS never had a vintage phase of aviation. It went from pioneer phase straight to classic phase. Of course vintage phase aviation sometimes originated from California, because it was trans oceanic and en route to Hawaii, or southbound into Central and South America. What goes for California goes for the rest of the CONUS. Nobody should be simulating flying commercial aircraft over the CONUS at any date whilst playing at navigator.


NO NAVIGATOR, NO MAPS, NO COMPLICATED MATHEMATICS.

In the classic and modern era cockpit there is no navigator and use of the complicated mathematics and maps associated with navigation is forbidden. The classic and modern era procedure is to update our *nil wind* flight plan leg by leg. If ABC to DEF was planned to take 20 minutes but takes 21 we have a headwind component. If it takes 19 we have a tailwind component. We measure that component in MINUTES or PER CENT, but never in degrees magnetic or knots.

When simulating the role of classic era pilots we must not pretend there was a navigator present in real life. Airline pilots were indoctrinated via the mandatory Instrument Rating to maintain a text flight plan, fly directly from one beacon to another, never to play at navigator, and always to follow published federally mandated procedures, step by step, and to the letter. Neither the employer, nor the employee was free to devise the procedures. Once the navigators had all been sacked, provided pilots didn't try to play at navigator, the result was a massive increase in safety.

In both the classic and modern phases of aviation any and all complicated mathematics were (and still are) done during planning on the ground; never in real time in the cockpit. The captain took as long as he needed to get the timings and planned levels on the flight plan 'correct' before boarding the aeroplane. In practice they might be prepared by an operations department or a computer and then checked and accepted by the captain. 2D navigation from one beacon to another, flight plan leg by flight plan leg, had become very simple and at last flying became safe. During the flight the captain monitors 3D navigation of the flight. In MSFS we must monitor operational ceiling as it varies through the flight, until certification ceiling is reached and not exceeded.

In the classic era, navigation of the aircraft in 3D is more demanding than navigating it in 2D. In real life it was often the flight engineer (if present) who studied the relevant tables and suggested to the captain that operational ceiling was now high enough to step climb another 2000 feet. In MSFS we must monitor the artificial horizon and respond to pitch variation instead. Under no circumstance is it necessary to know or calculate the velocity of the aircraft (TAS). Under no circumstance is it necessary to know or calculate the KTS (ground) speed of the aircraft. Under no circumstance is it necessary to know or calculate the position of the aircraft!


UPDATED ESTIMATES ARE THE KEY

However odd it may seem we are simply not required to know where we are in the classic era. It is irrelevant. ATC are allowed to ask us our estimate for anywhere on the text flight plan which we filed with them, and they approved after any amendment they required, and we are now updating with a pen, but if ATC ask us where we are we will answer as follows;

'N123MS is en route from ABC to DEF estimating DEF at time 1234'.

We must know where we are in the text flight plan in MINUTES. ATC need to know where we are in the text flight plan that they approved and issued clearance for in MINUTES. Nobody is using a map, nobody is interested in distances, nobody is interested in velocity (KTAS), and nobody is interested in KTS (ground) speed. They have been banished from aviation to create safety. Everybody in the entire infrastructure of aviation is looking at a simple text flight plan with times written on it.

Everybody is interested in TIME. That is why all the gauges in the cockpit relate to TIME.

Just like the 'paradox' that diving hard decelerates aircraft this is another 'paradox' that flight simulation users must come to terms with and practice. The en route flight planning and navigation of airliners ceased to be similar to the navigation and operation of terrestrial vehicles with the passing of the pioneer and vintage phases of aviation. By the classic phase, maps, velocities, speeds, and distances were not just banished; trying to calculate them was forbidden.

Stop trying!


TACAN and DME

About half way through the classic era when TACAN (co-located UOR+DME) became the principle means of navigating military and naval aircraft the commercial regulatory authorities relented somewhat. They allowed one specific circumstance under which a commercial pilot could take distance into account.

If the cockpit had a digital DME receiver and a pilot could *read* digital DME directly from it, (but under no circumstances ever had to *calculate* a velocity, a speed, or a distance), then the pilot was allowed to *read* a distance directly from a digital DME. DME still had very limited use and that could not possibly include anything relating to critical flight planning events such as time of descent (TOD).

Within FS9 we may assume that en route DME is available over the CONUS from 1955 onwards, but later elsewhere. If we are simulating a date before its local introduction we will include no airways fixes in our flight plan, (only airways beacons and airways intersections), and we will turn the DME receiver off.



PLANNING TIME OF DESCENT (TOD)

During classic and modern era navigation TOD is always a TIME never a distance. Even if the cockpit has DME, TOD can only be a TIME measured in minutes. There is no, feet per mile, gauge in a cockpit. There is only a VSI calibrated in feet per minute. This is not a ghastly error. We need to know only how many minutes we are from XYZ. We look at the text flight plan we have been updating and it tells us. We do not care how many miles we are from XYZ, we only care how many minutes.

We usually intend to descend any commercial piston engined aircraft at between 500 and 700 VSI but we ALWAYS *plan* TOD based on VSI = minus 500 feet per MINUTE.

Suppose we are cruising at FL200 and ATC instruct us to;

‘descend when ready to cross XYZ at FL100’

We must lose 10,000 feet. We always plan -500 VSI so TOD is 20 minutes before XYZ.

Most flight simulation users understand that TOD can be planned that way, but fail to understand that it MUST be planned that way. The reason that they fail to understand is because they are once again conditioned by experience of operating terrestrial vehicles and the way that they have always navigated terrestrial vehicles. Classic and modern era airline pilots are not allowed to play at navigator. They are not allowed to do time and distance calculations. Let’s try to understand why it was always both a total waste of time and dangerous anyway.

Suppose we are cruising at 240 KTAS and there is no wind. We must descend 20 minutes * 4 miles per minute = 80 miles before XYX. Now suppose there is a 60 knot headwind component. Now we must descend 20 * 3 = 60 miles before XYZ. Now suppose that there is a 60 knot tailwind component. Now we must descend 20 * 5 = 100 miles before XYZ.

Now grasp that we, whether trained pilot, or trained navigator, can only guess the average wind vector between FL200 and FL100 on this leg anyway and that there is no earthly reason to try. We have to descend 20 MINUTES before XYZ with any headwind, any tailwind, any crosswind or no wind at all. We have to do this in a Cessna, a DC3, or a DC7C.

Planning time of descent (TOD) could not be simpler. The simplest solution is the only solution that is always correct and never dangerous.

The whole point about the classic and modern eras of commercial aviation is that nobody gets to play at navigator, nobody gets to guess the wind wrongly, nobody gets to calculate the mathematics wrongly and we will never fail to reach FL100 at XYZ. Now grasp that ATC know when we are 20 or 22 minutes short of XYZ too, even if they have no radar, and they have even less clue what the wind is doing where we are. They don't care. They don't need to care. That is what the classic era of aviation was all about. Fail safe procedures that did not require anybody, anywhere in the aviation infrastructure loop, to play at navigator. Not even a little bit.

Most flight simulation users just don't get it and try to play navigator. Even the real navigators couldn't play navigator well enough to be safe. They and their procedures had to be banished. We must not pretend that we can do better than the real navigators. We must not pretend that one was present if none was present. In the classic and modern era pilots update and follow text flight plans minute by minute whilst following federal published procedures minute by minute and step by step. They don’t play navigator.

I will return to this subject in more detail later in the tutorial. First let it sink in that in the classic and modern eras of commercial aviation there is no navigator, no map, and no navigation calculations are going on at all. We don't ever need to know where we are, what our cruising velocity (TAS) is, what our (ground) speed (KTS) is. We don't care, and ATC don't care.

We and they only need to know *when the aircraft will be somewhere else* that we specified on our flight plan and they approved before departure. That information is on the text flight plan that we and ATC are both updating with a pen. Maps and navigation are not involved. Time and time again humans had proved that they simply could not cope with maps and navigation at aircraft velocities as the wind varied rapidly with place and altitude. Navigators and navigation were banished from commercial aviation at the end of the vintage era. When using flight simulators we must stop pretending otherwise.

No prepared flight plans are included in the tutorial. It is important that you experiment with creating the paperwork yourself using your preferred planner, whether freeware or payware. You will need to amend it by hand after printing anyway. Let's begin to examine how we use the printed text flight plan in detail.


REAL WEATHER INTERACTION WITH THE NIL WIND EN ROUTE FLIGHT PLAN

The preceding section of the tutorial has introduced in a simple way the most important difference between terrestrial and aerial navigation. The all important difference is the relevance of the wind vector during aerial navigation. It has the potential to make aerial navigation so complex that it becomes beyond human proficiency. We must grasp that it actually did. Then we must grasp what the solution was, and we must not pretend that there was no solution.

I cannot emphasise too strongly how important it is to let go of all the misconceptions you may have about the role of TAS and ground speed and distances in classic and modern era propliner navigation.

They are irrelevant.

They are rendered irrelevant by design; to be precise by cockpit design. All the gauges relate to TIME, not velocity, not distance, not ground speed and it is NOT a mistake. It is the solution. If you decide to fight the solution you will have both a miserable and an unrealistic experience during flight simulation. You will be overwhelmed by workload and will end up flying make believe procedures instead of real ones.

It is time to examine in detail how the wind vector is taken into account in the classic and modern era cockpit.


CROSSWINDS BECOME IRRELEVANT - ATC BECOME RELEVANT

Flying the beams made crosswinds irrelevant. If there had only ever been one aeroplane tracking a beam to a given radio beacon they would have made headwinds and tailwinds irrelevant too. But of course there was soon more than one aircraft flying the same beam or tracking to the same radio beacon along a different beam.

Aircraft now had to report estimates to ATC so that ATC could order aircraft to change level, or stop climb and descent due to conflictions with other traffic. This was all based on TIME not position or distance.

This is where flight simulation users become very confused. They become confused because they don’t prepare and use flight plans. They fail to create the real world classic and modern era solution and so they start to play navigator, decades after navigators had been banished. Nobody played at navigator in a classic era cockpit or in a classic era air traffic control facility. They used time based flight plans and nothing but time based flight plans to control and operate the aircraft.

Nobody gives a hoot about velocity, speed, wind direction and strength, drift or any other navigator nonsense. Everybody in the entire classic era infrastructure is just updating the estimates for each waypoint on a text flight plan whilst the pilots use needles to follow beams from waypoint to waypoint.

Now suppose the first cruising leg of our DC-6B flight is from ABC to DEF and on our nil wind flight plan it is estimated to take 20 minutes at 242 KTAS at FL220. Obviously we are nowhere near that high or that fast yet. Obviously it will be wrong!

It doesn’t matter!

Suppose our plan shows us crossing ABC at 1030 and DEF at 1050.

Suppose we do cross ABC at 1030. On each leg we simply compare the estimated time for the leg to the actual time taken to fly the leg. If it was planned to take 20 minutes and took 22 then we were 10% slower than planned.

If the next leg is to GHI and is planned to take 18 minutes we add 10% rounded up, which is two minutes. We note that we are already two minutes late passing DEF so we make our estimate for GHI 4 minutes later than on the original plan, then we make our position report to ATC.

(London) Airways N1234MS FL160 DEF 1052 estimate GHI 1112.

The airways controller updates her flight plan (flight progress strip) accordingly. She tells her assistant to pass the revised estimate to the next airways sector or the next air traffic control facility on the flight plan. Everybody knows when N1234MS will be over GHI and nobody cares where it is now, what its velocity (KTAS) is, or what its ground speed (KTS) is.

The really important thing to understand is that nobody gives a hoot why N1234MS was late at DEF. The crew may have applied the wrong power setting, delivering the wrong KIAS, they may have wandered back and forth across the radio beam, they may be in thicker air than the default flight plan assumption and at less than filed velocity (KTAS), or they may have encountered a headwind component which has reduced their (ground) speed (KTS), but not their cruising velocity (KTAS).

Nobody cares! Nobody plays navigator to calculate it. Nobody. There is no navigator. Nobody is using a map. Nobody is doing calculations more complicated than adding 10% to 18 and adding 4 minutes to 1108. Everybody is just altering times on a line by line text flight plan based on how many minutes the last leg actually took. The aircraft is being navigated and controlled using some lines of text and a clock, not a map.

The airways controller does her own calculation exactly the same way to see if she agrees the estimate given by the crew of N1234MS. If she doesn’t agree she challenges it. Eventually everybody agrees when N1234MS is likely to cross GHI. Nobody cares where N1234MS is now or what wind component may be affecting it. Everybody could calculate its KTS (ground) speed but nobody has any reason to. Nobody knows its velocity (KTAS) and nobody cares.

At 1053 N1234MS reaches zero pitch. The captain requests a step climb from FL160 to FL180.

The airways controller must separate N1234MS from every other aircraft routing via GHI. As it happens a Stratocruiser is on the airway that crosses GHI roughly at right angles and estimates crossing GHI at 1110 at FL170. Nobody cares what its speed, drag or wind vector is either. All the navigation decisions relate to TIME. Aerial navigation is a 4D process and the decisions concerning 2D route, 3D flight level and 4D timing of altitude changes are all made by ATC not aircrew. They are all made using a text flight plan and a clock. No maps or navigators are involved; on the ground or in the air.

During the classic era international law (known as the Chicago Convention) requires the request to climb through the Stratocruiser’s cruising level to be denied if there is less than ten minutes between the two estimates for GHI. Why there might be less than ten minutes is irrelevant.

At 1054 the airways controller responds; ‘N1234MS climb immediately FL180’.

International law requires all climbs and descents mandated by ATC to be conducted at not less than 500 VSI. The controller allows the crew of N1234 one minute to vacate FL160 and 4 minutes to reach FL180. Separation will be restored by 1059 and the Stratocruiser estimates GHI at 1110.

Nobody cares what distance apart the DC6B and the B377 are, nobody cares what their velocity, drag, speed and wind vector may be. Nobody. If they were both slow DC3s they would be the same number of minutes apart and a lot fewer miles apart. Nobody cares. In classic era aerial navigation distance, speed and drift are all irrelevant. Nobody is trying to calculate them. Nobody is getting it wrong. Stop trying to discover or calculate these things. By the classic era they were irrelevant. That is the whole point of classic era aviation.

In the classic era, the aircrew and ATC care whether aeroplanes are running early or late compared to the flight plan approved by ATC and for which ATC clearance was issued. ATC restrict aircraft cruising levels or force them to change level accordingly. Nobody cares why they are early or late. Nobody is interested in distance or speed. Everybody is navigating in 4D using a clock.

So does that mean that if we are running late compared to the flight plan we do nothing to get back on time?

Certainly not!

We will endeavour to get back on time if we are running ‘significantly’ late. What we won’t ever do in a classic or modern era aviation environment is play at navigator to resolve the problem.

It’s time to examine in detail what we must do instead and what we mean by ‘significant’.


CLASSIC ERA EN ROUTE NAVIGATION


Right at the start of the Propliner Tutorial we came to terms with the difference between velocity (KTAS) and profile drag (KIAS). Now we must come to terms with the difference between velocity (KTAS) and speed (KTS).

Our nil wind flight plan sets velocity (KTAS) equal to ground speed (KTS), but whether in real life, or within a simulator with real weather in use, velocity and ground speed will hardly ever be equal because there will hardly ever be no wind at all.

In real life we would obtain forecast winds aloft and plan accordingly. In MSFS we cannot. We must adopt a reactive solution, not a planned solution. Before we can do that we need to remind ourselves how the mathematics of both speed and velocity work, not just for aeroplanes in flight simulators, but for everything in the real universe.


TIME MATTERS - DISTANCE DOESN’T

Suppose we fly from A to B and back again, suppose the distance is 180 miles each way, and we fly at a velocity of 180 KTAS, in both directions. If there is no wind it takes 2 hours (120 minutes). If the wind is blowing directly from A to B at 60 knots it may seem that it will average out on the two legs of equal distance, but it won't.

Now we fly 180 miles from A to B at a velocity of 180 KTAS and a speed 240 KTS taking 45 minutes. Then we fly 180 miles from B to A at a velocity of 180 KTAS and a speed of 120 KTS taking 90 minutes. Now the round trip takes 135 minutes and we burn 12.5% more fuel even though we had exactly the same 60 knot wind fore and against over the same distance each way.

Distance is never, ever the point. Distance is irrelevant. What matters in aerial navigation (and therefore propliner flight planning and execution) is *TIME*.

During the flight above conducted entirely at a velocity of 180 KTAS we had a 60 KTS headwind for 90 minutes and a 60 KTS tailwind for only 45 minutes. That was an incompetent captaincy choice!

As a propliner captain we must maximise the *time* we fly with tailwinds and minimise the *time* we fly with headwinds. It is essential to grasp that this is a captaincy choice. Although we can do nothing about the distance that we suffer a headwind, we can, and must choose carefully how much time we suffer that headwind. It is a captaincy decision. Learning to make the correct captaincy decisions is what flight simulation is all about. We must understand the decision making cycle and we must get involved in the decision making cycle.

When we have a ‘significant’ headwind component we must increase power to the next higher cruise power setting to minimise the *time* we suffer that 'significant' headwind. In the DC-6B that would be high speed cruise.

****************************
High Weight/Speed Cruise: (1100hp x 4)
COWL FLAPS = CLOSED
MAP = 34 inches
RPM = 2100
Check CHT < 232C
Plan 2100 PPH
@ zero pitch climb 2000 ft & 500 VSI
Note - yields 251 KTAS at FL210 @ 89000lbs
****************************

With a significant headwind we increase from 4 x 1000hp (economical cruise power) to 4 x 1100hp (high speed cruise power) and we do not exceed FL210. The R-2800-CB16 series engines cannot produce fast cruise power above FL210. With a tailwind, or no significant headwind (the normal situation) we apply econ cruise power. We apply the higher power with a significant headwind to minimise the TIME we suffer the headwind.

If we have a ‘very significant’ = ‘severe’ headwind we will increase by two power settings and so we will use max cruise power (4 x 1200hp). In that case we must not exceed FL190 to develop 36 inches MAP at 2200 rpm. However if the CHT creeps above 232C we must reduce power back to fast cruise. That will depend on where we are over the planet and the weather today. Note that we must crack the cowls open and add drag to max cruise anyway. Max cruise is very uneconomical and is only used to battle headwinds.

****************************
Max Cruise: (1200hp x 4)
Use only to battle headwinds
Above FL170 DO NOT EXCEED Mno = 220 KIAS
COWL FLAPS = 1 degree
MAP = 36 inches
RPM = 2200
Check CHT < 232C
Plan 2350 PPH
Note: Yields 251 KTAS @ FL190 @ 89000lbs
****************************

The real world calculations are similar, but more complex, and are dealt with in aerial navigation textbooks. The above is what we must do in MSFS. We must make reactive captaincy decisions concerning applied power based on perceived headwind component. We perceive the headwind component using our text flight plan (or a CalClassic Notepad) comparing Estimated Time of Arrival (ETA) to Actual Time of Arrival (ATA).

Nothing more and nothing less.

Leg by Leg.

Depending on the perceived headwind on the last leg of our text flight plan we enter the decision making cycle. We may need to alter our 3D navigation (descend) and we may need to alter our 4D navigation (increase fuel burn to reduce TIME exposure to the perceived headwind). In the classic phase of aviation history 2D navigation is incredibly simple. We just centre a needle. The challenge is appropriate 3D and 4D navigation. In the classic phase of aviation history the en route decision making cycle is all about altitude and power applied, not heading, or course, or drift, or speed, or velocity, or anything else except terrain and fatal icing which must always be avoided.

These were not new ideas. Commercial sailing vessels had always avoided currents and tides moving in the wrong direction and they had always increased or reduced sail (power applied) according to the wind. The navigation of sailing vessels had never been entirely 2D either, but the big difference in aeroplanes is the ability to navigate in 3D. The propliner en route captaincy decision making cycle has very little to do with 2D navigation. It is all about deciding the correct altitude for the next leg and the correct power to deploy to combat or ride the wind at that prospective new altitude.


PERCEIVED HEADWIND COMPONENT

Whether in real life or in a simulator we have no way to know for sure what our velocity is in an aeroplane. The ASI only tells us our profile drag (KIAS), not our velocity (KTAS) or our speed (KTS). We could estimate our velocity, we could try to calculate our speed from that estimate, we can miscalculate our position, and we can crash our BSAA Lancastrian into a glacier on the wrong side of the Andes. Or we can crash our Martin M-130 into a mountain in California, but in the classic era we won’t do any of those things. Thankfully they are now forbidden.

In the classic and modern eras we will only react to the text flight plan. We will only react to a ‘significant’ difference between ETA and ATA, leg by leg.

Our DC6B flight plan assumes our velocity is 242 KTAS, but until we reach FL220 it will be less because we are in thick air ramming too many air molecules to reach that velocity. Our velocity will be less than, but slowly and steadily approaching 242 KTAS as fuel diminishes hour after weary hour. Even in nil wind we will therefore run a little late on each leg until we reach FL220. We expect that and we will not react to it other than to revise each and every forward estimate on the text flight plan with a pen. In real life we would pass (only the next) revised estimate to ATC. We must however define the ‘significant’ lateness to which we will react with a change of applied power.

During flight simulation we will define that as 15% late *leg by leg*.

If a leg that was planned to take 20 minutes takes 23 we are significantly late. We will react as though we had a significant headwind. We 'perceive' a headwind. If we are below FL220 at the time we know that a small part of the lateness was because our velocity was deficient in thick air, but there is no way that whilst cruising a DC6B our velocity was below 85% of 242 KTAS = 206 KTAS. If we ran 15% late on that leg we had a headwind and we must forecast a similar headwind on the next leg. We don’t know exactly how bad the headwind is we just define it as significant because (in combination with whatever and however many other factors) it caused 15% lateness and we react by calling for high speed cruise power if we are light (<89,000lbs) or calling for max cruise power if we are heavy (>89,000lbs). When we encounter a significant perceived headwind we increase but one cruise power setting form the one that was correct fro nil wind cruising.

Whilst our weight is above 89,000lbs we will not exceed FL190 whilst we are running ‘significantly’ late because a DC-6B cannot create max cruise power above FL190. We must be running ‘significantly’ late because a headwind component is reducing our speed (KTS) to be significantly less than out velocity (KTAS). We could increase velocity (KTAS) by climbing above FL190, but the chances are that the headwind will get stronger the higher we climb. The chances are that we would lose speed (KTS) faster than we would gain velocity (KTAS).

We must minimise the TIME we are exposed to the perceived headwind, so we will apply more power and fly lower than usual (below our operational ceiling) if we ‘perceive’ a *significant* headwind.

We perceive and react to a significant headwind if a leg takes 15% longer than planned. Obviously this means that we must have a text flight plan to react to. We will react with a request to ATC for descent below FL195 (if we are above FL195) and we will apply max cruise power. We will engage in 4D navigation.

Some flights may have several short legs. If so we must aggregate enough prior legs to compare ETA to ATA over more than 10 minutes and preferably more than 20. If the last four legs were planned to take 22 minutes in aggregate but actually took 26 then we have picked up a significant headwind and we must react. We must call for one higher power setting and may need to descend to achieve that higher power setting. If we advanced to high speed cruise power during the last decision making cycle and we were 15% late again we must advance to max cruise now. If we run 15% late using fast cruise power in aircraft which have that power setting we will define the headwind as 'severe' for that aircraft type and we will advance to max cruise power. This will require further descent to generate the MAP associated with the higher power setting we now require.

If we encounter weather in which the ‘perceived headwind’ reaches 30% in any aeroplane we must treat that as ‘severe’ immediately. If two extra stages of power are available we must apply them immediately. In a light DC6B we would go from econ power straight to max cruise power if a leg, or several legs, planned to take 20 minutes actually took 26, (or more).

We might need to descend even lower to generate the 36 inches MAP target associated with max cruise, and we would. We must become our own airways air traffic controller and issue ourselves with the necessary clearance. When we do this we must always remember that we must cruise at an odd level when our course is eastbound and an even level when our course is westbound. All such changes of altitude will be changes of at least 2000 feet. If he had descended to FL180 to fast cruise westbound we may now need to descend to FL160 (or even lower) to max cruise. Of course we must never descend into terrain to minimise exposure to headwinds.

By putting ourselves through the captaincy decision making cycle about every 20 minutes we deliver realism to ourselves. The job of the FD author is only to encode what real MAP and rpm deliver what power and up to what altitude. It is the flight simulation user who must work hard to extract the embedded realism. This is only possible by using a text flight plan, calculated for nil wind conditions and then reacting dynamically in 4D to the perceived headwind. Leg by leg.

The CalClassic notepads can now do some of the calculations for us, but of course they are not available fro all propliners.


SEMI CIRCULAR EN ROUTE CRUISING LEVELS ARE MANDATORY

We may of course need to make those changes for individual legs of a northbound flight plan when one leg is actually 355 and the next is 005. As we approach the leg whose flight plan track is 005 we must either climb or descend from an even level to an odd level.

That is another captaincy decision that we must make every so often whilst en route regardless of en route wind vectors. We will take the rest of the weather into account of course. Climbing would increase our velocity, but if that means entering turbulent cloud, or cloud below freezing temperatures where we may pick up significant ice, but descending would avoid entering that cloud, we would probably choose to descend a thousand feet instead. If we make the wrong choice we must admit it and ask ATC (ourselves) for re-clearance to a different semi circular level based on the *flight plan track* of the individual leg (never our heading).

Our heading will be whatever the wind requires it to be to track the radio beam we are following with a needle. We don’t attempt to calculate drift or headings. We just centre the VOR needle, or we may decide to track just right of flight plan to track in the twilight zone as explained earlier.


REACTION TO NO SIGNIFICANT HEADWIND OR A TAILWIND

Later during the same flight we notice that a leg (or legs) planned to take 20 minutes only took 19. Now we must react in the opposite way. We must seek a higher cruising level and we may reduce to one lesser stage of power from whatever we currently have applied. We never want our speed to exceed planned speed. We are being paid not only to reduce the TIME that our propliner suffers headwinds, we are also being paid to maximise the TIME it rides tailwinds. When we encounter a tailwind we climb in the hope of finding an even stronger tailwind at a higher semi circular cruising level and then we reduce power to enjoy the tailwind for as many minutes as possible.

This power reduction might potentially be a reduction from econ cruise power to long range cruise power. In some handling notes there will be an injunction against using LRC power until the weight is below a specified value or the fuel state is less than a specified percent.

In real life we discover these values by asking whichever crew member we appointed as Flight Engineer, (often this will be Pilot Not Flying = PNF), what they are. In MSFS we need to open the fuel and payload menu to obtain the answer or consult a CalClassic notepad.

The intention is, over the lifetime of the airliner, to maximise the time with a tailwind and minimise the time with a headwind. Over the long run it improves economy of operation and when simulating airline operations in propliners that is a major part of the 4D navigation process. If we always cruised at the same power setting we would spend more time flying with headwinds than with tailwinds. That would be very bad captaincy.

Real world aerial navigation is not a 2D process. It is very much a 4D process. The vast majority of the navigation task is the captaincy required to manage (reactively) the vertical profile of the flight and applied power versus perceived headwind. Simply planning and following the 2D course should be a tiny fraction of our navigation workload.


THE RANGE PARADOX

Obviously reducing fuel flow maximises endurance, but endurance and range (or combat radius), are chalk and cheese. The difference is life and death. As explained above when we have a headwind we must increase range by *increasing* fuel burn. This paradox can be very difficult for those used to operating terrestrial vehicles to grasp.

In a DC6B with a headwind we must increase from econ cruise power to fast cruise power; From 370 USG/hr to 400 USG/hr. With a severe headwind we must employ max cruise power burning 435 USG/hr. We must do this even if it pitches the aircraft nose down and even though it increases profile drag. The only caveat is that we will not exceed either Vno or Mno. We have already discovered that flying high in cold air imposes a lower maximum IAS due to the addition of transonic drag and the possibility of transonic shock. This is another reason that we descend when we must battle a headwind.

Flying into a headwind, every increase in fuel burn will increase our range.

If increasing fuel burn to increase range still seems counter intuitive due to expectations based on the operation of terrestrial vehicles then think very hard about the following example.

Consider a Cessna flying 50 miles from A to B in econ cruise power at a velocity of 100 KTAS into a headwind of 90 KTS. Suppose econ cruise power burns 10 USG/hr and the aircraft has 50 USG fuel aboard.

By now we all understand that the Cessna will take 5 hours to fly 50 miles at a speed of 10 KTS and a velocity of 100 KTAS.

After 5 hours employing econ cruise power it will run out of fuel. Its endurance in econ cruise power is 5 hours and its range is 50 miles.

If however we increase fuel burn by a third to 13.33 USG/hr we should be able to get a velocity of 110 KTAS out of this Cessna. Endurance plummets from 5 hours to 3.75 hours, but we will fly those 50 miles in half the time (2.5 hours).

At 10 GPH we get 5 hours at a speed of 10 KTS = 50 miles range.

At 13.33 GPH we get 3.75 hours at a speed of 20 KTS = 75 miles range.

Increasing fuel burn by 33% increased our speed by 100% and our range by 50% even though our velocity rose only 10% and our endurance fell by 33%.

Think very hard about the difference between aircraft velocity (KTAS), aircraft speed (KTS), and aircraft drag (KIAS). When using a flight simulator we must always think very hard about which needs to be maximised, and how we can do that. We must never fail to grasp the difference between velocity (KTAS) and speed (KTS) when using a flight simulator, nor may we confuse our profile drag displayed on the ASI (KIAS) with our velocity or speed.

Now work out what happens to our range if we reduce fuel burn and reduce our speed to 90 knots to ‘save some fuel’ and increase the endurance of this Cessna in this weather!!!

Endurance is only of consequence if we are in a holding pattern and trying hard to travel precisely nowhere. Only then, when desired range = zero, do we operate an aircraft to maximise endurance. In a holding pattern we target a profile drag (KIAS) to minimise fuel burn.

In propliner flight operations the range advantage of increasing power (fuel burn) into a headwind is less stark, but just as real. Reducing fuel burn with a headwind is quite likely to be fatal in real life.

We must always create a flight plan. We must always calculate the fuel required for a given trip. That fuel load will always include a headwind reserve, a holding reserve and a diversion reserve. Detailed guidance will be provided in Part 6 of this tutorial. If despite careful flight planning we are ever worried that we might not have enough fuel to reach destination we can only increase our chances of having enough fuel to reach destination by increasing the rate at which we burn the fuel. If that is not obvious yet you need to reread the preceding paragraphs until it is obvious.

Aerial navigation isn't at all about planning and following a 2D course. It's all about 4D (space and time) flight management. Anyone who intends to use real weather in a flight simulator absolutely needs to understand the 4D nature of aerial navigation. Without such knowledge it is very unwise to import real weather. Almost any expectation about aircraft operation based on experience of using terrestrial vehicles is going to be wrong. They just don't work the same way at all.

We are still some way short of knowing what we need to know before we can plan and execute the en route phase of a flight in a propliner, but greater detail must wait until we have examined how the en route phase transitions into the arrival phase. Before we move on to study the arrival phase though I intend to conclude examination of the en route phase with an explanation of the gradual transition of the third (classic) phase of aviation history into the fourth phase which we still call the modern phase.


CLASSIC PHASE = PROCEDURAL AIR TRAFFIC CONTROL

The point source infrastructure maximised airline safety because it allowed the publication of mandatory federal procedures for departure, cruise, arrival and approach using very precise timings in a 4D navigation environment. Those ATC procedures had to be followed to the letter, minute by minute, and step by step. The classic phase of aviation was a 'procedural' phase. Pilots followed needles and flight plans. They did not use maps.

What brought it to an end was Radio Direction finding And Ranging (RADAR).


RDF VECTORING GIVES WAY TO TRANSPONDER VECTORING


During the 1930s Britain replaced the HF squeakers in its fighter aircraft. They had allowed triangulation with pieces of string drawn tight across the RAF sector control plotting tables that were still in use a decade later in the Battle of Britain. With their location thus disclosed RAF fighters could be vectored to a target or back to base using radio telephony, or in the case of larger aircraft wireless telegraphy, whether or not the aircrew could see the scenery below or the sun and stars above.

The new British invention was called Identification Friend or Foe (IFF) at the time, but would later be called a transponder. IFF could squawk instead of just squeaking. A squeak provides a bearing to the ground or ship based controller, but a squawk provides a fix. A radar fix derived from a co-operating aircraft that is sending the information using a transponder (IFF) is a ‘secondary radar’ fix.


THE TRANSPONDER IS MARGINALISED

Within a year of developing transponders that could squawk as well as squeak, Britain developed primary radar good enough to detect a non co-operating 40 foot aircraft at 80 miles rather than a 400 foot warship at 40 miles or an iceberg at three miles in fog which had been the original design purpose of radar following the loss of the Titanic in 1912.

Once Britain had primary radar good enough to detect uncooperative aircraft, British air traffic controllers and fighter controllers started to use it instead of RDF to vector all kinds of aircraft, not just those that could squeak or squawk.

The transponder became a means to identify a particular aircraft, within a clutter of aircraft, but was no longer the primary means of detecting it, fixing its position, or vectoring it.


DANGERS OF POINT SOURCE NAVIGATION IN WARTIME

The arrival, approach and departure procedures described in parts 3 and 4 of this tutorial pre date WW2. The problem was that they relied on continuous transmissions from radio beacons that the enemy could also utilise for navigation. The enemy could not use data from an allied radar screen in an allied operations centre, on land, or at sea.

By 1945 RAF, USAAF, RN and USN air traffic controllers were talking aircraft down through a Ground Controlled Approach (GCA) using surveillance (primary) radar to control the approach (SRA). This allowed missions in weather four times worse than an RDF talkdown (QGH). By the end of WW2 the United States had developed the means to talk aircraft down to a blind landing using Precision Approach Radar (PAR).

Air traffic controllers based at airfields soon started to use radar to expedite aircraft departures and arrivals as well as approaches. Landings in fog could be spaced so close together that there was no time to depart an aircraft between the landings. There was suddenly a reason to build parallel runways at new post war airports like Heathrow. Expedition in these circumstances saved fuel as well as time. Taxpayers around the world were forced to stump up for a whole new tier of aviation infrastructure at airfields, but at different dates in different places.

With the war over new varieties of old pre war systems proliferated. VHF Omni Ranges (VORs) generating 360 radials replaced Radio Ranges generating only four radials, but it hardly mattered. No one had ever used more than two (defining an intersection) anyway. The post war VOR receiver hardly differs from the pre war US Army Signal Corps Receiver (SCR). It just receives and displays signals generated in a different radio waveband. We use them just the same.


EN ROUTE RADAR

For a long time however little use was made of radar to intervene in the climb, cruise or descent phases of airline flights being controlled from Air Traffic Control Centres (ATCCs). As I have explained elsewhere in this tutorial the range of a piston engined aircraft does not depend on its altitude. No fuel is saved by expediting the climb or descent of a piston engined aircraft in those phases. No one was willing to pay.

Then jets came into military and commercial service. The range of a jet aeroplane is doubled at 41,000 feet. The fuel consumption is halved. If a jetliner is not expedited up and down by vigorous ATC radar intervention it runs out of fuel and crashes (or hopefully diverts for fuel). So now the ATC system needed enough en route radar controllers to expedite just the jets. New Jet routes (known as Upper Air Routes (UARS) or J routes) were introduced. ATC airspace was re-sectorised to favour jets.

But jets were a small part of the mix until the low bypass ratio turbofan engine made its way into commercial service in the Tupolev 124 in 1962, the Boeing 727 in 1963 and the DH121 Trident in 1964. These turbofan engines were typically 25% more economical than the turbojet engines used until the early sixties and could make very substantial profits, but only with enough ATC radar controller expedition. Then in 1970 the first high bypass turbofan engine came into commercial service in the Boeing 747 and demand for jet flying mushroomed as costs and ticket prices fell whilst trip times were reduced. Win - win for the consumer.


PROCEDURAL ATC GIVES WAY TO RADAR BASED ATC

In some parts of the developed world most of the ATC movements were soon jet movements and en route ATC needed to move away from a procedural system with occasional intervention by radar controllers to expedite jets to a system in which all control was Radar Control with procedural back up at reduced flow rates if the radar failed or when it needed maintenance.


ATC COMPUTERS ARE ADDED

Meanwhile the USN had been shooting at the USAF and the USAF had been shooting at the USN over North Vietnam more often than the North Vietnamese managed to shoot convincingly at either. The many different American command and control systems needed to be uplinked, downlinked, computerised and co-located to stop the potential carnage.

IBM managed to run 3 x IBM 360 computers in triple redundancy to create an IBM 9020 computer that could do the job. As it happened it was just about ideal (by the standards of the day) to become the basis of en route 'Radar Control' in both the US and the UK at exactly the time they both had enough jetliners to really need to make the change to an aviation environment that became ever more reliant on expensive infrastructure outside the cockpit of the aeroplane.

So the next phase which we still call the modern/current phase/era is one in which airline pilots flying over the developed world no longer expect to fly the classic era procedures unless the radar is off. They expect to be radar vectored in just about every phase of the flight instead, but everyone still has to be able to revert to using the 'procedural' classic era infrastructure at the drop of a hat. Consequently the late classic era procedures are still available for free download. Any real airline pilot and any real air traffic controller may need to invoke them today.


AIRCREW ERRORS

During the vintage phase of aviation infrastructure, which lasted into the 1970s even at lesser locations in the developed world, procedures were made up by aircraft captains on the spur of the moment, all too often with fatal consequences.

Even during the classic and modern phases of aviation many (fatal) accidents have been caused by airline captains deciding that they could conduct the flight by visual reference to the scenery and then failing. They rejected the published procedures and they rejected radar control. Some jurisdictions still allow that. As a consequence sometimes aircrew fly into mountains. Sometimes they collide with other aircraft. Some crash into terrain short of the runway. Sometimes they just land on the wrong runway or on a taxiway either of which may be occupied. Sometimes they land on the wrong airfield altogether.


WHY SIMULATE THE FIRST THREE PHASES OF AVIATION HISTORY

Firstly because all three techniques are still in use today. Face it; most airfields still have no radar and no associated point source navaids. In low visibility they can only be located using pioneer or vintage era techniques. Just because an airfield has radar does not mean that it is staffed 24/7 or that the radar controller can provide radar service to every aircraft that requests it. Navaids and radar must be turned off for maintenance. Pilots must be able to navigate aircraft in accordance with the ATC clearance they are given, or are denied.

Secondly the fact that you are reading this tutorial means that you are interested in taking responsibility for navigating an aircraft yourself rather than letting Microsoft navigate it very badly for you. For those contemplating this for the first time that is a big step. It is a bad idea to start at the top of the learning curve. Real pilots learn to navigate using pioneer era techniques followed by vintage era techniques. Only during advanced training in pursuit of professional qualifications do they attempt 4D classic era navigation techniques. We should take pilot training step by step along the same pathway, becoming proficient in each technique before proceeding to the next.

It is also important that we become proficient in all three types of en route navigation before attempting the more difficult exercises described within later parts of the tutorial. Each part of the tutorial assumes that the prior step has been mastered.

THE BIG PICTURE - MULTI PHASE NAVIGATION


We must never lose sight of the fact that over many parts of the globe there was very gradual transition between phases because different parts of the globe were in different phases at the same time.

Any airliner of any airline departing Buenos Aires for Santiago for many years after WW2 might have been required to fly classic phase mandatory departure procedures using local point source radio beacons in the Buenos Aires Terminal Area before transitioning to using vintage phase wide area infrastructure RDF based GPS for the en route navigation phase. At some point those that did not impact a glacier trying to use outdated post medieval navigation would be required to comply with a mandatory transition to the Chilean government classic phase arrival and radio beacon approach procedures for the Santiago TMA. Outside the CONUS during and after WW2 a single flight was often conducted using both vintage and classic phase procedures based on the infrastructure available and mandated as the flight proceeded. If the weather was good enough pioneer era techniques might also be incorporated, but with substantial additional and pointless risk.


WHY PROVIDE MAXIMUM SUPPORT FOR THE CLASSIC PHASE?

The benefit of choosing to simulate the 'pure' classic phase anywhere around the planet (as generally supported and proposed by Tom Gibson’s CalClassic website and forum) is that we can download the real procedures from the real regulatory authority, study them for as long as it takes to understand just one of them. Then when we fly it by rote in the simulator we will be doing exactly what the real crew did in the classic era, or may be instructed to do tomorrow.

When we do that we can understand exactly what the real crew did and still do. We can fly a compliant procedure. We don’t need to make up some nonsense and just pretend we are doing what real aircrew do. There is no danger that what we are trying to make a propliner do something it was not designed to do. They were all designed to fly the real procedures, not the ones that flight simulation users make up, or ATC clearances and vectors that Microsoft make up, many of which are incompatible with realistic propliner flight dynamics.

Any flight planning software will explain en route waypoint planning in the classic or modern eras. That is the real point. Once we come to terms with the fact that the classic era is the one within which we do NOT need to know where we are, what our velocity is, or what our ground speed is, and we understand that all we have to do is follow a prepared flight plan minute by minute and leg by leg then we make flight simulation as simple as it can be.

When simulating vintage phase aviation we must think much harder about exact place and exact date, airline nationality, crew resource, etc, and then we must create a flight plan that will work in any weather. This is much harder than creating a viable classic era flight plan. If that were not so the death rate would have been higher in the classic era than in the earlier phases of aviation history. Once we stop importing pioneer and vintage era navigation baggage and workload into classic era simulation the classic era becomes the easiest one to simulate.


GETTING THE MOST FROM FLIGHT SIMULATION

It is wrong to fly a single crew Ford Trimotor other than by visual reference to the surface scenery anywhere, but once we need to formulate an operating strategy for a multi crew airliner outside the CONUS, prior to the arrival of the classic phase in a given location, a lot of thought needs to go into planning the simulation sortie, else we may as well just fly a Cessna using a VFR GPS in ways that are not allowed in modern aviation or fly a B767 and let Microsoft radar vector us atypically and quite likely into a mountain.

The problem with simulating multiple navigation phases in a single flight is that the strategy we decide upon and the location of transitions between the techniques may be different to those the real crew would have used and we can never be sure whether what we experienced was what the real crew experienced. We cannot download unpublished pioneer or vintage phase ‘spur of the moment’ procedures and flight plans such as the crew of BSAA Lancastrian ‘Star Dust’ invoked and fatally failed to fly safely. We can however use a simulator to experience and understand the difficult decisions that had to be made by aircrew because en route, departure, arrival and approach procedures were not federally mandated, tested, published and safe, prior to the classic era.

The more effort we put into planning a sortie in a flight simulator to ensure that it is realistic, the more we can learn from it, and the greater the chance that a propliner with realistic flight dynamics will cope with fully realistic, or intended to be realistic, flight planning.


CLASSIC JETS TOO

Within the flight simulation and wider aviation community the concept 'classic jets' exists. This concept is sometimes limited to turbojets, but often it is a reference to all the jets including those with low bypass turbofans that preceded the B747, the IBM 9020 ATC computer, and the Radar Control environment of the 1970s.

Let’s remember that the classic jets preceded the modern phase of aviation and flew the classic procedures by rote because although radar intervention was desirable for them all, it was not always available everywhere for them all.

Classic phase infrastructure, procedures, and aircraft crewed and equipped to fly them, were available right across California by 1939. The classically equipped and crewed piston propliner component of the real world air traffic mix peaked around 1959, but the classic phase wasn't symbolically over until the first 747 joined the fray in 1970. By then metropolitan California already had a fully modern radar based aviation infrastructure, but much of the world still did not.

Even in the UK various kinds of vintage era RDF talkdown (VDF and QGH) were still commonplace throughout the 1970s and across the wider world the vintage phase lasted much longer. Always remember that the vast majority of commercial airfields world wide still have no radar (especially H24) and are stranded in earlier phases of aviation history.


TIME TO PRACTICE AND REVISE NEW IDEAS ENCOUNTERED SO FAR.

We have now examined almost everything we need to know to plan and conduct the simplest phase of any propliner flight which is the en route cruise phase.

Depending on how you format it Part 2, the en route phase component of this tutorial, alone runs to maybe 60 pages of text. Each of the following parts is potentially more complex and some certainly are. I have no choice but to assume that you have understood everything so far. The only way to keep this tutorial below several hundred pages of text is to discuss only the increments of knowledge and complexity that arise in the more complicated phases of flight that follow. Most of the knowledge and techniques already discussed will be needed again. It may be a good idea to practice the new skills and techniques of cruising flight and to read the whole of the preceding text again before attempting to understand planning and conduct of the arrival phase.



PROPLINER TUTORIAL PART 3:- THE ARRIVAL AND HOLDING PHASES

In order to progress from pretending to fly an aeroplane to simulating the operation of an aeroplane we must progress from making up our own pretend procedures to understanding the real procedures and then teaching ourselves to implement them. The real procedures differed from era to era, but once any airfield had an approach controller as well as a tower controller those procedures soon became mandatory and complex. However we will begin by examining the situation in the pioneer era, moving on to examine classic era procedures in great detail. Then finally we will examine how the vintage phase of aviation history differed and how we must simulate vintage era arrivals within MSFS. The reason for leaving the vintage era until last will become apparent in due course.


ARRIVING IN THE PIONEER ERA

During the pioneer era the arrival and holding phases did not exist. The en route phase was conducted visually (by day or night) and continued all the way to the airfield visual circuit. This way of flying propliners more or less died out with the last of the single crew U.S. mailplanes which included the Wright Whirlwind engined variants of the Ford Trimotor as included by Microsoft within FS9. It was possible for the larger crews of a vintage era Handley Page H.P.42, Savoia Marchetti S.73, or Avro Lancastrian to emulate the techniques and death rates of the pioneer Ford Trimotor era, but in general they didn't, and we should not pretend that they did. Aircraft like the Boeing 247 and DC3 belong to the even more advanced classic era.


PROPLINER ARRIVALS IN THE CLASSIC ERA

After the pioneer era propliners no longer flew directly to airfields, nor did they descend uninterrupted from the cruise to the circuit pattern height. Increasingly they needed permission from ATC to enter a circuit pattern or to descend at all. After 1932 propliners in the U.S. increasingly flew airways at medium or high altitude and used radio beacons for guidance, day and night, regardless of the weather. These classic era procedures were adopted by all nations after they ratified the Treaty of Chicago, usually in the late 1940s or early 1950s. German aircrew had adopted them independently by 1936.

Subject to the cases specified later everything that follows also applies to the vintage era. We will rarely have access to the airline specific procedures for that era so even in the vintage era we will adopt and adapt the federal procedures that replaced them in the classic era. Those procedures are 4D not 2D. They are based on altitudes and times, not distances.

The arrival phase of each flight begins at TOD and ends only when we obtain clearance to begin our approach. The arrival and approach phases are distinct and separate phases. The arrival phase may be prolonged. We have no right to make an approach just because we have arrived. We may need to hold for two quite different reasons.


HOLDING

The arrival phase begins at Top of Descent (TOD) and includes any holding patterns prior to destination. Some arrivals to very large airfields may require holds to be flown at more than one location, whether or not there is any delay. The arrival phase gives way to the approach phase only when we are cleared by ATC to begin an approach.

In order to transition from the en route phase to the approach phase we must fly the arrival phase. During the arrival phase we may need to cross over an obstruction and descend in a holding pattern on the other side of the obstruction. An arrival phase may have more than one such obstruction and more than one such holding pattern. The obstruction can be fixed or mobile. Sometimes it will be conflicting air traffic, sometimes a mountain range, sometimes a military danger area. Obstructions come in many varieties.

This is the primary use of holding patterns. They are also used by ATC to sequence traffic, by delaying the approach of traffic, but that is not their primary purpose. In order to fly a propliner we must learn how to fly a holding pattern else we have no safe means to separate ourselves from obstructions of any kind. We will often need to proceed to a holding pattern carefully located by the regulatory authority to allow descent clear of mountainous terrain or other obstructions.

Before we take off we must obtain an ATC clearance. That clearance terminates at a holding pattern, not at an airfield. Our flight plan terminates at the last holding pattern in the arrival phase. When we take off we have no idea what runway we will land on, or what approach we will fly from the holding pattern for our destination where our ATC clearance terminates.

None of the above depends on the concepts of delay or sequencing. During the arrival phase propliners proceed to holding patterns, whether or not they are going to hold within them for approach sequencing. Aircrew are only told what approach they must fly during the arrival phase. The approach they are instructed to fly begins from the holding pattern, whether or not there is any delay to that approach.

Each airfield has one or more Initial Approach Fixes (IAFs). At least one of them is the location of a holding pattern. A busy airfield will have many IAFs and many holding patterns. A simple commercial airfield will have only one and that is where our en route flight plan terminates. In real life airliners cannot proceed directly to the circuit, the instrument runway, or the landing runway. They proceed to the holding pattern and await further instructions. If they are lucky they get further instructions, (are told what approach to fly), before they reach the IAF. If not they must hold until they do get permission to approach the instrument runway, which may not be the landing runway.

Most flight simulation users grasp very little of this and so this may represent a whole new raft of misconceptions that need to be relinquished.


WHERE IS THE INFORMATION?

The world's biggest airfields have complicated mandatory arrival procedures known as STandard ARrivals (STARs). If we intend to simulate flight into the world's most complicated airspace we must grapple with that huge complexity. It is obviously a bad place to start. We need to learn to walk before we try to run.

Smaller commercial airfields also have mandatory arrival procedures, but they are published within the ‘approach plate’ for the airfield. Most airfields are too insignificant to have either published procedures or ATC, but most of those airfields cannot handle propliners. We are not concerned here with airfields that exist to handle Piper Cubs and other puddle jumpers.

Before flying a propliner we need to download the relevant STARS and approach plates from the internet and we must plan our arrival using them. There is no list of relevant URLs here because they change from time to time. I have asked Tom to maintain a separate list to be updated from time to time within the tutorials section of www.calclassic.com/tutorials.


A major airfield may have dozens of such files which we must download. We have no idea what the wind will be when we arrive and no idea what approach we may need to fly. We will start by studying the real world procedures for somewhere much simpler. I strongly advise you to print out a hard copy of each arrival.pdf that you downloaded with this tutorial and place it in front of you as you read on. Make sure you understand what you must do to comply with the procedures before trying to fly any of them in the simulator. Detailed instructions follow.

If you are not accustomed to flying propliners in conformity with MSFS on screen handling notes and managing configuration changes during holding and approach, you are advised to practice this aspect of realism before attempting to fly the procedures that follow. Workload will be high and the ability to understand and achieve target airspeeds whilst making configuration changes is taken for granted in what follows. Use of handling notes in the easy to interpret, step by step, form that I distribute is also assumed.



AIRFIELD NDB ARRIVAL

The first real arrival we shall study is the arrival to Fryeburg in Maine, also known as Eastern Slopes Regional Airport, with the ICAO flight plan code KIZG. Make sure you have KIZG_NDB.pdf on your second monitor or a printed copy of it in front of you before reading on.

This arrival all revolves around a non directional beacon (NDB) called SEBAGO, positioned west of Sebago Lake, which emits both the Morse ident code SZO, and its bearing information, on a frequency of 227 Kilohertz (pronounced Kilocycles in the classic era). The inbound approach course is 323 degrees MAGNETIC.


It may surprise you to learn that the only difference between flying this arrival (and approach) using ADF in 1938 and GPS in 2008 is the instrument we glance at every so often during execution of the same procedure. The GPS procedure today is the pre WW2 NDB procedure. This is usually true. Possession of a GPS receiver in the modern era is not a license to make up your own arrival or approach procedures! The procedures are mandatory regardless of the gauge used to achieve 4D compliance.


ALTITUDE v HEIGHT (QNH v QFE).

KIZG is 454 feet above mean sea level (MSL). Displacement from mean sea level is called ALTITUDE. Sitting on the runway at KIZG if we set the current KIZG QNH on our altimeter it will read 454 feet plus the displacement of our altimeter above the runway surface. Displacement from the local terrain is called HEIGHT. We will be at a height of about 10 feet and an altitude of about 464 feet in the cockpit on the runway.

The difference between ALTITUDE and HEIGHT must never be confused when in a cockpit. When obstacles are shown on aviation charts the chart states their altitude, not their height. When an altimeter is set to show altitude the required pressure setting is the QNH. When an altimeter is set to show height the required pressure setting is the QFE. QNH is what the air pressure would be at mean sea level at that location. QFE is the actual air pressure at the runway surface.

The local ATC COM frequencies are stated on the plate. We must obtain the necessary pressure setting from one of them. At least one should be properly implemented in MSFS. We will always obtain the QNH from ATC because MSFS cannot calculate and provide the QFE, which would have been used as the normal altimeter setting for much of the 1932-55 era.

All the information above is right at the top of the plate. Locate it all now.

In MSFS we can just cheat if we are unable to obtain the QNH from ATC. Press the B key and MSFS will autoset our altimeter to the local QNH. If flying below FL185 in the U.S. we must obtain and reset the local and latest QNH frequently and then adjust our height back to our assigned or mandated minimum altitude. I recommend use of a registered copy of FSUIPC to smooth weather transitions in MSFS since the default weather model is poorly implemented, but we will need to obtain the QNH from ATC if we do since the B key cheat is effectively disabled with FSUIPC weather smoothing in use.


HOLDING PATTERNS.

Note that a holding pattern is promulgated at the SZO. This type of hold is known as a racetrack pattern. We must fly the hold with left hand turns. Each turn must be flown at rate 1 using the turn co-ordinator on the panel so that we take exactly one minute to turn 180 degrees. The inbound and outbound legs of the hold are also one minute each. One hold should take exactly four minutes. The outbound course is 143 magnetic and the inbound 323 magnetic. This is the course we must make good, not our heading. We must adjust our heading to allow for crosswinds.

I chose this approach for the tutorial because there are some hills and two masts close to the hold both reaching altitudes above 2500 QNH. We will be almost a thousand feet above them at the lowest level in the hold and if we fly the hold correctly we will pass close to both. Whether we turn inside or outside the masts depends on our KTS (ground) speed. Notice that the legs of the hold and the turns of the hold are based on TIME, not distance, nor constant radius turns. The turns must take one minute regardless of radius variation with our velocity (KTAS). Remember the length of each side of the racetrack will depend on our speed (KTS), but the radius of each turn will depend instead on our velocity (KTAS). Neither will depend on our drag (KIAS). However as I explained in Part 2 we don't need to worry about any of that because real aviation procedures are based on TIME. We are going to base what we do only on TIME. We will navigate the hold using a clock.

The linear legs have a specified TIME. Each turn has a mandatory TIME. Each interval is one minute. In practice within MSFS we will make the outbound leg tracking 143M exactly sixty seconds. Depending on the wind vector it may take more or less than a minute to fly the consequential inbound leg whose track is 323M.



PRACTICE, PRACTICE, PRACTICE.

Many flight simulation users have never attempted accurate navigation of any aircraft. Now is the time to come to terms with the need for accurate navigation in 4D and the skill required to simulate real procedures. The ability to fly timed turns and timed legs is assumed in all that follows. Flying a holding pattern is the basic test of that skill. It is time to practice, practice, practice until we can fly timed legs and timed turns using the (gyro) compass, clock and turn co-ordinator.

Not all aircraft in MSFS have a useful stopwatch on the panel. If you are going to simulate flying propliners consider wearing a real one on our wrist. You need one to fly holding patterns to enter the approach and for other reasons to be explained later.

We will use a full function autopilot as much as we need to whilst we learn. Hand flown procedures can be practiced later. For the moment the goal is to understand how the real procedures work and to develop the skill to comply using a full function autopilot.


USE A SUITABLE AIRCRAFT FOR TRAINING.

Real pilots need lots of training in these procedures and so do we. We must take this one step at a time and avoid trying to run before we can walk. The Grumman Goose for FS9 released by Bill Lyons is a good choice of instrument trainer. Revised flight dynamics and a suitable VC environment for all the training exercises that follow are supplied with this tutorial. Make sure you can handle these procedures flying a nice slow propliner with simple dynamics like the ones supplied within this tutorial for the Goose before trying to fly them in faster and more complicated propliners.

If you have not obtained and installed Bill Lyons' Goose and have not added the tutorial update files now is the time to do so.

We must use the supplied full function autopilot as much as we need to during training. The most important thing to learn is what the real procedures are, not to test our skill at hand flying them. That can come much later. Don't make these exercises more difficult than they need to be by trying to learn whilst flying fast, difficult to control aircraft, with limited function autopilots. That can all come later once the basic skills are in place. Let's proceed in small steps just like real pilots.


LOAD and SLEW

O.K. now we have installed and updated the Goose as our instrument trainer we can select a flight that starts at KIZG. Type KIZG into the airport ID box. Once on the runway at KIZG enter the virtual cockpit of the enhanced FS9 Goose.

From the Views menu open the radio stack sub panel.

Tune the ADF to the SZO = 227.0 Kcs.

Right click in the sub panel and select undock from the right click menu.

Use your mouse to grab the radio stack (hold left button down)

Slide it top left of screen.

Slide it up until only the autopilot, elevator trim and ILS receiver are showing.

We always need to do this so that we can trim the Goose carefully for take off anyway, but this is also the default position for the avionics stack during instrument training. We can slide it down any time we need to change a frequency. In real life it would be a bit higher up in the roof but we don't want to bother with that during instrument training. We want it to be where we can see it and grab it wherever we scroll or pan to in the VC. If you have little experience of undocking sub panels and placing them exactly where you want them, hiding what you want to hide, and seeing only what you want to see, but where you can grab the whole panel with the mouse and slide it again, practice that for a while until it is second nature during flight simulation.

Open the World/Weather menu; choose weather themes; and choose 'clear skies'.

Select user defined weather.

Open the customize weather menu and set wind speed to 'none'.

Set clouds to overcast.

Set visibility to 20 miles.

Select advanced weather.


Select stratus cloud, no turbulence and light icing.

Use the +cloud icon to create a cloud layer.

Set the base to 4500 and the top to 5000 feet (QNH).

Set base altitude random variation to minus 250.

Set precipitation to none.

During instrument training we will always need to control the difficulty of the weather environment to one that we can cope with. We can gradually make it more difficult, but not yet. If you have previously made little use of the FS9 weather menus now is the time to practice using them to control the skill you need to deploy during a given flight. Hopefully the conditions above will make this holding exercise very easy. We will always be below the overcast and the visibility will be better than average with no showers to interrupt our view. We shall however be navigating using the instruments, not the scenery.

Now slew to a position about 20 miles east of Fryeburg, north of the northern end of Lake Sebago. Slew up to an altitude of 4000 QNH. You can fly to that position instead if you prefer. Set up econ cruise power at 20 inches and 2000 rpm. Use the full function AP throughout this exercise. Turn the AP on and select a heading of 180 at 4000 QNH. Now pause the simulation.

Look at the KIZG approach plate. Locate the circle with MSA SZO 25 NM above it. This mandates a minimum (sector) altitude (MSA) of 4000 feet QNH for propliners approaching KIZG from north east of the SZO. All propliners arriving at Fryeburg must do so via the SZO and the altitudes they can descend to is not an aircrew choice. By the time we are where we have slewed to just north of Lake Sebago we want to be level at 4000 QNH, but we must not be lower, and we must be overhead the Initial Approach Fix for KIZG, (which is SZO), before we may descend below 4000 QNH.

The ADF (double sided) needle on the RMI above the yoke is pointing to the SZO. Our first task is to track to the SZO so that we can descend below 4000 QNH after reaching it. In real life we may or may not be ordered to enter the SZO hold. During this exercise we will enter the hold because it is a holding exercise, but nothing above relates to whether we are going to hold. We must anyway proceed to the initial approach fix and at an altitude no lower than the MSA regardless.


We could just track to the SZO from wherever we are right now, but we know that the inbound track of the Sebago hold is 323 magnetic so we will be a little smarter than that. We will intercept the inbound track. We will fly south until the track to SZO is almost 323. Then we will turn to a heading of 323 so that (in nil wind) we are tracking to the hold already flying the inbound track of the hold. With no wind our heading and our course will be the same.

Unpause the simulation and head south at 4000 QNH. The ADF needle will slowly indicate the changing bearing of the SZO. We will act as the bearing approaches 323.

This exercise is to a large extent about learning to make rate 1 turns using the turn co-ordinator. Notice the triangles to the left and right of the centre mark. To fly a rate one turn (3 deg/sec) we must place the needle over the triangle. We are using a late classic era autopilot to fly an instrument procedure so we must control our energy state so that rate 1 turns are compatible with its bank angle limit of 25 degrees. We will need to have a profile drag of 140 KIAS (= 160 MIAS in a Goose) or less in order to keep our velocity below 145 KTAS or 165 MTAS in order to use a classic era AP to fly instrument procedures. In many propliners we will need to deploy flap to achieve those energy state targets. It all depends on the aircraft in use. Fortunately the Goose econ cruises at less than 160 MIAS with no flap, but don't forget that flap will be required in most propliners if the AP is used to fly any instrument procedure.

As you begin to track south over Lake Sebago look right and identify the radio masts that we might blunder into if we descended below 4000 QNH in worse visibility or in cloud.

We will not wait until the ADF needle reaches 323. We will anticipate. As it passes 315 we will dial 323 into the AP so that it begins to capture that target inbound heading just before that is the course to SZO. If we judge this just right the Goose will roll out of the turn heading 323 and tracking 323 to the SZO. We are not only inbound to the IAF for Fryeburg we are inbound on the inbound leg of the SZO holding pattern.

Whilst inbound to SZO maintain situational awareness. Look at the approach plate. It shows two high masts (or clusters of co-located masts). We expect to track over one of them with the other passing down the left hand side from around 10 o' clock. Identify the key obstructions to this arrival. They are what shape this mandatory procedure. During the pioneer era, whilst height keeping at 1500 QFE, single crew mail planes like the Fokker Trimotor had been at great risk of just blundering into them in low visibility. The arrival procedures of the classic era prevent this.

At some point during this exercise you may be able to identify the airport. If so ignore it. This is a holding exercise. When we reach SZO the ADF needle will swing quickly as we start to go over or abeam the beacon and enter its cone of silence. Don't chase the needle. Just before the needle becomes horizontal we will dial the outbound magnetic heading of the hold (143) into the AP. Since we have now reached the IAF we may descend to 3500 feet to hold at 3500 QNH. I will explain why only 3500 QNH shortly, but those masts that we identified are a big clue; for the time being dial 3500 into the AP and then minus 700 VSI. We have entered the SZO hold. Notice that the AP is flying a rate one turn in compliance with the mandatory holding procedure. It will take 60 seconds to reverse course. It can only achieve that after we have achieved our energy state target < 140 KIAS = 160 MIAS.

Pause the simulation.

We are using a full function late classic era AP to fly this procedure. We must keep our drag below 160 MIAS to keep our velocity below 145 KTAS so that the 25 degree bank limit of the AP supplies enough G to achieve a rate one turn. Consequently we must not select a VSI that causes drag to exceed 160 MIAS (=140 KIAS). In many propliners that will restrict the available VSI to only minus 500 VSI. Altering altitude at less than 500 VSI is illegal.

We must never be thinking in 2D during aerial navigation. Flying the real 2D tracks of the procedure is not very difficult. We must think in 4D and we must control our energy state with throttle, or VSI, or by varying the flap configuration. Adding more flap may require us to limit the airframe to even less drag and may become self defeating. We must plan our arrival very carefully with regard to the 4D ballet that we must dance and the energy state that we must target to perform the dance; especially if we intend to use an AP during the 4D dance. Autopilots are not video game cheat modes. They are real systems with real limits. We must understand and observe those limits. We must control our energy state to stay within them.

This should be very easy in a Goose, but in many propliners it requires a lot of planning and a lot of skill. Consequently many flight simulation users lose control of their energy state and lose control of the aircraft during the arrival phase, even before they begin the approach.

We have entered the SZO hold and we are awaiting approach clearance descending to 3500 QNH. Locate the clock. It has a second hand but no stop watch function. If you are not wearing an aircrew chronometer on your wrist you will have to make do with the cockpit clock. As soon as the AP rolls off the G to exit the rate one turn we must either start a stop watch or note the position of the second hand. Write the seconds on your flight plan. We intend to go outbound for 60 seconds, but we will anticipate the turn, so about 58 seconds later we need to dial 323 into the AP so that it will reverse course again at the other end of the hold.

With an older type of AP we would need to hold the turn knob over to achieve the target heading, or we could hand fly the rate one turn if we have developed that skill. We must fly a level rate one turn so that we are again inbound to SZO tracking 323. Any old turn rate back to 323 will not do. Rate 1 is required else we will not roll out of the turn on the inbound course back to the SZO.


Get ready to start timing the outbound leg. Unpause the simulation.

As the AP rolls off the G identify the mast whose altitude is 2549 feet. Correlate what you see from the VC with what you see on the approach plate, but keep one eye on the clock.

In the turn at the far end of the hold identify the mast whose altitude is 2534 QNH. We don't need to start a stopwatch when inbound. If the ADF needle shows that the track to the SZO is not quite 323 we will use the AP to adjust our heading to intercept that track. We will turn outbound again when we go over, or close abeam, the SZO. Practice several holds until it is all pretty easy in this weather. The only tricky part should be adjusting the inbound leg so that it tracks exactly 323 to the SZO. Practice correcting this until you get the hang of it. Don't beat yourself up if it is a few degrees out.

Don't be tempted to make hand flying these procedures the next step. The next step is to practice the same exercise with cloud below instead of above and then with the Goose in cloud. It should make no difference to the difficulty at all. That's the point of the classic era procedures. Being able to fly the real procedures in a propliner, in any real weather, using a full function AP is more important than being able to hand fly a propliner in nice weather.

Now that we have learned how to fly a holding pattern at the initial approach fix (IAF) we can return to our study of different arrival procedures, all of which terminate at an IAF and most of which are followed by at least one hold.


TRANSITS and PUBLISHED TRANSITIONS.

It is possible to 'transit' from anywhere to the SZO, with the intention of landing at KIZG, from any direction, but most propliners will arrive from airways. When an arrival procedure links an IAF to an airway it is called a 'transition'.

A transition may be more complicated than those represented within this tutorial. It may proceed via more than one beacon, or via intersections. It may mandate level changes. What these more complicated transitions require should not be hard to deduce or implement once we understand the basics.

KIZG has two published transitions from the modern airways system. Down near the bottom of the 2D diagram is a VOR symbol. It represents the current VOR at Kennebunk transmitting on 117.1 Megahertz and coding ENE. It is 29.6 miles from the SZO. Propliners inbound from all points south of KIZG follow the airway to Kennebunk (ENE) then they fly the published transition to the SZO.

Make sure you can locate all of that information on the approach plate so that you will be able to locate it for other arrivals and on other plates. Until about 1955 the beacon at ENE would have been a Radio Range. The means by which we can simulate Radio Ranges using a VOR1 or VOR2 receiver in MSFS was explained in parts 2A/B of this tutorial.

When flying a propliner into KIZG from anywhere to the south we home to the beacon at ENE using NAV 1 for guidance. During the latter stages of our flight to KIZG, before reaching ENE with 117.1 tuned on NAV 1 we must tune 227.0 on ADF 1. On reaching ENE we turn towards SZO and home the SZO using ADF1 for guidance to the SZO.

After about 1955 we could fly the 003 radial generated FROM the ENE VOR. That makes following the CRS to SZO easy. When Kennebunk was a Radio Range it did not generate a 003 radial and we would have homed to the SZO using only ADF1 for track guidance. During flight simulation which we choose to do just depends on the year we decide to simulate. Before or after 1955.

In the timeframe 1932-1955 when transitioning from the last Radio Range (or VOR) on Airways to the IAF for our destination we cannot use the post 1955 VOR radial. We will locate the IAF using only the radio signals from the IAF. In this case the IAF is an NDB at SZO so when simulating 1932-1955 we use only ADF for guidance after leaving airways at Kennebunk. Remember however that at some airfields the IAF may be a VOR (or a Radio Range). If so we will use it at any date.


IDENTIFICATION and PROTECTED RANGE.

Some types of radio beacon are subject to many types of interference. Some have very weak transmitters. This is deliberate. Two NDBs may need to use the same frequency but be less than 100 miles apart. Whenever we use ADF we must be very careful that the NDB the needle is tracking is the correct NDB and not another on the same frequency. We must also ensure that we are inside the 'protected range'. The ADF needle may be able to 'swing' long before it can deliver safe guidance. We may be receiving two NDBs on the same frequency at once. The needle may interpolate. We must guard against this. In the real world this is complicated and is just one of the reasons that NDBs make poor en route (airways) beacons. During flight simulation we can guard against using an interpolating or parked ADF needle simply by listening for the NDB ident.

There is no guarantee that we will be able to receive, let alone safely use, the SZO from 29.6 miles away. It depends on the weather, our current altitude and the power of the beacon. M/F radio signals do not travel through hills and at these frequencies they do not bend around the curvature of the earth. So we leave ENE on a course of 003 magnetic and may need to wait for the ADF Morse ident to play the code SZO and the ADF needle to 'unpark' and point reliably at the SZO.


Make sure you have ADF audio turned on in your propliner start-up flight, (.STN file). Make sure that you have turned on ADF 1 ident using the avionics panel selector. Get used to listening much more for Morse tones when flying in the classic era. Don't worry, you will not need to learn Morse to use these procedures, but if you wish to check the codes the dots and dashes are shown as such on the plate. Locate that information now.

Never use an ADF needle for guidance unless you can hear the Morse ident associated with that NDB, but having heard the ident you can then switch the ident function off until you next tune an NDB. In the 1932-55 timeframe you will often be tracking to a radio facility that you cannot yet receive. You must not try to use the 'needle' for guidance until you are within 'protected range'. During flight simulation we know that it has become safe to use the needle once we hear the NDB audio ident. Having thus confirmed that we are within the 'protected range' we can start to use the ADF needle for track guidance and turn off the Morse ident. Get used to doing this for VORs as well.



CLEARANCE LIMIT.


Before we took off in our propliner we were given an ATC clearance something along the lines of, 'N700MS cleared flight plan route to Fryeburg -- do this -- do that'. That ATC clearance is to the SZO and terminates at the SZO. Clearance to Fryeburg neither includes clearance into the visual circuit of the airfield, nor clearance to fly an instrument approach from the SZO to KIZG. The ATC clearance limit is the initial approach fix (IAF) for our flight plan destination. The IAF for Fryeburg is the SZO. From all directions and regardless of the landing runway.

Note that everything revolves around the SZO beacon. It is the IAF for KIZG. Nothing revolves around the airfield at KIZG.

Notice that KIZG is a commercial airport, but is not on (under) an airway. When Eastern Slopes Regional Airport is our airways destination we will route via airways for as long as we can (to ENE if arriving from the south) and 'transition' to the SZO (not KIZG) until we have received a new clearance from ATC to enter the visual circuit at KIZG, or else a new clearance to commence an instrument approach to KIZG. In MSFS we must issue those clearances to ourselves; the canned ATC is too dumb.


SPEED LIMIT POINTS.

Until the modern era it was illegal for a propliner to exceed a drag of 175 KIAS in a holding pattern or during an approach procedure. We must reduce our IAS below 175 KIAS before reaching the IAF. If we intend to use autopilot we must reduce below 140 KIAS (= 160 MIAS), deploying flap as necessary. We must not exceed 175 KIAS whilst executing a missed approach (see later).


MANDATORY MINIMUM ALTITUDES.

When flying the ENE transition into KIZG we can fly between ENE and SZO as low as 3500 QNH, right over the mast at 2549 QNH. Descending early in poor visibility would be fatal. Remember these masts are held erect by wires attached near the top and splayed at an angle down to the ground. It is not the mast that will kill us. In low visibility aircrew using pioneer era techniques see the mast just before they impact the guy wires. In the classic era (1932 or later over the CONUS) we will normally cross ENE above 3500 QNH and will aim to reach 3500 QNH before reaching SZO so that we enter a period of level flight during which our profile drag reduces below 175 (or 140 with AP) KIAS before the IAF.

Now look top left of the plate. The other modern airway transition to the IAF for KIZG proceeds via a DME fix at NOTTY inbound on a course of 135 Magnetic to the SZO. NOTTY is 16.5 miles from the SZO. Today we can use DME to determine when we reach NOTTY and after passing NOTTY for SZO, (subject to clearance from approach control), we can descend safely to 4900 QNH.

Before about 1955 timeframe there was no long range DME for civilian use, so there was no fix at NOTTY, so there was no published transition via NOTTY. Back then the only published transition was from the Radio Range at ENE. We must turn all DME receivers OFF when simulating a date before 1955.

This means that after downloading the approach plate for our destination we may need to disregard all modern transitions and procedures on the current plate that require use of DME. They are 'modern'. Remove them and the plate regresses to the form it had before 1955. Simply print the plate and cross them through with a pen, write 'not available until 1955' or whatever to remind your self when they become available.

Do that to the NOTTY transition now.


MINIMUM SECTOR ALTITUDES.

Now look at the circle to the right of the ENE VOR. It shows the Minimum Sector Altitudes (MSA) within a 25 mile radius of SZO. On leaving airways at ENE we fly a course of 003 *magnetic* to the SZO. We are therefore approaching the SZO from the south west, tracking north east *by reference to the magnetic pole*. Notice that all approach plates and other relevant aviation diagrams are however aligned on TRUE NORTH, but that nevertheless *all* the bearings are relative to MAGNETIC NORTH. The track from ENE to SZO is 003 MAGNETIC.

When we flight plan direct to the SZO from the southwest if we fail to follow the airway to ENE the MSA is 4100 QNH and we must maintain 4100 QNH all the way to the SZO. One of the advantages of flying a transition from airways rather than a transit from a random direction is that the minimum altitude for the transition following a known course between two beacons may be at a substantially lower altitude than the off route transit from an ill defined starting point to just one beacon.

Most flight simulation users make no attempt to flight plan their arrivals properly and blunder directly towards airfields at very inappropriate altitudes and speeds when they should be proceeding to that airfield's IAF at a carefully planned minimum altitude and with a limit of 170 KIAS before the IAF. If we intend to use an AP that limit must become 145 KIAS (= 160 MIAS) so that the AP can fly rate 1 turns.

Microsoft have no clue about any of this. Their canned ATC is just as blundering. It will happily vector us right through the approach path of another airport, into a mountain, or into a mast. It is functionally useless even if it provides some 'audio flavour' of modern era radar vectoring. The audio flavour of the canned ATC is neither realistic nor safe. The canned Microsoft ATC makes no attempt to avoid obstacles laterally or vertically. When flying a propliner we must learn to do both and to do that we must turn the canned ATC off and follow the real world published arrival and approach procedures.


OFF ROUTE TRANSIT = HIGHER MSA

The SZO can of course be approached as an IAF from any direction, but if there is no published transition the transit must be flown at or above the MSA. Prior to 1955 it was possible to leave airways for KIZG at the Montpelier Radio Range, (off plate to the northwest beyond NOTTY), and transit to the SZO, but since the later published transition relies on DME we will not treat it as a published transition prior to 1956. Prior to 1956 the transit from Montpelier must be flown at 7400 QNH or above.

We can approach the SZO from Montpelier 1932-55 just fine, but not at 4900 QNH as we can after 1955. Before VOR + DME is installed at Montpelier (nominally in 1956) we cannot tell which side of NOTTY we are. In most weather conditions we have no idea whether we are still over the White Mountain Range between Montpelier and NOTTY. Without DME we must transit at or above 7400 QNH until we reach the SZO. The only way we know for sure that we are southeast of the mountains is to be over the SZO. The procedure is safe day or night, above, within, or below cloud, in any visibility.

That is what the classic era was all about. No more blundering. No more guessing by navigators playing with maps; just radio beams and beacons. Arriving from Montpelier we will always enter the hold at any date, in order to descend safely in the narrow confines of the hold from either 7400 QNH or 4900 QNH to 3500 QNH during flight simulation.

In order to stop just pretending to fly propliners and start simulating their operation we must be able to determine the real world arrival procedure to any airfield, from any direction, at any date.

Look hard at the approach plate and make sure you understand how to plan the minimum altitude allowed during an arrival from each direction. If not please re-read the preceding sections of the tutorial until you do understand how to determine the minimum altitude for a propliner arrival from any direction, at any date, and how that depends on whether the arrival is a transit or a transition and why that might depend on the date being simulated.


TIME OF DESCENT - AGAIN

Long ago I promised that we would return to this topic. Now we can because it should now be obvious that TOD depends on the minimum altitude published in the arrival procedure and nothing else at all.

At any date after leaving airways at Kennebunk we must descend to be level 3500 QNH by SZO, but prior to 1956 after leaving airways at Montpelier we must descend to be only 7400 QNH at the same TIME.

TOD from the south must be sooner than TOD from the north west. Since TOD must always be planned at minus 500 VSI in a propliner (even though we intend to descend faster) TOD must be 7400 - 3500 = 3900/500 = 8 minutes sooner when arriving from the south.

TOD is an event that relates to the IAF and the altitude at which the arrival crosses the IAF. TOD has no relationship to the airfield or its elevation at all. It has no relationship to location, distance, speed or velocity. None!

Suppose we are cruising at FL230 coming northeast bound up the airway to ENE. We estimate SZO at 1200. We need to lose 19500 feet at 500 VSI. TOD is always 39 minutes short of SZO so it is at 1121 absolutely regardless of distance, velocity, speed, wind vector or even aircraft type!

TOD is not a place. It cannot be a distance. Cruising at FL230 and arriving via ENE it is always 39 minutes before SZO regardless of the wind, distance or anything else at all; regardless of drag or speed or velocity; regardless of the type of propliner. TOD is a TIME.

When we are northeast bound to Montpelier at FL230 also estimating SZO at 1200 we need to lose only 15,600 feet at 500 VSI. TOD is 31 minutes before SZO. TOD is always 8 minutes later at 1129.


TOD is a time (based on minus 500 VSI) back calculated from the IAF and the altitude at which the mandated arrival crosses the IAF. Nothing more, nothing less. It is time to stop pretending that things like DME, TAS and speed might be relevant to TOD. Another cherished misconception must be relinquished.


FLYING the DESCENT in a PROPLINER.


We must always switch the canned ATC off if we desire realism. It is far too dumb. We must flight plan TOD carefully as above and we must clear ourselves for descent at the correct TIME on the flight plan. We have been amending it with a pen throughout the flight.

We have planned descent at 500 VSI but we intend to descend faster to level at the minimum altitude specified for the transit or transition so that we can shed drag before the IAF which is the speed limit point. Max 175 KIAS for hand flown procedures or max 140 KIAS = 160 MIAS using an AP.

Prior to TOD we have spent many hours optimising our energy state during the cruise. We did not plan to achieve a specific profile drag (IAS) just prior to TOD. We could not plan that because we could not forecast the wind aloft for the prior leg of the plan. We planned a velocity (TAS) instead.

Nevertheless whatever the optimum drag (IAS) for the cruise at our current weight in the current weather eventually turned out to be it is also the optimum drag for descent at our current weight in the current weather. The optimum drag (KIAS) just prior to TOD will differ flight by flight for all the reasons explained in Part 2 of this tutorial, but when we arrive at TOD we can see what it is in the weather today just by looking at the ASI.


In an L-049A optimum drag might be 170 KIAS today. I will soon invite you to fly what follows as a tutorial exercise using the DZN L-049A, but for the moment read the text and only fly the exercise after you are sure you have understood it all.

Today 170 KIAS is the target drag (KIAS) for the descent. However there are other targets to be met and they may be more important. At TOD we pitch the nose down to sustain (exactly) the legal minimum of minus 500 VSI. No more, no less. Our profile drag (IAS) will of course rise in this power dive. If you find this too difficult when hand trimming use the full function AP until you develop the necessary skill to trim for any target VSI without using AP.

Throughout the descent we must ensure that we do not exceed the drag on the tail associated with either Mno or Vno. From the L049A handling notes;

****************************
Descent:
Above FL200 NEVER EXCEED 210 KIAS (Mno)
DO NOT EXCEED 236 KIAS (Vno)
*****************************

Neither Mno nor Vno is a target speed in a propliner. We should avoid them. Descending a Constellation we can only allow drag to rise to 210 KIAS initially and 236 KIAS later. The margin between drag in the cruise and Mno is never large. Initial descent must always be at the minimum legal rate (minus 500 VSI) whilst we size up the situation.

During initial descent from TOD (today) we have a profile drag target of 170 KIAS and a profile drag limit of 210 KIAS. Our velocity (KTAS) is much higher but irrelevant, and our (ground) speed (KTS) is equally irrelevant.

In a turbine engined aircraft we can reduce throttle quite rapidly, but when operating an aircraft with complex piston engines we must reduce MAP very slowly to prevent shock cooling of the engines.

****************************
Descent:
RPM - cruise rpm or max 2000
REDUCE MAP in stages of 3 inches (per minute)
Until MAP = RPM/100
OIL => 45 PSI
*****************************

As we approach TOD we may have anything between max cruise and econ cruise MAP applied; anywhere from 31 to 25 inches. RPM could be anywhere from 2300 to 1800. If we were max cruising into a headwind we reduce from 2300 to 2000 rpm else we leave cruise rpm applied. Whatever MAP is applied approaching TOD we reduce by 3 inches at TOD and by a further 3 inches every sixty seconds until we are running 'square' with MAP = RPM/100.

Usually (in an L-049A) we will be econ cruising at 25 inches and 1800 rpm as we reach TOD. Our MAP target is 18 inches. We reduce to 22 inches at TOD and a minute later (*only 500 feet lower*) we reduce to 19 inches. A minute later and only 1000 feet below final cruising level we reduce to 18 inches at 1800 rpm.

Most flight simulation users fail to plan TOD correctly, fail to vacate cruise at TIME = TOD, and then fail to manage their energy state competently after their mistaken TOD. Consequently most flight simulation users soon loose control of drag altogether, because they descend too late, too steeply, and with too much power applied.

Avoiding Mno above the level warned in the handling notes is not difficult, but it requires competent flight planning followed by competent pursuit of the MAP and VSI targets. Nothing in a propliner is unplanned or devoid of energy state targets; especially the arrival phase which always incorporates the descent phase.

In a Constellation northbound to KIZG via ENE final cruise will normally be FL250. TOD will then be (25000-3500)/500 = 43 minutes before SZO. We need to manage our energy state so we must manage our power targets with care. Two minutes after TOD we are passing FL240 with 18/1800 applied and we are still forty-one minutes short of SZO and maybe more than fifty minutes short of landing at KIZG.

We must get a grip on how long it takes to descend a propliner from cruise to the IAF and how shallow the descent may need to be to avoid first Mno and then Vno, and finally to achieve the drag limit at the IAF which is just 140 KIAS if we intend to use an AP to fly the mandated procedure.

We hope to fly the entire descent with cruise drag applied to the airframe (170 KIAS today). Doing that exactly is not possible, but we must work hard to approximate that target drag during the 43 minutes of the descent phase. It is a significant chunk of the flight and we must not squander the entire profit from the flight by mismanaging it.

At first we cannot prevent drag rising above cruise drag. Today it might rise from 170 KIAS to 185 KIAS, because we must comply with the legal minimum descent rate of minus 500 VSI. However we are now descending at minus 500 VSI through FL240 with 18/1800 applied. We have avoided Mno by descending at only minus 500 VSI and by retarding MAP as fast as it is safe to do so. Now that we have the power back to 18/1800 only a thousand feet below final cruising level drag will start to reduce instead of increasing. Eventually it will reduce to 170 KIAS. This may take many minutes, but when the drag is back to our target of 170 KIAS we will increase to minus 600 VSI.

Throughout the descent we monitor MAP. As we descend into thicker air it will eventually rise uncommanded. We must prevent that with throttle. We must trickle reduce throttle to peg 18 inches. Many flight simulation users neglect to restrict MAP to match target MAP during the descent. Drag will soon settle at just above our target of 170 KIAS. If later it falls through our target (170 KIAS today) we will increase to minus 700 VSI. Descending with constant profile drag we are decelerating steadily as we impact ever thicker air. If we decelerated any faster we would be making a poor conversion of the potential energy we accumulated by climbing to FL250 back into kinetic energy. By sustaining cruise drag we maximise the conversion rate of potential energy to kinetic energy, minimise fuel burn, and maximise profit.

Once we reach the critical altitude of our engines MAP will no longer tend to increase uncommanded, but power may increase at constant MAP. We reduce to minus 500 VSI. In this example we will have descended about 10% faster than flight planned (average 550 VSI) and we will be level about 10% before the IAF. In this case 10% of 43 minutes or about 4 minutes. If when we level at the MSA or minimum level for the published transition our drag exceeds 175 KIAS we will have plenty of time to reduce through 175 KIAS to meet the legal limit at the IAF.

The optimum drag for extending FLAP 1 in a Constellation is 152 KIAS and that is our next drag target. However the maximum safe drag for FLAP 1 is 174 KIAS. From the L-049A aircraft.cfg;

[Flaps.0]

flaps-position.0=0,0
flaps-position.1=24,174 ;60%
flaps-position.2=33,127 ;80%
flaps-position.3=41,127 ;100%

The real flight dynamics author of the real Constellation realised that aircrew would normally wish to enter and fly the hold using AP so whilst the drag limit for FLAP 2 is only 127 KIAS he made sure that FLAP 1 could be extended before the IAF by making its drag limit almost identical to the IAF drag limit. Having leveled at 3500 QNH about four minutes short of the IAF we hope to reduce to 152 KIAS before the IAF, but if we intend or need to use the AP to fly the arrival procedure we will extend FLAP 1 on reaching the IAF so long as we are below 174 KIAS and if we flight planned and flew the arrival competently that will be no problem at all.

If we achieve 152 KIAS before the IAF we will not extend FLAP 1 until just before the IAF. As we approach the mandated Initial Approach Fix we apply approach RPM and open the cowl flaps to 30%. As our profile drag reduces we have insufficient drag to ensure cooling of the engines and we need to direct extra air over them. If we intend to use AP to fly the hold (and we normally will) we extend FLAP 1 and increase MAP to run square or oversquare. In this case we must increase from 18 inches to at least 23 inches to match the required 2300 rpm.

****************************
Approach and Landing:
< 77,800 lbs
COWL FLAPS = 30%
RPM = 2300
MAP - as required
****************************


If the weather is nice enough we will identify the 2549 QNH mast and use it to judge how close we are to SZO and when to deploy these changes of configuration and power targets. Else we must use the ADF needle alone.

The drag limit for using a classic era AP to fly mandatory instrument procedures is 140 KIAS so we will in fact increase MAP to sustain 140 KIAS with FLAP 1 deployed and 30% cowl flap, whatever MAP that requires at our current weight in the current weather. The RPM and IAS targets are constants and the MAP target becomes dynamic.

Now would be a good time to fly this more complex arrival exercise in FS9 followed by a couple of holds using a more complex propliner than the Goose. I recommend that you use the DZN L-049A as described above.

As an alternative it is possible to descend at more than an average of 550 VSI, sustain a higher drag than cruise drag, and level more minutes before SZO losing the excess drag in more minutes of level flight. However this has no bearing on TOD which must be at the same TIME and both Mno and Vno must be avoided anyway.

The practical problem with that alternative strategy is that it requires *you* to research the base of the airway and not descend below the base of the airway before ENE. The strategy that I have set out above ensures that we reach 3500 QNH only a few minutes short of the IAF at a TIME when it is safe to reach 3500 QNH. Remember we have no reason to suppose that it is safe to be at even 4500 or 5500 QNH before ENE. We only know it is safe to descend to 3500 QNH after ENE. If *you* decide to descend more steeply *you* must do all the extra terrain research that you could avoid by descending gently to level at the MSA only a few minutes short of the IAF.

During flight simulation the most appropriate technique is to reach the minimum level specified for the arrival only a few minutes before the IAF. We make sure we are level a few minutes before the IAF by descending at slightly more than the planned minus 500 VSI, but not so steeply that we exceed Mno or Vno. Propliners have very low Mno and avoiding Mno is a critical target, especially in cold air. That is why propliners must fly such shallow descents and must have a planned TOD so many minutes before the IAF. Unlike Concorde they have fragile tailplanes. They cannot dive hard to increase drag and decelerate quickly in a power dive.

When flying complex propliners early stages of flap must be deployed long before entering the circuit pattern. Early stages of FLAP will usually be deployed during the arrival phase and more during the approach phase, before ever entering the circuit pattern. Most flight simulation users deploy flap far too late in the flight. The Goose does not require flap to fly rate 1 turns using AP. Most propliners including the L-049A do.

In real life aircraft cannot make a continuous descent to the runway elevation. They hold, they fly arrival procedures, they fly approach procedures, or they get vectored all over the sky by ATC. It makes no difference to our flight planning. We plan descent based on minus 500 VSI, but after vacating cruise no later than TOD we try to average a little more over the entire decent so that we are level several minutes before the IAF.

We do this in part so that we can employ the autopilot with the aircraft in an energy state that it can tolerate and control. The AP will start to lose control at any drag in excess of 140 KIAS. An autopilot is not a video game cheat mode. It is a real system with real system limits. We are responsible for operating the aircraft within those limits before we use the AP.


THE WIDER PICTURE

Even today, when flying an aeroplane on a private flight (owned or rented) we can fly passengers, provide we do not charge them, and we can endanger their lives by employing dangerous procedures from the pioneer or vintage eras. It's their life and their private risk. In real life, in the United States today we are about 15 times more likely to die if we travel 1000 miles in an aeroplane flown by an amateur pilot, than if we make the same journey with an amateur driver in a car.

Public transport is a different deal. It is not conducted by amateurs and it works to different safety criteria. If we have no interest in those criteria and no interest in applying them during flight simulation we have no logical interest in flying classic propliners. Public transport flying is all about compliance. It’s all about understanding the real 4D procedures and acquiring the skill to comply with them; at first with an autopilot and then much later maybe without. Having the skill to fly an entire flight in compliance with the real procedures using an AP is more valuable than having the skill to hand fly an aircraft through an unrealistic pretend procedure.

The vintage era was the last era within which commercial or military aircrew were allowed to guess whether they were southeast of the White Mountain Range before descending below 7400 QNH when arriving at Fryeburg. Cessna pilots still guess. They still die.

Classic era propliner flying is all about compliance with the alternative way of operating. We navigate using radio beacons. The only way to be *certain* we are beyond the White Mountains when arriving from the direction of Montpelier is to reach the first radio beacon south east of the White Mountains, and that is the SZO.

The sale for use by civilians of DME receivers in the modern era provides a safe alternative that did not exist prior to 1955. The RAF and the Luftwaffe had deployed long range DME from about 1941 and the USAAF from 1943, but civilians could not buy the equipment to decode the signals until later.

After 1932, within the CONUS, wherever we start from in a propliner, our flight plan into KIZG will proceed via a series of beacons, or their intersections, which delineate a series of Airways, that eventually pass close to SZO. No modern or ancient Airway actually routes via the SZO. Like most airports KIZG is reached via a published transition from Airways or an unpublished transit at or above the relevant MSA. At the nearest Radio Range or VOR we begin our transit to the IAF. If there is a published transition in the current plate that does not require use of DME we shall descend to the altitude shown for that transition on the current plate, else we transit not below the MSA. All plausible transit routes exist. Only some have published transitions allowing early descent to altitudes below the relevant MSA.

Note the mountain up to 3268 QNH shown top left of the plate. The White Mountains lie beyond. Many are much higher than 3268 QNH. The White Mountains are much closer to KIZG than to the SZO. KIZG (Fryeburg) is also called Eastern Slopes Regional for a reason.


EXERCISES - TRANSITION AND TRANSIT

The next training exercise is a small step beyond the last. Using the Goose and starting from the Montpelier VOR at 9000 QNH fly the pre 1956 transit to the SZO descending to 7400 QNH using only the SZO on ADF 1 for guidance until reaching SZO, then enter the hold, and only then descend in the holding pattern to maintain 3500 QNH in the hold. Holding patterns exist to ensure safe descent, not to impose delay.

Make sure you can hear the SZO ident before you attempt to use the needle on ADF 1 for track guidance. You may need to fly in the general direction of SZO for a while before you receive the ident and it is safe to use the ADF needle. This is quite normal. Our flight plan will always tell us the track to the next waypoint or during the arrival the downloaded STAR or the approach plate will.


ENTERING HOLDING PATTERNS

In real life there are complicated rules for entering holding patterns. Consult the appropriate training manuals and impose those rules on yourself if you wish. For the purposes of this tutorial and subsequently when arriving at an IAF pointing the wrong way into the hold you may instead turn 30 degrees further away than the outbound heading and cross diagonally to the far corner of the hold tracking outbound for 60 seconds before turning inbound. In this case arriving from the northwest leave SZO on a course of 173 magnetic for one minute and then fly a rate 1 turn left hand to establish inbound 323 in the hold to SZO. We have already practiced adjusting our inbound track to match the published mandatory track.

Note how much of 'approach plate' deals with arrival procedures not approach procedures. We have not yet considered any approach procedures. Each such plate shows how to 'arrive' at the Initial Approach Fix as much as it shows how to 'approach' from the Final Approach Fix. As we have just seen often most of the last hour of any propliner flight must be conducted in accordance with the 'approach plate' because it explains all the criteria for the arrival which may last more than 40 minutes, even if we are not required to hold, and which will be followed by approach procedures and often an additional circuit to land which may take at least a further 15 minutes. A propliner arrival often begins more than an hour before landing. TOD in a propliner can easily be more than an hour before landing. Most flight simulation users fail to grasp this.



PROPLINER TUTORIAL PART 4 - THE APPROACH PHASE.


The arrival phase takes us to the initial approach fix and includes any descent in the hold to the altitude at which the approach may begin and any further delay imposed by ATC. During flight simulation when flying propliners we will always fly the real arrival including any mandated descent in the holding pattern. Whether we impose further delay is up to us. We must be our own ATC since the Microsoft ATC is too dumb to cope.

The SZO is the initial approach fix (IAF) for every runway at KIZG. We have flown the transit(ion)s from airways to the IAF and taken up the hold at 3500 QNH and we are awaiting approach clearance. It does not matter where we started from, everything is the same from now on.

It is now time to turn our attention from the 2D diagram at the top of the plate which describes and mandates the arrival to the vertical diagram at bottom right of the plate that describes and mandates the 'approach'. The vertical diagram shows the one minute inbound and outbound pattern we are established in at 3500 QNH. It is underscored. That means it is a minimum. If it were overscored it would be a maximum.

Why might there be a maximum?

Because the airspace above might belong to a different airfield, or even a different nation. At KIZG it doesn't.


INSTRUMENT RUNWAY versus LANDING RUNWAY.

Now take a closer look at the 2D overhead view of the procedure.

The Instrument Runway at KIZG is always RWY 32 even when the landing runway is RWY 14. Get the difference between the instrument runway and the landing runway clear in your mind before going further. Of course the instrument approach runway is sometimes the landing runway, but that is by no means automatic. Since this is an NDB arrival to an entire airfield the only way to identify the instrument runway is to study the 2D overhead diagram. The instrument approach procedure points at RWY 32 so RWY 32 is the instrument runway.

The approach course is inline with RWY 32 and it would be easy to suppose that this approach is one in which we descend straight ahead to land on RWY 32 just like a modern radar vectored approach to an ILS.

Think again.

Like many others this arrival and approach procedure does not terminate at a runway. It terminates at an entire airfield. It is the means by which airliners locate the entire airfield before joining one of the visual circuits to land. If this were an instrument approach to a runway the plate would show the runway landing length (Rwy ldg) and touch down zone elevation (TDZE) of RWY 32, not just the general airfield elevation in the top left boxes.

Some airfields have no published approach procedures. Some airfields have published approach procedures, but they do not point at any particular runway, in which case no runway is defined as an instrument runway; in which case none of the runways may have any lights. If an airfield has one or more runways with approach lights, the one with the most visible lights will normally be chosen to be the instrument runway and usually, but not always, the published approach procedure will point us at its lights.

When flying propliners in we will normally be flying from and to airfields that have published arrival procedures. They will usually have at least one instrument runway and they may have many, but never assume that the instrument runway is the landing runway.


APPROACH CLEARANCE.

We must determine whether we have completed all the requirements of the arrival phase and have also met all of the requirements for approach clearance.

Once we have reached 3500 feet, the next time we reach the SZO instead of turning outbound in the hold again we will continue inbound to the instrument runway. We must issue approach clearance to ourselves. Before doing so we must establish which runway is the landing runway. We can do this by tuning the relevant frequency on which it is being announced or at most airfields by simply examining the current weather using a freeware utility such as FSMETAR and clearing ourselves to join the circuit for the runway that is most into the wind and sufficiently long for our aircraft type. Remember the canned ATC will not take into account our aircraft type and landing distance required. We must do that and we must issue the ATC clearance to ourselves accordingly.

Provided we are at 3500 QNH and inbound to SZO tracking 323M we give ourselves approach clearance to KIZG. By magic the SZO becomes the Final Approach Fix (FAF).


NON PRECISION APPROACH

As we pass the FAF on the approach to KIZG *we restart our stopwatch*, in our mind we call beacon inbound to ATC, and we descend as rapidly as we like to 1900 QNH on a course of 323 magnetic. There is no glidepath to follow. We begin to look ahead for the instrument runway (lights).

This is a non precision approach. We must try to fly a mandated course, but we are free to pick our own glidepath down to 1900 QNH. This makes our life much easier than trying to fly an ILS. The fact that we can descend at any VSI does not mean we can descend as far as we like. For now the new minimum is 1900 QNH. Locate this underscored information on the approach plate.

Now just in case you have missed the point entirely we not only have no glidepath guidance we also have no track guidance. The ADF needle is pointing through the tail of the aircraft at the SZO, but it would do that whatever course we flew away from the SZO.

That is why this non precision approach begins with a holding pattern. We had to establish in a precise holding pattern so that we could use the ADF to home TO the SZO NDB tracking 323 because after we go beacon inbound we are just going to descend blindly on the track we carefully established in the hold. A holding pattern is a means of setting up an approach track. It is not about delay. We have to set up the approach track using the racetrack even when we have no delay.

Note that 1900 QNH is also underscored. It is our minimum descent altitude (MDA).

The diagram shows that the SZO is 8.5 miles from the instrument runway touchdown zone (TDZ). However we are not flying an approach to the instrument runway. We are only cleared to approach the airfield. We are pointing the nose at the instrument runway which is always 32, but we are not cleared to land on any runway and the landing runway may be RWY 14. We are cleared only to attempt to locate KIZG, and if we succeed, to announce visual and request clearance to enter the visual circuit for the landing runway. That is all. We must not descend below 1900 QNH in our attempt to locate KIZG. We must not enter a circuit pattern without clearance. We must meet the criteria for circuit clearance before we request it.

The approach to KIZG is always made from the SZO holding pattern even when there is no delay; even when the landing runway is RWY 14.

Literally.

Inbound from ENE we may not fly to SZO and turn left onto a track of 323 and descend to 1900 QNH. We must turn left into the hold. We need that one minute inbound leg on the east side of the hold to set ourselves up so that we pass exactly over SZO and leave SZO on a course of 323. We must not fly a looping left turn ENE - SZO - KIZG. We would wind up parallel to the approach course displaced to the north.


MISSED APPROACH.

Now suppose for the moment that there is solid cloud with its base at an altitude of 1850 feet QNH. The cloud base is therefore at a height of about 1400 feet. Did you remember the difference between altitude and height?

Traffic is happily flying round and round the busy KIZG circuit, with the base of cloud 1400 feet above the airfield, but during our approach we will never see the runway lights of the instrument runway because we must not descend below 1900 QNH. We will never break out of the bottom of the cloud at 1850 QNH. Once we reach MDA we must maintain MDA. We must not keep descending and suddenly blunder into the circuit at circuit height.

If at any point during the NDB approach we realise we are failing to comply with the procedure we must execute a MISSED APPROACH. The missed approach procedure is stated top right of the plate.

Turn LEFT and CLIMB to 3500 QNH, proceed DIRECT to the SZO, and enter the HOLD maintaining 3500 QNH. The upper 2D part of the plate shows this from above.

Like everything else execution of the missed approach depends on TIME. We must estimate our (ground) speed KTS during the approach and calculate the TIME from the FAF to the Missed Approach Point (MAP). A chart for standard approach (ground) speeds (KTS) is provided far bottom left of the plate. We must consult this chart and calculate a time from FAF to MAP based on our expected speed between FAF and MAP. In a Goose we might expect that to be 120 KTS with nil wind.

The chart tells us that at a speed of 120 KTS, (allowing for the headwind or tailwind), it will take 4 minutes and 15 seconds to be overhead the TDZ of the instrument runway, (RWY 32). As we cross the FAF inbound we start our stop watch again and as soon as 4 minutes and 15 seconds have elapsed we have reached the Missed Approach Point (MAP).

Since we are still in cloud at 1900 QNH. We initiate the Missed Approach Procedure. No time for indecision or inattention. We will treat this as a go around. Call for TOGA power turn left at Rate 1 and climb to 3500 QNH.

Note the hill right in front of us at 2369 QNH as we go around in cloud at 1900 QNH! There is a mountain at 3268 QNH just beyond. That short black line on the plate below [MACRL] is the runway. It is only a few miles from the White Mountains which are well above the MDA for this approach. We must pay close attention to our stopwatch and go missed at the right TIME.

Rate 1 left and climb!

Back to the SZO hold. Don't dawdle. Remember the mast at 2549 QNH. Decide whether it's worth trying again or whether to divert. If we are flying with a weather theme the base may change, if not it won't. It will still randomise locally in accordance with our choice in the advanced weather menu though.

We have just learned a valuable lesson. In real life we are not the only person in the airspace. We cannot simply blunder about in any direction convenient to us, descending to any altitude convenient to us. We must take other aviators and their safety into account. The procedures to be followed in real life are not just about our safety and the risks we may be happy to take. The real world procedures mandate that we do things to protect the safety of others. If we desire realism during flight simulation we must operate aircraft in ways that take other aircraft, in other traffic flows, into account. That those flows are not present in MSFS is not the point. In real life we cannot always figure out why the procedure says we must not do X. We just have to accept it and comply.


THE CIRCUIT PATTERN.

Now on another day we will be luckier. There will be no cloud below 3500 QNH and the visibility will be 10 miles or more. As we cross the SZO inbound at 3500 QNH we can already see the airfield lights 8.5 miles ahead. We grant ourselves clearance to enter the circuit pattern, making sure we know which runway is the landing runway, based on the current wind direction.

In theory MSFS should be announcing this on an appropriate COM frequency. However I recommend that you install a freeware program such as FSMETAR as it will reliably provide you with the weather and wind state (on screen) even if Microsoft have screwed up the frequency allocation. You may already have a payware program that has this facility. We will study runway selection again in Part 7 of this tutorial.

So how do we know the altitude of the circuit pattern?

We will use two simple rules.

We take the airfield elevation from the plate, add 900 feet and then round up to the next hundred. So for KIZG 454 + 900 = 1354 which rounds up to 1400 QNH.

We now consult the CIRCLING minima at bottom right and we consult the lowest value in the C column. In this case that is 1720 QNH. We use whichever of the two values is the higher. We will fly any visual circuit at KIZG at 1720 QNH in a propliner.


MARKER FANS.

KIZG is also blessed with a marker (MKR) called GRINN, which is positioned 3.2 miles short of the RWY 32 touchdown zone.

In real life it causes the MKR lights to illuminate, and the MKR tone to play, if an aircraft inbound on the approach passes over it. During descent to 1900 QNH in cloud or low visibility a real pilot is awaiting the MKR tone from GRINN to confirm that the aircraft is still on course for the airfield.


Unfortunately Microsoft left most of the MKRs out of MSFS. Eye candy was evidently more important than the ability to conduct flight simulation of real approaches. We have to work around this deficiency.

In real life aircrew can descend from 1900 QNH to 1720 QNH after they see the approach lights and after they have also passed over the MKR at GRINN. Both must be true. In MSFS we must base everything only on visual contact with the lights. After seeing the lights, if the landing runway is RWY 14, we can ease right and enter the left hand downwind leg of the pattern, but only after locating any traffic ahead of us in the landing sequence for RWY 14. We maintain 1900 QNH whilst we tally any circuit traffic and especially anything departing RWY 14 and turning left into the circuit ahead of us. By the time we have done that we will be 'inside' GRINN anyway.

If the landing runway is RWY 32 remember that this is not an approach procedure for landing on the runway it points at. This is just an approach to the entire airfield ALWAYS followed by a visual circuit. The downwind leg for RWY 32 starts at the far end of the airfield.

For reasons that will only become apparent later RWY 32 at KIZG has a non standard right hand circuit to the north of the field. When the landing runway is 32 we must ease left onto the dead side of the circuit pattern and CIRCLE round the field to join right hand down wind for RWY 32. We now issue the relevant ATC clearance to ourselves and comply. There is no hurry to descend from 1900 QNH to 1720 QNH, but we must be level at 1720 QNH before entering the downwind leg for either runway.

Note that the plate also shows the circling heights for pilots using QFE. At some airfields MS actually remembered to place the MKRs. We will use them as published if they are there, but we cannot assume they will be there in MSFS. We must formulate our approach strategy accordingly.


APPROACH MINIMA.

Those boxes at bottom right show us our minima for this approach. Today minima are categorised differently to the classic era and to more complicated criteria. For most of the classic era they were categorised by speed at the threshold and there were only two categories;

A) Single engined aircraft and other aircraft with a threshold reference speed (Vref) of 65 KIAS or less

C) All the rest.


The threshold target speed is shown in my handling notes either as such or thus;

Cross airfield boundary 87 KIAS (@ 63,500lbs)

So for our classic era simulation purposes if the (weight adjusted) value of Vref is below 66 KIAS or we are flying any single engined propliner our minima are CAT A. If multi engined and the threshold / airfield boundary target speed exceeds 65 KIAS assume they are CAT C as defined by the modern criteria on modern plates.

All the propliner FDE I have released have CAT C minima and that includes the Goose.

We may not commence an approach to KIZG, in a propliner, under any circumstances if the reported visibility is below 3 miles or the reported cloud base is below 1900 QNH. If we were flying a Beaver we would have the same cloud base minimum but the visibility minimum would be 1.25 miles. Make sure you can find all this information bottom right of the plate

Modern approach minima work differently. See official publications.

There are a lot of dangerous obstacles around KIZG and so the approach minima are high. Don't disregard your minima. Divert. You will need to be a skilled FS pilot in current practice to stand much chance of succeeding with a visibility of 3 miles. Think about your own skill level. Be realistic. Maybe you should set your minima at double those of a real airline pilot?

That more or less explains the situation when the airfield is below (our self imposed skill related) minima and also when the weather is beautiful. Often the situation is in between and life is more complicated. Suppose there is a 5/8 cloud base up at 4000+ QNH with rain falling from those clouds. Suppose the visibility below cloud is 10 miles, but 3 miles in rain showers.

If we acquire a visual tally on the airfield, but subsequently lose sight of the airfield at any time, we must fly the Missed Approach Procedure. Wandering into the foothills of the White Mountains just beyond in a rain shower would be very easy. That hill at 2369 QNH is really close to the visual circuit, which is at 1720 QNH.


I DONT WANT TO FLY INSTRUMENT APPROACHES.

Well that sounds like a good reason to avoid flying any kind of airliner, but it's not really the point. When we depart anywhere for KIZG after 1932 intending to have a realistic flight we will usually flight plan and fly Airways to the general vicinity of KIZG. We will leave airways at the closest modern VOR. When arriving from the northwest that may be Montpelier, or from the south Kennebunk.

Having arrived at the last Airways VOR we intend to navigate to the IAF, which is SZO, because we only have permission to proceed as far as SZO. We do not have permission to proceed to KIZG and ATC will not grant such permission until we announce that we have a visual tally with KIZG *and all the relevant safety hazards*.

In real life, if there is no ATC at destination, (ever, or just at that time of day), we must not give ourselves permission to proceed to enter the visual circuit until we have a visual tally on the airfield and all the relevant hazards. The presence or otherwise of ATC at KIZG is therefore not relevant, either during flight simulation or in real life. What we need to ensure as aircrew before approaching KIZG is the same either way.

We must remain clear of all obstacles. We descend below MSA (or the transition) only after we can see and identify them. Never because we cannot see them and are assuming that we are already clear of them. That is how propliners impacted glaciers in the vintage phase of aviation. Classic era propliners deserve to be flown using classic era procedures and safety criteria.

Until we see and identify the obstacles, and also the airfield, we must remain at an altitude that is above the unidentified obstacles and the visual circuit. We must navigate to the IAF, at or above the MSA, or in accordance with a published transition, until we have identified both the obstacles and the airfield. That is the only way to ensure a safe arrival.

If we still cannot identify everything that we need to identify when we reach the IAF we must fly the published approach procedure, and if we still cannot visually identify the necessary things when the stopwatch says we have reached the MAP we must fly a missed approach.

We must do these things whether it is light or dark, dry or raining, good visibility or bad, VFR or IFR, with or without ATC at destination.

The alternative is to divert. There is no alternative based on blundering suddenly into the obstacles, or the visual circuit, from a random direction, at a random altitude.

Of course we hope to become visual with the airfield and relevant local obstructions before SZO, so that we can position for a visual circuit as soon as possible. However the visibility is not always 10 miles or more, cloud annoyingly forms below us, and it gets dark. Some airfields are hard to pick out, in MSFS and in real life. This is not an excuse for blundering around in a random way looking for them. There is right way and a wrong way to locate our destination. There is a sensible series of directions to fly and a series of sensibly decreasing altitudes.

The arrival plate explains what they are, which radio beacons we need to tune, and how to navigate realistically in 4D between them. This is the difference between pretending to fly a propliner and simulating flying a propliner.


SITUATIONAL AWARENESS.

The significant difference between just pretending to fly an aircraft and actually flying one is the degree of situational awareness required. In a real aircraft or during flight simulation we never blunder about in hope. We know our estimate for each waypoint on our flight plan all the time. We know which waypoints we are between. We know the minimum safe altitude between those waypoints. We must know our 4D orientation to ground features we cannot see yet, as well as the features we can see already.

On many trips, especially if we are not familiar with the airspace, we will end up using the published arrival to set us up so that we know our orientation to the airfield as we approach it. We know the procedure will prevent us flying into any obstructions. What differs, day to day, or night to night, is when exactly in the process we manage to get a visual tally on all the relevant obstructions and the airfield itself, so that we can begin to position visually and safely for an entry to the downwind leg for the landing runway. On trips when we cannot get a visual tally on all the relevant masts, the relevant mountains, and the airfield we need to continue to the IAF at the MSA and enter the approach procedure else we have inadequate situational awareness.

The approach procedure is there to point us at the brightest approach lights on the airfield, from a safe position, at a safe starting altitude and most importantly a known orientation; known to us and to everyone else. It is the only way to stay safe until either we can see all relevant obstructions and the airfield, or we know we are 'inside' the obstructions and on the extended centreline of the instrument runway. We will not 'blunder' into the active side of the visual circuit. We will not be confused about which runway is which or where left hand downwind for RWY 14 begins. The more runways an airfield has the more important it is to arrive with known orientation so we know exactly which runway the nose is pointing at when we first tally the airfield. Then we can 'count round' the runways and determine which one is the landing runway and figure out where downwind left hand begins.

Remember this is a non precision approach to locate an entire airfield. Although we set up the approach track using a race track holding pattern we have no course guidance from the FAF to the MAP. We must not expect the airfield to appear dead ahead at 12 o’ clock. This type of approach is not nearly precise enough to achieve that all the time. Often the airfield will appear at 10 o’ clock or 2 o’clock. This is the classic era so we are transitioning from flight by instruments to flight by visual reference to the scenery as late as we possibly can, but our destination is just some scenery and therefore just another landmark that could pass by outside the limits of visibility, or off to one side due to our aircraft being drifted by the wind.


Between the FAF and the MAP we must swivel our head in the VC looking left and right for the airfield. The lower the visibility the more important this becomes. The great benefit of a VC is that all the correct sight lines are blocked. We will not be cheating by sitting outside the aeroplane while we fly it. We will see exactly what the real pilot could see. Provided we use a flight simulator and not a video game.



SEE AND BE SEEN.

In real life aviation does not revolve around us and our virtual airline. When we announce, 'N700MS 4 miles centreline RWY 32 1900 QNH (request) positioning left hand downwind for runway 14' everyone knows where to look to get a tally on us. That includes anyone in the circuit, anyone in a Tower and anyone with a radar screen. If we desire realism then operating the aircraft so that it is where everyone else expects it to be in 4D is important. In a real aircraft we must work hard to improve the situational awareness of other airspace users and controllers.

On COM 1 we need to announce our 4D position, and a precise intention, in a way that allows everyone listening to understand how we will proceed from one to the other. The published procedures make that easy. If we just 'arrive from the south' how accurate is our position report going to be? Without GPS or DME how will we calculate our range and bearing from the field so that everyone else knows where to look when we report, or request, joining the circuit pattern?

When we fly propliners we must try to simulate the reality of a crowded sky. Communication is an important aviation skill. In real life, we would need to communicate our 4D position accurately to a lot of other people all the time. In the days before radar that included ATC and it was even more important.


PROCEDURAL ENVIRONMENT.

In a non radar environment frequent and precise position reporting in 4D was essential, whether flying VFR or IFR. A non radar environment is known as a 'procedural' environment because it requires much greater adherence to published procedures, not just so we can find our way around the sky, but so that we can keep telling people exactly where we are in 4D all the time. Their situational awareness is as important as ours. They may kill us. There is no radar controller to warn them where we are.

In a non radar environment we must be able to report our bearing from somewhere relevant to other pilots and ATC on demand. We must be able to provide a good estimate for the next waypoint on our flight plan. We have to cue other airspace users that we are becoming a threat to them. In the classic era, and especially earlier, there was precious little radar control to do it for us. That's the big difference; procedural control versus radar control. Procedural flying versus radar monitored flying.

If we have the intention of simulating flying propliners in the classic era we have the intention of taking responsibility for many things that are now resolved by a radar controller in the modern era; whatever our destination. A non radar environment requires more precise 4D navigation because it requires aircrew to deliver more frequent and more precise estimates for beacons and intersections, VFR or IFR, with or without ATC.

However we must never forget that most commercial airfields around the world today, even in the modern era, are just like Eastern Slopes Regional Airport. They still have no radar in 2008. Only the largest airfields have a radar controlled environment even today. Most have no radar at all and many more have no radar at night or at weekends. These procedures are not dead and buried. They are current. That is why we can still download them from the web sites of the relevant regulatory authority. The ubiquitous availability of canned ATC radar vectoring within MSFS is just a cheat mode and one that works badly because it does not allow for obstructions or the performance envelopes of older aircraft.

The faster the aircraft we are flying the more important it is to cue everyone else into what we are doing and are about to do. The more predictable our flight path needs to be to everyone else. They have less time to get a tally on us before we become mutual threats to one another.

The alternative arrival call 'N700MS approaching from the south 2500 feet with field in sight' gives no one any great clue where to look for us, and ATC have to waste time asking if we are aware of the mast at 2549 QNH and whether we can see it. Staying alive in a crowded sky is also about being where people find it easy to see and avoid us.


'OBSTACLES'.

All propliner approaches to KIZG must be made from the South East via the SZO. The SZO is always the IAF. The terrain immediately to the North West is the White Mountain range. That terrain is too dangerous to allow propliner straight in visual, or instrument approaches from that direction even when RWY 14 is the landing runway.

Some airfields have more than one instrument runway. Many do not. There may be no approaches allowed from the other direction(s) for a multitude of reasons including prohibited areas, danger areas, nature reserves, other major airport airspace etc., as well as terrain and masts. Hills and masts constitute physical obstructions that can be located and avoided easily in good weather. Nature reserves and danger areas, which must also be avoided while positioning visually, are harder to 'see and avoid'.

Obstacles to be avoided come in many forms. We must fly the published inbound routes to the IAF, and maintain the MSA until we know we have reached a safe location from which to begin our approach to the airfield. The only really safe location from which to start is the IAF at the promulgated altitude descending only to the MDA. This is especially true if we are not a regular visitor to the airspace.


Finally note that although this approach is to the airfield at KIZG and not either of the runways, the runway information is anyway at bottom left of the plate. 4200 feet is enough for most propliners including some big four engined ones, especially landing into wind.

Eastern Slopes Regional is a real airport serving a popular winter resort area. This is the real approach plate. In real life, it still does not have any kind of approach that leads straight in to land on any of its runways. There is no ILS. No VOR. No DME. No radar.


MODERN ERA GPS.

Look top right of the plate. It announces that this is the NDB or GPS-B approach procedure. Another misconception must now be set aside. The possession of a GPS receiver is not a license to fly any procedure we like. It is a license to use the GPS to fly these same procedures in 4D using GPS instead of ADF. Having a GPS does not change federal regulations and it does not alter or abbreviate the 4D ballet that must be performed. Having a GPS does not mean that we can avoid maintaining MSA or descending in holding patterns. It just means that in 2008 if we have one we can look at a GPS instead of an ADF whilst performing exactly the same procedures.

Actually in real life there is so much red tape and cost associated with having permission to use GPS for anything as useful as arrivals and approaches that it rarely used for that purpose at all. In real life it is much cheaper to fit an ADF that is accurate enough to be used to fly arrivals and approaches. Most GPS equipment used in aircraft is still not accurate enough in real life to be used in the approach phase. Just as in the RDF vintage era most real GPS equipment is still only accurate enough for en route use.

The only difference between 2008 and 1938 is that in 2008 we can use an appropriately and expensively certificated GPS to fly exactly the same procedure as has been flown using ADF since before WW2. The rules have not changed. What is required to avoid flight into obstructions has not changed. What is required to ensure that everyone else who needs to know where we are, what we are doing now, and what we are going to do next (in 4D) has not changed.

We will visit KIZG again during the tutorial on departure procedures (Part 5). Now is a good time to use a pen to write on the KIZG plate anything that will help you to remember the things discussed above so that you can refer to them again when reading Part 5.



STRAIGHT IN NDB APPROACHES.

Even in the 1930s there were also instrument approaches that allowed aircraft to descend right down to an instrument runway and land from what is known as a straight in approach. They were also increasingly based on non directional beacons (NDBs) and flown using only ADF for track guidance.

We will now visit Greenville, also in Maine. Flight plan code for Greenville Municipal is 3B1. The IAF for Greenville is an NDB called SQUAW, which codes XQA on 236.0 Khz. It is on the north side of Big Squaw Mountain. The approach course is 143 magnetic. Print the plate and study it as you read on.

This is a different ball game. It illustrates nicely all the alternative procedures and situations to Fryeburg. This approach is an approach straight in to a runway (RWY 14 at 3B1) and also an airfield approach to two different destinations!

Greenville also has a hydroplane base. Note that the vertical diagram shows two runways one on Moosehead Lake and one on land at 3B1. The hydroplane RWY 14 really is exactly in line with the landplane RWY 14 and about 2 miles short of it. You water taxi to and from the hydroplane anchorage in the inlet shown on the plate.

Look bottom right. Regardless of whether we are approaching the lake runway or any of the land runways our MDA is 2300 QNH. We may not descend below 2300 QNH until we have a visual tally on the approach lights for RWY 14 at 3B1. Even if we wish to land on the lake we must locate the lights of RWY 14 at 3B1.

The line beginning S-14 contains our minima for Straight (in approach) to RWY 14 at 3B1. All the other possibilities are shown simply as CIRCLING. Notice that at 3B1 it makes not the slightest difference. At other airfields it will.

In this case the airfield is at 1400 QNH. To determine the visual circuit altitude we add 900 and round up to obtain 2300 QNH. We consult the CAT C minima. This time we get the same result both ways. We will fly any of the visual circuits at 2300 QNH including the lake circuit.

The difference at 3B1 is that if cleared to do so by ATC, and if we see the lights in time, we do not have to circle to land on RWY 14, we can instead land straight in, (a straight in approach). We know this because the length and TDZE are given at the top of the plate and S- minima are given for RWY 14.

Our CAT C minimum visibility is 2.75 miles.



OPTIONAL HOLDING CRITERIA

Now transfer your attention to the horizontal diagram above. The approach at Greenville is not entered from a holding procedure. However if we arrive high at XQA, or we want to hold at XQA for training, we must comply with the dotted holding criteria. There is no defined leg length. However we must hold left hand to the North West of the XQA and comply with the inbound and outbound courses and stay within ten miles of XQA using our stopwatch.


RESERVED AIRSPACE

The most interesting thing about Greenville is its proximity to two Military Operations Areas (MOAs) called CONDOR 1 and CONDOR 2. These constitute an obstacle that is difficult to define geographically from the air. Consequently they are difficult to 'see and avoid' laterally. They are best avoided vertically. There are two published Airway transitions, both from the South. The one that traverses right across CONDOR 2 from Augusta 72.3 miles to the south requires inbounds to descend not below 6500 QNH until reaching XQA. The one that just clips the corner of CONDOR 2 inbound from Bangor allows descent not below 5100 QNH until the XQA.

For reasons relating to terrain rather than CONDOR 1 any traffic approaching XQA from any other direction would be unsafe below 4900 QNH, but it is anyway mandatory to begin the approach to Greenville by crossing XQA at or above 5100 QNH (see vertical diagram).

There are a couple of small masts, but both are below circuit altitude. Apart from CONDOR 1 and CONDOR 2 the significant problem is Big Squaw Mountain at 3262 QNH just right of the final approach path.

Reserved airspace comes in many forms. The rules that specify the precise circumstances under which aircraft may traverse a particular type of airspace are complicated and vary over time. Unless you are familiar with the specifics I recommend that you never route a propliner through airspace reservations significant enough to be highlighted on the plates you download. In real life there is also a raft of small print in the airline insurance policy that limits what rules you can employ and what airspace you can utilise.


PROCEDURE TURN

At KIZG we entered the approach procedure from a holding pattern. At Greenville we will enter the approach via a procedure turn. Note that during the procedure we must never proceed more than 10 miles from XQA. The only way to ensure this is with a stopwatch.

Arriving from Augusta we are descending to 6500 QNH. We will try to be level by XQA. As we reach XQA we start the stopwatch and clear ourselves for the approach. We turn left onto a course of 323 magnetic. We do not have to fly around a mandatory holding pattern even if we are still descending to 6500 QNH. We could if we wished. Having arrived at 6500 QNH before XQA, (and having slowed to <= 175 KIAS or <= 140 KIAS if we intend to use autopilot), on passing XQA on this flight we will just descend as fast as we please (subject to Vno) to 5100 QNH and turn left onto 323 magnetic. If we descend at 700 VSI it will take 2 minutes to reach 5100 QNH.

How far we proceed on course 323 is entirely up to us so long as we are never more than 10 miles from XQA. The only way to know is to use the stopwatch. We will proceed on course 323 for 2 minutes and level at 5100 QNH. Now we start the procedure turn, only a part of which is shown on the plate.

We turn right 45 degrees at rate 1 onto a course of 008 magnetic. When on course 008 we restart the stopwatch. We fly 008 for 90 seconds. Now we fly the procedure turn, which is a rate 1 turn away from the airfield (to the left) through 180 degrees. It is identical to one end of any holding pattern. This procedure turn is always in the opposite direction to the entry turn, always away from the airfield, and reverses our course to 188 magnetic. We are closing the final approach course at 45 degrees watching ADF 1 and will turn inbound at rate 1 to XQA when the needle shows that we have almost reached an inbound approach track (QDM) of 143 magnetic. We are more than 2 minutes from XQA, but less than 10 miles.


CONTINUE APPROACH

As soon as we are inbound to XQA established QDM 143 (but no sooner) we can descend as fast as we like to 3700 QNH. No lower until beyond XQA. Remember Big Squaw Mountain just off to the right at 3262 QNH. After passing XQA inbound still tracking QDM 143 we continue descent to MDA = 2300 QNH looking ahead for the RWY 14 approach lights at 3B1.

As we pass XQA inbound we start the stopwatch again. If we are at 120 knots groundspeed (in the Goose) we will go missed after 3 minutes. (Look bottom left). This time the distance from the FAF to the MAP is only 6 miles. We will go missed if we don't see the 3B1 lights, even when we are flying a Grumman Goose and intend to land on the Lake from a visual circuit. There is no straight in approach to the water runway. Lake landings must be made from the Lake circuit pattern. Only RWY 14 at 3B1 has an authorised straight in approach.

There is no track guidance once beacon inbound. We intercepted and flew the QDM using a procedure turn on the other side of the beacon to be certain that we were on exactly the correct course before we crossed the beacon inbound and lost all track guidance. There is no glideslope. We choose our own rate of descent but if intending to land on RWY 14 we must lose 2300 feet in 3 minutes, which is just over 700 VSI.

However we can only descend 1400 feet to 2300 QNH until we see the RWY 14 approach lights so we will continue down at 700 VSI. When, and only when, we see the approach lights for RWY 14 we can descend to land on it. When you identify the lights transfer from the approach frequency to the tower frequency and grant yourself landing clearance.

There is no MKR to assist us. We must rely on the stopwatch to go missed after 3 minutes if flying at 120 knots groundspeed and we never see the approach lights at 3B1. We will still be on the approach frequency. We will never talk to Tower.

It is time to fire up FS9 and practice a different arrival and approach in the Goose, this time involving a procedure turn. Observe all the 4D restrictions of the procedure. Make maximum use of the autopilot. Choose the weather conditions to be fairly easy the first time you fly the arrival and approach. During the first exercise save a convenient start position for flying further arrival and approach exercises to 3B1.

Then repeat this exercise with more marginal weather, but always use nil wind. Practice straight in approaches to 14. Practice joining the lake circuit to land on 14 Water, and then practice joining the visual circuits for both RWY 03 and RWY 21. Land on a different runway each time you fly the approach. Remember that you may only make straight in approaches to RWY 14.


MISSED APPROACH

Study the plate. If we go missed we must first climb straight ahead to 2800 QNH and only then rate 1 right turn back to the XQA climbing to 5100 QNH. This pretty much ensures that even if we are slow to clean up the flaps and go TOGA in a big propliner we will manage to scrape over Big Squaw Mountain at 3262 QNH. We won’t always be flying a propliner with the performance of a Goose. We fly the procedure again or divert. Note how this is displayed in the vertical diagram as well as in words at the top of the plate.


DIVERSION

Make sure you understand that we must fly the missed approach procedure towards XQA until we are above the MSA which is 4900 QNH. If we are diverting to Bangor we may not simply set off for Bangor from the vicinity of 3B1. The minimum altitude for a transition towards Bangor is 5100 QNH. We go missed, climb straight ahead to 2800, turn right rate 1 to the XQA climbing to 5100 and only when we are at or above 5100 QNH can we turn away from CONDOR 2 en route to Bangor.

In real life ATC would read all this out to us as a diversion clearance. The canned ATC is way too dumb. We have to study the plate and work out what the diversion requires by studying the MAP, the relevant MSA and the minimum altitude for any relevant and published Airway transition. *We* have to write it down on the plate and read the ATC clearance to ourselves.

It is not that hard to work out what is required in the event of diversion, but we need to do so before we boot up MSFS. This is part of our pre flight planning. Flying a propliner in the classic era is not a make it up as you go along experience. It is about achieving planned targets, whether performance targets from the handling notes, or 4D navigation targets from real world ATC procedures.

Before flying into an airfield, in the simulator, study the arrival plate, work out what you have to do to divert safely to your alternate, and then hand write the diversion procedure on the back of the plate before flying. Write what you are required to do to achieve 4D compliance in a format that you will be able to understand and hour later or a year later. If the need to divert arises or you decide to divert for training you have the ATC clearance ready to read to yourself.

You may also wish to write the arrival and approach procedures, in plain words, on the back of the approach plates you download until you are familiar with their graphical format and find it easier to work out what to do from the diagrams alone.

Some propliners have a poor rate of climb in climb power. To divert via Augusta we may need to climb within the optional holding pattern at XQA until we are at or above 6500 QNH, on or north of the approach course. Then and only then we can set course for Augusta traversing over the MOA. This is why 3B1 needs an optional holding pattern. The hold is used to climb safely during a diversion via Augusta. The holding criteria are still nothing to do with delays and in this case not really relevant to arrivals.

If diverting to somewhere in Canada (to the North) we could set course once above 4900 QNH, but we would probably choose to start from XQA anyway.

Before reading on, study the 3B1 plate, deduce what your ATC clearance to divert via Augusta would be, and then write it down line by line on the back of the plate.


OPTIONS.


Now let's backtrack. When we flew the procedure turn we decided to descend outbound from the XQA until we were level at 5100 QNH. That was our choice. We could have flown the procedure turn still descending to 5100 QNH. The point is that we cannot descend below 5100 QNH until after we have been outbound from the XQA and are re-established inbound on the final approach course.

Arriving from the north (east) we must turn outbound in the optional hold and fly outbound course 323 until ready to fly the procedure turn. How long the procedure turn legs are is not very important. They won't be of equal length, but the whole procedure must take place within ten miles of the XQA. We control our energy state accordingly and use our stopwatch carefully.

Make sure you understand that we cannot come straight in from the North West descending to 3700 QNH by the XQA. We have to go outbound and intercept the final approach track (QDM) knowing for sure that we are inside ten miles first.

Note that all turns in all holding and approach procedures are left hand unless the procedure mandates a turn to the right. The procedure turn which starts with a right turn of 45 degrees is actually a left hand procedure turn, the direction being that of the 180 degree turn which reverses our course. Unusually the MAP at Greenville mandates a right turn; but only after reaching 2800 QNH.



PRACTICAL CONTEXT.

Now let me try to put this procedure in a practical context for flight simulation in all weathers. In real life it is very difficult to determine where the 'edge' of 'obstructions' such as an MOA really are in terms of ground features. It is much easier, and more certain, to use the altimeter to avoid them vertically. The detour coming in from Augusta would be large if we chose to attempt lateral avoidance of the Condor MOA.

If we run a small charter airline in 1938 that operates a single Grumman Goose we need to be able to access Greenville when the cloud base is low, or when the visibility is low, or at night. Even aircraft of Goose size are propliners and can do anything a DC-3 can do. After dark the Goose will have to land at 3B1 rather than on the Lake.

On a nice day inbound to Greenville from Canada, where there are as yet no airways and the vintage phase of aviation is still in place, in our Goose we will have every intention of turning for Greenville and descending early, but we will track to the XQA not below 5100 QNH, just in case we have trouble seeing the airfield.

On a nice day we will identify Moosehead Lake when much more than 30 miles short of the XQA and will get a tally on the airfield at whatever maximum range the BGL author (Microsoft or third party) decided we should be allowed to see it, or its lights. Maybe 20 miles, maybe much less. Then, and only then we leave 5100 QNH for 2300 QNH, forget about the XQA, and route direct to join left hand downwind for whichever runway we intend to land on. We need a clearance from ATC to make an approach or enter the circuit. We need it so that we know the landing runway (QFU). We could instead deduce the landing runway using a weather report from freeware such as FSMETAR and if our destination has no ATC (at that time of day) we must always do that to determine the landing runway. We may need to allocate a longer out of wind runway to ourselves depending on the type of aircraft we are flying.

The XQA MSA is 4900 QNH in all directions, but the procedure starts at 5100 QNH. We don't know why. We don't need to. We must comply even though we do not know why. We just stay at or above 5100 QNH until we reach the XQA when inbound from the south, or from the north proceed to the XQA at or above 5100 until we have visual contact with both our destination and Big Squaw Mountain at 3262 QNH. Approaching 3B1 from the North they are the only objects we need to identify and tally. We will usually be able to descend early. From the south we will never be able to descend early due to the MOA. How far we can see is irrelevant. Identifying the airfield and physical obstructions is not the point. In real life it rarely is the whole point. Reserved airspace is very common. The only safe way to avoid it is vertically. Try to avoid it laterally and you will eventually blunder into it.

If you now spend a few hours flying into these two airfields arriving from all directions, into all the runways, at all three landing sites, entering the approaches from a holding pattern at KIZG and a procedure turn at 3B1 you will be able to interpret and fly any other NDB approach at any other location.


There is a third type of approach course reversal, known as a tear drop reversal, but it is little used in the United States, and if you encounter it elsewhere it will be obvious from the diagram what is required. Remember in your multi engined propliner you going to simulate CAT C minima and procedures whilst using a flight simulator.

The point about flying real approaches is that they are all different because the obstacles are always different and learning to cope with a slightly different procedure every time is a large part of the challenge and fun of flight simulation. From about 1940 to 1955 most airports significant enough to have instrument approaches were served only by NDB approaches and for many that is still the case today.


RANGE (VOR) APPROACH.

The Range approach was conducted using the Radio Ranges that delineated the new U.S. federal airways. There were 231 Radio ranges in use within the CONUS by May 1939 and a few dozen in Europe operated by Lufthansa. The Range approach diminished in importance from 1939 onwards but was not finally withdrawn until the last Radio Range in the US Airways system had been replaced by a VOR about 1960.

There are now more than 231 VORs in the United States and thousands world wide. We can use them to simulate either a Range approach or the VOR approach that replaced it from the 1950s. They hardly differ. We must use VOR1 receivers to fly these approaches in MSFS and we must tune the modern VHF frequency on NAV 1.

Remember when flying a propliner 1932-55 we should turn DME off. Thus a modern VOR/DME approach may need significant interpretation to convert it back to the simpler Range (VOR) Approach. Current VOR approaches that use no DME need no conversion so let's study one of those.


Continuing our tour of Maine we will visit Sanford Regional (KSFM). Print the plate and study it now.

We see that it is very simple. There are no published transitions from Airways. We would not expect any since the Range and later Omni Range is one of those that marks the course of an airway. Kennebunk (ENE) VOR features again.

Whichever direction we approach Kennebunk from when we first cross ENE and enter its cone of silence (High Cone) we simply enter the ENE hold and descend to 2000 QNH in the hold. Once we are established *inbound* in the hold *at 2000 QNH* we can clear ourselves for the approach. Then we may descend to 1700 QNH. As we come inbound at 1700 feet for the last time over ENE (low cone) we set course for KSFM tracking 261 magnetic from the Range and look ahead for the lights of RWY 25.

If RWY 25 is also the landing runway (S-25) we can descend as fast as we like to 600 QNH. If the instrument runway is not the landing runway then our MDA is 740 QNH for CIRCLING to other downwind visual joins. Our visibility minimum is 1 mile or 1.5 miles. The implied circuit altitude is 1200 QNH. Our minima are low. This time we are using a Range or an Omni Range and we have track guidance FROM the range towards destination.

Note especially that our track is not the instrument runway track. We are tracking below the Airway, on its centreline. We are not tracking the centreline of the instrument runway at KSFM. We are using navaids established by the federal government for airways use. The local tax payers and/or the owners of KSFM contribute no more to their cost than the tax payers of California. They have no say when they will be switched off for maintenance. At many other airfields the course we track away from the Range that delineates the airway, towards the airfield, may be even more different to the runway, even if the approach allows a straight in landing to be made (promulgates S- minima).

Although we may descend before ENE the ENE is the FAF and we start our stop watch at the FAF, not when we descend. Rules for going missed as before, but with different criteria of course.

These were the earliest and most primitive instrument approaches. They are the easiest to understand.


LORENZ BEAM APPROACH.

The first such Instrument Landing System was installed at Berlin during 1934. By 1939 the system was global and was used at major military bases as well as major airports. The LBA tutorial is part of the Savoia Marchetti S.73 (v2) Propliner Tutorial package available from Avsim. I advise everyone to download it and learn to fly LBA approaches using it before proceeding with the rest of this tutorial. Today we call an LBA approach a LOC or LOC+DME approach.

The observant among you will have noticed that the DZN L-049A panel has always had functional LBA/SBA lights and associated DME. They may be incorporated (for our personal use) within late vintage or early classic era propliner panels, or on a pop up window, when flying a Lorenz (Standard) Beam Approach in places where DME refers to nautical miles.

The LBA gauge provided within the Savoia S.73 release can be incorporated (for our personal use) within late vintage or early classic era propliner panels or on a pop up window when flying a Lorenz (Standard) Beam Approach in places where DME refers to kilometres, but the relevant gauge was actually used as a surveillance radar approach style ‘height should be’ QFE reference in metres.

A full tutorial and associated approach plates are within the Savoia Marchetti S.73 package. The tutorials can of course be flown using the DZN L-049A with ILS gauge removed instead, after downloading the Savoia package.

Whilst a variety of LBA and SBA gauges have been released for use in MSFS, all of which are adequate for use in a DME = nautical miles environment, those who wish to train in a metric environment are strongly advised to obtain and use the relevant gauge set from the Savoia S.73 as some other gauge sets have bugs.

Do not skip this part of the tutorial just because it requires a separate download. The modern ILS approach which we shall study next is significantly harder to fly than an LBA.


ILS APPROACH.

Primitive forms of ILS were also introduced within the United States for commercial and military use from 1934. The glideslope beam was usually projected from the wrong end of the runway and was very steep. Aircraft had to fly under the beam to land, but aircrew had access to a gauge which allowed them to monitor deviation from the beam. No such gauges exist for use within MSFS.

In 1936 a different type of ILS was first installed at Newark. This had the glideslope data generated from well short of the touchdown zone and was associated with an MDA at the glideslope emitter. Final descent from MDA to a blind landing was allowed after hearing the inner marker tone.

Strictly speaking these do not exist in MSFS either, but we can simulate these types of approach by using a default ILS and self imposing an MDA which is 200 feet above runway elevation, descending from 200 feet above runway elevation at the inner marker. This should only be attempted to long runways.

Before WW2 these approaches had no mandatory missed approach if the inner marker tone was heard. The flight continued to a blind landing which might be a crash landing. There was simply nowhere better to divert to if the fog was thick and the inner marker had been located. Failure to hear the inner marker required a missed approach. All the relevant inner markers ARE present in FS9.

These pre war U.S. systems were little more than an excuse to reduce landing minima below safe values within the CONUS and they did not spread elsewhere. LBA/SBA was the de facto international standard for beam approaches.

Any ILS approach is the hardest type of approach to fly because it has the lowest minima and requires very tight adherence to the published criteria.

Modern ILS in which the glideslope beam leads to the touchdown zone of the runway was developed for military use by U.S. armed forces soon after WW2 and became widespread commercially after each nation ratified the Treaty of Chicago and adopted the latest U.S. standards and recommended practices (SARPS) which had become the ICAO (United Nations) SARPS with little modification.

Since we can fly a modern ILS approach in any aircraft at any time in I suggest that the propliner community avoid ILS approaches unless they are the only type of approach available. I will however explain the reality so that the dumb Microsoft radar vectoring into the nearest mountain or mast can be avoided.

We will continue our journey around Maine and visit Auburn-Lewiston Municipal. Flight plan code KLEW. I chose KLEW for training purposes in this tutorial because the navaids available and approach complexity at KLEW in the 21st century are fairly typical of how things might have been at a really major airport around 1950. You should understand the general principles of instrument approaches by now so I am only going to cover new concepts. Print the ILS plate for KLEW and study it now.

In this case Kennebunk (Radio Range = VOR) is an IAF for KLEW just as it was for KSFM. Nobody associated with KLEW is paying for it either. Some (real) aircraft do not have VOR or Radio Range receivers so they can instead use the NDB at ORHAM (which codes PW) as an IAF for KLEW. These are just options. Pick one. Note that we must fly a course of 037 or 031 to intercept the LOC whose course is 041. We must not turn onto a course of 041 before intercepting the LOC.

NoPT.

The words 'NoPT' mean no Procedure Turn required. We leave ENE or PW on the indicated course. We have no course guidance. We just continue along the mandated course until we receive and intercept the signal from the LOC which transmits on 108.90 and which we tuned on NAV 1 as soon as we turned over ENE. As soon as we intercept the glideslope we descend on the GS. Note that GS intercept is before the LEWIE NDB.

Note however that we MUST tune LEWIE on either ADF1 or ADF2. It is the FAF. There is no DME at KLEW today and there was no DME associated with most classic era ILS approaches. Short range DME was associated with Lorenz (Standard) Beam Approaches and the distance to go indicator was part of the LBA/SBA gauge.

Just like the other approaches we start our stop watch as we pass the FAF and we must enter the missed approach procedure after the correct elapsed time based on ground speed. In the Goose 120 KTS is a reasonable estimate with nil wind.


We can descend as low as 2200 QNH after either ENE or PW, whichever we chose as the IAF. After intercepting the glideslope we can descend to 471 QNH if we intend to land straight in on RWY 04 (S-ILS4), but only 840 QNH if we intend CIRCLING around the airport to join downwind for any other runway. For RWY 04 our minimum visibility is 0.75 miles. For any other runway it is 1.5 miles. Further descent in *both* cases is contingent upon seeing the RWY 04 lights.

This is a precision approach with both course and glideslope guidance all the way to the touchdown zone of the instrument runway and so it allows lower minima. The penalty is that we must develop the skill to fly both the mandated course and the mandated glideslope. Most flight simulation users never develop that skill and should not attempt ILS approaches to real world minima.


Notice that there is also a published transition from Augusta (Radio Range or VOR) to the North East. In that case, or indeed if we arrive from anywhere other than ENE or PW, we must treat LEWIE NDB as the IAF and we must go outbound in the LEWIE hold as our means of commencing the procedure before turning inbound. Just like the SZO at KIZG. The turn at the other end of the LEWIE hold is compulsory when arriving from anywhere other than the ENE or PW published transitions. They are the only arrivals with No PT required.

In a Goose we must set your stopwatch and go missed after 2:33 at 120 KTS groundspeed regardless, but in practice we will want to go missed if we hear the middle fan marker without seeing the lights. Make sure you can identify the different audio tones of the different marker beacons. MKR audio should always be ON when simulating the classic era.

For any runway we may descend to 840 QNH even though it is below the normal visual circuit altitude at 288 + 900 rounded up = 1200 QNH.

We only descend and circle the airfield to land as low as 840 QNH if we really need to, due to the cloud base, else we fly the circuit at 1200 QNH. If the cloud base is at a height of 600 feet there will be no circuit traffic.

Study the plate for KLEW and think yourself through the approach in 4D from all directions. It may seem as though KLEW is a lot more complicated than KIZG, but the reality is that there are just more options, none of which is individually more complicated. Focus on the one you intend to fly and the complication goes away.

Although I recommend avoiding ILS approaches altogether when flying propliners I recommend that you fly all the permutations above using the Goose in FS9 for further training. Again start with good weather and work your way down to marginal weather. That means marginal for *your* current skill level not marginal for a real airline pilot. The best way to progress in flight simulation is to be very aware of our own skill level as it improves and to always set ourselves a challenge that is marginal by our own standards.

That concludes our study of classic era propliner approaches, but remember that both types of approach covered by the Savoia S.73 tutorial package are relevant to the classic era too.


ARRIVALS and APPROACHES IN THE VINTAGE ERA

During the vintage era, which existed only outside the CONUS, by definition there were no legally binding arrival procedures. Sometimes an airline or air force mandated arrival procedures. Sometimes aircrew were allowed to invent their own. Sometimes they were imposed by local ATC whether military or commercial, public sector or private sector.

The problem within MFFS is that we are very unlikely to have access to those ancient variable and specific procedures. For major airfields we can often substitute the current federally mandated procedure because it is nothing more than an amalgamation of the prior airline, ATC, military specific procedures. The Savoia Marchetti S.73 package available from Avsim and elsewhere provides the relevant tutorials within. It is a supplement to this tutorial and should be downloaded and studied by those who wish to explore the operation of vintage phase propliners arriving at major airfields or military bases. The Goniometer and Lorenz (Standard) Beam Receiver tutorials are within that package.

However during the vintage phase of aviation in any particular place most airfields had either no ATC, or only a tower controller to control the aerodrome and circuit. At those simple airfields holding did not need to take place in the vintage phase of aviation. There was nowhere safe to descend and consequently many aircrew and passengers died after navigators miscalculated.

Remember the vintage era has limited relevance to US owned airlines operating outside the CONUS, but no relevance to any airline flying over the CONUS. Over the CONUS commercial aviation went directly from the pioneer era to the classic era.


CASE 1 - VINTAGE ERA DESTINATION lacks both NDB and Lorenz Beam (MSFS ILS) terminal guidance.

If our destination lacks terminal guidance navaids we must use GPS to descend plenty early enough, else plenty late enough, as described in the en route navigation tutorial (see Part 2A). After descending to visual contact with the scenery many miles away from destination the flight becomes a pioneer era flight and is conducted accordingly and by visual reference to line features leading to landmarks.



CASE 2 - VINTAGE ERA DESTINATION absent from MSFS

Often the vintage era airport, such as Croydon for London, no longer exists. If it has been recreated as a scenery, or an AFCAD, the creator will usually have failed to include the relevant navaids because he was unable to find the necessary data. In MSFS we should depart Croydon but flight plan to its modern replacement, which in this case is nearby Gatwick.

We will make an instrument approach to Gatwick and then use pioneer phase navigation techniques to navigate by visual reference to nearby Croydon at or just above circuit height before joining the circuit at Croydon. That is how many real airfields with no navaids are located by aircrew in real life. Aircrew file a flight plan to a major airfield and once visual with the local scenery declare a diversion to the minor airfield which is their real destination. It is just an extended version of the instrument runway not being the landing runway.


If however the weather is awful when aircrew arrive at the major airfield they have no choice but to ‘divert’ to the major airfield they declared as ‘destination’. Such flight plans explain the real intention to ATC in the comments section, and subject to local legislation are entirely appropriate.

On one trip we may become visual with the scenery from 30 miles away and ‘divert’ to our ‘real destination’ from thirty miles out without ever flying an instrument approach to our ‘declared destination’ using a goniometer or a Lorenz Beam receiver. The next day we may be down to circuit height on the Lorenz Beam before we are below cloud and can navigate to our real destination using pioneer era techniques. Our flight plan is the same either way. We just follow it for longer in bad weather.


CASE 3 – The ZZ Approach

Most flight simulation users fail to understand how many classic era propliners / fighters / bombers outside the CONUS made their instrument approaches using COM not NAV. PF, PNF or WTO continuously asked the approach controller (APC) for the magnetic bearing to the initial approach fix using COM, and subsequently to the bearing to the final approach fix still using COM not NAV.


Throughout the vintage and classic phases of aviation history many / most aircraft outside the CONUS made instrument approaches using COM to places with no radar. The pilot’s assigned heading was provided, (with quibbles about HDG versus CRS), by an approach controller who had no radar.

Those pilots flew a complicated procedure almost identical to the NDB approach. They just used COM to obtain the bearings (QDMs) that would have been visible on the ADF if they had an ADF and the airfield had an NDB. In the UK this was normal well into the 1970s and was the norm much longer in less developed nations. Allowing a Dragon Rapide equipped only with a COM radio in real life, to also have a pop up ADF and a NAV1 tuner may seem inappropriate in MSFS, but it is actually necessary to deliver realism. In real life the Dragon Rapide pilot just asked for a QDM (magnetic bearing to the DF station) using COM 1 as often as he or she wished.

In MSFS we just pop up the ADF and read the QDM given by the approach controller in real life, which is visible at the end of our ADF needle. The thing to remember is that we still need the NDB approach plate and we still have to fly that NDB approach, even in a Dragon Rapide. During the vintage phase of aviation history, outside the CONUS, any aircraft with COM 1 could fly the relevant instrument approaches, including Tiger Moths, Bf-109s or Spitfires, not just propliners like the Dragon Rapide.

Even a goniometer was a luxury in many vintage era aircraft, including many vintage era propliners.

To maximise realism within MSFS vintage era propliners, like the Dragon Rapide or Handley Page HP42, operating outside the CONUS, should have a two rotating needle RMI (as fitted in the default FS9 DC3) receiver on a pop up window. That pop up window must provide us with the bearing data to first the Initial Approach Fix, and later the Final Approach Fix which in real life was provided by the approach controller using RDF.

It may seem inappropriate to download a VOR approach plate to simulate a bad weather arrival by a Dragon Rapide or other vintage airliner with COM and no NAV in the 1930s, but within MSFS we must use the RMI to obtain the QDMs that were provided on COM 1 in real life.


CASE 4 – The QGH approach

If the destination was military or naval or shared military/commercial the aircraft was increasingly often 'talked down' by the approach controller via those fixes using COM during a QGH talkdown approach.

This has nothing to do with radar. ATC talkdowns pre date radar by many years. The Royal Navy began to recover aircraft to its aircraft carriers using talkdowns from 1923 and also routinely vectored naval aircraft for other purposes from the same date. It is quite likely that Zeppelins had been ‘talked down’ by the Imperial German Navy a decade before that. Britain established an integrated air defence system within which fighters were vectored by ‘sector controllers’ from the debut of the Gloster Gamecock in March 1926. Once land based aeroplanes were being vectored to interceptions there was no reason not to vector them for landing.

Of course once Lorenz Beams were in place from 1934 the ZZ approach or QGH approach was increasingly vectors to the LBA which might or might not also have DME. Across the British Empire it was possible to vector aircraft to a Standard Beam Approach where no Standard Beacon Approach was available, (see Navigating the S.73 within the S.73 tutorial package).

Before, during, and after WW2 these ZZ approach techniques spread throughout the British, Dutch and German spheres of aviation influence.

Now remember that the COM D/F aerial (whoever was using it) was no more likely to be on the airfield than the VOR or NDB is today. It is quite likely to have been in the hut that now houses the relevant NDB or the VOR, so unlikely as it may seem the vintage era approach procedure is quite likely to have been a close analogue of the current mandated NDB or VOR approach procedure, whether or not those navaids are now on the modern airfield. Remember just as the VOR at Kennebunk serves many airfields, so a single D/F station may have served many airfields. A vectored approach to an airfield in 1938, 1958 or 2008 does not necessarily involve any people or equipment located on our destination airfield.

So in passing let us also grasp that the approach controller for a particular airfield, who is talking aircraft down to land on that airfield, may never have visited that airfield in his or her entire life. He or she may be hundreds of miles away in an air traffic control centre or a bunker with a land line to a remote equipment site serving many airfields that they have never visited.

The IAF and FAF for an aircraft carrier will hardly ever be on the aircraft carrier. They are usually on one or more picket ships (aircraft direction frigates/ destroyers) at a pre briefed offset from the carrier. That offset may change hourly according to the mission pre briefing and may be large.

Finally remember all these procedures date from before WW2. Which procedures we should use where and when in MSFS depends on whether we are over the CONUS, the local infrastructure elsewhere at a given date, and our aircraft crew complement of specialists.

Within MSFS we will use a dual needle RMI to simulate ZZ or QGH approaches whilst flying the modern NDB or VOR arrival which we have downloaded from the internet. If our destination has ILS in 2008 and we are simulating the vintage phase of aviation history we will fly a Lorenz Beam Approach using an LBA receiver instead (See S.73 tutorial).


CASE 5 - VOR or TACAN in MSFS versus NDB in the VINTAGE PHASE

From time to time within MSFS we will encounter a destination whose approach procedures revolved around an NDB in the vintage phase of aviation history, but where that NDB has since been replaced by a VOR or TACAN. We can resolve that anomaly by using a two needle RMI of the type in the default DC-3. Its rotating needles will mimic an unoccluded arc ADF obtaining bearings from an NDB even when we use a VOR in MSFS for terminal guidance.

If our vintage phase destination has no NDB approach, but has a VOR approach, we will fly the current VOR approach using the default DC-3 two needle RMI. Once we use an RMI to discover bearings TO a VOR that VOR has the functionality of the NDB that would have been present at an earlier date.

Now remember we use an RMI to approach *outside* the CONUS *in the vintage era* because the VOR we are using in MSFS was once an NDB or a D/F hut providing bearings. Over the CONUS that VOR instead used to be a Radio Range providing just four course radials and we will instead use a VOR 2 receiver to fly a Range approach over the CONUS where a VOR approach exists today.

Note that all the above, for all cases, is true if we are simulating an approach flown using COM1 to obtain bearings from the non radar approach controller or a D/F operator. COM only approaches were commonly used by large propliners outside the CONUS well into the 1970s.


AVAILABILITY ISSUES.

Whilst many major airports had ILS by 1955, most airliners still didn't. A very expensive post war airliner like the L-049A Constellation may have been delivered with both a Lorenz Beam Approach receiver and a Bendix ILS receiver. That is the situation in the DZN L=049A. However a war surplus C-47 would not have had an ILS receiver in 1946 even if it had an LBA gauge. By the time of the Korean War every little fighter in Alaska had ILS and DME, but most medium and short haul airliners still had neither and many were not fitted with ILS receivers until they needed a VOR gauge to track the airways in the late fifties. Only then were most cheap propliners retrofitted with a combined ILS and VOR receiver (VOR 1 gauge as defined by Microsoft).

Until the late 1950s cheap propliners should fly LBA approaches, not ILS approaches, to airfields in MSFS that have ILS. Think about whether you would be able to make an ILS approach with the aircraft you are flying, at the date you are simulating, before making one. Frankly if you want to fly ILS approaches you may as well fly modern aircraft.


The tutorial concerning Lorenz (Standard) Beam Approaches and Lorenz (Standard) Beacon Approaches is contained within the Savoia Marchetti S.73 (v2) package available from Avsim.


OBTAINING MORE PLATES.

Tom Gibson maintains a list of URLs from which thousands of real world plates can be obtained here;

www.calclassic.com/propliner_tutorial_charts.htm


CONCLUSION

What may seem like complicated and unnecessary procedures at the moment are simply the means by which real pilots make sure that they are certain of their 4D position in relation to all obstacles, of all kinds, at all times. They point us at a particular runway, (the one with the brightest lights), in a perfect orientation for landing on it, or joining the various visual circuits, starting from the most appropriate position and altitude, descending to the most appropriate altitude, at an appropriate rate of descent, and with a little care on our part also at an appropriate drag (IAS). We also get the satisfaction of simulating real events rather than just pretending and making daft procedures up as we go along.

Try to master the arrival concepts of MSA, IAF, FAF, MAP and variable approach minima as they apply to transits, arrival transitions, race track holding, procedure turns, NDB, Goniometer, VOR, LBA, ZZ, QGH and ILS approaches before proceeding to read Part 5, which deals with departures and assumes detailed knowledge and practice of Part 4.


Continued in next post...

[Tom/CalClassic]

PROPLINER TUTORIAL PART 5 - DEPARTURE PHASE

Welcome to Part 5 of this tutorial. Having studied and mastered arrival and approach procedures we have already covered most of the ground. In this section I will try to provide a framework for using MSFS to simulate the departure phase in a non radar environment.

The departure procedures below will work for any airfield provided you can obtain its ARRIVAL plate. These are often easier to obtain from the web than the standard instrument departure procedures or equivalent. Many current departure procedures require radar monitoring and / or DME and are not applicable to the pre 1956 era anyway, though you can attempt to substitute timed legs for DME if you can stand the workload.

When published departure procedures are available they should always be studied for additional information. We will examine why later, but for the moment here is a generic solution.


PROCEDURAL DEPARTURES

Suppose we are about to depart Fryeburg in Maine for Burlington in Vermont in a DC3 during the late 1940s. It is late in a summer afternoon. The intermittent cloud base is at about 2600 QNH and there are big summer showers about. Nothing that will prevent a propliner from flying of course, but the direct route to Vermont is via Montpelier across the White Mountain Range.

Study the provided KIZG arrival plate once again. The runway in use at KIZG today is 32. It points in more or less the correct direction for Vermont, but there is no safe way to climb straight ahead into the White Mountains. On a hot clear day at max gross we might not be able to clear the mountains on a direct climb anyway. We certainly won't be risking it in cloud and rain.

You will remember that inbound from Montpelier we had to maintain MSA until the SZO and descend, clear of all obstacles in the SZO hold. Holding patterns were not created to impose delays. They exist to provide a safe location for climb and descent clear of all obstacles. Climb and descent.


QFG.

After take off from KIZG we must fly to the published holding pattern, climb clear of the obstacle, in the holding pattern, and only when above the obstacle will we set course. This is the QFG procedure.

For KIZG the published holding pattern is at the SZO. Yes, it's in the wrong direction for Vermont. It doesn't matter because we won't reach the required altitude to cross the White Mountains in a hurry anyway. It is the only way to be certain we will be safely above the White Mountains, and in the classic era that is how commercial flying was conducted.

Remember that airfields like Greenville have QFG holding criteria available for diversions and departures even though they are not mandatory for arrivals. A departure via Augusta from Greenville is almost the same thing as a diversion via Augusta. The truth is we already understand how to fly generic non radar departures. They are just 'diversions' starting from a lower altitude.

If we were departing a hot desert airfield in a KC-97 tanker we might need to QFG for the best part of an hour in a hold before setting course over a nearby mountain range.


COMMERCIAL CHOICES.

The KIZG arrival plate tells us exactly how to proceed. It tells us how to enter the SZO hold from the airfield. We take off. We fly the missed approach procedure. We take up the hold and we QFG in the hold to 7400 QNH before setting course to Montpelier VOR. This will take a long time and will incur considerable expense, but actually over the last few years it has reduced our insurance premiums by so much that it is actually cheaper than the old dangerous way of flying. It is now much, much cheaper to insure a $100,000 propliner than an equivalent fleet of trucks. Our airline hasn't made an insurance claim since 1938.

There is an alternative. Route south of the White Mountains. This also incurs a cost, but is also safe. We will however be required to fly Airways so the alternative is to fly the Kennebunk transition in the opposite direction and to join airways down by the coast at the ENE Radio Range or VOR. We still take off, fly the missed approach and head for SZO, but on reaching the SZO we can set course for ENE without needing to climb in the holding pattern.

It's just a commercial choice, but those are the only valid choices. Which way we flight plan will probably depend on the MSA and / or published transition at Burlington that these two flight routes 'empty into'. Maybe arriving from the south will be easier at Burlington? We study the Burlington arrival plate and even though it may seem odd at first we may decide our departure strategy from Fryeburg based on the arrival criteria at Burlington. I will leave you to resolve the correct solution as homework.


OTHER FACTORS.

This happens to be a summer day. Suppose it was mid spring and the freezing level was at 6500 feet. Should we choose to cross the mountains climbing to at least 8000 in snow showers? Do we want to ice up? This is a westbound flight. We have to cruise at an even level. In winter might 6000 feet via ENE and south of the mountains be a better idea? Do we ever want to go as high as 8000 when flying from Fryeburg to Burlington in a DC3?

The answers are potentially complex and require knowledge of aerial navigation if we intend to fly with imported winds. We will explore this complexity further in Part 6, but for the time being the strategy we must adopt is simple.


3D PLANNING.

Download the *arrival* plate for the *departure* airfield. Work out where the (‘best’) holding pattern is. There may be more than one at some airfields. Work out what the missed approach procedure to that hold is. Fly it and if necessary QFG in the hold until reaching an altitude above the published transition, or if none is published above the relevant MSA.

Only when we have studied this problem can we work out which direction we will set course to join airways. We must work out the optimum departure before we start to work out the flight plan route, because the first VOR in the flight plan route will depend on the departure we choose and not the other way round.

It is obvious that Montpelier is in exactly the right direction to reach Burlington, but it may not be the point at all. As an airline captain we have to make command decisions before we even get into the aircraft. Flight planning and navigation are not about finding and following the shortest distance between two points. They are all about thinking in 4D.

How high will I have to climb on that route? How long will it take to reach the minimum semi circular level on that route? How much ice will I pick up at that minimum level?

The shortest distance is irrelevant on short journeys. Our job is to find the minimum time path consistent with safety. The shorter the flight, the more the minimum time path will depend on minimum altitudes to be achieved, and the less it will depend on a direct track.

The correct decision in the example above may depend on aircraft type, or even on our departure weight and the temperature today. The only wrong answer is to simply ignore all the minimum altitude requirements during flight planning.

If departing an airfield which has no IAF and no holding criteria we must study our flight planning utility and try to work out which local airfield is big enough to have one. Download its arrival plate and after taking off from the minor airfield fly to the holding facility of the larger airfield and set course using its IAF and MSA criteria. Pick a big airfield on the same side of the mountains!


Concentrate on thinking in 4D, rather than 2D.


QFG in the 21st CENTURY?

Even today aircraft may be issued a QFG departure clearance. Onward clearance may depend on a particular radar controller being able to identify the departure. It may be necessary for the departure from airfield A to QFG at the IAF for airfield A until it has climbed into the radar cover of the radar controller at big airfield B or Control Centre C.

Many current procedures rely on radar vectors for safety. The radar controller now has responsibility for much that was once done by airline pilots. In the event of radio failure, (at either end and for whatever reason), no radar vectors are available. In the 21st century at some airfields with radar departing aircraft that lose contact with ATC must QFG. Before radar and DME it was like that all the time at airfields with adjacent 'obstacles', and I hope I have demonstrated how varied 'obstacles' can be. Remember most airfields still don't have radar in real life anyway.


FLIGHT SIMULATOR DEFICIENCIES.

Flight simulators give us far too much apparent freedom to fly in straight lines at any altitude of our choice. They may have a full function GPS that reports some reserved airspace violations, but by no means all of them. The real aviation world is a complex 4D environment full of geometric blocks of airspace that must be avoided. Many of them must be avoided vertically. Climb performance in climb power is a bigger issue than it may seem and it was a much bigger issue when or where no radar controller is solving many of the problems.

The MSFS canned ATC will simply ignore this issue and will happily vector us into a mountain or any other obstacle, whether departing or arriving. In real life there are many more types of 'obstacles' to avoid than masts and mountains.


NON RADAR ATC CLEARANCE

The published procedures explain exactly how to ensure that we avoid all obstructions in the absence of radar and DME. It's just a paradox that we may need to consult the arrival plate to figure out the generic non radar departure procedure that ATC would imposed in the absence of radar and DME.

Before we ever boot up our flight simulator we must paradoxically study the arrival plate for our airfield of departure. We must work out the generic non radar departure procedures for our intended direction of travel and hand write them on the reverse of the plate. This is all part of flight planning. When we reach the holding point we can then read the departure clearance to ourselves from the back of the plate. Then we can refer to both sides of the plate during the departure phase.

In the case of a northwest bound departure from KIZG we would write;

'N700MS after take off RWY 32 turn right direct Sebago climb 8000 QNH and on reaching Sebago enter the hold. Cross Sebago 3500 or above. On passing 7400 QNH in the Sebago hold turn left direct Montpelier maintain 8000.'

Did you do the homework I set in part 4?

On the back of the plate for 3B1 you should have written the generic non radar diversion procedure via Augusta. The generic non radar departure procedure you would fly is exactly the same!

'(After take off RWY 14) climb straight ahead. On reaching 2800 QNH turn right direct Squaw climb 8000 QNH and on reaching Squaw enter the hold. Cross Squaw 5100 QNH or above. On passing 6500 QNH in the Squaw hold turn left direct Augusta maintain 8000.........(expect further climb from Boston Centre)'.


In the modern world there may be alternatives and we will examine them shortly.


CLIMB PLANNING.

Once we ignore the canned ATC and incorporate this level of realism into our simulation instead we need to conduct climb planning as part of our 4D navigation. The realistic ATC departure clearance, 'Cross Sebago 3500 QNH or above' requires this.

Just as max endurance and max range are chalk and cheese so a good rate of climb and a good climb gradient are very different concepts. Suppose a departure procedure for a particular airfield requires all aircraft to climb straight ahead to a beacon 20 miles away.

A long range jet departs and climbs at 240 KTS and 1200 VSI in nil wind.

In five minutes it crosses the beacon passing 6000 feet.

A very old propliner departs next and climbs at 120 KTS and 700 VSI.

It takes 10 minutes to travel the 20 miles and is passing 7000 feet as it crosses the beacon.

The old propliner climbed much better, but the jet had a vastly superior rate of climb.

Read the lines about climbing above, over and over again, until you understand why there is no contradiction in the sentence above. 4D navigation is a complicated business *even with nil wind* and once again aerial navigation is all about TIME not distance.


BEST CLIMB - Vx versus Vy

For any aircraft there is a particular drag (IAS=Vx) that maximises climb gradient and there is an always a higher particular drag (IAS=Vy) that maximises climb rate. There are two optimum climb drags just as there is one drag that optimises endurance and a different always higher drag that optimises range.

However in a classic era propliner we don't strive to maximise range, we strive to minimise cost, to maximise profit, whilst flying at the maximum achievable velocity compatible with that aim. To do that we must reach operational ceiling in the minimum elapsed time, so we need to maximise climb rate, so normally we climb at IAS = Vy. Here is the extract from the Goose handling notes for example;

***************************
Climb:
MAP = 30 inches
RPM = 2200
110 MIAS
Plan 390 PPH
****************************

Vy (110 MIAS) is the only drag that maximises rate of climb. Any more drag and we lose climb rate. Any less drag and we lose climb rate. During the climb (acceleration) phases we must vary VSI as necessary, to sustain IAS=Vy, else we lose climb rate, which delays acceleration, and the only reason we are climbing is to accelerate as quickly as possible.

During commercial flights we use only climb power, because any more would cost too much. Flying a KC-97 tanker for the Air Force we just climb in military power and bill the taxpayer for the engine overhauls every 100 hours, but we still take care to climb with the drag pegged at IAS = Vy because IAS = Vy maximises climb rate at any applied power. From the KC-97G handling notes for instance;

**********************************
Military Power:
RESET Stop watch
COWL FLAPS = MID
57 inches MAP
2550 RPM
ACCELERATE 180 KIAS @ 100 VSI
MINIMUM 2000 feet AGL
FLAP = UP
180 KIAS
PLAN 6500 PPH
AFTER 30 minutes in military power
CALL for operational climb power
***********************************

For these reasons my handling notes for commercial propliners usually mandate IAS (constant drag) = Vy as the dynamic target during climb. There were however some propliners that could legally depart so heavy that to maintain the minimum lawful climb rate of 500 VSI it was necessary to use uneconomical power settings.

The handling notes for those aircraft mandate climb at the legal minimum VSI whilst monitoring drag (IAS). Once the drag exceeds a stated limit power is reduced to improve operating economy. In a propliner economy is always more important than performance, but the legal minima must be observed regardless of profit margins. Propliners of this type have multiple climb stages within their handling notes. Each stage represents the adoption of more profitable power settings, but only once they are compatible with federal regulations.

In general my handling notes placard an approximation of Vy only, but normally they call for the aircraft to climb at a lower drag in METO power so that the procedures more closely approximate a steep gradient climb (at IAS=Vx) over potential obstacles near airfields, followed by transition to IAS=Vy after retarding power from METO to climb. What I put in the handling notes just depends whether the original ops manual suggested this was normal practice as opposed to 'an option'. It is always an option.

From the DC-7B handling notes;

**********************************
METO Power: (Climb stage 1)
COWL FLAPS - MID
49 inches MAP
2600 RPM
155 KIAS
Climb 2000 feet QFE (agl)
FLAP - UP
ACCELERATE 175 KIAS @ 500 VSI
CALL for climb power

***********************************
Climb Power: (Climb stage 2)
MIXTURE - AUTO
COWL FLAPS - MID
42 inches MAP
2500 RPM
175 KIAS
IF UNABLE to maintain 500 VSI @ 175K
LEVEL OFF & REQUEST STEP CLIMB
WHEN ABLE CLIMB 500 VSI
IN 2000 foot steps
Plan 900 PPH per engine
***********************************

When flying the DC-7B the handling notes call for us to target Vx=155 KIAS until 2000 feet above the airfield then transition to Vy = 175 KIAS.

Now we must recap. Above I said;

'........we must reach operational ceiling in the minimum elapsed time, so we need to maximise climb rate, so normally we climb at IAS = Vy.'

Normally, yes.

When we receive, (issue to ourselves), the realistic ATC clearance, 'cross Sebago 3500 or above' the default case no longer applies. Sebago is a fixed distance from KIZG. Climb rate is unimportant. We must target a good climb gradient. We must target Vx, not Vy.

The DC-7B handling notes, or any other handling notes, cannot cover the details of all real departure procedures everywhere. We have to adapt them to each specific case. In this case we will target Vx until we have complied with the clearance 'cross Sebago (at an ALTITUDE of) 3500 or above' and not just until passing a HEIGHT of 2000 feet which is the generic suggestion in the handling notes. The generic HEIGHT suggestion is only there to prompt you to flight plan correctly and discover the relevant ALTITUDE for switching from a drag target of Vx to drag target of Vy.

Departing KIZG (empty!) in a DC-7B we will climb with FLAP 1 extended at 155 KIAS until passing 3500 QNH. We will also stay in METO power. The generic requirements of the handling notes must be translated into the specific requirements of the departure phase from each particular airport.

It is the process of planning a different procedure with different operating targets, for each departure that makes flight simulation interesting.

In a KC-97 tanker we would retard from METO to military power while QFG. Either way we stay in stage 1 climb power until we have met all the 'cross above' ATC restrictions of the departure.

In this case when flying a DC-7B we climb 3500 feet QNH (not climb 2000 feet QFE) and only on passing 3500 QNH we change target IAS from Vx to Vy thus;

FLAP - UP
ACCELERATE 175 KIAS @ 500 VSI
CALL for climb power

There is no change to the promulgated procedures for flying the DC-7B realistically. What this part of the tutorial explains is how to substitute realistic departure by departure ALTITUDE criteria for the generic HEIGHT criterion stated in the handling notes.

The handling notes for the DC-7B always reflected the fact that it has a poor post take off climb gradient at IAS=Vy and that unlike most propliners it usually has to target a lower IAS in a higher lift configuration immediately after departure. What the DC-7B must do as a norm, any other propliner may need to do during some particular departures.

If the handling notes do not promulgate extended climb in METO power, or else do not promulgate a climb IAS target less than the continuous target (=Vy) then we must consider the need in particular circumstances. Where no lower target is quoted for max gradient climb we reduce the stated IAS climb target by 10% and use that. If, and only if, flap was mandated for take off, we will retain FLAP 1 when climbing at this implied IAS=Vx. We would NOT retain FLAP 2 if FLAP 2 was mandated for take off.

Consider the case of a CV-340 departing KIZG. The CV-340 has a rate of climb at IAS=Vy that is usually more than adequate to fly most real departures. The crew do not need to use METO or target Vx for a prolonged period by default. In a particular circumstance they might though. Under those circumstances study the handling notes and deduce the procedure.

The default CV-340 handling notes say;

***********************************
ROTATE at 105 KIAS (@ 47000lbs)
Establish positive rate of climb
GEAR UP
ACCELERATE > 130 KIAS @ < 500 ft/min
CLIMB 300 feet AGL
FLAP - UP
CALL for METO Power (1800hp)
45 inches MAP
2600 RPM
ACCELERATE to 150 KIAS @ <= 500 ft/min
CALL for Climb power (1350hp)
***********************************

If we apprehend that we (given our personal skill level) might not make 3500 QNH by Sebago we will instead retain a power setting of 45/2600 (METO power) and will accelerate only to a drag of (150 KIAS - 10%) = 135 KIAS until passing 3500 QNH. Only then would we;

FLAP – UP


ACCELERATE to 150 KIAS @ = 500 ft/min

Now notice that the CV-340 handling notes include an unusual default power setting;

***********************************
Max climb: (1500hp)

COWL FLAPS - MID
39 inches MAP

2400 RPM
150 KIAS
Check CHT < 232C
Plan 250 USG per hour
***********************************

This power setting has two uses. Firstly it is for use whilst climbing QFG. We use Max climb power to climb in the SZO hold until passing 7400 QNH and only then reduce to;

***********************************
Normal climb BELOW FL170: (1350hp)

COWL FLAPS - MID
35 inches MAP
2400 RPM
150 KIAS
Check CHT < 232C
Plan 225 USG per hour
***********************************

However when we have a departure clearance with a 'cross above' restriction, in an aircraft that has a max climb power setting, we will never reduce below max climb power until we have achieved the ATC cross above restriction.

So if we have no doubts that we can make 3500 by Sebago we would clean the aircraft up quickly and only stay long enough in METO power to accelerate to 150 KIAS (=Vy) and then climb at Vy in max climb power until passing 7400 QNH. If in any doubt we use METO with FLAP 1 at Vx until above 3500 and then target the max climb power procedure until setting course above 7400.

When departing in a CV-340 with no 'cross above' restriction we will retard straight from METO power to normal climb power without ever invoking max climb power.

All the relevant power settings have always been in the handling notes. If they are not there then they are not relevant to that aircraft type. The way that different propliners are operated through the same departure differs considerably. The only really new idea here is that we may need to calculate 'Vx' as 90% of the promulgated continuous climb IAS target 'Vy' once we impose realistic departure clearances on ourselves. The simulation becomes much more variable. The way we operate the same aircraft differs from place to place and becomes much more interesting. The canned ATC in MSFS pretends that every departure is the same. In reality they are all different and that makes flight simulation much more interesting.

If in any doubt amend a COPY of the .txt version of the handling notes to match the specific departure, using Windows Notepad, and then print the realistic procedures you intend to fly, to achieve the realistic ATC clearance you intend to impose upon yourself.

In this case for a CV-340 if apprehensive about making 3500 QNH by Sebago (it will depend on your flying skill) you might amend and print;

*************************************
ROTATE at 105 KIAS (@ 47000lbs)
Establish positive rate of climb

GEAR UP
ACCELERATE 135 KIAS @ <= 500 ft/min
CLIMB 300 feet QFE
CALL for METO Power (1800hp)
45 inches MAP
2600 RPM
Left turn Rate 1 direct to SZO
On Passing 3500 QNH
FLAP - UP
ACCELERATE 150 KIAS = 500 ft/min
CALL for Max Climb power (1500hp)


***********************************
Max climb: (1500hp)
COWL FLAPS - MID
39 inches MAP
2400 RPM
150 KIAS
Check CHT < 232C
Plan 250 USG per hour
On Passing 7400 QNH

CALL for Climb power (1350hp)
***********************************



WEIGHT DEPENDENT ISSUES.

To increase realism we should calculate rotation speed (Vr) for your real take off weight as;

Stated IAS * SQR(actual take off weight / stated max take off weight)

and include that in the revised notes for that flight since RWY 14/32 at KIZG is too short for a CV-340 at max gross. A CV-340 can operate out of KIZG, but without a decent headwind it will have to do so at significantly less than max gross and Vr will be critical.

We should also recalculate the airfield boundary target speed (Vref) at the end of the approach in the same way as;

Stated IAS * SQR(actual landing weight / stated max landing weight)

Many V speeds, (but not Vno or Vx), are variables that depend on the square root of our current weight.



KIZG QFU 14.

So what do we need to do when the take off runway at KIZG is RWY 14. As we shall soon discover that will be more often than is currently apparent. Making 3500 QNH by Sebago only 8.5 miles away is asking an awful lot of a loaded propliner even at IAS=Vx and even in METO power.

During flight simulation (only!) the answer is of course simple. If we cannot find real world departure procedures on the web, or we cannot be bothered to look for them, we depart 14 and turn left into the visual circuit. When we reach 1900 QNH we fly the missed approach procedure to Sebago. This allows us to retard from METO to Max climb as soon as we are above 300 QFE and cleaned up, but we might elect to stay in METO until above 1900 QNH and in any event we would stay in max climb power until above 7400 QNH (if routing via Montpelier).


PRELIMINARY CONCLUSION.

I hope I have now explained how to construct a safe generic non radar departure clearance from an arrival plate for any airfield and how to translate the generic step by step climb procedures based on height in the handling notes into specific steps and targets based on altitude for specific departures at any date within the classic era which is potentially from 1932 onwards over the CONUS.


Note that the departure phase ends only when we set course above the transition or MSA. Only when we are above the level of the arrival transit(ion) will we set course and transfer ATC COMS (QSY) to the Airways sector controller at Centre. In real life the departure controller would instruct this once she had separated us from all arrivals, and since these might be higher than the minimum level due to fixed obstructions, the COMS transfer, and different control transfer which mark the end of the departure phase might be at greater altitude in real life.

Of course at many airfields like Amsterdam the transition / MSA is at a low altitude and climbing above it takes no time at all. These rules still apply, but rather briefly. I have deliberately chosen to demonstrate the issues involved and generic solutions at airfields where there is a significant problem to solve. Many airfields are near obstacles of one kind or another and require us to solve the same problems, not just blunder about using our own pretend procedures, or follow the blundering pretend procedures of the canned Microsoft ATC.


EARLIER ERAS OF AVIATION

Once a nation, or one of its air arms, entered the classic era all the above became mandatory for the relevant aircrew. Prior to that it had only been necessary! The problem was that many aircrew tasked with working out all of the above each time they took off miscalculated and flew procedures made up on the spur of the moment that did not work and which killed them.

Just because a QFG procedure after take off was not mandatory in the vintage era does not mean that it was safe to do otherwise. The problem for the vintage era crew was that for much of the vintage era they had no published holding patterns, within the terminal area of the airfield they were departing, and no pre-calculated cross above restrictions. They had to decide where to QFG and when to set course.

They still had to QFG!

The correct solution was of course the one that is now mandatory. The pioneer era crew, nearly always singular, could only concentrate on height keeping below cloud. The much larger crew of specialists operating within vintage era aviation infrastructure at any date, and potentially today in some third world nations, who intend to depart in marginal weather (by their skill standard) must do what they can to approximate the mandatory procedures, potentially without access to the necessary radio beacons.

They must climb in circles over the airfield of departure until they are above the nearby enroute obstructions, whether those obstructions are mountains, or the Japanese fighter patrols north of Honk Kong in 1941, or the Chinese flak batteries just north of Hong Kong throughout the 1950s. Air Defence Interception Zones are just another kind of obstruction to be avoided by propliner aircrew.


IF THE CURRENT PROCEDURES CAN BE FOUND.

It is time to study the final pdf in the tutorial (NE1TO.pdf). There is no real need to print it. This contains departure (take off) minima for airfields in the North East of the CONUS, including the ones we have been using in this tutorial. Scroll down until Fryeburg is on screen.

First we search for additional information.

We discover that the 32 circuit is right hand and like the 14 left hand circuit is therefore north of KIZG. This is unusual. It is due to the hill south of the field that we would impact if we took off from 32 and turned left. The departure turns the opposite way to the missed approach, which starts above the hill.

We learn that it is always forbidden to take off from 32 at night, or if there is cloud observed or reported below a HEIGHT of 2200 QFE by day, or if the visibility is less than two miles. We add 454 to 2200 and note that we may never take off from 32 unless the lowest reported cloud is above an ALTITUDE of 2654 QNH.

We note that we can take off from 14 with cloud base of just 400 QFE = 854 QNH.

We can see that on this summer afternoon with the cloud base at 2600 QNH we can only depart 14 however awful the tailwind on 14. It may not be possible to depart because the runway is too short with a tailwind or because we cannot sustain the mandatory climb GRADIENT with a tailwind.

The real take off procedures are complicated. You will have to decide whether you want to incorporate this level of realism during your simulation. If you import wind you will need to be able to calculate take off distances and climb gradients with tailwinds. Microsoft canned ATC is way too dumb to take any of this into account. It will happily allocate a runway that ensures death.

Reading on we see that the FAA have granted various exemptions from the terrain and obstacle separation rules for aircraft departing Fryeburg PROVIDED that they comply with all the above including the mandatory CLIMB GRADIENTS.

PROVIDED you comply with all the real world requirements you can substitute an ATC clearance 'cross SZO above 2600 QNH' for the generic requirement 'cross SZO above 3500 QNH' and you can turn for ENE passing SZO and above 2600. You would adjust from Vx to Vy and set climb power accordingly.

Even in theory this just gets you a few feet above the two masts and your passengers in the back may not be altogether delighted when the top of the mast passes what will look like a few feet under the wing in real life. In MSFS we have another problem. Neither the mesh nor the masts and other macros are accurate enough for the precise altitude exemptions issued by the FAA in the real procedures to work and prevent impact with 'obstacles' in MSFS. Flying the real procedure with great skill and still impacting a hill or mast tends to be even less satisfactory than flying a generic procedure that ensures success.

I recommend that only real world aircrew attempt to make use of listed exemptions and they need to take the above into account.

Note also that nothing in real FAA departure procedures makes it OK to enter military danger areas, nature reserves, airspace around nuclear power stations etc, etc. We still need to route around those unless we use the QFG procedure to climb above them before setting course. The 'propliner way' is to climb above them, not to try to route around them.

Scroll on down until you reach Springfield VT. Note that the only way to depart RWY 23 in real life is QFG SXD 5000 QNH. Even in the CONUS, even today, QFG is a current procedure. Radar coverage allowing radar control just means that it is required in fewer places these days. In the modern era radar controllers have taken over most of the 4D navigation of aircraft in the vicinity of airfields.


FINAL CONCLUSION.

Where radar control is not available QFG is commonly the only departure procedure at many airfields. If you search for them you may find that there are other real world alternatives providing specific exemptions from the current complicated rules for public transport departures, but often they will turn out to require radar, or to be even more complicated to plan and implement than the QFG procedure. Some will fail if flown perfectly due to mesh errors which also elevate anything standing on the mesh.

We will need generic procedures when we can find no others. Outside the U.S. we will be hard pressed to find the departure procedures for many airfields on the web. We will need to devise a realistic departure procedure from the arrival plate, write it on the plate *during flight planning*, and later issue the relevant clearance to ourselves at the holding point. The holding point is not the place to be working out what it is.

Non radar departure procedures have changed much more over the last 70 years than the non radar arrival procedures so maybe the answer is anyway to fly the modern departure procedures from the web when flying modern aircraft and the QFG procedure explained above when simulating propliner operations in both the vintage and classic eras.

In the pioneer era we aim to height keep at a *height* of 1500 feet above the terrain and any construction ahead. If we need to orbit (QFG) to clear the next ridge by 1500 feet we must do so, whether that ridge is near to the departure runway or later. In the pioneer era if we cannot height keep at 1500 QFE without entering cloud or losing sight of obstacles ahead due to poor visibility we must always divert back to the last suitable airfield we passed. We must be able to recognise a height of 1500 feet by always using only cockpit environments that do not distort scenery placement and perspective due to bad design.


PROPLINER TUTORIAL PART 6 - ALTITUDE and FUEL PLANNING

Welcome to Part 6 of the propliner tutorial. I will recap in places, but it assumes familiarity with all that has gone before. Once again it relates to propliners and is not a general guide for all aircraft. The goal of this part of the tutorial is to provide all the remaining clues to propliner flight planning that can reasonably be covered in a free web tutorial.

Flight simulation users tend to fall into two camps; those who do no flight planning at all, and those who plan in excessive detail given that they cannot forecast the winds aloft within their simulator. Propliner flight planning within flight simulators should be a simple task carried out using 'default' values not 'realistic' values. We must always plan without knowing what winds we will encounter and execution will always differ from the plan. The plan is not a precise calculation of fuel required or the times at which we actually expect to cross given locations.

During the cruise, *and only during the cruise*, we will monitor per cent difference between ETA and ATA leg by leg and we will respond in the ways described in detail in part 2B of this tutorial. Our dynamic response to perceived headwinds must be complex and 4D. Our plan must also be 4D, but it does not need to be complex.

We will examine fuel planning shortly but first let's get flight plan cruising level out of the way. In part 2B of this tutorial I explained how to obtain the default flight plan cruising level and TAS from the handling notes, but I explained that short hauls were a special case. We must now study that special case.


PLANNING SHORT RANGE FLIGHTS

Suppose we wish to fly a propliner from Boston (KBOS) to Fryeburg (KIZG). First we must download both sets of arrival plates and study them. It becomes clear that the arrival to KIZG will be via a Kennebunk (ENE) transition to the SZO NDB. We need to create an airways route from KBOS to ENE.

Quick study of our flight planner shows that the route is via airways Victor 3 and Victor 106.

The only relevant VORs on V3 are Boston which codes BOS on 112.70 and Pease (Portsmouth) which codes PSM on 116.50. The only relevant VOR on V93 is Kennebunk which codes ENE on 117.10. We must locate the intersection of the two airways at YUKES during the flight using VOR 1 and VOR2 or by switching between the frequencies of PSM and ENE on VOR1 to check whether we have reached the 241 radial FROM ENE whilst tracking 020 from WITCH.

Our flight plan route is BOS - WITCH - PSM - YUKES - ENE - SZO. Drag and drop or manually enter those beacons and the intersection at YUKES into the plan. Our flight planner should now show the distances and the magnetic courses. The total distance is only 98 miles. The flight is eastbound. It must be flown at an odd cruising level.


MINIMUM EN ROUTE ALTITUDES.


We must check whether there are mountains en route between these two places. We might use a flight planner, a sectional chart, a real flight planning document or just a cheap atlas. In the propliner era the minimum en route altitude is 1500 feet above any terrain (mountains) within 15 miles of track or 1000 feet above any terrain within 25 miles. Figuring out how high the mountains are along the whole flight plan track may take some time, but it should not need any further explanation.

Some charts showing the relevant MEA for some locations are available on the web, but MEA data is harder to obtain (for free) than MSA arrival data.

Since there are no mountains en route between KBOS and KIZG the minimum altitude which drives selection of cruising altitude for the flight is that of the lowest airways transit(ion) whether on departure from Boston or on arrival to Fryeburg. In this case we see that will be the ENE transition to SZO at 3500 QNH.

It follows that the lowest we can cruise on this eastbound flight is 5000 feet in any aircraft since we must cruise at odd thousands of feet.


FLIGHT PLAN CRUISING LEVEL - SHORT HAUL

Calculating the correct flight plan cruising level for short haul flights is more complicated than calculating the minimum. Recall that in a propliner we plan 2 minutes for every thousand feet to be lost from top of descent (TOD). We plan minus 500 VSI, but intend to descend more steeply.

The next step is to determine how many minutes the (short haul) flight will take. We never have any idea how long we may need to hold. We will examine how to plan for that contingency shortly. The relevant flight plan time is the time from take off to the initial approach fix (IAF).

The rules for determining flight plan cruise TAS were explained earlier. We discovered that for a DC6B the answer is 242 KTAS. We know perfectly well that we will never be able to accelerate a DC6B to 242 KTAS during a short haul flight, but we plan the en route phase on that basis regardless.

When planning a short haul we proceed on the basis that we will spend one third of the flight departing, only one third of the flight cruising, and the final third arriving. Only the middle third is planned at 242 KTAS. The departure and arrival phases are planned at two thirds of the flight plan cruise TAS.

Most software based flight planners cannot cope with this. Most are useless for anything other than planning a 2D route. We must ignore the false times that they calculate and provide our own estimated times of arrival (ETA). For this purpose when flying a propliner we will always assume that the climb (departure) phase has the same duration as the descent (arrival) phase. We will assume this now during calculation of elapsed times and again later during fuel planning. The extra power (fuel flow) used for climb will be equalled by the reduced power (fuel flow) during the arrival. As we dive during the arrival our drag (IAS) will increase and our velocity (TAS) will reduce. The acceleration we impart by climbing is negated by the deceleration we impart by diving.

We must allow for holding, approach and/or diversion separately and later. For the moment we are only interested in the total elapsed time from take off to IAF. We will execute the climb and descent at the target values in the handling notes, but we flight plan simplistically and as above. During climb and descent our *planned* TAS will be two thirds of our planned cruising TAS.

242 KTAS * 0.666 = 161 KTAS

The average planned velocity of a *short haul* flight divided into three phases in a DC6B is therefore *always* (161 + 242 + 161)/3 = 188 KTAS.

For any aircraft we can obtain the same result more easily by taking flight plan cruise TAS and multiplying by 0.777

242 KTAS * 0.777 = 188 KTAS

Note that this is our average planned TAS from unstick to the IAF. These flight plan events are only 98 miles apart. We therefore expect elapsed time from unstick to IAF to be 60 * 98/188 minutes = 31 minutes in a DC-6B.

We never plan a flight so that the arrival phase (from TOD to IAF) exceeds one third of the flight. It follows that on this flight we will not plan a descent exceeding 10 minutes. Since we always plan descent at 500 VSI we will not plan a descent exceeding 5000 feet.

The approach plate shows that the transition from ENE to SZO is at a minimum of 3500 feet and so we must be able to reach 3500 feet by the SZO. Since 3500 + 5000 = 8500 we cannot plan to cruise our DC6B above 8500 feet on a short haul from KBOS to KIZG.

But wait. This is an eastbound airways flight. The semi circular rule requires it to be flown at an ODD thousand foot altitude. The maximum cruising level in a DC6B is therefore 7000 QNH. The lowest is 5000 QNH in any propliner.

Cruising at 7000 QNH, from KBOS to KIZG, TOD is seven minutes before the SZO. 7000 - 3500 = 3500 feet at minus 500 VSI = 7 minutes.

We must not forget however that if the departure from KBOS had required us to climb above 7000 feet to avoid an obstacle near KBOS we would have no choice and if a mountain between KBOS and KIZG required us to climb above 7000 feet we would have no choice. In extreme cases we may depart a runway above 7000 feet for a runway at sea level. The minimum level for the flight may be determined by departure, en route, or destination obstacle criteria. We must always calculate the minimum first, then we calculate the optimum, then we flight plan for the higher result. Usually the optimum level is well above the minimum level, but not always.

Short haul flight plan cruising level is usually driven by descent planning and descent planning is always driven by the altitude of the arrival transit or transition. Between KBOS and KIZG in a DC6B we will flight plan at 7000 QNH and plan to descend 7 minutes before the SZO. We will actually descend a little faster than 500 VSI to be level before the SZO so that we are < 175 KIAS to be legal and < 140 KIAS if we wish to use the AP. If you do not remember why you need to reread parts and 2 and 3 of this tutorial.

Cloud, visibility, sunshine and darkness have no bearing on any of this. We optimise economy of operation from KBOS to KIZG whilst maintaining the appropriate level of public safety by climbing to 7000 QNH to cruise. If on a beautiful day we see the airfield at KIZG, and the masts, and the hills from overhead ENE we may start to position for a downwind join from ENE, but it's not very likely is it?

Now if we make the same flight in a DC-3 things are different. Typical en route cruise TAS in a typical variant of DC3 might be only 148 KTAS.

148 KTAS * 0.777 = 115 so we expect a DC3 to take about 50 minutes to make the same trip. The question now arises is this actually a short haul for a DC3 or is it a normal haul? It is a normal haul if flight plan cruising level will be limited by operational ceiling or certification ceiling rather than climb/descent planning criteria.


In a DC3 (no more than) one third of the trip is 16 minutes which is 8,000 feet and since we would again be descending to 3500 feet the maximum cruising level is 11,500 feet. But this is an eastbound flight so the choices are 11,000 or 13,000. Since DC3 certification ceiling (in the United States) is 12,000 feet this trip is long enough for a DC3 to reach semi circular rule constrained certification ceiling. At 50 minutes this trip is just long enough to be a normal haul for a DC3 even though it is obviously a short haul for a DC6B.

In a DC3 (by default) we will flight plan at 11,000 feet. We will need to descend 7,500 feet during the arrival transition. TOD will be 15 minutes before SZO.


PLANNING versus EXECUTION

Just like everything else in aviation the concept short haul cannot be defined as a distance. It is defined by TIME. KBOS to KIZG is a short haul for a DC6B because it is fast and has a high operational ceiling. The elapsed TIME is too short, either to reach operational ceiling, or to descend from operational ceiling, in a DC-6B.

For a DC3 the flight plan TIME is long enough for this to be a normal haul because a DC3 is slow and has enough TIME to reach its unpressurised certification ceiling. Everything revolves around TIME.

*By using TIME as the basis of aerial navigation during flight planning we eliminate the need for speed versus distance calculation during execution of the flight.*

We flight plan using TIME as our reference and we execute the flight using TIME as our reference. Any calculations relating to velocity or speed or distance are made BEFORE FLIGHT during the flight planning stage above. Once we are in the aeroplane we navigate in 4D using a clock and a text flight plan with estimated times of arrival (ETA) on it that we correct as we fly along, and we respond to the per cent TIME correction. Distance, velocity and speed are irrelevant once we are airborne. They are too difficult and too dangerous to correlate given that we can only guess the wind vector ahead of us.

We flight plan using velocity (KTAS) not speed (KTS) or drag (KIAS). We do not expect to match our planned velocity exactly and we expect the wind actually encountered to force us to deviate from default planned cruising criteria in a trip of any length (see part 2B of this tutorial). We expect to revise our estimates. We must respond dynamically to the magnitude of the revision.

We plan descent at 500 VSI. Just as we do not expect the planned TAS to be the actual TAS, so we do not expect the planned VSI to be the actual VSI. We must not confuse planning with execution.

During the flight our targets are those in the handling notes. If achieving those targets causes ETA to differ *significantly* from ATA, leg by leg, during the cruise we must do something about it. Most of the variation will be due to the actual wind being something other than nil wind. Within a flight simulator, *unlike real life* we have no way of forecasting by how much it will differ. We must plan at default TAS and default VSI assuming nil wind and respond dynamically if a 'significant' perceived wind vector is encountered.

Remember we do not begin to test for a perceived headwind until we have been cruising for at least 20 minutes and have accumulated enough ETA v ATA data to judge whether we have a 15% perceived headwind. On flights with less than 20 minutes of cruising flight we can ignore headwinds in any propliner. By the time we noticed we had a significant headwind adding power for the rest of the brief cruise phase would barely alter time of arrival anyway.

Most flight planning tutorials, even those said to be relevant to MSFS, simply ignore the fact that we cannot obtain forecast winds aloft and then talk only about how things are done in real life. Those techniques won’t work in MSFS and are far more complex than we need to use within MSFS.

As we discovered in part 2B of this tutorial a long haul flight in a DC-6B targets FL220 as cruising level by default and 242 KTAS by default. There is no need to be more accurate during flight planning. We plan for our targets. We will miss them by some per cent. We will respond dynamically using the techniques explained in part 2B of the tutorial, but planning is default and simple.

We do not expect to replicate a propliner flight plan during execution. We plan according to our handling targets and we load enough fuel to cope with any wind, and any other weather, we may actually encounter.

*The plan is the same for the same route every day.*

Execution differs. How much of the fuel reserve is still aboard at landing differs, day by day, with the weather.


FUEL PLANNING

The next step is to *plan* the fuel to be loaded to fly the *route* with nil wind. This does not include the fuel needed for holding, approach or diversion. Nor does it include the fuel needed to battle headwinds. We will examine those flight planning criteria very shortly.

Planning does not reflect the way we intend to execute the flight. We are not 'calculating' the exact amount of fuel required. We cannot. We have no idea what winds we will encounter.

Suppose a DC6B must fly a 1000 mile route. There is no need to calculate fuel flow during different phases of this route. This is just a plan. Reality will always differ. We will shortly add reserves to cope with any and all the different realities we will encounter day by day over the same route.

The route fuel is simply route distance multiplied by fuel burn in pounds per hour (PPH) divided by planned TAS.

****************************
Econ Cruise: (1000hp x 4)
Use only <= 89,000lbs
COWL FLAPS = CLOSED
MAP = 32 inches
RPM = 1850
Check CHT < 232C
Plan 1900 PPH
@ zero pitch climb 2000 ft & 500 VSI
Note - Yields 242 KTAS at FL220 @ 89000lbs
****************************

So in this case 1000 * 1900 / 242 = 7851 lbs

Now we must calculate the necessary reserve fuel.


HEADWIND RESERVE

Since we cannot obtain forecast winds aloft we flight plan for nil wind. However during fuel planning we must always assume that we will meet, and will need to battle, a significant headwind. Any lesser assumption would obviously be unsafe. Since we have defined a significant headwind as one that causes our speed (KTS) to be 15% less than our velocity (KTAS) the headwind reserve must be 15% of the flight plan route fuel.

7851 * 0.15 = 903 lbs


HOLDING RESERVE

The Treaty of Chicago mandates a holding reserve of 45 minutes. An airline might decide to carry more, particularly if fog or runway snow clearance operations were expected at destination. On this flight we will plan for the bare legal minimum. If the supplied handling notes provide a planning value for terminal holding that should be used, else the lowest relevant fuel flow stated in the handling notes. This may be a long range cruise section associated with high altitude. It matters not. If we plan our fuel correctly we will be down to the weight or fuel state that limits use of the specified MAP and rpm, (and thus the associated planned fuel burn), before we reach the IAF and commence holding.

*****************************
TerminalHolding:
Approaching IAF / Hold
COWL FLAPS = 1 degree
2000 RPM
REDUCE < 160 KIAS
FLAP = STAGE 1
REDUCE < 150 KIAS

Crossing IAF entering Hold
FLAP = STAGE 2
MAINTAIN 140 KIAS
Check CHT < 232C
Plan 2100 PPH
****************************

2100 * 0.75 = 1575 lbs


DIVERSION RESERVE

It is not mandatory to carry a diversion reserve, but if that choice is made, no holding is possible at destination and immediate diversion to alternate must be declared in lieu of holding for destination using the holding fuel above to fly the diversion. Whilst this is legally acceptable it would not be profitable for an airline to divert instead of holding. Diversions add costs and reduce profits.

During the classic era typical airline policy was to carry 45 minutes of self imposed diversion fuel in addition to the 45 minutes of mandatory holding fuel. The diversion itself could be flown using the minimum fuel flow shown in the handling notes too, but in practice propliners that diverted usually climbed from their holding level at destination before cruising to alternate so that diversion constitutes a second en route phase which we plan using econ cruise fuel burn.

1900 * 0.75 = 1425 lbs


TOTAL FUEL RESERVE

The reserve fuel required for a public transport flight of 1000 miles in a DC6B is;

903 headwind + 1575 holding + 1425 diversion = 3903 lbs

At this point notice that the holding and diversion reserves do not relate to the route distance. They must always be present as we reach any IAF however short the flight and they total 3000 pounds for any flight. The headwind reserve could be much less or much more depending on the length of the trip.

Flying about a hundred miles from KBOS to KIZG the headwind reserve would be about one tenth of the amount above, but the holding and diversion fuel would be the same. Let's think about why that is true.

Until the installation of blind landing equipment in airliners from the de Havilland Trident onwards airliners frequently departed runways into fog or low cloud that would prevent them from finding and landing on the airfield they had just departed. If fog blankets the whole coast and when we reach KIZG ATC announce that the visibility at KIZG is less than 3 miles they will withhold approach clearance, (see part 4 of this tutorial), we will not be given approach clearance. We may need to hold for 45 minutes waiting for the visibility *from the tower* to exceed 3 miles. We must then divert. If there is still fog all along the coast we cannot divert to KBOS just because we started at KBOS. How far we must divert when destination is still below minima when the holding reserve runs out does not depend on where we started from.

When we have calculated holding and diversion fuel for a given aircraft once we can add that information to its handling notes. It will not alter. We need to calculate a variable headwind reserve according to route but of course we could just add 15% to the route distance rather than going through two steps. In this case

Route fuel including headwind reserve = 1000 * 1.15 * 1900 / 242 = 9029 lbs

When we calculate route fuel for the DC6B in this way the route fuel is proportional to the route length. A 2000 mile route requires twice the route fuel = 18,058 pounds plus unchanged holding and diversion fuel = 3000 pounds so the fuel required for a 2000 mile trip in a DC6B is 21,058 pounds.

For reasons which should be obvious that is how we actually calculate route fuel in MSFS.

If DC-6B route fuel (including the headwind reserve) is 9029lbs for 1000 miles we can just multiply by the actual route length to define the route fuel for a route of any length and then just add the invariant 3000 pounds needed for holding and diversion on any route however long, or however short.

For a trip of 98 miles from KBOS to KIZG the (minimum) fuel load is 3000 + 9029 * 0.098 = 3884 pounds


PLANNING versus EXECUTION - Again

What differs from day to day, as we fly the same route with different payloads and different weather, but exactly the same default planned fuel, is how much of the reserve we actually use to battle weather and to stay more or less on time.

On a few days each year the *perceived* mean headwind will exceed 30% of our *planned* cruising velocity (242 KTAS). As we battle the unusual 'severe' headwind with much higher fuel burn at potentially much lower altitudes we will start to eat into our other reserves.

We do not eat into our holding reserve. That is mandatory. Our default plan calls for us to arrive over the IAF for destination with 90 minutes fuel remaining. Even if our destination is 98 miles from our point of departure. Some days we actually have more, some days less when we reach the IAF.

On the days when we have less we must subtract the missing fuel from our holding reserve. Suppose we arrive at the IAF with only 70 minutes of fuel remaining. If the visibility never gets above 3 miles at KIZG, when we get down to 1425 pounds, (the diversion fuel reserve), we can no longer hold at the SZO for weather improvement at KIZG. We must divert to our alternate.

After we enter a hold we must constantly monitor fuel remaining and we must divert when we get down to diversion fuel. There are certain circumstances, (such as flying to an island in mid ocean), when the only diversion airfield is much more than 45 minutes away. Under those circumstances we must increase diversion fuel accordingly or divert back to point of departure before the point of no return.

The thing to grasp is that, except during short haul altitude planning, we do not calculate climb TAS or descent TAS. Nor do we ever import forecast winds into our flight planning. We *allow* for these things by loading fixed reserves. We do *not* calculate wind vectors, climb TAS, descent TAS etc, during propliner flight planning.

We load a standardised reserve to combat any and all weather we may encounter on the day. We battle significant perceived headwinds with higher fuel burn, when and if we meet them. Then we execute the dynamic captaincy choices concerning power setting and cruising level examined in part 2B of this tutorial.

Many flight simulation users give themselves a miserable time by loading too much, or too little fuel, for the flight. Fuel planning is not complex, but if we fail to plan, we plan to fail. So before we depart on any trip we will always flight plan carefully and then load the flight plan fuel using the payload and fuel menu. We can then use the same menu to increase payload if we wish, but that introduces another flight planning constraint which we must study next.

First though a word of warning. Some propliners may not have handling notes that disclose flight plan TAS. If the relevant TAS is not listed in the Reference File then we must calculate it by test flying the aircraft at 50% fuel with econ power applied at the highest whole flight level mentioned in the cruise sections of the Reference File; or FL120 if the aircraft is unpressurised and none is mentioned. During the test use the realism menu to disclose cruise TAS then check the airspeed indicator. Make sure it changes to TAS (some don't; the latest DC-6 and Convair ASI's do). Remember to change the realism option back to IAS after the test!

*Apart from such testing of aircraft with deficient handling notes it is never necessary to know either our velocity or our speed during flight simulation.*

The real world handling reference is either drag (KIAS or MIAS or KmIAS), or VSI, or a power setting, which is why they are the only values disclosed in the real cockpit. Velocity (TAS) and speed (KTS) are relevant only before flight, not during flight.



PAYLOAD PLANNING - ZERO FUEL WEIGHT

The parameter that limits payload in real life is zero fuel weight (ZFW). This is the maximum weight to which the aircraft may be loaded before fuel is introduced to the fuel tanks. It is set by the certification authority mostly by reference to the strength of the wing spar. For obvious reasons ZFW is always less than the Maximum Landing Weight (MLW) since even when carrying maximum payload an airliner always lands with some fuel remaining.

The difference between ZFW and MLW correlates to the maximum fuel that the captain may specify as the holding and diversion fuel. When carrying maximum payload, if the aircraft neither holds nor diverts, it may land with all that fuel still aboard, but no more. Although other factors intervene the certification authority will usually set ZFW around 94% of MLW allowing the captain to carry around 6% of the maximum landing weight as holding and diversion fuel, even when airline management require the aircraft to carry its maximum payload.

For the purposes of flight simulation we normally gloss over ZFW, but pay careful attention to MLW. I normally state MLW in the aircraft.cfg and if the relationship between MLW and ZFW was abnormal I usually state ZFW too. I always state MLW in the handling notes or the aircraft.cfg. For instance the relevant section of the DC-6B handling notes says;


******************
REDUCE < 120 KIAS
FLAP - STAGE 5
Cross airfield boundary 105 KIAS (@ 88,000lbs)
FLARE and LAND
******************

It is the 88,000lb MLW that determines how many passengers can be aboard a DC-6B. The Maximum Take Off Weight (MTOW) only determines how much fuel may be loaded in addition. Consequently MTOW is the variable that controls maximum range. However odd it may seem MTOW has no relevance to maximum payload at all.

Cabin volume is irrelevant as well since it does not predict the strength of the wing main spar which is what limits MLW. The shock of (a heavy) landing is what matters. Taking off imposes little load on the wing spar. MTOW (fuel load and range) are limited by horsepower to lift the fuel whilst MLW (payload) is limited only by structural weakness.


AIRCRAFT PREPARED FOR SERVICE WEIGHT

Now at this point we must remember that Empty Weight (EW) does NOT include the crew, their bags, hundreds of pounds of oil in the oil tanks, the galley, catering, and so on. Nor does it even include the seats, the number of which varies over time. The weight that includes all these extras is the Aircraft Prepared for Service (APS) weight. The difference between EW and APS is lost on Microsoft, but I always set the empty weight variable = APS to correct their error. Accordingly when planning a simulated flight; if ZFW is not declared within the download, assume that the maximum payload on any flight must not exceed;

Max Payload = (MLW * 0.94) - APS

If the flight dynamics are realistic the empty_weight variable within the aircraft.cfg will have been set equal to the APS. Reducing fuel below the maximum does not allow an aircraft to carry more than its maximum payload.

ZFW is a certification limit. APS is an airline variable. Some airlines may offer no catering. Some may have lightweight seats. However a typical APS weight for a DC-6B in all economy class is 64,300lbs.


EXAMPLE - DC6B


So if ZFW is typically 0.94 * MLW then ZFW for a DC-6B may be taken to be 88,000 * 0.94 = 82700 thus permitting us to land a fully loaded DC-6B with up to 5300lbs of fuel remaining.

We have just examined why the holding and diversion fuel is always 3128 pounds so allowing 5300 pounds may seem excessive, but of course we must also load a headwind reserve and on some flights we may use none of it!

*The certification authority has ensured that we can never be pressured by airline management to substitute payload for any part of that 5,300 pound reserve fuel allowance.*

Consequently the max payload for a DC-6B with all economy seating is about;

82,700 (ZFW) - 64,300 (APS) = 18,400 (max payload)

By law (during most of the classic era) an airline had to assume that every unseen passenger to whom they sold a ticket weighed 170lbs and they had to calculate the baggage allowance for the flight accordingly. If a particular airline allowed thirty pounds of baggage per passenger the payload seat divisor was therefore 200 pounds.

18400/200 = 92 passenger seats maximum


However if a different airline offers a DC-6B walk on shuttle service specifying only hand baggage which may not exceed ten pounds then the divisor is 180.

18400/180 = 102 passengers maximum

If another airline offers no food and no drinks and completely removes the galley the APS might go down by 900 pounds and the maximum number of passengers allowed to board a DC-6B walk on, no frills, shuttle service might reach 107, which was I believe the largest number of passenger seats that was ever fitted to a DC-6B in commercial airline service within the U.S.

When we need to know the maximum number of passengers that can be loaded *with maximum fuel aboard* we have look in the weight and balance section of a realistic aircraft.cfg where it is always stated in plain English. The DC-6B aircraft.cfg discloses that the maximum payload falls to exactly 10,000lbs with maximum fuel. Again assuming a 30lb per passenger baggage allowance this equates to a maximum of just 50 passengers.

How many passengers a DC-6B can carry depends on what we intend to use it for, but all the information required to work out any of the permutations (real or simulated) is always stated in the relevant aircraft.cfg. If the flight dynamics are realistic it is all there waiting to be read and understood.


EXAMPLE - DC6

The DC-6 was a different and earlier aircraft delivered in two distinct versions, intercontinental and international with many sub variants of those two types. We must ensure that we use the correct aircraft.cfg. The international.cfg explains that payload with full fuel equates to a maximum of 47 passenger seats. Hardly fewer than the larger DC-6B, but the DC-6 has a much lower MTOW, and therefore much less range. Final DC-6 deliveries had an MLW of 85,000lbs, as stated in the handling notes, but most were limited to 80,000lbs with a ZFW of only 74,000lbs and DC-6 APS in all economy configuration was typically 57,500lbs.

74,000 - 57,500 = 16,500lbs and assuming 30lb bag allowance = 82 passenger seats max for short haul.

In practice at least one airline dumped the galley plus catering and fitted 86 seats, probably the largest number fitted to a DC-6 in commercial airline service within the U.S.


EXAMPLE - DC7C/F


As the relevant aircraft.cfg explains the DC-7C was limited to a maximum of only 44 passengers with full fuel for long range operations. Later it had MLW = 111,000 but ZFW was still only 101,500lbs whilst typical APS in all economy seating was 82,000lbs.

101,500 - 82,000 = 19,500 which divided by 200 = 97 seats max for short haul.

Again in practice one airline ripped out the galley and managed to fit 105 seats. The cabin of the DC-7C is bigger than the cabin of the DC-6B, yet it cannot be fitted with as many passenger seats.

So when first introduced the DC-7C typically had fewer seats than the very much smaller DC-6 despite having a much larger cabin. Later after relegation to shorter hauls the DC-7C had far more seats than the typical remaining DC-6. Despite this the DC-7C was restricted to fewer seats than the smaller, much cheaper to operate DC-6B because the DC-7C ZFW and MLW were more restrictive. That is one reason that the older DC-6B was still flying from every major airfield after all the DC-7Cs were rotting and unloved parked around the perimeter.

Again all the relevant information is in each aircraft.cfg and realistic ones usually also provide the non default data we need to substitute within the default aircraft.cfg to turn e.g. a DC-7C into a DC-7CF so that we can fly and land the cargo conversion with a realistic payload, at realistic weights, to discover the difference in performance and handling.


LONG HAUL v SHORT HAUL

So a DC-6B when new and long hauling typically had just under 50 seats and a DC-6 just under 47, but late in life when only short hauling many of the former had almost 107 whilst the latter had no more than 86. The cabin size has little bearing on how many seats may be fitted. Payload is all about the ZFW, which in turn relates to the MLW, which in turn correlates to the strength of the wing spar.

The average number of seats fitted over the lifetime of each of these aircraft, in all parts of the world, would approximate the average of the values above and so;

DC-6 = 61 passenger seats on average

DC-7C = 74 passenger seats on average

DC-6B = 78 passenger seats on average

However the average number of seats over a long time and the typical seating are not the same thing at all since there was a tendency to flip flop from long range operations with minimum seating plus maximum fuel to short range operations with maximum seating and minimum fuel. A DC-7C tended to have about 44 seats or about 97 seats rather than the average of 74.

During flight planning we must ensure that the payload does not exceed the maximum payload, regardless of how little fuel we plan. However the default payload should be compatible with any fuel load. Provided we fuel plan and payload plan we never risk flying an approach at destination in excess of Maximum Landing Weight.


REALISM and VARIETY

Incorporating realism into the simulation takes some effort but introduces much variety. Not just randomised variety, but realistic variety.

Before you do anything else I suggest that you prepare flight plans for a CV-340 flight from Boston (KBOS) to each of the four airfields in Maine used as examples in this tutorial. Fly those plans and make the arrivals and approaches described in parts 3 and 4 of this tutorial. Create user defined weather to challenge your own ability before you fly. Think hard about power settings as well as altitudes. Concentrate on 4D navigation not simplistic 2D navigation.


PROPLINER TUTORIAL PART 7 - NEAR RUNWAY OPERATIONS

Welcome to part 7 of the Propliner Tutorial which examines the landing phase, glideslope recognition, approach planning, visual circuit pattern planning, crosswind landings, use of flap, controlling pitch versus glideslope, use of external pitch cues, and ground handling. It concludes with some relevant aircraft specific reminders and cautions.


FLOATING and SINKING.

Every aeroplane ever built can descend along a minus three degree glideslope, right into the ground. In propliners floating is caused by pilots, not aerodynamics. Floating is just a bad pilot choice when simulating operation of a propliner. It makes no difference whether the aircraft has a nosewheel or a tailwheel, whether turbine or piston engined.

Small taildragging aeroplanes are flared to a three point attitude and allowed to float parallel to, and just above, the runway surface whilst airspeed decays to Vmin, before sinking onto the runway in the three point attitude with the IAS still well above Vs or Vs0 which are associated with higher pitch angles than the tail down angle. That is not the correct landing technique for propliners; even propliners with tailwheels.


FLARING.

In a propliner the flare should begin when the bottom of the mainwheels are about 30 feet above the touchdown elevation. The altimeter in the cockpit may however be 50 feet above the touchdown elevation. If we do not flare and are descending along the three degree glideslope at (say) minus 600 VSI the wheels will impact 3 seconds later. During those three seconds the airliner will travel forward about 500 feet. The possibility of float simply does not exist unless pilot flying (PF) intervenes to create it.

We must teach ourselves to recognise when we have reached a height of 50 feet (50 QFE), using the external runway perspective. We must always use files that deliver real perspective and placement of the scenery so that time and distance are not distorted (see Part 2A). The value 50 feet does not need to be precise, but nor is it a random number. There are freeware utilities that will cause PNF to call height approaching touchdown. If you are having trouble understanding when to begin the gradual flare manoeuvre, use all the help you can get.

In a propliner, having nailed the threshold target speed (Vref), descending through 50 QFE, we flare from (say) minus 600 VSI to about minus 100 VSI, or a little less, at the moment of runway contact. We flare only gently so that it takes about five seconds, rather than three, to touch down from 50 QFE. The increased interval is a function of the VSI decrease. It is chosen by pilot flying (PF). It is not a function of real aerodynamics, air files, or scalars.

During those five seconds a typical propliner will travel about 800 feet in nil wind. The flare adds about 300 feet to the unflared point of impact; less with a normal headwind. This 800 feet difference between the *landing distance* from 50 QFE and the *landing roll* is typical for a propliner with Vref <= 100 KIAS. Propliners with difficult landing characteristics may need to be handled with kid gloves and consequent touchdown may be a little more delayed. BOAC really issued those kid gloves.

Propliners won't bounce from a touchdown at minus 100 VSI. They will stop within the certification landing distance. In MSFS rather too easily if pilot flying ignores real limits relating to use of reverse pitch with flap deployed and the fact that the aircraft would probably just skid if pilot flying applied the wheel brakes continuously in real life. The runways in MSFS are never wet. Most propliners did not have ABS to auto apply cadence braking. Realistic flight dynamics will nevertheless apply cadence braking for you when you apply continuous braking in MSFS.

Below 50 QFE PF decides whether to float or sink. It's as simple as that. If PF nails Vref, then it is just a question of achieving the appropriate negative VSI at the end of the flare manoeuvre when the mainwheels are placed onto the runway. Minus 300 may cause a significant bounce in some propliners, but not others. Minus 100 is good. Minus 0 so the wheels never touch until the aircraft stalls is simply pilot error. If PF does not over rotate in the flare from 50 QFE the mainwheels will always hit the runway in under ten seconds. Unless using STOL landing techniques it should not be less than five seconds.

Landing a propliner is just one more carefully controlled energy state transition, with a defined VSI target, conducted at a defined height, and IAS. Landing a classic propliner usually requires less judgement and skill than landing many light aircraft from the vintage and classic eras.

Float is caused by arriving at 50 QFE with IAS > Vref or by over rotation to positive VSI at Vref.


CROSSWINDS

Throughout this tutorial we have encountered the idea that the direction the nose is pointing may differ from where the aeroplane is going. The difference between our course and our heading is our drift and we have learned that we must differentiate between course and heading. We must vary our heading to achieve flight plan course. We achieve our required heading by rolling to the required heading with aileron. We use rudder to centre the slip ball to negate slip. In a turn we require yaw, induced with aileron, calibrated with the turn rate needle, but we must eliminate slip using rudder, calibrated with the slip ball.

This does *not* change when we fly the final approach in a propliner. We do *not* use rudder to induce (side) slip in propliners. We use rudder to negate slip.

If we have drift on final approach we must use aileron to roll to the required heading which causes our course to be the final approach course. If we have a crosswind our flight path vector is along the final approach course and our nose must be pointing somewhere else to negate the drift. We use rudder only to eliminate slip. We do *not* use rudder to induce yaw down the final approach.

We are already familiar with the idea that we must ‘flare’ our pitch on reaching 50 QFE at Vref. When we must make a crosswind landing we must also flare our yaw. The process is the same. During those last few seconds of descent we moderate sink with the joystick to <= -100 VSI and we moderate yaw with rudder to zero yaw versus the runway at the moment of mainwheel contact. We fly the aeroplane into the required vertical and lateral alignment with the runway; then we place it on the runway, when we are ready.

When we reach Vref at 50 QFE we are not crash landing. We are in full control. We choose how long we float. We choose when we place the mainwheels on the ground. We place the mainwheels on the ground when we have achieved a sink rate of <= -100 VSI and when they are aligned with the runway. Hydroplanes must also be landed with zero yaw versus the water. With no marked runway this is harder to judge, but we must succeed anyway.

We use rudder to yaw propliners only in the last few seconds of any flight and only below 50 QFE. For the rest of the flight we use rudder only to eliminate slip. Those who do not possess rudder pedals for use in MSFS may struggle to control slip with precision because the full range of twist movement within relevant input devices is very small. It may be appropriate to use auto coordination of rudder to eliminate slip automatically throughout the flight.

However if you always fly with auto co-ordination turned on you may remove the yaw authority required to flare the aircraft in yaw below 50 QFE during a crosswind landing. You should consider adding an auto co-ordination gauge to every cockpit environment that you use so that you can turn it off passing about 100 QFE during final approach to a crosswind landing.

In propliners yaw is induced with aileron and balanced with rudder. Slip is undesirable (excess / inadequate) yaw. Slip adds unnecessary drag. Slip is never wanted in propliners. In propliners we use rudder to induce yaw only when we need to flare in yaw and only below 50 QFE.


DISPLAY DISTORTION again

In real life pilot flying will be head up and using external pitch cues both to judge glideslope and to moderate the rate of descent without arresting it. Many users of MSFS allow themselves to be seduced into using cockpit environments that distort scenery perspective, placement and parallax and consequently never learn to recognise a three degree glidepath, or to recognise when to flare. Avoiding broken 2D panels in FS9 and broken aircraft in FSX is especially important during near runway operations.

Whilst you are teaching yourself to recognise a three degree glideslope and 50 QFE first learn to flare each aircraft by going 'half head down'. On passing 50 QFE use the VSI to moderate descent to minus 100 whilst remaining 'half head up' and noting where the horizon is in the windscreen during a minus 100 VSI touchdown at <= Vref. During self training progress to being entirely head up and using only the external pitch cues. Obviously the pitch cues vary from aircraft to aircraft. In some aircraft it is appropriate to fully close the throttles passing 50 QFE. In others we should carry some power to touchdown.

As we shall discover shortly there are times when we will have no intention of flying a three degree glidepath, but we need to be able to recognise whether we are below a three degree glidepath regardless. If we perceive that we have sunk below a three degree glidepath we should add MAP to negate sink and regain the 3 degree glidepath.


VC VIEW is OPTIMAL

Aircraft released with only a 2D panel and no VC often have a compromised pilot view. The move to virtual cockpits with realistic parallax, which obscure only what is obscured in real life is the solution to this problem. All that producers of 2D panels can do is to minimise the compromises inherent in the blocking of the real view by out of scale panel bitmaps in 2D cockpit view. That compromise is very carefully chosen and tested by the developers of a high quality aircraft for use in MSFS. The 2D panel can be harmonised to allow VFR operation down to VFR minima and IFR approaches to be flown in visibility as low as 2 miles, but most well designed 2D panels cannot cope realistically with less. The VC environment requires no compromises. Some taildragging propliners can only be operated realistically on the ground from the VC environment. The 2D panel usually denies the necessary peripheral view of the runway or taxiway edge.

If a fully functional VC is available it is best to simulate operation and navigation of any aircraft from that cockpit environment. This is especially true of near runway operations.

These issues are explained and illustrated in greater detail within the simulation control interface tutorials available from;

www.calclassic.com/tutorials


UNSTABLE UNRUSHED APPROACH

Propliners with flaps must fly an unstable approach. Both IAS and configuration must change during the final descent to land. During a straight in approach propliners with flaps should be flown down a three degree glidepath using power to hold the glidepath even when approaching a grass runway with no lights. We will consider approaches from the circuit and circling to land shortly.


VISUAL APPROACH SLOPE INDICATORS

A straight in approach is much easier to fly than a circuit. We should learn to land propliners from long straight in approaches, using glideslope guidance from the Visual Approach Slope Indicators (VASIs) of major runways before attempting any other kind of final approach.

When we are maintaining the glidepath correctly the upper lights will be red and the lower lights will be white. Red means too low and white means too high. Whilst we hold the VASIs at 'pink' by varying power we must imprint the ‘picture’ of the runway *perspective* as we maintain the three degree glideslope.

The parallax picture of the runway varies with our pitch. Our pitch will rarely be the same as our flight path vector (glidepath). It is not possible to recognise a 3 degree glidepath using a parallax cue. The correct glidepath can only be recognised using a perspective cue.

We must practice, practice, practice, always with an unbroken cockpit environment, until we can recognise a three degree glideslope from runway perspective alone. Not all runways have lights. When they don't the only way to fly a safe approach is to use runway perspective to judge the safe glidepath. We must train ourselves to recognise the perspective of a runway from 3 degrees. We must imprint that ‘picture’ on our brain. We must never alter the real world perspective, placement or parallax of runways by using FS9 panels or FSX aircraft which impose false zoom to misplace scenery.

This is especially important for anyone currently employing only a flight simulator, but who may one day fly real aircraft. It is essential to imprint the real perspective of a runway from a three degree glideslope on our brain. Anyone who eventually operates real aircraft will replicate what they imprinted in a simulator. That is the purpose of flight simulators. We use them to imprint a ‘picture’ of how things should be and we operate the aircraft to match that picture.

If the software used imposed false perspective via false ZOOM, the picture imprinted may one day kill us in real life. Now would be a good time to study again FSXvc.jpg and FSXcv.jpg to grasp how different ‘the picture’ looks when it is distorted by the designer and we fail to fix it, delete it or just avoid using it.


FLY BY THE NUMBERS

Some vintage and classic propliners had very marginal performance envelopes. They were just about safe for public transport use according to the laws of the day. To ensure safety their energy state has to be controlled very accurately. They are very demanding to operate, but that is what makes them so interesting to simulate. As far as possible I try to avoid talking about V speeds within the individual handling notes and in any accompanying documentation, but the more realistic the flight dynamics, the more necessary it becomes to operate by the numbers.

Bad landings are not just the consequence of over or under rotation in the flare. It is important to achieve Vref. It is therefore necessary to calculate Vref which is the airspeed we must achieve at 50 QFE.

The handling notes do not tell us Vref for our approach weight. They tell us the numbers we need to calculate Vr or Vref for our particular take off or approach weight. The essential difference between an airliner and a light or executive aircraft is how much their weight varies. Airliners therefore have complicated performance envelopes. To fly them well we must learn to fly them by the numbers, but those numbers are variables, not constants. We must calculate the V speeds during flight planning. In general the structural *limit* speeds do not vary with current weight, (some that are not used in MSFS do), but in general the *target* speeds all vary with square root of current weight. You may wish to prepare a table cross referencing weight and Vref for aircraft that you fly often rather than calculate them each time you fly.

In accordance with the handling notes, Vref for the CV58 is 105 KIAS at maximum landing weight = 52,000lbs.

****************************
REDUCE < 140 KIAS
SHORT LANDING ONLY - FLAP = STAGE 4
Cross Airfield Boundary 105 KIAS (@ 52,000lbs)
FLARE and LAND
****************************

As in all other aeroplanes Vref reduces as the square root of the landing weight until it may equal Vmc which is 92 KIAS for the CV58. 52,000lbs is the maximum weight at which a CV58 may land. With appropriate fuel planning a more representative CV58 landing weight might be 44,000lbs.

At 44,000 pounds CV58 Vref becomes 105 * SQR(44000/52000) = 97 KIAS.

The drag at which we must rotate (IAS = Vr) varies in the same way.

As a tutorial exercise try flying the CV58 at 44,000lbs down an ILS glideslope at 100 KIAS steady state with Gear and Flap 3 deployed. Make no attempt at all to flare. At about 50 QFE simply close the throttle(s). It doesn’t matter if the aircraft misses the runway. Pause and switch to chase plane view and then unpause to watch side on what happens at touchdown, with no flare at all.

All the flare is intended to do is moderate that observed 'impact' which constitutes a heavy landing. Propliners will ‘survive’ a collision with terrain at Vref and at 3 degrees. Flaring from 3 degrees turns a heavy landing into a comfortable landing.

Even with appropriate energy state management, most landings will not be 'greasers'. Often the main wheels will 'skip'. A bounce over less than a fuselage length is acceptable.


MEASURE YOUR OWN ABILITY

Use the video option to review your landings. Pause it. The tyre smoke effect will display the distance between first and second mainwheel contact (if any). Provided there are only two mainwheel contacts, and the gap is less than a fuselage length, and first nosewheel contact is after final mainwheel contact, flaring technique is 'appropriate'. If it takes much more than five seconds from 50 QFE to first contact the flare is too aggressive. Floating is simply pilot error and is caused by over aggressive rotation. A heavy landing is pilot error and is caused by complacent under rotation.

Neither error is ever in the flight dynamics. However inadequate the feedback from small plastic joysticks may be, an aircraft only floats if pilot flying increases angle of attack so far in the flare that the extra lift causes VSI to become zero, or even positive. Equally airliners only bounce if the flare is rotated to an inappropriate pitch or VSI at mainwheel contact.


PROPLINERS MUST BE 'WHEELED ON'.

The idea when flying propliners, or equivalent military aircraft, is to place the mainwheels firmly on the runway at a speed slightly below Vref, thus ensuring that PF still has full elevator authority and control over VSI. PF simply chooses the sink rate at mainwheel contact using the joystick. Big aircraft, with or without tailwheels, are not 'stalled' onto the runway from level flight over the runway.

Three point technique, used in tiny taildraggers, requires very precise judgement of wheel to runway displacement during the float. During the 1920s and 1930s the height of the wheels above the runway became more and more difficult to judge as cockpits became higher and higher above the mainwheels. In propliners the cockpits were also getting further and further ahead of the mainwheels.

Propliners are flown down the glideslope onto the runway at a controlled rate of sink and make mainwheel contact whilst still flying. If we don't over rotate to positive VSI we cannot float. If we reduce VSI enough we won't bounce. The trick is to moderate the rate of descent, during the last five seconds of the approach, without arresting it. We must reduce VSI by about 500 ft/min over about five seconds. Elevator authority will always be much more than adequate for this task at Vref since it must be more than adequate to rotate a heavier aircraft, more aggressively, at Vr during take off.

Many real pilots like to add a fraction of the wind component to the calculated Vref to guard against wind shear. Most FS users should target Vref unmodified as that will minimise the landing problem. Real pilots should be able to do whatever they do in real life.


LANDING DYNAMICS VARY

It is the job of the real world flight dynamics author to ensure that if PF puts the aircraft into landing configuration, achieves Vref at 50 QFE, and moderates descent to about minus 100 VSI over the next few seconds, the attitude of the aircraft will automatically be a viable landing attitude. In other words an attitude compatible with adequate elevator authority, yet appropriately nose up to prevent premature nosewheel or tailwheel contact, with modest propensity to bounce. The MSFS FD author attempts to replicate what the real world FD author achieved, or failed to achieve.

Real world FD authors sometimes make mistakes. Those of you who have read the classic propliner forum for many years will know that the real FD author at Martin miscalculated these issues with the M202 and M404 whilst the real FD author at Boeing miscalculated with the B377. Passing 50 QFE at Vref in landing configuration those aircraft were very nose down and simply moderating descent to minus 100 VSI at Vref did not always prevent premature nosewheel contact. The really nasty landing characteristics of those aircraft give us a bigger problem to solve, and this makes Vref a critical number to calculate and achieve during simulation.

The propliner FD available from calclassic.com are not intended to be 'real easy' regardless of the aircraft being simulated, they are intended to be 'realistic'. However MSFS imposes many compromises. Sometimes it is necessary to decide whether rotation and landing characteristics should be realistic, or whether ground handling characteristics should be realistic. I confess that I am much more interested in what happens on the runway during take off and landing than in what happens on the apron and taxiway. Consequently in my FD if a compromise is required I always favour ‘realistic’ rotation and realistic propensity to bounce on landing over realistic low speed ground handling characteristics around the apron.


THE VISUAL CIRCUIT PATTERN

Most of the time our destination will have an approach procedure that allows a straight in approach to the landing runway. On other days, and in other places, we will need to fly a circuit pattern in a propliner. This is much more difficult than flying an instrument approach to land on the instrument runway and should not be attempted without substantial prior experience of making unrushed straight in approaches.

How to enter visual circuits correctly in different jurisdictions is explained elsewhere on the web. During flight simulation by default we will locate the airfield from its initial approach fix pointing at a known runway, we will count round the runways to identify the landing runway, and then we will position at the approach Minimum Descent Altitude to intercept the left hand down wind leg for the landing runway, from outside the circuit, at an angle of 45 degrees, reaching pattern altitude just before we intercept the down wind leg, at the mid point of the landing runway.

We should make the effort to download the real approach plates when available and adjust our pattern altitude and direction using the means described in Part 4 of this tutorial. The available plates may describe procedures specific to an individual destination and we should eventually acquire the ability to comply with all of them.


Let’s examine approach planning in a DC-7 when the landing runway is not the instrument runway.

*********************
Approach and Landing:
MIXTURE - MANUAL RICH
COWL FLAPS - MID

2300 RPM
MAP as required

REDUCE < 170 KIAS
FLAP - STAGE 1
>>>>>>>>>>>>>>>>>>>>>

We reduce below 170 KIAS and deploy FLAP 1 before the IAF and usually at least 15 minutes before touchdown. If we wish to use AP we must reduce to 140 KIAS *before* we use AP to turn. Today we might decide to hand fly the approach so we deploy only FLAP 2 as we cross the IAF.

>>>>>>>>>>>>>>>>>>>>>
REDUCE < 160 KIAS

FLAP - STAGE 2
>>>>>>>>>>>>>>>>>>>>>

We will need to apply more bank than an AP can apply to achieve the mandatory rate 1 turns of the approach. We must bank as hard as may be required to achieve rate 1 because we did not slow to 140 KIAS just after the IAF. Eventually we clear ourselves to commence the approach. Before we descend inbound to the instrument runway we must comply with the following.

>>>>>>>>>>>>>>>>>>>>>
Nearing Glideslope

REDUCE < 150 KIAS

FLAP - STAGE 3
>>>>>>>>>>>>>>>>>>>>>

We will usually be about three minutes away from the instrument runway at this point in the approach and perhaps ten minutes from touchdown on the landing runway.

We descend to MDA and search for the airfield whilst making modest progress. We do not want the world to be rushing by as we try to identify first our destination, then the instrument runway, and then the landing runway. We need time to work out how we will position to join left hand downwind for that landing runway. We will hardly ever join a circuit pattern in a propliner with profile drag exceeding 140 KIAS. We will normally have reduced below 140 KIAS whilst still trying to identify the landing runway and several minutes before joining its circuit pattern.

Most MSFS users just don't get this and approach airfields with the aircraft in an excessive energy state. Everything happens faster than they can cope with. Most MSFS users only ever fly rushed approaches. We need to plan and fly unrushed approaches.


USE OF FLAP

From time to time we all see posts in forums which say that an aeroplane is flying nose down in level flight. We studied this in Part 2B of this tutorial which explained;

<<In the cruise if we are pitched very nose up we have either applied too little power or we have climbed too high for our current weight. Conversely if we are nose down we have applied too much power, or we are too low for our current weight. We should adjust one or the other, but all things being equal we should adjust our altitude and run the engines at optimal MAP and rpm. Mountains, ATC, turbulence, icing, etc, mean that sometimes we have to adjust power instead. Aeroplanes never cruise nose down. Only pilots do that. Most of the time we should avoid doing so.>>

Approach procedures are ATC procedures which constrain us to assigned altitudes. Our intention (in level flight) is to operate the aircraft at or just above zero pitch, with or without flap deployed.

That is what flaps are for. They are fragile. They are not air brakes. We use them to vary wing camber to control aircraft pitch. As we reduce IAS during the approach phase we need more and more flap to sustain zero pitch in level flight. We always desire zero pitch in level flight unless we are battling headwinds. When we slow down the mechanism we use to deliver that goal is variable flap.

We add enough flap to achieve zero pitch.

Each stage of flap rotates the aircraft more nose down due to increased wing camber. We keep doing this so that we can see where we are going at lower and lower IAS. We need to be at zero pitch to see where we are going in the hold, whilst maintaining mandated altitudes in the instrument approach, and whilst maintaining assigned altitudes in circuit patterns.

The aircraft specific handling notes provide guidance concerning flap deployment during the approach, but like everything else it really depends on both current weight and current weather. We deploy flap to sustain zero pitch in each level flight segment of the approach. There are IAS targets for each stage of the approach. If the aircraft is pitched nose up in level flight after we achieve that IAS target we need another stage of flap, or more power.

However many/most aircraft require us to deploy flap in fixed stages.

During a level flight segment of the approach, at the correct target IAS, we recognise that pitch is several degrees positive, making it difficult to see the scenery ahead, we recognise that it should be zero so that we can see the scenery ahead, we act and we deploy another whole stage of flap. However that whole stage of flap may pitch us to negative pitch. This is just a particular case of the general case studied in part 2B which is;

<<if we are nose down we have applied too much power, or we are too low for our current weight.>>

Since our altitude is mandated we have too much power applied. Approach rpm is mandated so we reduce MAP to restore zero pitch. IAS will decay. This is not a problem. Aeroplanes cannot stall at zero pitch, flap up or flap down. They can sink, but not stall. We moderate power with throttle to sustain zero pitch in level flight. This is just a particular type of cruise condition. This is not about measuring pitch to fractions of a degree in any cruise condition. During the approach phase it is all about seeing where we are going. We apply enough flap to achieve zero pitch to see where we are going and if that whole stage of flap pitches us nose down we reduce MAP to achieve zero pitch in the current weather at our current weight.

The supplied aircraft specific handling notes cannot provide guidance for every weather circumstance and every weight for any phase of the flight. We must adapt the general case to match our current weather and weight. At light weights we need less flap to achieve zero pitch at a given IAS, or alternatively we need less MAP. We must act accordingly.

We reduce IAS in accordance with the handling notes and we deploy more flap and / or more power if that target IAS reduction caused us to become nose up in level flight. If that next whole stage of flap pitches us nose down in level flight we correct that with MAP.

There are however some aero engines that will not tolerate low MAP in flight. We do not reduce MAP below the minimum stated in the handling notes and those aircraft may develop nose down attitudes at light weights with flap deployed. The stated MAP minimum may be absolute or may relate to applied rpm. We need to see where we are going regardless. The approach phase is the one in which we must always transition to pioneer navigation by reference to the surface scenery and we must pitch the aircraft (in level flight) with flap and MAP so that we can see and identify that scenery.


CONTINUE APPROACH

In our DC-7 we must deploy FLAP 3 before we descend to MDA (or the height at which we plan to cross over the visual circuit to join it if higher – see later).

>>>>>>>>>>>>>>>>>>>
Nearing Glideslope
REDUCE < 150 KIAS
FLAP - STAGE 3
>>>>>>>>>>>>>>>>>>>

For the time being any IAS not exceeding 150 KIAS is OK. We may reach the high 140s during the descent to MDA. However when we reach MDA we must adjust MAP to sustain zero pitch with FLAP 3 deployed whilst we search for the airfield maintaining MDA. We treat each level flight segment of the approach as a cruise segment and we target zero pitch. The resulting IAS will vary with weight and weather, but will always be safe for level flight and descending flight.

From the time that we reach and level at MDA until just before we turn base leg in a visual circuit we will be retaining FLAP 3 and the MAP that sustains zero pitch. We do all of our identifying of our destination, and the instrument runway, and the landing runway, and where the left hand join for that runway is, while sustaining zero pitch so that we have the appropriate and necessary view ahead.

Only at the end of the downwind leg will we vary configuration and power again as we begin the final descent to land. We will study that in more detail during visual circuit planning shortly. We will fly the base turn at the IAS we have been sustaining for several minutes and which we know is safe in level flight. However low it is it will also be safe in turning descending flight so long as we target bank angle with care. See later.

>>>>>>>>>>>>>>>>>>>>>
ON descending
GEAR DOWN
23 to 27 inches MAP
FLAP - STAGE 4
>>>>>>>>>>>>>>>>>>>>

We turn final. Now we have FLAP 4 we can fly the final turn at lower IAS. Then when established on final approach;

>>>>>>>>>>>>>>>>>>>
REDUCE <130 KIAS
FLAP - STAGE 5
Cross AIRPORT BOUNDARY 110 KIAS
>>>>>>>>>>>>>>>>>>


Having studied IAS targeting and use of flap during the approach we come to the most difficult skill flight simulation which is the ability to judge our distance from the landing runway.


STANDARD PATTERN PLANNING

During flight simulation we will, by default, treat every circuit pattern as displaced 6000 feet laterally and 1000 feet vertically from the landing runway, but if the approach plate indicates that we should proceed differently we will.

However we must always remember that many airfields have rising ground and masts nearby. We must learn to recognise a lateral displacement of 6000 feet. This is a very basic skill, yet one which most flight simulation users never acquire. It is only safe to fly the circuit pattern at circuit height if we fly downwind displaced by (no more than) 6000 feet. Any greater lateral displacement may collide with terrain or obstacles at circuit height.

A displacement of 6000 feet is another 'parallax picture' that we must learn and implant. We must fly only with real scenery placement else we cannot formulate and implant that picture. We must not allow panel makers in FS9 and aircraft makers in FSX to randomly misproject the scenery and the mesh. False scenery projection via erroneous zoom factors has no place in flight simulation.

It is time to study the supplied 'Goose downwind QFU 14 3B1.jpg'. Please double click it in the tutorial folder to get it on screen; and study it now. It shows where we should be by default after turning downwind in a standard circuit pattern (assuming we departed the landing runway for circuit pattern training). Notice that one of the things that makes the FS9 Goose such an ideal trainer is the ability to judge lateral offset using the parallax between the float and the landing runway.

Note that when we fly downwind in a standard circuit pattern in the FS9 Goose *at the correct height* all we need to do to achieve 6000 feet of lateral displacement is intersect the float with the landing runway in the manner depicted. We use parallax to position ourselves versus the scenery. Most aircraft do not offer that easy to recognise parallax lateral displacement cue.

During self training we must learn to fly at the correct circuit height and also to position the float to intersect the landing runway correctly. We will at first be struggling to position the Goose correctly downwind 6000 feet abeam the landing runway, but that is only our primary and easy objective. Once that becomes second nature we must learn to recognise what the runway, the airfield, our installed autogen objects, and our installed 3D objects look like when we parallel the landing runway laterally by 6000 feet. We must learn to recognise 6000 feet of lateral displacement without a convenient float to track down the runway using parallax to recognise a 6000 foot baseline from 1000 feet. We use the float to achieve it, but then we must learn to recognise what 6000 feet looks like without a float to impose as a parallax picture. Realistic scenery placement is essential and the enhanced realism files within this tutorial deliver it in FS9 when we use Bill Lyons’ Goose.

Without the ability to recognise and achieve the correct lateral displacement we cannot learn to fly a standard circuit pattern or to join a standard circuit pattern. Most MSFS users never learn how to recognise, let alone create, a standard circuit pattern, yet they attempt to end many flights with a wild approximation of one. No one learns to recognise the correct downwind displacement from the landing runway with just a few minutes of practice. It takes hours of familiarisation to imprint 'the picture' in real life and it will take hours of circuit training in a simulator. It is however a basic skill that must be acquired.

Unfortunately we have chosen to fly propliners so life is not that simple! We must acquire a second skill which is an extrapolation of that basic skill which should always be acquired first.


HIGH PERFORMANCE (PROPLINER) CIRCUIT.

6000 feet is one nautical mile. Everything in aviation works to base 60 because everything depends on TIME. Time is the universal constant between the imperial and metric systems.

After the downwind leg we need to make two right angle turns. If we flew those turns at Rate 1 (3 deg/sec) each 90 degree turn would take 30 seconds. If we fly a 360 circle at Rate 1 at a velocity of 120 KTAS it takes two minutes at 2 miles per minute. The circumference is 4 miles. Consequently the diameter is 4 divided by PI = 1.27 miles, which is about 7500 feet. When we fly a holding pattern at 120 KTAS the inbound and outbound legs are about 7500 feet apart; the diameter of the semi circles at either end of the hold.

Now remember we need to create a base leg, at right angles to final approach, between the downwind and final legs. It should be obvious therefore that we need to fly the turns in circuit patterns at significantly more than Rate 1. No AP can cope with that. We must hand fly the turns and we need to target higher bank angles than an AP can deploy. It is safe to hand fly the descending base turn with up to 45 degrees of bank generating substantial rates of turn. Light aircraft and combat aircraft may. We can do that in a Goose too of course, however paying passengers do not enjoy large bank angles, especially near the ground.

Consequently 'propliners' normally fly a high performance circuit which in MSFS we will displace laterally by 10000 feet.

However we have already grasped that displacing our downwind leg by more than 6000 feet may cause collision with terrain at circuit height. Therefore when we fly a high performance circuit we add 500 feet to the standard pattern altitude so that the default propliner circuit height becomes 1500 feet.

Now is the time to study 'Goose High Perf Circuit.jpg'. Please study it *alongside* the previous jpg on screen now.

It shows what QFU 14 3B1 (Greenville) looks like from a lateral displacement of 10000 feet and vertical displacement of 1500 feet. The first thing you may notice is that having increased lateral displacement by 66% and vertical displacement by 50% barely altered intersection of the float by the runway.

This is very important information. Provided we position at the correct height *for either circuit* when we re-create the ‘parallax picture' we will position at the correct new lateral displacement associated with the correct new height. The downwind lateral displacement 'picture' has invariant parallax, for any circuit height *provided we use only cockpit environments that place the scenery correctly*.

Again it is a question of spending however many hours it takes in the FS9 Goose to learn to position correctly downwind in both circuits. Once doing so in both circuits is second nature in the FS9 Goose we must begin to imprint what runways and trees and buildings look like from 10000 feet abeam the landing runway. Most aircraft will not have a convenient float to deliver an easy parallax comparison to make circuit pattern training easy.

At this point some readers may make the fatal mistake of supposing that all they need to do is position the runway at a certain position on their monitor. That does not work. Eyepoint is different in every aircraft. The unseen eyepoint is at a different place on your monitor aircraft by aircraft and cockpit environment by cockpit environment. This is illustrated further within the FS9 simulation interface tutorial from www.calclassic.com/tutorials.

Position within the monitor screen is not relevant information. To fly head up in any aeroplane we must be able to determine the distance of objects in the scenery. It is an absolutely basic skill, and just as in real life we must use the size of things as our frame of reference for judging distance. Fortunately objects are less variable in size in simulators than they are in real life *provided we use only cockpit environments that place the scenery correctly*.

In real life most people need to learn to judge the distance of motor vehicles up to 600 feet away quite accurately in order to survive, but never teach themselves to judge distances out to 10000 feet. To use a flight simulator we need those increments of skill. We can only develop those increments of skill if we always fly with realistic scenery placement so that the ‘picture’ never changes.

This may have sounded complicated, but in reality the ability to judge distance is a very basic and essential skill. Using the ‘enhanced realism’ FS9 Goose, with its convenient float, allows us to create the two parallax pictures we need to learn to recognise so that we can re-create them as we fly the circuit in different propliners. Remember slow propliners like the Martin M-130 can quite happily fly a standard circuit to land on the lake runway at Greenville. The deciding issue between a standard circuit and a high performance circuit is circuit velocity not aeroplane mass.


KEEP IT SIMPLE STUPID (KISS)

Once we have learned how to position downwind, however many hours that may take, the next basic skill we need is recognising when to terminate our downwind leg to turn onto base leg.

During flight simulation we will simply turn base about 60 seconds after we go abeam our touchdown point. We will use a stopwatch to achieve that. That plan removes all need to consider velocity in different aircraft and is of course based on TIME. Having reversed direction via two 90 degree turns faster propliners will automatically allow themselves a longer final approach in miles, *but not in minutes*. The TIME from abeam the touchdown point to touchdown will be nearly constant in any propliner. The tower controller is in fact relying on this to sequence traffic onto the runway and it is our job to deliver that invariance. ATC may require us to report late downwind (abeam our touchdown point) as a reminder to them that we have become a threat to the runway. In low visibility they will. In either circuit we must not proceed downwind for more than a further 60 seconds else we may impact terrain or obstructions at the relevant circuit height.

Having resolved the problem of when (not where) to turn base leg we must resolve the problem of when (not where) to begin our final descent. Now we must grasp that we can descend at minus 500 VSI from a circuit height of 1000 feet, to touchdown elevation, when we are two minutes from touchdown, in every headwind, to every runway ever built, and in every aeroplane ever built!

The key decision is when to descend from 1000 feet at minus 500 VSI in the current headwind. We must all develop the skill to judge when we are two minutes from touchdown else we cannot plan or fly a visual circuit in any aeroplane. Aerial navigation is always 4D, never 2D or 3D. Almost everything in aerial navigation is about time not distance and everything must be planned.

Failure to plan operating targets and procedures just makes flying terribly difficult. Realism isn’t about adding difficulty. It’s the solution. We must plan our operating targets. We must plan which operating targets we will keep constant and which we will vary. If we plan logical and easy to manipulate operating targets flying becomes easy. We must impose our plan on the aeroplane and we need a plan that is as invariant as it can be.

If, a particular airfield, has a circuit height of 800 feet then we descend at minus 400 VSI instead so that we can fly the same circuit pattern. We just vary our target VSI with the circuit height so that the final descent always takes two minutes. When we fly a high performance circuit at 1500 QFE we intend to descend at minus 750 VSI. We intend to descend two minutes before touchdown without variation. That way we only need to recognise when we are two minutes from touchdown.

Consequently the only mistake we can make is to turn base or begin descent less than two minutes from touchdown. During pattern training we concentrate on learning to position downwind and when (not where) to turn base leg.

During a visual circuit, (or circle to land procedure), we do *not* plan to fly the 3 degree glidepath throughout the final descent. From the visual circuit we approach at the relevant VSI. That will be minus 500 VSI from a standard pattern and minus 750 VSI from a high performance propliner pattern.

All of our circuit planning thus far has in fact been aimed at achieving an easy way to recognise two minutes from touchdown. We have planned our circuit so that two minutes from touchdown will usually be somewhere in the base turn. Since it will take us many seconds to achieve the target VSI we reduce MAP to that required to achieve the target negative VSI *before* we roll into the base turn. It is the final act on the downwind leg and therefore about 50 seconds after we go abeam our touchdown point. The base turn is flown as a descending turn at low but carefully targeted IAS, in a carefully targeted FLAP configuration, at a carefully targeted TIME. Descending minimises risk of stall in the base turn and our turn onto final from base will also be a descending turn of course.

The headwind we encounter on the final approach will vary day by day. Our decision to initiate descent as we roll into the base turn will always be wrong to some degree. Except in nil wind (the most difficult and dangerous case) our target VSI and ‘early’ descent will be converging us with the 3 degree glide path from above.


SAFETY FIRST

During a visual circuit we do *not* plan to fly a 3 degree glidepath throughout the final descent; mostly because up to half of the final descent is flown down the base leg where we have no hope of judging a 3 degree glidepath. From the high performance visual circuit in all relevant aircraft we approach at minus 750 VSI.

However during that final approach we must be able to recognise the ‘reference picture’ that represents a 3 degree glidepath, even when the runway has no lights, even when flying a visual circuit. We will not descend below a 3 degree glidepath during a visual circuit. By default we have inadequate separation from obstructions below the 3 degree glidepath. We would cause both concern and noise nuisance to others.

We descend at our target VSI until we intercept the 3 degree glidepath from above. Where we intercept it just varies with the current headwind. When we intercept it we increase MAP and sustain the 3 degree glidepath until it is time to flare.


TIME and TIME again

Our plan is simple. Every phase of any flight needs pre planned numerical targets else we end up trying to solve simple problems with complicated solutions that have too many variables to solve and control at once in real time. Each problem we may need to solve is associated with a pre planned variation of a single operating target variable. There is no time during flight to invent or calculate solutions.

We turn base at the same TIME on every flight, in every aeroplane, to every runway. We descend at the same TIME on every flight, in every aeroplane, to every runway. We vary VSI with circuit height. It is the current headwind that determines where we intercept the 3 degree glidepath whose ‘picture’ we must recognise and sustain with variation of MAP as we allow our IAS to decay to aircraft and weight specific Vref on the final leg.

Of course all of this requires that we never fly with ZOOM set to anything other than the value which delivers real scenery placement during flight simulation. If we develop the habit of flying with randomised zoom factors we soon lose the ability to judge distance, relative height, and therefore in accordance with Pythagoras’ theorem we lose the ability to judge glideslope too. That is the worst thing we can do to ourselves in any flight simulator. Using files or display modes with inhuman randomised zoom values that impair our ability to judge height, time to go, distance and glideslope during flight simulation is the worst mistake of all. We examined that in some detail in Part 2A of this tutorial. If you have forgotten how to recognise broken cockpit environments which misplace the scenery you should revise that section now.


SINKING and BALLOONING

Any aeroplane can descend nose up. It is not diving it is sinking. Any aeroplane can ascend nose down. It is not climbing it is ballooning. An aeroplane may sink due to flap retraction or balloon due to flap extension. However these terms are not explicitly linked to use of flap. We can also make aeroplanes balloon or sink with power. If ballooning and sinking are transient we may ignore them, else we must correct with power.


TURN RATES and BANK ANGLES

Most flight simulation users skip basic training and never learn to fly a co-ordinated 30 degree banked level turn. That skill is both elementary and essential. It must be practiced with and without flap. That skill must then be extended to flying a 30 degree banked turn at both minus 500 VSI and at minus 750 VSI, at typical approach weights, and in all relevant approach configurations. The MAP required at approach rpm for each configuration should be noted.

Flight simulation users must also learn to fly 45 degree banked level turns in aircraft like the Goose. In both cases the skill must be learned using gauges to sustain 30 and 45 degrees of bank, but that head down skill must then be transferred to become a head up skill using the external horizon as the pitch and roll cue instead of an artificial horizon. In order to fly circuit patterns we must develop the skill to fly head up and without gauges. Circuit pattern flying is all about positioning correctly using realistic scenery and mesh projection and parallax with some part of our aeroplane. Downwind the reference we compare to the landing runway may be a float, or a wing tip, or a prop boss, or a rivet on the side window. On final it will be scenery position versus the top of the panel. Circuit patterns must be flown head up with only occasional head down glances at gauges.

These are basic skills which must be practiced time and time again.

Even from the high performance circuit, in order to generate adequate rates of turn, both the base turn and the final turn need to be flown with 30 degrees of bank. Those turns must also be flown as descending turns with profile drag already below 140 KIAS.


REALISTIC MINIMA

We now have a simple and almost invariant high performance propliner circuit plan based only on being able to recognise a lateral separation of 10000 feet, and timing 60 seconds on a stop watch.

However this plan will only work when the current visibility is at least 4 miles. We intend to stay within 4 miles of our touchdown point, but we do not intend to stay within 3 miles. I strongly recommend that flight simulation users who are not qualified pilots make only straight in instrument approaches to land when the visibility is less then 4 miles, or when the cloud base is below high performance circuit height. Most flight simulation users who are not qualified pilots will find flying a circuit in a propliner in a visibility below 4 miles, or with a cloud base below the high performance circuit, too challenging.

Most flight simulation users should not even contemplate circle to land procedures below the normal circuit height and inside the normal 6000 foot lateral pattern. Most lack the skill to fly head up to keep the runway in view whilst making all the configuration and IAS target changes required.

Even experienced flight simulation users who are not qualified pilots should intend to fly propliners around the high performance circuit, by default at 1500 QFE, all of the time when they do not make a straight in instrument approach to an instrument runway. Throughout this tutorial I have talked about descending to MDA when the published procedures allow that. For straight in approaches (where allowed) we should. However whenever we intend to fly the pattern we should not descend below the height of the high performance circuit which we intend to fly.

The real (supplied) approach plate allows descent to 2300 QNH for both straight in approaches and landings on the other runways at 3B1. When 14 is not the landing runway flight simulation users who are not qualified pilots should not descend below 2800 QNH and should not even commence an approach if the cloud base is below 2900 QNH <> 1600 QFE. Be realistic about your own minima. For any runway other than 14 at Greenville a visibility of 4 miles and a 1600 foot cloud base will be very challenging even for experienced flight simulation users attempting to fly propliners.

We keep as many things as possible in our plan constant. We have reduced the problem of pattern planning to three learned skills and one calculation. We must acquire the skill to recognise and impose a lateral distance of 10000 feet in MSFS. We must acquire the skill to recognise and impose a three degree glidepath in MSFS and we must acquire the skill to calculate and impose Vref.

Practice, practice, practice.

Every problem we may need to solve is associated with a pre planned variation of a single operating target variable. The plan is as invariant as it can be. Calculations are made on the ground *before* flight, during flight planning. During flight we only seek to recreate pre planned ‘pictures’ using simple pre-planned solutions.

We join left hand downwind abeam the mid point of the landing runway turning to track downwind 10000 feet laterally from that runway. We note, or estimate, when we go abeam our touchdown point. We start the stop watch. About 50 seconds later we reduce MAP to induce our target approach VSI. Then we turn base and begin final descent. We vary target approach VSI with circuit height. When we intercept the 3 degree glidepath we transition to fly the three degree glidepath. We reduce to Vref.

Practice, practice, practice.



USE OF FLAP – IN DESCENT.

By now we are very familiar with the idea that our nose, (and therefore default eyeline), may be pointing somewhere that the aeroplane is not going in the yawing plane. Our heading and our course will often be different. We have also encountered the idea that our flight path in the vertical may not match where the nose (and our default eyeline) is pointing in the pitching plane. We have studied the level flight case throughout this tutorial. We have studied how we vary and control pitch in level flight using altitude, power and flap.

We can be pitched nose up or down in level flight. Now we must grasp that level flight is not a special case. We can also be pitched either nose up or nose down in climb or in descent. Those are just choices we make and which we impose on the aeroplane with power and flap.

We have a flight path vector. It points where the aeroplane is actually going. It may be going left or right of where the nose and our eyeline are pointing and it may going above or below where the nose and our eyeline are pointing.

In level flight we may not have zero pitch. We desire it, we seek it and we impose it, but it is not something that just happens. It is an operating target that requires skill to achieve. For most of the flight we use only variation of altitude and power during deployment of that skill, but as we have seen when we need to reduce to low IAS and our altitude is mandated we must also deploy flap to achieve our pitch operating target.

Descent is *not* a special case.

If for instance our target flight path vector is minus three degrees then our pitch may not be minus three degrees. We simply choose what our pitch will be as we descend on a 3 degree glidepath and we impose our choice on the aeroplane. Since during near runway operations our altitude is being mandated by ATC procedures we must vary our pitch with power and flap to achieve our target pitch whilst sustaining a flight path vector of minus three degrees; instead of a flight path vector of zero degrees in the cruise case. We must learn to control and impose our target pitch independently from our target flight path vector whether we are cruising with a target vector of zero degrees or descending with a target vector of minus three degrees.

Pitch versus flight path vector is not something scripted by a flight dynamics author. It is something that is imposed by pilots. We must impose the correct target pitch, not just in the cruise, or when maintaining MDA searching for our destination, but all of the time, including descent. The correct pitch does not just ‘happen’ and it is independent of the target flight path vector. We are required to acquire the skill to impose both of these operating targets at the same time; whether cruising or descending.

Most flight simulation users never quite grasp this. Some have learned to control pitch in level flight, but most still fail to control pitch in descent, concentrating only on achieving the target flight path vector. We must control pitch independently from flight path vector in both cruise and descent because it controls what we can see! We need to see where we are going! We need to be able to see our touchdown point.

If we fly the minus 3 degree glidepath at random pitch that is a worse error than cruising at random pitch yet it is an error that most flight simulation users perpetrate. Most never quite grasp that flaps are wing camber changing devices which are present to control pitch independently from flight path vector. That is as true in descent near the runway as it is in level flight near the runway. Flaps are not present to slow aeroplanes down. They are the aeroplane pitch control mechanism.

We must also retain some flap for a while after take off to reduce our pitch versus our upward inclined flight path vector so that we can see any obstacles ahead as we climb up the climb slope. In aircraft like the DC-7 we must retain FLAP 1 for an extended period after take off. Part 5 of this tutorial explained how to know when to retract FLAP 1 and when to target Vy in place of Vx.

During the approach we need flap to control pitch too. We need to see where we are going! We must transition from classic era, or vintage era navigation, to pioneer era navigation. We must end every flight navigating by visual reference to the scenery. We must locate the touchdown zone of the landing runway. To locate it we must be able to see it. Every flight ends by pointing our flight path vector into collision with it.

During a straight in approach, or during final approach to the touchdown zone from the visual circuit, we need to see the touchdown zone through the windscreen. We must point the windscreen at the touchdown zone. Our glidepath (flight vector) is mandated. Our pitch is not!

We must use flap to control pitch to place the touchdown zone in the windscreen where we can see it. In the cruise (at zero pitch) our eyeline through the middle of the windscreen is just above the far horizon. Hour after hour we seek the correct parallax relationship between the windscreen and the horizon.

During final approach our touchdown point substitutes for that horizon. The parallax relationship between our windscreen and the touchdown point is neither random, nor scripted by somebody else. Each parallax relationship is one that we must manage with skill. We need to spend most of the final approach with the touchdown zone about where we placed the horizon in the cruise.

Some flight simulation users grasp that, but then behave as though the glideslope were not mandated and they vary their glideslope instead of their pitch. We must maintain the mandated 3 degree glideslope with power whilst varying only our pitch with flap.

Just as in the level flight case the aircraft specific handling notes cannot tell us the correct IAS at which to deploy another stage of flap for every weight and every weather. They can only offer guidance. The DC-7 notes mandate that we reduce below 150 KIAS and deploy FLAP 3 before we descend down the glidepath.

>>>>>>>>>>>>>>>>>>>>
Nearing Glideslope
REDUCE < 150 KIAS
FLAP - STAGE 3
>>>>>>>>>>>>>>>>>>>>

They do not, and cannot, explain how much less than 150 KIAS is the correct value at a given weight in a given weather pattern, on a given day. They can only prompt us to reduce below the conceivable maximum correct value. The correct IAS is the one that will cause our eyeline to be just above the touchdown zone *while we maintain a 3 degree glidepath*.

In principle that implies that we should target minus 3 degrees pitch when our desired or mandated flight path vector is minus three degrees. However we must grasp that we have independent control over pitch. We can pitch the aeroplane to more than minus 3 degrees with flap, whilst maintaining a minus 3 degree glidepath with throttle if we choose to have a better view of the ground whilst searching for our destination descending to MDA.

Glidepath is mandated. Pitch is our choice!

Having deployed FLAP 3 we use MAP to sustain the mandated glidepath using the ILS needle, or the VASIs, or ‘the parallax picture’. Glidepath is always maintained with MAP. Never with the joystick / yoke. Now we use the joystick or elevator trim to demand the IAS that places the touchdown point where it should be in the windscreen. Head up flight is all about controlling the parallax relationship of the content of the rear window of the simulation with the front window of the simulation.

Power controls sink rate and thereby controls glidepath. Stick or elevator trim controls IAS. Because classic era propliners fly unstable approaches we will be dialing lower and lower IAS with the elevator trim throughout the straight in approach until we dial and demand Vref with elevator trim. While we dial our IAS target with elevator trim we maintain the glidepath with throttle. Our IAS target is the value which places the touchdown zone in the correct parallax relationship with the windscreen.

Minus three degrees of pitch is *not* necessarily the default choice when flying a minus three degree glidepath. We may point (PITCH) the nose, the windscreen, and our default eyeline through that windscreen a little short of where the glidepath is going. Whilst we make the transition to pioneer navigation by visual reference to the scenery we want a really good look at the ground! We want to engineer that circumstance *before* we can see the ground as we descend in cloud towards the instrument runway!

Do not confuse our glidepath with our pitch. We maintain a three degree glidepath with throttle. We pitch the aeroplane with flap and IAS independently of the mandated glidepath. During the early stages of an approach we may wish to impose more than minus three degrees of pitch on the aeroplane as we descend along the mandated minus three degree flight path vector to have a better view of the ground, (especially in poor visibility). We rotate the aeroplane in pitch around the flight path vector with flap and IAS.

As the final approach progresses, and we slowly reduce to Vref, we will need more and more flap to pitch the nose down so that we can continue to position the touchdown zone correctly in the windscreen to sustain the ‘parallax picture’; *all the time maintaining the 3 degree glideslope = flight path vector with throttle*.

However each time we need to deploy another whole stage of flap the downward pitch rotation we achieve will become excessive and we will need to demand a lower IAS with elevator trim to put the touchdown point parallax picture where we want it in the windscreen; *all the time maintaining the 3 degree glideslope with throttle*.

We are using throttle to collide with the touchdown zone in a very controlled way, down a very controlled flight path vector. We are using FLAP and variation of IAS to control pitch and what we can *see*. We must *not* control what we can see by departing from the mandated minus three degree flight path vector. We must control what we can *see* by pitching the aeroplane with IAS and flap whilst sustaining the mandated flight path vector with MAP.

The correct IAS for each stage of flap varies with weight and weather. It is anyway just the IAS that positions the touchdown zone parallax picture appropriately in the windscreen. The aircraft specific handling notes indicate the location of the IAS ballpark and the size of the IAS ballpark.

>>>>>>>>>>>>>>>>>>>>>>>>>
Nearing Glideslope
REDUCE < 150 KIAS
FLAP - STAGE 3

ON descending
GEAR DOWN
23 to 27 inches MAP
FLAP - STAGE 4

REDUCE <130 KIAS
FLAP - STAGE 5
>>>>>>>>>>>>>>>>>>>>>>>>>

We WILL reduce below 150 KIAS before the glideslope. Before we reduce to 130 KIAS on the glideslope we WILL need FLAP 4. We WONT deploy FLAP 5 until we are below 130 KIAS. We will be deciding when to deploy FLAP 4 and when to allow IAS to decay through 130 KIAS using the external parallax pitch cue, *not* something happening inside the cockpit. We pitch the aeroplane with FLAP and IAS to keep our touchdown point comfortably in view using FLAP and IAS; *all the time maintaining the 3 degree glideslope with throttle*.

For the DC-7 the handing notes also provide some guidance concerning the MAP required to maintain the glideslope, (at different weights in different weathers), with FLAP 3 deployed. However by this stage in the tutorial it should be obvious that it depends on the weather day by day. We always need to battle headwinds with higher fuel burn. Final descent is not a special case.

After we have deployed the final stage of flap we can only control pitch with IAS. We are using power to maintain the glideslope regardless of our chosen and imposed pitch. As the final approach progresses to its conclusion we no longer wish to aim the windscreen, our head and the nosewheel at the touchdown zone. We develop the intention to aim the mainwheels at the touchdown zone and the windscreen, nosewheel, our head and our eyeline at somewhere beyond.

It is our *glidepath* which we are controlling with throttle that makes the whole aeroplane collide correctly with the touchdown zone, but it is *pitch* which decides what we can see as we fly the glidepath, and it is *pitch* that determines which part of the aeroplane collides with the runway.

We control glidepath with throttle. We control pitch with flap and IAS. The IAS which is Vref delivers the correct pitch (within landing flap deployed) when we reach a height of 50 feet.

After we have deployed the final stage of flap, the closer we get to the runway the more we control IAS, to control angle of attack, to control pitch, to allow the touchdown zone to slide down the windscreen in a slowly changing parallax relationship. However we will *not* allow IAS to reduce below our carefully calculated Vref until 50 QFE and we will *not* allow pitch to become so high that we lose sight of our touchdown point until we flare when the cockpit is 50 feet up and the mainwheels less. In any reasonable crosswind we have no excuse for missing the runway from there even if we lose sight of it during the last 30 or so feet of descent of the mainwheels over the next five seconds.

If we have a crosswind, and therefore need to see the runway to achieve zero yaw, we must restrain pitch during flare to achieve that goal.

Flaps are camber changing devices that rotate aeroplanes in pitch around their flight path vector. Each whole stage may cause over rotation in pitch. We restore the pitch we desire, to place what we need to see through the windscreen into the correct parallax relationship, by reducing IAS and we target IAS with elevator trim. Early in a straight in approach we may wish to be pitched below the flight path vector, but later in the approach we will wish to be pitched above the flight path vector. We control pitch with flap and IAS, but we *decide* the correct target pitch using only the projected scenery seen through the windscreen. During any approach the pitch cues which drive how we control the aeroplane are *external pitch cues*. They are the ‘parallax picture’.

A flight simulator within which the scenery is misplaced is useless. The parallax relationships between the scenery in the rear window and the windscreen or side window of the aeroplane in the front window of the simulation are what flight simulation is all about.

Microsoft do not understand what a flight simulator is!

In FSX cockpit view scenery placement is wildly wrong. In many Microsoft FS9 panels the zero pitch eyeline was not corrected for parallax. Many / most third party designers of panels have no idea how to encode the parallax relationships which are at the heart of flight simulation. These issues are explained and illustrated in greater detail within the simulation control interface tutorials available from www.calclassic.com/tutorials.


MSFS users worry far too much about realistic flight dynamics. The gross errors in MSFS are in the scenery projection code. Many / most FS9 panel.cfg files are seriously broken. Many are just a liability. Almost all FSX aircraft are seriously broken. They can all be fixed, but *you* have to bother. If you do not bother you will never be able to control scenery parallax. You will never develop head up flying skills. If you have real world head up flying skills you may impair them!


IMPRINT THE REAL LIFE PICTURE

I cannot over emphasise how much flight simulation, (and flying real aeroplanes), is about learning to use *external* pitch cues. It is all about imprinting a ‘parallax picture’ and then recreating that ‘parallax picture’ time and time again.

That ‘picture’ is projected in the rear window (outside view) of the simulation. It is not inside the cockpit environment projected on the front window (the panel, etc.). The ‘picture’ of the scenery projected in the rear window of the simulation must be *real*. The scenery projection in a flight simulator must obey the laws of the real world. Many people involved in creating FS9 panels and FSX aircraft, (including some employed by Microsoft), have been too lacking in aviation knowledge to calculate and deliver what is required.

Flight simulation is all about teaching ourselves to recognise a ‘parallax picture’ from experience. Then we fly the aeroplane to recreate that picture, whether that picture is 10000 feet abeam a runway, the picture containing runway perspective from a 3 degree glidepath, or the correct and carefully varied parallax of the touchdown point in the windscreen during final approach. Those imprinted head up ‘pictures’ must be invariant and real. They must be learned, imprinted and then recreated flight after flight.

When we use a flight simulator we depend on component makers to deliver realistic scenery projection and many have failed us. They simply lack the necessary aviation knowledge however impressive their software and painting skills. All too often no one with adequate aviation experience was involved in component creation. Inside or outside Microsoft.

Even after using MSFS for many years many MSFS users still cannot judge whether they are one mile or two miles abeam a runway, or when they are on a three degree glidepath. They cannot control pitch on final approach and so they cannot control energy state on final approach. They never learn what the ‘parallax picture’ looks like because they allow component producers to vary the picture with false ZOOM factors, and randomised VIEW_FORWARD_DIR values that nobody bothered to calculate correctly, because no one involved had sufficient aviation knowledge.

Real student pilots usually learn to recognise and imprint all those ‘reference pictures’ in under ten hours of relevant training. They can only do that because each ‘reference picture’ they need to imprint is invariant. We must make the effort to exclude panels and aircraft with fake scenery projection.

MSFS users who allow randomised ZOOM factors, or randomised VIEW_FORWARD_DIR values have no hope of ever making progress with flight simulation. Don’t make the worst mistake of all. For flight simulation we need real world pitch cues and real world scenery projection. If you think you might fly real aeroplanes one day you need to avoid other possibilities like the plague. Imprinting the wrong picture by frequent use of a ‘flight simulator’ with randomised external pitch cues may kill you.

You may wish to review Part 2A of this tutorial where that issue was explained in more detail before flying the Part 7 exercises which follow.


TUTORIAL EXCERCISES

Make sure you have installed the FS9 Goose files supplied with this tutorial over your original FS9 Goose download. That is essential.

Choose summer as your season. Fly the FS9 Goose round the 14 pattern from Greenville and practice turning downwind in both the standard and high performance circuit. Learn to fly yourself ‘into the picture’ from the Goose VC.

Now slew away from Greenville to the north east and practice joining both circuits from outside the circuits. Now repeat all of that for the other land runways. Use the relative position of the float to assist. Don’t switch aircraft until you can always position 10000 feet laterally in the Goose.

Fly the early exercises in 20 miles visibility, then 10, then 5.

During training in 5 miles visibility start overhead the airfield at 3300 QNH and fly a left hand down wind join from *outside* the circuit descending to 2800 QNH just before joining with 10000 feet lateral offset. Think about how you are going to position so that you do not lose contact with destination whilst flying the circuit join in a visibility of 5 miles.

Now try to fly yourself into the same picture using a different VC at each visibility. When you think you have established parallel 10000 feet lateral downwind offset, pause the simulation and switch aircraft to the Goose. Does the ‘picture’ still look right? If not work out what mislead you. Keep practicing until you can eventually identify what 10000 feet lateral offset looks like from any propliner cockpit environment *and can intercept it at 45 degrees from outside the circuit*.

For the moment concentrate on identifying when a runway has 10000 feet of lateral displacement and intercepting that displacement. Only when you can do that reliably is it time to practice the rest of the circuit, turning base from the correct 10000 feet lateral + 60 seconds offset from the touchdown point. Remember to apply adequate bank! Remember location of the runway on your monitor is a function of your virtual eyepoint and not of distance.

When you can do all that for the land runways use the supplied approach plate to learn to recognise where the water runway is at Greenville and learn to position downwind for 14 Hydro based on its known location.

Now choose winter. Can you still recognise 10000 feet with snow on the ground? Learn to cope with snow conditions.

Now go and practice circuit patterns at other airfields. Start with the enhanced realism FS9 Goose at each and then try to replicate lateral displacement using your improved ability to judge distance from the scenery in other aircraft. It is more important to practice joining, to sustain a lateral offset of 10000 feet, than to fly the whole circuit. When you are confident you have recognition of 10000 feet nailed continue to make some landings, but mostly slew away and practice again, measuring how well you did by switching aircraft and 'measuring' with the float of the FS9 Goose.

Expect to spend more than ten hours or self training before you can recognise an offset of 10000 feet and complete the circuit from the 10000 feet parallel downwind plus 60 seconds offset, in any season, down to a visibility of five miles, to any runway.

Of course nobody needs to learn to fly visual circuit patterns to enjoy flying propliners. Those with limited experience should stick to flying published approaches which they have downloaded and which allow straight in approaches to an instrument runway. Impose user defined weather at destination that delivers a headwind to that instrument runway and a 4D navigation challenge in terms of visibility and cloud base that slightly challenges your current level of 4D navigation skill. It is not obligatory to learn the more difficult skills required to join and fly a visual circuit pattern in a propliner. If you intend to learn those skills do not handicap yourselves with broken ZOOM factors and broken VIEW_DIR values. You will just be wasting your time.

The least interesting thing we can do with any aeroplane is operate it on the ground, but that too requires careful energy state targeting and head up skills.


TAXI AT FAST WALKING PACE



It is inappropriate to taxi an aircraft around taxiway turns at more than fast walking pace. Some FS users do not taxi from inside the cockpit and do not carefully control the intersection of the marked taxiway centreline with the panel at a constant position by careful moderation of the nosewheel angle. Some FS users suppose that if they apply a larger nosewheel angle the aircraft should turn better.



When an aeroplane is on the ground it becomes a terrestrial vehicle. Turning the steering to full lock will just cause the nosewheel to skid even at walking pace. Just like a car, for any radius of turn there is a maximum viable speed, and an exactly correct nose wheel (steering) angle. A bigger nosewheel angle is not the way to get round the turn more easily. It is the means to induce a skid; especially in a fifty ton tricycle.

To taxi around a normal taxiway turn we must be travelling at no more than fast walking pace and we must apply the correct nosewheel steering angle. Not too little, not too much. If the intersection of the centreline and the top of the panel changes, we are not tracking the radius of the turn. This is far too difficult to judge correctly from outside the cockpit environment.


OVERSTEER

To track the radius of the turn we must apply the exactly correct nosewheel angle for our current ground speed. Swerving from one full lock to the other as we fight to control a skidding vehicle is not the correct way to drive any terrestrial vehicle. When the terrestrial vehicle is a tricycle we must corner especially slowly and carefully. We must moderate both the velocity correctly, and the nosewheel angle correctly, and then the aircraft will track the turn radius.

If you are having trouble keeping the centreline intersection at a constant panel location you might like to try halving the real maximum nosewheel angle specified in the contact points. The chances are that you are oversteering into every taxiway turn and inducing skid. You should also slow down.

Desk top simulation input devices provide no useful feedback of oversteer and understeer during ground handling. We may need to slow down to compensate, but applying the correct steering angle versus the radius of the turn and our current velocity is just another energy state targeting skill to be mastered.


STRATOCRUISER EXERCISES

The B377 Stratocruiser is an ideal propliner in which to learn how to taxi realistically. Even in 2D cockpit view, where the real head up view is always impeded by panel bitmaps, we have an adequate view down over the nose and can easily place the centreline intersection behind, or just left of, the pillar at all times. We should however use the VC in aircraft where one is available and properly integrated with the flight dynamics. The B377 has a particularly good one. Most of all when operating the B377 in the simulator we have an advantage that the real pilot did not have. We have an ASI that is accurate below ten knots. Make sure you practice near sea level and with nil wind else the B377 ASI will just tell you the relative headwind.

When we taxi a propliner we should not normally exceed ten knots. It is not critical. Anywhere between 5 knots and 10 knots will do, but many flight simulation users allow energy state to get out of control and exceed 10 knots during ground handling. This is just one more pilot error involving a failure to control the energy state of the aircraft.

Learn to taxi the B377 in nil wind so that the indicated speed never exceeds 10 knots. Do this for long enough to learn how fast the world outside travels by and what 10 knots looks like in a flight simulator so that you never again exceed 10 knots when ground handling a propliner with an ASI that does not read in the relevant range, or whenever you taxi with real weather enabled.

Practice, practice, practice.

Too many flight simulation users become wholly reliant on gauges to judge energy state, height, glidepath and many other things. Provided broken cockpit environments are rigorously avoided MSFS is a good enough flight simulator to allow realistic 'head up' operation of the aircraft using the relative bearing, perspective and progression of the scenery to judge energy state without relying on gauges. Every MSFS user should use the gauges to create many situations and then to learn to recognise that situation without using the gauges. Learning to fly a 3 degree glidepath head up, or to taxi at 5 to 10 knots head up are key skills. In adequate visibility they do not require gauges, except to monitor compliance whilst learning the skill.


LEARN TO FLY and TAXI HEAD UP

The whole idea behind flight simulation is to learn to recognise and sustain a level turn, or to height keep at 1500 QFE for en route flight by visual reference to the scenery, or sustain a three degree glideslope, or to recognise 50 QFE for flaring, or the correct landing attitude, or the correct downwind offset, or the correct taxi speed entering a taxiway turn, *without gauges*. We must however use gauges whilst learning the relevant skill. We must monitor whether our head up flying skills are adequate or whether we need more practice, practice, practice.

Taxi from inside the cockpit and learn to hold the centreline intersection with the panel at a constant position on the panel and you should have no difficulty following real centrelines around real turn radii. It is the point of intersection that must be constant, not the angle of intersection.

There are of course some taxiways and parking bays that are not suitable for use by B377 size aircraft. Their turn radii are not compatible in real life.

If we never exceed 10 knots we will never need to stamp on the wheel brakes and the softness or otherwise of the nosewheel oleo will not be a factor. We should control taxi speed with very slight and carefully varied throttle advance, not the wheel brakes. Scrubbing side force on the tires will decelerate the aircraft through any turn. During a prolonged turn we may need slightly more power. Taxi with the airscrews fully fine unless handling notes mandate otherwise. Following a long straight taxiway, it is of course possible and safe, but not always lawful, to exceed 10 knots.

'Real easy' flight dynamics are intended to allow sim pilots, (but especially the Microsoft AI engine), to make errors without significant or realistic consequence. The real limits and targets are deliberately not encoded. 'Realistic' flight dynamics are intended to demonstrate pilot error. To do this ‘realistic’ limits and targets have to be encoded. It is the only way to learn about propliners, but with small plastic joysticks, tiny throttle levers, no rudder pedals, and no toe brakes, it may be harder than in the real thing to control and judge critical dynamic events.

Failure to negotiate bends in taxiways, bouncing and floating are all the result of failure to achieve the appropriate energy state input and output targets. These failures are no different to failing to control aircraft pitch in the cruise. It is possible, even likely, that users may need to restrict some of the propliners to taxi speeds a little lower than they could tolerate in real life, but that's exactly what pilot flying has to do when it rains or the temperature is below freezing and the surface is wet or slippery in real life. Perfectly dry and warm isn't the only realistic surface state.

If you do not have the patience to taxi a propliner at realistic speed around real taxiway curves then start on the runway, or slew to the runway after taxiing clear of the apron.


LANDING THE STRATOCRUISER

Nothing in any download from calclassic.com calls for any aircraft to be landed nosewheel first. The B377 handling notes call for it to be flared to zero pitch since, as I understand it, which was the recommended real world technique. However for this technique to work we must calculate and achieve Vref with precision.

The B377 handling notes disclose that maximum landing weight is 121,700lbs which is associated with Vref = 100 KIAS, but having conducted appropriate fuel planning the approach is more likely to be flown at around 102,000lbs. Vref depends on SQR(W).

At 102,000lbs B377 Vref becomes 100 * 319/349 = 91 KIAS.

Any faster and the aircraft will be so nose down that we need to rotate many degrees nose up to reach level pitch and prevent a nosewheel first landing. If we increase AoA rapidly in that manner we will promote ballooning, and when the mainwheels make contact the sudden increase in lift from the suddenly much higher AoA will promote bounce.

We must use the Windows calculator, or some other means, to calculate Vref during flight planning after we have calculated the payload and the fuel load for the flight using the methods set out in Part 6 of this tutorial. We can then predict the approach weight with ease since it is expected to be take off weight minus route fuel. We could create our own Weight versus Vref cross reference tables.

Landing a B377 at 102,000lbs it is necessary to nail 91 KIAS at 50 QFE. The B377 requires very precise energy state targeting. In stable descent on the minus 3 degree glide path, at 91 KIAS, passing 50 QFE, in landing configuration, close the throttles, and *very carefully* over the last five seconds of flight, bring the nose up to barely positive pitch. Due to the high inertia of a 102,000 pound mass the aircraft will not suddenly fly level, it will impact the runway slightly nose up, but if PF nails all the numbers it will do so with only slightly negative VSI and the propensity to bounce will be small.

No one should expect to get a greaser in a B377. It didn't happen. There is however nothing in the release flight dynamics that will cause unsatisfactory bounce from a touchdown at just under 91 KIAS, at slightly negative VSI, at just positive pitch, below maximum landing weight. Failure to meet the critical demands of this deeply flawed real aircraft will however be demonstrated. Don't beat yourself up if it takes a lot of practice to land a B377 well. Work your way up to really difficult, badly designed aircraft, like the B377 via aircraft which had fewer real life flaws.


SHORT LANDINGS (in Convairs)

With regard to the Convairs in particular every set of handling notes says in one form or another;

SHORT LANDING ONLY - FLAP = STAGE 4

When using FLAP 4 we are committed to using STOL techniques. If you find landing the Convairs is a problem don't attempt short landing techniques and configurations. The normal landing configuration is FLAP 3 which generates less lift via less wing camber and makes life easier, but requires a slightly longer runway.

A real airline pilot, qualified on type, and in current practice, may be required to demonstrate the ability to land a CV58 on a 4300 foot runway in nil wind using FLAP 4 and good STOL technique. Anyone who lacks these qualifications is doing well if they can land it on a runway 10% longer in FS9. Longer still above sea level of course.

Landing the CV58 in FS9 without floating or bouncing is not a significant problem, because it is not a significant problem in real life. It is however more difficult than landing the CV34 because we have more inertia and more residual thrust from much more powerful engines. To compensate the real (and CalClassic) CV58 has more reverse thrust available after landing. Make no mistake the tricky task is delivering the aircraft to the runway threshold in stable descent, in landing configuration, on the minus three degree glide path, correctly trimmed, and at the correct Vref. Having concurrently achieved all those energy state targets, reducing to minus 100 VSI over the next five seconds is easy whether with FLAP 3 or FLAP 4.

Making the CV58 as easy to land as a CV34 is not the objective, and making it, or any other propliner, respond well to being landed like a Cherokee is not the objective either. Making it a doddle to land with FLAP 4 deployed for STOL is not the objective. The objective is to make it respond badly to the wrong techniques, the wrong configuration, and the wrong energy state so that users obtain realistic feedback from the simulator output that their input was inappropriate and can learn from the experience.

I am told by those who have flown the real CV58 that the significant pitch authority versus relatively poor roll authority currently encoded, at low IAS, are about right. That the controls are poorly harmonised at low IAS is therefore the point, not a mistake.


AUTO CO-ORDINATION (in Convairs)

Concerning yaw authority at low IAS, remember that auto rudder should be ON in the realism screen when flying Convairs. They are interconnected to improve yaw rate in real life. Poor yaw rate due to poor rudder co-ordination is often reported as an error in flight dynamics, but in most aircraft this is also a problem that has to be solved by pilot flying, not the flight dynamics author. Without rudder pedals that is more difficult to achieve than in the real aircraft. However if you fail to implement auto rudder when flying the Convairs you are electing to fly with a control system failure. Failing to turn it on is just another pilot error.

If you have no rudder pedals, and you never land in significant crosswinds, you may wish to turn auto rudder on whenever you fly propliners.

Overall I believe the current FD, when used in conjunction with the correct panels, their carefully integrated gauges, and the FS9 auto co-ordination facility, deliver a pretty fair impression of the difficulty involved in operating the CV58 into a dry runway, less than 5000 feet long, in nil wind, and allow that difficulty to be compared sensibly to the same task when flying a CV24 or CV34 or CV44 at their lower weights and with their different range of engines and / or wing areas. In real life there are more systems and factors to be taken into account, but MSFS cannot simulate those, and the level of realism it permits is challenging enough.


TAKE OFF

To achieve a realistic take off run we must set carb heat cold (if applicable), we must trim the aircraft correctly, apply automixture, (or real aircrew (only) may prefer to calculate exactly the correct manual mixture), deploy the correct flap configuration, run up against the brakes, and calculate Vr in the same way that we must calculate Vref.

During public transport operations neither Vr nor Vref should be less than Vmc if Vmc is declared in the handling notes. Vmc is the minimum control speed after the critical engine fails. Remember the numbers we may read in books and magazines do not necessarily assume all the legal restrictions associated with public transport operations.


The developer of an aircraft for use in flight simulation cannot tell you how much runway you will require. It depends on weight, weather, and altitude. Such calculations are too complex to fit within a simulation such as MSFS and in any event whether you could lawfully take off from that runway at all often depends on the things explained in Part 5 (the departure phase components of this tutorial), not the runway length.


USING THE PROVIDED PANEL IS MANDATORY

MSFS has a retail flight model that requires compromises and has some deficiencies. At calclassic.com the retail flight model is patched using gauge code. Then both the panel code and the gauge code are carefully integrated with the flight dynamics.

Flight dynamics and panels are NOT mix and match. They must be integrated before release. A (replacement) panel can never be created for use with a given aircraft (MDL). A panel, its code, its gauge content, and their code content MUST be integrated with specific flight dynamics before release; but many are not. Many are just a random collage of artwork that deliver random gauge readings, and randomised aircraft performance together with randomised scenery placement.

Pretty looking panels with random code and randomly chosen gauges that interact incorrectly with the retail flight model, the retail scenery display system, and the third party flight dynamics are functionally useless however pretty they may be as artwork. Many flight simulation users condemn themselves to a horrible experience by using broken panels and gauges that were never properly beta tested. Don't make the same mistake.

Most of the aircraft downloads from www.calclassic.com have patches for the relevant retail flight model within their integrated panels, (and virtual cockpits when supplied). Use of the supplied or recommended cockpit environment is not optional. There is much more to making a panel than replicating photographic appearance.


HIGHLY PAID SKILL

As I bring this part of the tutorial to a close let's remember that we purchased a flight simulator to acquire and practice real world knowledge and skills worth hundreds of dollars per hour in real life.

We have not been discussing a video game with invented rules and concepts that require the acquisition of skills worth precisely nothing in the real world. This tutorial is all about how to replicate the experience of aviation history, and how to acquire valuable real world and compliant skills that may subsequently be used in real aeroplanes. No one can learn how to fly any aeroplane solely by using a flight simulator, but we can learn a lot of what we could learn at much greater expense in real aeroplanes. It will just take longer in a simulator, not because it is a simulator, but because we lack one to one instruction and remedial teaching. I hope this tutorial will do something to bridge those two gaps.

Teaching ourselves real time simulation of a complex, highly paid, real world skill implies a very steep learning curve, but that is precisely what makes flight simulation so rewarding compared to video gaming. There are so many levels of real world skill to explore.


PROPLINER TUTORIAL PART 8 - MANAGING THRUST

Welcome to the final and shortest part of the propliner tutorial. It attempts to illustrate the difference between applied power and applied thrust. Its secondary purpose is to remind flight simulation users that all aircraft, including those with aircrews are propelled by thrust, not power, and that whilst we control fuel burn with the throttles we must also learn to control thrust independently with the rpm levers.

Propliners from the vintage era, such as the Savoia Marchetti S.73, had only controllable pitch (c/p) screws. Fine pitch was used for take off, perhaps retained for initial climb, and then course pitch was selected for most of the rest of the flight. Those vintage era propliners had only first gear and overdrive. They were inefficient. Classic era propliners have modern constant speed screws and gear boxes with many gears available for manual selection. This part of the tutorial applies only to classic era aircraft with rpm levers.

We use those rpm levers to control a gear box mounted at the airscrew hub, but the same lever controls screw rpm, engine rpm, and turbine rpm, each of which is different. For propliners the reference value is always engine rpm, even though we use the rpm lever as a gear shift lever mostly to control airscrew traction.


TAKE OFF.

Once we unstick following rotation the problem is not lack of climb performance. It is preventing excessive climb rates. Rate of climb must quickly be restrained to almost nothing until our IAS reaches the target profile drag specified for the particular aircraft. Before take off we must trim the aircraft to promote post unstick acceleration from Vr to Vx and to preclude climb. In effect we trim for IAS = Vx. In most propliners we hope to achieve our Vx target before we are required to power down from TOGA power to METO power, and TOGA power may be limited to only 90 seconds after throttle up in some complex engines. TOGA power is very abusive.

In this part of the tutorial I will use the DC-7C as the worked example.

****************************
Take Off:

APPLY BRAKES
MIXTURE - AUTO in realism screen
COWL FLAPS - MID
TRIM 30% full range NOSE UP
FLAP - STAGE 1
CALL for TOGA POWER (3400hp)
PROPS FULLY FINE
Slowly apply FULL THROTTLE
BRAKES - OFF
ROTATE at 122 KIAS (143,000lbs)
Establish positive rate of climb
GEAR UP
ACCELERATE 160 KIAS @ <500 VSI
CLIMB 300 feet QFE (agl)
CALL for METO Power
**********************************

Note that we should hold the aircraft below 300 AGL until 160 KIAS is achieved. Climb rate should be very low. This post unstick phase is all about using the only briefly available TOGA power to accelerate the aircraft from Vr on the ‘wrong side’ of the drag curve to Vx on the 'right side' of the drag curve as fast as possible. It is not about climbing.

Once we have achieved Vx = 160 KIAS less than 300 feet above the runway elevation we stop thrashing the engines to death and power down to METO power.

**********************************
METO Power: (Climb stage 1)

COWL FLAPS - MID
51 inches MAP
2650 RPM
160 KIAS
Climb 2000 feet QFE (agl)
FLAP - UP
ACCELERATE 190 KIAS @ 500 VSI
CALL for climb power
***********************************

We have just shifted up from first gear to second gear. Classic era propliners have manual shift gear boxes. One gear shift lever for each airscrew. In an aeroplane we call the gear shift levers rpm levers. In a car with manual shift we need to select first gear for pulling away from rest. The engine must be revved hard even at very low speed to get things rolling. Once we are rolling and have developed enough speed we must select second gear. Staying in first gear would be wrong and shifting straight up to third would be wrong. In first gear rpm would be too high and in third too low. We also need to shift up (reduce rpm) manually in a classic era piston propliner, as we accelerate.

When we are about to climb a hill in a car we must make the gear ratio (rpm) match both the steepness of the hill and the velocity at which we approach the bottom of the hill. Aeroplanes are no different. In the DC7C first gear = 2900 rpm is great for pulling away from a standing start and getting things rolling, but now we have reached 160 KIAS we must shift up to second gear = 2650 rpm. We cannot accelerate a car with a manual shift gear box to economical cruising speed in first gear and it doesn't work in aeroplanes either.

The principle reason that users of the DC7C fail to climb the hill after take off without stalling is that they try to climb a steep hill at 500 VSI before achieving their take off phase target of 160 KIAS and also try to do it in the wrong gear. In a propliner we must both increase velocity and select the correct gear (rpm) before tackling a hill climb. In an aeroplane we choose when and at what speed to tackle a hill climb. By now you will have noticed that much of the Propliner Tutorial is about how and when to even attempt a hill climb.

Once the DC7C is in the correct gear it will accelerate to 190 KIAS, even whilst climbing a hill at 500 VSI. If we try to tackle a hill that steep starting from below 160 KIAS at the bottom of the hill, or in the wrong gear for that gradient at that entry airspeed, it just won't make it up the hill.

We are now accelerating (up hill) in second gear (2650rpm at 51 inches). When we have achieved 190 KIAS second gear is too low. We shift up to third by selecting 43 inches and 2500rpm.

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Climb Power: (Climb stage 2)

MIXTURE - AUTO
COWL FLAPS - MID
43 inches MAP
2500 RPM
500 VSI
SPEED WILL DECAY - MINIMUM 172 KIAS
IF UNABLE to maintain =>172 KIAS
REQUEST LEVEL OFF & STEP CLIMB from ATC
ACCELERATE > 190 KIAS
WHEN CLEARED BY ATC CLIMB 500 VSI
IN 2000 foot steps - Repeat as necessary
Plan 950 PPH

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Each acceleration both requires and allows us to shift up to lower rpm. By doing so we reduce the load on the engine (reduce its rpm) and extend its useful life (time between overhauls). After we have accelerated to 190 KIAS we can select gears (rpm) that allow as to continue acceleration (up hill), with less and less power, burning less and less fuel, so we choose to do just that retarding throttle to 43 inches.

High gears (low rpm) are more efficient, but they are incompatible with climbing hills at low velocity. We can only shift up as our airspeed increases, but we must shift up (reduce rpm) at the right time and make sure we choose the correct climb rate for the current IAS and gear selected. The aircraft specific handling notes explain how steep a hill climb we can handle, what IAS we must achieve before we attempt the hill climb, what power we need to supply with the throttles, and what gear we need to select using the rpm levers.

After the take off phase is over international law requires us to climb at not less than 500 VSI. If our virtual airline or military employer wants us to climb more steeply they supply handling notes that explain the throttle and rpm values required for the higher target VSI, or they specify constant IAS with varying VSI. To maximise economy of operation and profit a DC7C normally climbs at the legal minimum rate of 500 VSI from the end of obstacle avoidance to the cruise phase.

Of course when we are ready to cruise (when we reach operational ceiling) we shift up again from third to fourth.

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Econ Cruise at max weight (about 1700hp):

COWL FLAPS - CLOSED
2300 RPM
PLAN 4 x 735 PPH
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In a DC7C we don't move the throttles we just shift up (reduce to 2300 rpm). When we are running light we still don't move the throttles but we take the opportunity shift up to fifth (overdrive = 2100rpm).

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Econ Cruise at light weight (about 1600hp):

COWL FLAPS - CLOSED
2100 RPM
PLAN 4 x 680 PPH
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Just don't try climbing steep hills from 160 KIAS at the bottom of the hill in overdrive. It won't work. When we hit the built up area and the heavy traffic density near our destination we need to slow down and shift down again (to higher rpm).

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Approach and Landing:

MIXTURE - MANUAL RICH
COWL FLAPS - MID
2300 RPM
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If we need to go around we must select full throttle and first gear because we will be about to climb a steep hill from very low velocity,

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Baulked Landing:

CALL for EMERGENCY POWER
PROPS FULL FINE
FULL THROTTLE
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Maybe this is all more apparent to Europeans who nearly always drive cars with manual shift gearboxes, but I suspect that failure to depart and climb the big propliners without difficulty is the result of not fully understanding the above even though it has always been promulgated in the handling notes.

RPM is no more a random choice in an aeroplane than gear selection is a random choice in a car. The RPM selected must match the phase of the journey. Cruising a car in first gear at very high RPM does not work. It just trashes the engine. Climbing steep hills in overdrive from low velocity does not work either. Applying lots of throttle does not solve the problem in any vehicle with a manual shift gear box. It only wastes fuel or causes wheel spin (airscrew slip).

The throttle only controls fuel burn = power in any vehicle. It is the rpm lever that controls thrust in any vehicle whether it has wheels or aircrews. We need to apply the correct thrust (traction) for the current throttle position and the current vehicle velocity, whether in the cruise, or for any hill we may intend to climb. The correct rpm is not a random choice for any of these events in any vehicle. In a car the lever that controls rpm independently from fuel burn is called the gear shift lever. In an aeroplane it is called the rpm lever. It does the same job, but in an aeroplane we have an infinite number of gear ratios available. In practice we only use a few of them, but we must select them correctly and at the right moment as we accelerate, or decelerate, or as we attempt a hill climb.


OBSTACLE CLEARANCE

Climb Stage 1 is for obstacle clearance. The obstacle can be a mountain, a mast, a gunnery range, another airfield's holding pattern or a nature reserve. The departure procedures for the runway will not usually tell us why we must proceed to a given fix after take off and cross that fix at a minimum altitude, but we must. The only way we will be able to maximise our climb gradient is to select the correct RPM in any vehicle.

As we depart Los Angeles eastbound in good visibility the obstacle we must climb above is all too obvious. We must retain FLAP 1, and climb at only 160 KIAS (Vx), using exactly METO MAP and exactly METO rpm (51 inches at 2650 rpm). We must target much more than 500 VSI at very restrained profile drag (IAS), until we are above those mountains, but once we are clear of all obstacles we will retract the flap and accelerate to 190 KIAS (Vy) at only 500 VSI. Only when we have achieved 190 KIAS at 500 VSI can we proceed to climb stage 2.

During each departure we decide when we are clear of all obstacles, ideally using the real airfield departure procedure downloaded from the web site of the real regulatory authority (see part 5 of this tutorial), else we must decide what altitude is adequate by other means and on passing the altitude we decided upon in our flight plan begin acceleration from Vx (best climb gradient) to Vy (normal climb).

The handling notes for the DC7C have always reflected the fact that it has a poor post take off climb gradient at Vy = 190 KIAS and that unlike most propliners it has to target a lower IAS = Vx = 160 in a higher lift configuration (FLAP 1) immediately after departure. What the DC7C must do as a norm, any other propliner may need to do during some particular departures.

Although I continue to stress the need for careful flight planning many MSFS users do not bother. Those who do not plan an Eastbound departure from Los Angeles in a DC-7C using real world procedures must use the placement and displayed height of the scenery and mesh (the mountains) to judge when to forsake Vx for Vy and when to forsake METO power targets for climb power targets. Unfortunately those who do not flight plan are also those most likely to use broken FS9 panels and broken FSX aircraft which cause scenery to be grossly misplaced.

That concludes the 2008 propliner tutorial. I hope you find incorporating additional realism into your flight simulation experience useful as well as challenging. In many ways incorporating additional realism is the only solution to many / most of the problems that are reported in forums.


Copyright FSAviator April 2008