Post by volkerboehme on Aug 10, 2008 9:15:06 GMT -5
Greetings Volker,
I often need to edit my contributions down from a much wider context to fit into the California focus of this forum and Tom has already answered your questions as they apply to California.
However my post would have been different and the answers to your questions are different if the context is widened beyond single crew airliners and the Continental United States (CONUS) of which California is a component. With Tom’s indulgence I will try to illuminate the wider picture in this post.
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 not happened in eras. It 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 a wider context it is more appropriate to substitute the word phase wherever I have said era.
Desk top flight simulators allow those with no aircrew experience to access aviation from the inside looking out. Aviation is much more than aeroplanes because the things achieved by aeroplanes and those who flew them depend on a complex external infrastructure that is often ignored. In my writings here I try to convey the wider concept of aviation as an infrastructure, or lack of it. During the vintage 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 travellers."
No single crew aeroplane could have done that in the stated timeframe. The necessary public sector infrastructure did not exist. Air mail planes and their pilots were being sacrificed almost every month and as soon as the airlines attempted to carry passengers with the air mail, which had already paid for the entire flight, passengers began to perish too. When celebrities started to perish, the media started to take an interest, 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.
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 regulation they imposed.
The vintage 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. The classic phase was characterised by mandatory procedural compliance with government regulation, using an infrastructure provided at public expense, to ensure both regularity of service and enhanced safety.
This means that within the CONUS I define the vintage phase of commercial aviation as giving way to the classic phase from 1932. The transition for the USAAC, USN and USMC happens later and has no particular relationship to the CONUS.
Suppose however that instead we wish to simulate the situation in Europe in general or Germany in particular. The answers to your questions are then different. In Germany the classic phase of aviation began about 1937 quite uniformly for both commercial and military aviation because both were fully under state control.
Suppose we wish to simulate a flight from Copenhagen to Berlin in 1939. Germany has already entered its classic phase, but Denmark has not. There are comprehensive radio navigation aids in Berlin including a Radio Range which any DLH flight will use to the full. By 1939 every multi engined DLH airliner has a (Radio) Kompass which is the German equivalent of the US Army Signal Corps Receiver. DLH aircrew have the German government code books and the radio navigation charts. They know the frequencies to tune and where all the beams point. The aircrew of the Danish airline DDL do not have the German government code books or German radio navigation charts. Nor do DDL have access to Kompass technology in 1939. Nor does any British, French, etc, etc, airline.
Prior to each nation ratifying the Treaty of Chicago which 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 a 'chosen instrument' of the national government who would deny that infrastructure even to their domestic 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 has 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. Before attempting simulation of historic airline schedules, (or ad hoc charters), we need to answer the following question 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 at the chosen date’.
For instance the Ford 4-AT-E Trimotor had engines rated at sea level and was optimised for flight at low altitude. It could not be fitted with an autopilot and had no blind flying panel. If a blind flying panel was retrofitted the airline had to hire as co-pilot someone who was both an instrument rated airline pilot and a trained mechanic. In practice even after the CONUS had an IFR point source infrastructure, complete with mandatory departure, arrival and approach procedures imposed by federal ATC clearance, a 4-AT-E could not access them. It was from the vintage phase of US commercial aviation and was not worth updating to work in the classic phase. They disappeared from the schedules quickly but survived to fly ad hoc charters using vintage CONUS techniques. That situation must be read across to airliners with inadequate crew complement everywhere.
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 both vintage phase infrastructure and classic phase infrastructure in a single flight.
The turning point was the 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 Treaty 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.
From a world wide perspective individual mid air collisions had no impact at all. They sometimes caused a single nation to improve its aviation infrastructure or to bring its federal safety regulations more into line with international law as set out in the Treaty of Chicago.
What follows is not really new, but nevertheless forms the logical Part 2 of any vintage phase mini tutorial. It is just an extension of things touched upon in the notes explaining how to use my Boeing 314A Clipper flight dynamics when conducting vintage era flight simulation outside the CONUS.
Let’s consider the rules of conduct for flight simulation of a DDL (Danish) Focke Wulf Kondor flying from Amsterdam to London ex Copenhagen or a DLH (German) Focke Wulf Kondor flying from Amsterdam to London ex Berlin in mid 1939. Neither will have access to any useful Radio Ranges whether or not they have a multi waveband Kompass receiver. Both must use contemporary Dutch and then British aviation infrastructure.
Both Wireless Telegraphy (W/T = Morse) and Radio Telephony (R/T = Voice) pre date the powered aeroplane. Aircraft usage 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) his transmission. The bearings supplied back to the qualified WTO/RO were then plotted on a chart by a qualified navigator. Ideally three bearings from different D/F operators in sequence were used to triangulate present=recent position. Just as in a ship the navigator then instructed the helmsman what heading to steer based on where the vessel was believed to have been a few minutes earlier. Before WW2 the only airlines flying along beams to a beacon were based in Germany or the CONUS. That was also true in most places long after WW2.
Nobody believed for a minute that aeroplanes could achieve scheduled operation using sextants for astronavigation. Attempts usually ended in death. Of course 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. But now 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 no idea where they are for days on end. That sometimes included airships, but not aeroplanes. Of course sextants were installed in aeroplanes they were just useless weight much of the time in any aircraft that had to maintain a schedule. Sextants were much used by air forces and navies, but they just postponed missions for days on end until the weather was good enough to fly them.
Radio Direction Finding = RDF (in the HF band = HFDF pronounced Huff Duff) began to replace sextants for oceanic navigation world wide from 1909. Aircraft were simply no different. No one attempted scheduled ocean crossings without both a qualified radio or wireless operator and a qualified navigator aboard. It soon occurred to the Imperial powers that the Sahara and the Arabian Deserts and even India were just another kind of ocean. Then they decided to treat the entire planet as an ocean upon which they could never afford to site thousands of radio ranges. Their taxpayers were never going to pay for radio ranges across entire empires on which the sun never set.
By 1929 RDF was possible using HF stations 1200 miles away. Aircraft with significant useful loads not designed for use over the CONUS had large crews whether military or commercial and used RDF to navigate. That is why the Kondor or a Boeing Clipper 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 beacon to beacon.
RDF was a global positioning system (GPS) long before WW2.
The USN had 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 infrastructure. Their fatality rate was dreadful. Over the CONUS federally imposed detailed procedures were introduced from 1932. Outside the CONUS all US aviation slowly caught up with the USN and everybody else by introducing RDF.
RDF is a wide source infrastructure. It is not associated with federal regulations, airways, air traffic control, or mandated procedures. Everywhere except the CONUS it was widely available allowing multi crew aircraft to navigate above cloud without visual reference to the surface, and just as easily below cloud without visual reference to heavenly bodies, 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 ships anyway.
The shortcomings of all the early GPS systems were complex radio encoding requiring a dedicated radio operator whilst manual plotting of the decode also requiring 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 have been available in British GPS moving map systems such as Decca Navigator since the 1950s.
We must never forget that for aircraft with large useful loads, everywhere except the CONUS, GPS in the form of Marconi + Adcock RDF was the primary commercial, military and naval navigation system in use from WW1 onwards. During and after WW2 it was gradually replaced by the German naval GPS system to which British Intelligence assigned the acronym LORAN (LOng Range Aerial Navigation).
In theory the MSFS GPS code could be made to behave exactly like a human navigator waiting for decodes from a human WTO or RO before plotting the symbol on the map with suitable inaccuracy and delay, but as I explained in the notes accompanying my Boeing Clipper flight dynamics this is not really necessary.
The rules for conducting a GPS navigated flight using Marconi + Adcock technology during the vintage era of aviation only require self disciplined use of the default MSFS GPS.
1) The aircraft, (whether civil, military or naval), must have at least a WTO/RO and a Navigator. Naval aircrew classified as observers were often, but not always, navigators.
2) The range selected on the GPS should be of such small scale that either maximum range is selected, or for shorter flights both the departure point and the destination are visible throughout the flight. No flight plan should be entered into the default GPS. Distance gone/to go should be estimated from the GPS (potentially max range) map.
3) The GPS should be consulted by popping up the window only at substantial intervals during cruise. Perhaps every 10th minute for a short haul flight or every 30th for a trans oceanic flight.
4) Once every position update interval a course correction, not exceeding five degrees, and always rounded to five degrees, is made after trying to work out from the inadequate scale GPS picture whether the flight is currently left or right of track due to wind drift and any other cumulative navigation errors.
What is being simulated here using intermittent course changes and headings, which will be wrong by up to 4 degrees 80% of the time, is the error that arose from the manual plotting delay and the bearing errors inherent in using HFDF at extended range. 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 with inadequate crew resource could only fly by visual reference to the surface. Consider how useless that was to a torpedo bomber crew for instance and it is easy to grasp why torpedo bombers needed (at least) three crew. However remember that military and naval operations sometimes need to be conducted in radio silence until the mission is detected.
So everywhere except over the CONUS 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 above cloud, directly on track to destination. Then every ten to thirty minutes intermittent use of a potentially max range GPS update 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 to make a visual arrival followed by a visual approach.
When flying either a DDL or DLH Kondor from Amsterdam to London in 1939, the visual departure to somewhere safe before climbing into or above cloud is simple. Once in the cruise at an altitude of three or four thousand metres the goal is to transition back to flight by visual reference to the surface before that arrival transition becomes dangerous.
We must use GPS to reach a terrain feature big enough to be located on the potentially max range GPS display. That feature must also be something we will recognise once in contact with the surface below cloud. In this case it will obviously be the Thames Estuary. Before it is too late we descend below all cloud whilst still over the sea, and based on the last known intermittent GPS plot, once below cloud, we head for the south shore of the Thames Estuary left of the landmark from which we intend to initiate inland navigation by visual reference to the surface.
Both Kondor captains must now act as though they were single crew in a Ford Trimotor and must locate destination using a VFR plan prepared for the arrival and approach. If they can see several landmarks ahead they will cut corners and fly from landmark to landmark on the plan. Else they will seek line features leading to them. The German crew are flying a better equipped Kondor, but in mid 1939 the equipment is of no use west of the German border.
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 and the line feature that must be found is the entire coast of the Hawaiian chain; preferably, but not necessarily, the correct island.
In the absence of mandatory arrival procedures published by a Government agency via an arrival and approach plate the key decision is always voluntary placement of Top of Descent (TOD) to terminate the GPS component of the vintage phase flight outside the CONUS. We must descend through cloud somewhere that does not risk collision with terrain in the descent. We must plan and then vertically limit the descent accordingly.
We must try to estimate the altitude of the terrain below and terminate descent 1500 feet (or 500 metres) altitude above that estimate. Descending over the sea makes this simple, but other cases must be attempted by FS9 users in due course. The elevation of the destination airfield should always be known to the user and the elevation of other airfields can easily be found using a flight planner.
In the two examples above we use GPS to ensure that we descend plenty early enough. On the other hand if simulating a BSAA Lancastrian schedule from Buenos Aires to Santiago in the late 1940s we must ensure that the navigator uses RDF = GPS to instead ensure that we descend plenty late enough to have crossed the Andes else all the Santiago RDF operator will hear of the WTOs Morse message 'starting descent' is S T E? * * * N * D E * C * * * as we descend behind the shadow of the Andes and just before we impact the Glacier.
If when simulating a BSAA Lancastrian crew setting off for Bermuda in the late 1940s, using dead reckoning, or better still a sextant, or much better still RDF = GPS, then we can personally simulate starting 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 located reliably by any means before a Radio Range or NDB was installed on the island. Even then the airliner needed an LF or MF receiver that could actually tune either of them in.
Remember that for a nation or airline stranded in the vintage phase of aviation that means remembering to take the correct crystals to install in the crystal set avionics. Many early avionics were single channel or 12 channel, not 360 or 720 channel and there was no point pushing the pre set button(s) to select the frequency if the correct crystal was not in place.
So this is not really a question of era. Some British airlines were still stranded in the Zeppelin era = RDF phase of aviation history, even in the late 1940s. They were still reliant on wide source infrastructure and not subject to adequate safety regulation anywhere, and they still had the accident record to match.
The world wide picture from about 1923 to the ratification of the Treaty of Chicago from 1948 onwards was not that of single crew multi engined airliners navigating by visual reference to the surface. That was peculiar to the CONUS. Until 1932 airline navigation over the CONUS was way behind the rest of the world, but by 1939 it was well ahead (Germany excepted).
From about 1923 onwards multi engined airliners in the rest of the world progressively used the British form of GPS known as RDF. Some later transitioned to the German LORAN GPS system, and then all transitioned to the 'American Way' when they ratified the Treaty of Chicago in the very late 1940s or during the 1950s; often pressurised to do so by linked economic aid programs. The Soviet Bloc, Communist China and North Korea did not ratify the Treaty but the USSR soon developed superior alternatives to simple RDF. I believe there are aircraft or gauge uploads that explain their usage in some detail, but perhaps only in Cyrillic.
By the late 1950s the 'west' had adopted either Radio Ranges or VORs or TACAN augmented by weak signal NDBs for local non precision approach guidance. This form of point source infrastructure then became international and was the primary means of navigating airliners within a mandatory, expensive, heavily regulated, safe, air traffic controlled environment that I identify as the classic phase.
You ask;
'When would this era end, and what innovations made a change possible or necessary'?
Unfortunately that is not simple to explain either.
The point source infrastructure maximised safety because it allowed the publication of mandatory procedures for departure, cruise, arrival and approach using very precise timings in a 4D navigation environment. Those ATC procedures were followed by rote. The classic phase of aviation was a 'procedural' phase.
What brought it to an end was RAdio Direction finding And Ranging (RADAR).
During the 1930s Britain replaced the HF squeakers in its fighter aircraft. They had allowed triangulation with string on the RAF sector control plotting tables that were still in use a decade later in the Battle of Britain. The new British invention, which would later be called a transponder, could squawk instead. A squeak provides a bearing to the ground based controller, but a squawk provides a fix.
Within a year Britain developed primary radar good enough to detect a 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 purpose of radar following the loss of the Titanic in 1912.
Once Britain had (primary) radar good enough to detect 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. By 1945 air traffic controllers talking an aircraft down through a Ground Controlled Approach (GCA) using surveillance radar to control the approach (SRA) allowed missions in weather four times worse than an RDF talkdown (QGH). By the early 1950s it was theoretically possible 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 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. This time the US lagged behind.
For a long time however little use was made of radar to intervene in the climb, cruise or descent phases of the flight being controlled from Air Traffic Control Centres (ATCCs). As I have explained elsewhere the range of a piston engined aircraft does not depend on its altitude. No fuel is saved by expediting 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 40,000 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 (UARs) 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 B747 and demand for jet flying mushroomed as costs and ticket prices fell whilst trip times were reduced. Win - win for the consumer.
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 if the radar failed or when it needed maintenance.
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 even more reliant on expensive infrastructure outside the aeroplane.
So the next phase which we still call the modern phase/era was one in which airline pilots no longer expected to fly the classic era procedures unless the radar was off. They expected to be radar vectored in just about every phase of the flight instead, but everyone had 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 airline pilot and any air traffic controller may need to invoke them today.
During the RDF phase of aviation infrastructure, which lasted into the 1970s even at lesser locations in the developed world, procedures were often made up by aircraft captains on the spur of the moment and sometimes with fatal consequences. Sometimes they were published by employers, but that meant involving lawyers to determine if the employer could be held liable if anything went wrong. Much better to blame a dead crew. :-<
Even during the classic and modern phases of aviation many (fatal) accidents have also been caused by airline captains deciding that they could conduct the flight by visual reference to the surface and then failing. They rejected the IFR procedures and they rejected radar control. Some jurisdictions still allow that. As a consequence sometimes they 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 of course. Sometimes they land on the wrong airfield altogether.
So the situation is that the current regulations and airspace definitions for anywhere in California are available for free download and are so complicated that only two lawyers in the world claim to understand them all and have three opinions about what they mean. Since airliners in the modern phase of aviation are almost always going to be radar vectored instead there is little point in anyone who is not forced by their employment to understand the complexity to even try. That is one reason that I favour simulation of the classic and vintage phases of aviation.
However we must never lose sight of the fact that over many parts of the globe there was very gradual transition between the vintage and classic 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 radio beacons in the Buenos Aires Terminal Area before transitioning to using vintage phase wide area infrastructure RDF for the en route navigation phase. At some point those that actually made it across the Andes 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 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.
The benefit of choosing to simulate the 'pure' classic phase anywhere around the planet (as generally supported and proposed by Tom’s website and forum) is that users can download the real procedures, study them for as long as it takes to understand just one of them, and then when they fly it by rote in FS9 they will be doing exactly what the real crew was doing in the classic phase of aviation at that location and will see what they saw. Consequently they can actually understand exactly what was involved. Classic era procedures included mandatory visual approach procedures as at Kai Tak in Hong Kong.
When simulating vintage phase aviation users have to think much harder about exact place and exact date, airline nationality, crew resource, etc, and then they have to create a flight plan that will work in any weather.
Outside the 21st century it is wrong to fly a single crew Trimotor other than by visual reference to the surface anywhere, but once an FS9 user needs 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 they 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 them badly and atypically.
The problem with simulating both vintage phase techniques (RDF and navigation by reference to the surface) is that the strategy we decide upon and the location of transitions between the methods 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 since we cannot download unpublished vintage spur of the moment procedures and flight plans. We can however experience and understand the difficult decisions that had to be made by aircrew because departure, arrival and approach procedures were not yet mandated, tested, and safe.
Finally note that within the FS9 and wider aviation community the concept 'classic jets' also exists. This concept is sometimes limited to turbojets, but often it is a reference to all the jets including low bypass turbofans that preceded the B747 and the IBM 9020 and Radar Control and therefore includes any jets that preceded the modern phase of aviation and that flew the classic procedures by rote fairly frequently because although radar intervention was desirable for them all, it was not always available everywhere for them all.
Tom and I discussed this recently in the context of his updated classic propliner AI traffic sample and the forthcoming classic era AFCAD project. The cut off dates for the AFCAD project are intended to facilitate those who fly classic phase jets as well as classic phase propliners whilst the AI traffic sample is intended to replicate the moment when the number of classic phase piston propliners in service maximised world wide. That occurred just before the more profitable low bypass turbofans, with much greater passenger appeal, made their debut.
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 at the end of the 1950s, but the classic phase wasn't symbolically over until the first 747 joined the fray in 1970. By then California already had a fully modern aviation infrastructure, but much of the world still did not. Even in the UK various kinds of RDF talkdown were still commonplace throughout the 1970s.
FSAviator 11/06
I often need to edit my contributions down from a much wider context to fit into the California focus of this forum and Tom has already answered your questions as they apply to California.
However my post would have been different and the answers to your questions are different if the context is widened beyond single crew airliners and the Continental United States (CONUS) of which California is a component. With Tom’s indulgence I will try to illuminate the wider picture in this post.
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 not happened in eras. It 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 a wider context it is more appropriate to substitute the word phase wherever I have said era.
Desk top flight simulators allow those with no aircrew experience to access aviation from the inside looking out. Aviation is much more than aeroplanes because the things achieved by aeroplanes and those who flew them depend on a complex external infrastructure that is often ignored. In my writings here I try to convey the wider concept of aviation as an infrastructure, or lack of it. During the vintage 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 travellers."
No single crew aeroplane could have done that in the stated timeframe. The necessary public sector infrastructure did not exist. Air mail planes and their pilots were being sacrificed almost every month and as soon as the airlines attempted to carry passengers with the air mail, which had already paid for the entire flight, passengers began to perish too. When celebrities started to perish, the media started to take an interest, 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.
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 regulation they imposed.
The vintage 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. The classic phase was characterised by mandatory procedural compliance with government regulation, using an infrastructure provided at public expense, to ensure both regularity of service and enhanced safety.
This means that within the CONUS I define the vintage phase of commercial aviation as giving way to the classic phase from 1932. The transition for the USAAC, USN and USMC happens later and has no particular relationship to the CONUS.
Suppose however that instead we wish to simulate the situation in Europe in general or Germany in particular. The answers to your questions are then different. In Germany the classic phase of aviation began about 1937 quite uniformly for both commercial and military aviation because both were fully under state control.
Suppose we wish to simulate a flight from Copenhagen to Berlin in 1939. Germany has already entered its classic phase, but Denmark has not. There are comprehensive radio navigation aids in Berlin including a Radio Range which any DLH flight will use to the full. By 1939 every multi engined DLH airliner has a (Radio) Kompass which is the German equivalent of the US Army Signal Corps Receiver. DLH aircrew have the German government code books and the radio navigation charts. They know the frequencies to tune and where all the beams point. The aircrew of the Danish airline DDL do not have the German government code books or German radio navigation charts. Nor do DDL have access to Kompass technology in 1939. Nor does any British, French, etc, etc, airline.
Prior to each nation ratifying the Treaty of Chicago which 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 a 'chosen instrument' of the national government who would deny that infrastructure even to their domestic 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 has 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. Before attempting simulation of historic airline schedules, (or ad hoc charters), we need to answer the following question 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 at the chosen date’.
For instance the Ford 4-AT-E Trimotor had engines rated at sea level and was optimised for flight at low altitude. It could not be fitted with an autopilot and had no blind flying panel. If a blind flying panel was retrofitted the airline had to hire as co-pilot someone who was both an instrument rated airline pilot and a trained mechanic. In practice even after the CONUS had an IFR point source infrastructure, complete with mandatory departure, arrival and approach procedures imposed by federal ATC clearance, a 4-AT-E could not access them. It was from the vintage phase of US commercial aviation and was not worth updating to work in the classic phase. They disappeared from the schedules quickly but survived to fly ad hoc charters using vintage CONUS techniques. That situation must be read across to airliners with inadequate crew complement everywhere.
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 both vintage phase infrastructure and classic phase infrastructure in a single flight.
The turning point was the 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 Treaty 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.
From a world wide perspective individual mid air collisions had no impact at all. They sometimes caused a single nation to improve its aviation infrastructure or to bring its federal safety regulations more into line with international law as set out in the Treaty of Chicago.
What follows is not really new, but nevertheless forms the logical Part 2 of any vintage phase mini tutorial. It is just an extension of things touched upon in the notes explaining how to use my Boeing 314A Clipper flight dynamics when conducting vintage era flight simulation outside the CONUS.
Let’s consider the rules of conduct for flight simulation of a DDL (Danish) Focke Wulf Kondor flying from Amsterdam to London ex Copenhagen or a DLH (German) Focke Wulf Kondor flying from Amsterdam to London ex Berlin in mid 1939. Neither will have access to any useful Radio Ranges whether or not they have a multi waveband Kompass receiver. Both must use contemporary Dutch and then British aviation infrastructure.
Both Wireless Telegraphy (W/T = Morse) and Radio Telephony (R/T = Voice) pre date the powered aeroplane. Aircraft usage 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) his transmission. The bearings supplied back to the qualified WTO/RO were then plotted on a chart by a qualified navigator. Ideally three bearings from different D/F operators in sequence were used to triangulate present=recent position. Just as in a ship the navigator then instructed the helmsman what heading to steer based on where the vessel was believed to have been a few minutes earlier. Before WW2 the only airlines flying along beams to a beacon were based in Germany or the CONUS. That was also true in most places long after WW2.
Nobody believed for a minute that aeroplanes could achieve scheduled operation using sextants for astronavigation. Attempts usually ended in death. Of course 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. But now 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 no idea where they are for days on end. That sometimes included airships, but not aeroplanes. Of course sextants were installed in aeroplanes they were just useless weight much of the time in any aircraft that had to maintain a schedule. Sextants were much used by air forces and navies, but they just postponed missions for days on end until the weather was good enough to fly them.
Radio Direction Finding = RDF (in the HF band = HFDF pronounced Huff Duff) began to replace sextants for oceanic navigation world wide from 1909. Aircraft were simply no different. No one attempted scheduled ocean crossings without both a qualified radio or wireless operator and a qualified navigator aboard. It soon occurred to the Imperial powers that the Sahara and the Arabian Deserts and even India were just another kind of ocean. Then they decided to treat the entire planet as an ocean upon which they could never afford to site thousands of radio ranges. Their taxpayers were never going to pay for radio ranges across entire empires on which the sun never set.
By 1929 RDF was possible using HF stations 1200 miles away. Aircraft with significant useful loads not designed for use over the CONUS had large crews whether military or commercial and used RDF to navigate. That is why the Kondor or a Boeing Clipper 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 beacon to beacon.
RDF was a global positioning system (GPS) long before WW2.
The USN had 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 infrastructure. Their fatality rate was dreadful. Over the CONUS federally imposed detailed procedures were introduced from 1932. Outside the CONUS all US aviation slowly caught up with the USN and everybody else by introducing RDF.
RDF is a wide source infrastructure. It is not associated with federal regulations, airways, air traffic control, or mandated procedures. Everywhere except the CONUS it was widely available allowing multi crew aircraft to navigate above cloud without visual reference to the surface, and just as easily below cloud without visual reference to heavenly bodies, 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 ships anyway.
The shortcomings of all the early GPS systems were complex radio encoding requiring a dedicated radio operator whilst manual plotting of the decode also requiring 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 have been available in British GPS moving map systems such as Decca Navigator since the 1950s.
We must never forget that for aircraft with large useful loads, everywhere except the CONUS, GPS in the form of Marconi + Adcock RDF was the primary commercial, military and naval navigation system in use from WW1 onwards. During and after WW2 it was gradually replaced by the German naval GPS system to which British Intelligence assigned the acronym LORAN (LOng Range Aerial Navigation).
In theory the MSFS GPS code could be made to behave exactly like a human navigator waiting for decodes from a human WTO or RO before plotting the symbol on the map with suitable inaccuracy and delay, but as I explained in the notes accompanying my Boeing Clipper flight dynamics this is not really necessary.
The rules for conducting a GPS navigated flight using Marconi + Adcock technology during the vintage era of aviation only require self disciplined use of the default MSFS GPS.
1) The aircraft, (whether civil, military or naval), must have at least a WTO/RO and a Navigator. Naval aircrew classified as observers were often, but not always, navigators.
2) The range selected on the GPS should be of such small scale that either maximum range is selected, or for shorter flights both the departure point and the destination are visible throughout the flight. No flight plan should be entered into the default GPS. Distance gone/to go should be estimated from the GPS (potentially max range) map.
3) The GPS should be consulted by popping up the window only at substantial intervals during cruise. Perhaps every 10th minute for a short haul flight or every 30th for a trans oceanic flight.
4) Once every position update interval a course correction, not exceeding five degrees, and always rounded to five degrees, is made after trying to work out from the inadequate scale GPS picture whether the flight is currently left or right of track due to wind drift and any other cumulative navigation errors.
What is being simulated here using intermittent course changes and headings, which will be wrong by up to 4 degrees 80% of the time, is the error that arose from the manual plotting delay and the bearing errors inherent in using HFDF at extended range. 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 with inadequate crew resource could only fly by visual reference to the surface. Consider how useless that was to a torpedo bomber crew for instance and it is easy to grasp why torpedo bombers needed (at least) three crew. However remember that military and naval operations sometimes need to be conducted in radio silence until the mission is detected.
So everywhere except over the CONUS 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 above cloud, directly on track to destination. Then every ten to thirty minutes intermittent use of a potentially max range GPS update 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 to make a visual arrival followed by a visual approach.
When flying either a DDL or DLH Kondor from Amsterdam to London in 1939, the visual departure to somewhere safe before climbing into or above cloud is simple. Once in the cruise at an altitude of three or four thousand metres the goal is to transition back to flight by visual reference to the surface before that arrival transition becomes dangerous.
We must use GPS to reach a terrain feature big enough to be located on the potentially max range GPS display. That feature must also be something we will recognise once in contact with the surface below cloud. In this case it will obviously be the Thames Estuary. Before it is too late we descend below all cloud whilst still over the sea, and based on the last known intermittent GPS plot, once below cloud, we head for the south shore of the Thames Estuary left of the landmark from which we intend to initiate inland navigation by visual reference to the surface.
Both Kondor captains must now act as though they were single crew in a Ford Trimotor and must locate destination using a VFR plan prepared for the arrival and approach. If they can see several landmarks ahead they will cut corners and fly from landmark to landmark on the plan. Else they will seek line features leading to them. The German crew are flying a better equipped Kondor, but in mid 1939 the equipment is of no use west of the German border.
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 and the line feature that must be found is the entire coast of the Hawaiian chain; preferably, but not necessarily, the correct island.
In the absence of mandatory arrival procedures published by a Government agency via an arrival and approach plate the key decision is always voluntary placement of Top of Descent (TOD) to terminate the GPS component of the vintage phase flight outside the CONUS. We must descend through cloud somewhere that does not risk collision with terrain in the descent. We must plan and then vertically limit the descent accordingly.
We must try to estimate the altitude of the terrain below and terminate descent 1500 feet (or 500 metres) altitude above that estimate. Descending over the sea makes this simple, but other cases must be attempted by FS9 users in due course. The elevation of the destination airfield should always be known to the user and the elevation of other airfields can easily be found using a flight planner.
In the two examples above we use GPS to ensure that we descend plenty early enough. On the other hand if simulating a BSAA Lancastrian schedule from Buenos Aires to Santiago in the late 1940s we must ensure that the navigator uses RDF = GPS to instead ensure that we descend plenty late enough to have crossed the Andes else all the Santiago RDF operator will hear of the WTOs Morse message 'starting descent' is S T E? * * * N * D E * C * * * as we descend behind the shadow of the Andes and just before we impact the Glacier.
If when simulating a BSAA Lancastrian crew setting off for Bermuda in the late 1940s, using dead reckoning, or better still a sextant, or much better still RDF = GPS, then we can personally simulate starting 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 located reliably by any means before a Radio Range or NDB was installed on the island. Even then the airliner needed an LF or MF receiver that could actually tune either of them in.
Remember that for a nation or airline stranded in the vintage phase of aviation that means remembering to take the correct crystals to install in the crystal set avionics. Many early avionics were single channel or 12 channel, not 360 or 720 channel and there was no point pushing the pre set button(s) to select the frequency if the correct crystal was not in place.
So this is not really a question of era. Some British airlines were still stranded in the Zeppelin era = RDF phase of aviation history, even in the late 1940s. They were still reliant on wide source infrastructure and not subject to adequate safety regulation anywhere, and they still had the accident record to match.
The world wide picture from about 1923 to the ratification of the Treaty of Chicago from 1948 onwards was not that of single crew multi engined airliners navigating by visual reference to the surface. That was peculiar to the CONUS. Until 1932 airline navigation over the CONUS was way behind the rest of the world, but by 1939 it was well ahead (Germany excepted).
From about 1923 onwards multi engined airliners in the rest of the world progressively used the British form of GPS known as RDF. Some later transitioned to the German LORAN GPS system, and then all transitioned to the 'American Way' when they ratified the Treaty of Chicago in the very late 1940s or during the 1950s; often pressurised to do so by linked economic aid programs. The Soviet Bloc, Communist China and North Korea did not ratify the Treaty but the USSR soon developed superior alternatives to simple RDF. I believe there are aircraft or gauge uploads that explain their usage in some detail, but perhaps only in Cyrillic.
By the late 1950s the 'west' had adopted either Radio Ranges or VORs or TACAN augmented by weak signal NDBs for local non precision approach guidance. This form of point source infrastructure then became international and was the primary means of navigating airliners within a mandatory, expensive, heavily regulated, safe, air traffic controlled environment that I identify as the classic phase.
You ask;
'When would this era end, and what innovations made a change possible or necessary'?
Unfortunately that is not simple to explain either.
The point source infrastructure maximised safety because it allowed the publication of mandatory procedures for departure, cruise, arrival and approach using very precise timings in a 4D navigation environment. Those ATC procedures were followed by rote. The classic phase of aviation was a 'procedural' phase.
What brought it to an end was RAdio Direction finding And Ranging (RADAR).
During the 1930s Britain replaced the HF squeakers in its fighter aircraft. They had allowed triangulation with string on the RAF sector control plotting tables that were still in use a decade later in the Battle of Britain. The new British invention, which would later be called a transponder, could squawk instead. A squeak provides a bearing to the ground based controller, but a squawk provides a fix.
Within a year Britain developed primary radar good enough to detect a 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 purpose of radar following the loss of the Titanic in 1912.
Once Britain had (primary) radar good enough to detect 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. By 1945 air traffic controllers talking an aircraft down through a Ground Controlled Approach (GCA) using surveillance radar to control the approach (SRA) allowed missions in weather four times worse than an RDF talkdown (QGH). By the early 1950s it was theoretically possible 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 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. This time the US lagged behind.
For a long time however little use was made of radar to intervene in the climb, cruise or descent phases of the flight being controlled from Air Traffic Control Centres (ATCCs). As I have explained elsewhere the range of a piston engined aircraft does not depend on its altitude. No fuel is saved by expediting 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 40,000 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 (UARs) 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 B747 and demand for jet flying mushroomed as costs and ticket prices fell whilst trip times were reduced. Win - win for the consumer.
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 if the radar failed or when it needed maintenance.
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 even more reliant on expensive infrastructure outside the aeroplane.
So the next phase which we still call the modern phase/era was one in which airline pilots no longer expected to fly the classic era procedures unless the radar was off. They expected to be radar vectored in just about every phase of the flight instead, but everyone had 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 airline pilot and any air traffic controller may need to invoke them today.
During the RDF phase of aviation infrastructure, which lasted into the 1970s even at lesser locations in the developed world, procedures were often made up by aircraft captains on the spur of the moment and sometimes with fatal consequences. Sometimes they were published by employers, but that meant involving lawyers to determine if the employer could be held liable if anything went wrong. Much better to blame a dead crew. :-<
Even during the classic and modern phases of aviation many (fatal) accidents have also been caused by airline captains deciding that they could conduct the flight by visual reference to the surface and then failing. They rejected the IFR procedures and they rejected radar control. Some jurisdictions still allow that. As a consequence sometimes they 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 of course. Sometimes they land on the wrong airfield altogether.
So the situation is that the current regulations and airspace definitions for anywhere in California are available for free download and are so complicated that only two lawyers in the world claim to understand them all and have three opinions about what they mean. Since airliners in the modern phase of aviation are almost always going to be radar vectored instead there is little point in anyone who is not forced by their employment to understand the complexity to even try. That is one reason that I favour simulation of the classic and vintage phases of aviation.
However we must never lose sight of the fact that over many parts of the globe there was very gradual transition between the vintage and classic 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 radio beacons in the Buenos Aires Terminal Area before transitioning to using vintage phase wide area infrastructure RDF for the en route navigation phase. At some point those that actually made it across the Andes 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 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.
The benefit of choosing to simulate the 'pure' classic phase anywhere around the planet (as generally supported and proposed by Tom’s website and forum) is that users can download the real procedures, study them for as long as it takes to understand just one of them, and then when they fly it by rote in FS9 they will be doing exactly what the real crew was doing in the classic phase of aviation at that location and will see what they saw. Consequently they can actually understand exactly what was involved. Classic era procedures included mandatory visual approach procedures as at Kai Tak in Hong Kong.
When simulating vintage phase aviation users have to think much harder about exact place and exact date, airline nationality, crew resource, etc, and then they have to create a flight plan that will work in any weather.
Outside the 21st century it is wrong to fly a single crew Trimotor other than by visual reference to the surface anywhere, but once an FS9 user needs 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 they 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 them badly and atypically.
The problem with simulating both vintage phase techniques (RDF and navigation by reference to the surface) is that the strategy we decide upon and the location of transitions between the methods 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 since we cannot download unpublished vintage spur of the moment procedures and flight plans. We can however experience and understand the difficult decisions that had to be made by aircrew because departure, arrival and approach procedures were not yet mandated, tested, and safe.
Finally note that within the FS9 and wider aviation community the concept 'classic jets' also exists. This concept is sometimes limited to turbojets, but often it is a reference to all the jets including low bypass turbofans that preceded the B747 and the IBM 9020 and Radar Control and therefore includes any jets that preceded the modern phase of aviation and that flew the classic procedures by rote fairly frequently because although radar intervention was desirable for them all, it was not always available everywhere for them all.
Tom and I discussed this recently in the context of his updated classic propliner AI traffic sample and the forthcoming classic era AFCAD project. The cut off dates for the AFCAD project are intended to facilitate those who fly classic phase jets as well as classic phase propliners whilst the AI traffic sample is intended to replicate the moment when the number of classic phase piston propliners in service maximised world wide. That occurred just before the more profitable low bypass turbofans, with much greater passenger appeal, made their debut.
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 at the end of the 1950s, but the classic phase wasn't symbolically over until the first 747 joined the fray in 1970. By then California already had a fully modern aviation infrastructure, but much of the world still did not. Even in the UK various kinds of RDF talkdown were still commonplace throughout the 1970s.
FSAviator 11/06