Adventures of a Trainee Navigator Dec 24, 2018 15:22:46 GMT -5
Post by connieguy on Dec 24, 2018 15:22:46 GMT -5
Some years ago I abandoned flight simulation of modern jets as too boring and took up flying propliners because there seemed to me to be simply more to it. This was particularly the case once I discovered the Manfred Jahn/Connie Team Constellations, where the various statistics available on the engine information panels often tally very closely with those given in flight manuals for the real aircraft. Some simmers take the view that they are the pilot and that as navigating the aircraft was the role of the navigator they are therefore fully entitled to use a modern GPS or the display in a program such as the freeware Plan G to tell them where to go. I have no argument with this, because it is for them to do as they wish, and indeed it is what I have done hitherto. However, as time has passed I have become increasingly uneasy about it. One has only to read works like Gann's 'Fate is the Hunter' to realise how dangerous flying propliners could be, and that part of this was the danger of getting lost. Thus, there were times when the navigator was not simply a subordinate to the pilot, but the most important person on board, upon whose professionalism the lives of all the others depended. There are other threads on this forum which discuss the navigation aids used on multi-engine aircraft in the 1950s, including the system known as Loran. However, there is no simulation of Loran available for FS9 and even if there were it is clear that it was not always as effective as was desirable, even in the limited areas where it was available. In these circumstances aircraft navigators crossing large expanses of sea and desert fell back, like mariners in the case of the seas, upon celestial navigation, based upon a knowledge of the heavens which went back thousands of years. In this context two of the vital instruments were the driftmeter and the sextant, both of which are available for FS9 thanks to the efforts of members of the virtual airline DC3 Airways and especially those of Dave Bitzer and Mark Beaumont.
Just one more point before this rather long post concludes. On an earlier attempt at this flight I looked out of the astrodome and could see The Plough (aka The Big Dipper) and the Pole Star quite clearly. However they were slightly to port of the aircraft nose when I knew they ought to be to starboard for me to be travelling north west as I needed to be. Once the correction had been made all was well, although I was well off course. However, the amended stars for FS9 show the constellations quite clearly and the next thing is to become much more familiar with them.
My skills have never included things remotely mathematical. When I was at school Algebra seemed to me to be complete fantasy and even today I have only to look at the simplest mathematical formula to remember the sense of panic which often gripped me sitting at a school desk fifty years ago. Hence I have approached 'real' navigation with considerable trepidation, downloading the Beaumont-Bitzer sextant several times, looking at it, leaving it on my hard drive without doing anything with it, and then eventually deleting it. Now that I have made some real progress I have realised that I was right not be satisfied with the gps, because real navigation is exciting and when you get it right extremely satisfying. I have also realised that while I would not describe it as easy, nor is it as difficult as I anticipated. Of course this thread is not intended for those determined to stick to the gps or for those who are already expert navigators, for I know that among the forum's members may well be people who navigated real aircraft before the age of gps. It is intended for people who, like myself, might be interested if they can be shown how to do it in a way which is accessible and reasonably easy to understand. If experts wish to chip in that will be good and much appreciated, but whether they do or not here goes:
Firstly, there will need to be some modifications to FS9. A utility which I have used for some time and which is absolutely essential is Nils Meier's PDFKneeboard, which allows pdfs to be read in the cockpit without even going out of full screen. Also essential if you are going to be looking at stars (and you are) is a better representation of them than that in stock FS9. I am using one called MyFSStars which was done by Juergen Haible some years ago and displays the stars you need to see in an uncluttered way. Unfortunately, the website from which I obtained it is no longer in existence. Another version with a lot more stars is available from Norbert Pachner, but the greater number of stars tends to make the important ones stand out rather less well, at least on my system. A very good free and portable astronomy program is Stellarium, and it is easy to see the night sky from any geographical location and date that you want. Iceland in December 1956? No problem. The Pachner stars are available here:
Then there is the Dave Bitzer driftmeter, which is readily available. I believe Version 7 to be the latest and that is the one I have. On the sextant I recommend the version reworked for FSX (it works in FS9 too) by Kronzky:
This contains a very clear explanation of how to take a series of three sextant shots, although you will get a fuller manual if you also download the version of the gauge issued by Mark Beaumont and Dave Bitzer in 2008 and the first version of (I think) 2005. However, I have found the clickspots for changing the digits rather confusing, at least on my system, in the 2008 version, while in the Kronzky edition things are more straightforward. The link above will also take you to two rather good You Tube videos done by someone who has navigated the A2A Constellation in the Pacific in FSX. All these things have to be installed, of course, and I give below an image of the modified virtual cockpit of my Jahn/Connie Team L 1049H.
Quite some time ago I removed the autopilot from the glareshield and replaced it with: firstly, on the right the analogue clock with adjustable hours by Pierre Fasseaux which will not change as the aircraft crosses FS time zones. It can therefore be set to Zulu/UTC/GMT time and will remain there, avoiding at a stroke the problems caused by FS9's inadequate treatment of time zones. Correct local times can nearly always be found in airline timetables from the period, and I set these on the two clocks on the main panel. Zulu time is also available on the sextant; secondly, a magnetic compass. This one, on trial at the moment, is from the MAAM DC3; thirdly, a little panel which allows me to switch the rmi indicator between VOR and ADF signals. This is adapted from the Connie Team L 1649 Starliner. Important things - the autopilot, engine information panel, sextant, driftmeter and flight engineer's station - are summoned by means of invisible clickspots over some of the gauges (the engineer's and engine panels are also available from icons provided by the Connie Team). I use the freeware FSRecorder to move around the virtual cockpit and have added two new views - the first simulates what would have been the view from an astrodome and the second produces the view below the aircraft necessary to use the driftmeter. The simulated sextant can in fact be used without looking outside at all, but nevertheless a very clear view of the heavens can in certain circumstances come in extremely useful - see below.
Then there is a certain amount of hardware and literature beyond the sextant manual. I think probably essential if one is going to replicate the old methods fairly fully is a Dalton E6B Flight Computer. I got mine on E-Bay but they and similar things are still in use by pilots and available new, for example from Flightstore. Something else that is almost priceless is the introduction to navigation issued by the Army Air Forces Training Command in 1944 and available here:
It can be downloaded complete or in individual sections. The latter are rather easier to handle and of course particularly important pages, such as that on calculating double drift, can be printed out. Not all have the gift of explaining reasonably complicated things which they understand perfectly to complete novices, but the authors of this manual made a pretty good job of it, and the descriptions of how to use the Dalton E6B I have found easy to follow. The sextant gauge includes a chart but even so I have found it difficult understanding where a star shot is actually placing the aircraft and as a result have created a physical chart. Lines of longitude and latitude have been drawn on a piece of graph paper and a piece of clear plastic fastened down on top of it. Each square of latitude represents five nautical miles and varying distances in longitude. This can be used to plot courses and parts of courses with a dry wipe pen (using whatever lines of latitude and longitude are appropriate) and everything can be wiped clean when done ready for the next use.
You will also need a timer. This can be done within FS, but I have preferred to buy a kitchen timer which will count upwards and therefore act as a stopwatch. This might all seem a lot of effort, but it is worth it. Let us now get to a real flight. My early efforts saw basic errors such as not realising that the course offered by the sextant gauge after a star shot is a reciprocal course and that therefore 046 means actually steering 226, with whatever allowance is necessary to convert this True Heading to Magnetic. However, I am now hopeful that I can do rather better.
My chosen route is from Burtonwood (US designation S590) near Manchester in the UK (Prestwick would do just as well) to Keflavik, Iceland. First of all, it is a route I have flown both ways a number of times and I am familiar with the sort of winds one might encounter, especially quite strong south westerlies but also quite strong easterlies, sometimes both on the same flight. Also, at nearly 900 nm and about four hours it is a suitable length and as there are radio beacons at both ends the distance which needs serious navigation is considerably less. The first thing to do is plot a flight plan, using the freeware Plan G which calculates automatically various things that real navigators would have had to do manually. As the flight is taking place in 1956 I am not using radio aids which were not present then, so there is no VOR at Benbecula or at Keflavik. There is one at Dean's Cross and also an NDB with a range of 75 nm at Barra. After that we are on our own until we pick up the 112.5 nm range NDB at Vestmannaeyjar off the southern coast of Iceland. The plan is of course routed through these points, and also through two user waypoints created in Plan G in the north Atlantic, waypoints which I have called ICO13 and ICO10. The Plan G flightplan tells me the True Heading and Magnetic Heading from one point to another and distance between them, as well as the time it will take to fly these distances assuming a cruising speed of 240 knots. I have gone for 240 even though I know that a Super Constellation flying at FL160 with a relatively light fuel load will probably be doing something between 250 and 260 knots true airspeed. A screenshot can be taken of this flight plan, it can be converted into a pdf and as such consulted through the pdf viewer during the flight.
It is mid December and we shall take off at about 14:30 Zulu (and Local) Time. By the time we reach Barra night should be falling and we shall be able to see the crucial stars, but prior to that views of the ground should enable us to see what we make of the driftmeter. The next thing is that we need a weather forecast. I use FS Global Real Weather and opt for a dynamic file starting about 2pm on the afternoon of 22nd December 2018. Once downloaded I put in the flight plan and am given the winds for all the points upon it, including ICO13 and ICO10. This I copy and paste into Word and then save as a pdf, so that it too can be consulted in the cockpit. And it has an interesting tale to tell. Over the British Isles we can expect strong westerlies - 41 knots at 279 degrees at 17,500 feet at Dean's Cross and 22 knots at 269 degrees at Barra. However, by ICO13 there has been a change to a 9 knot wind from 029 degrees and this is maintained at ICO 10 with a 12 knot wind from 031 degrees, while Vestmannaeyjar is not too dissimilar. Of course, these winds may have changed by the time we get to the points concerned.
The first part of the flight is straightforward. On what is a dark afternoon we take off from Burtonwood runway 27 and turn north for Dean's Cross. Climb to FL160 is uneventful and I set the engines for cruise in high blower at 1700 BHP. Fuel to air ratio is 0.064 after I have pulled the mixture levers right back, which is ideal. Once on the autopilot I shall need to check the engine settings periodically but it is time for the real business to begin. Fortunately we are high enough to pass over a thunderstorm raging below. I have connected the flight to Plan G and can see it proceeding there, but as I approach Barra I cover the monitor so that I can see nothing. After we land, if we get there, I will eventually be able to see on the Plan G track exactly what happened. The Barra NDB will get us off to a good start, because I can follow the correct course by aligning a needle now pointing backwards on the right heading. I know that somewhere between Barra and ICO13 the wind is likely to change and this is where the driftmeter comes in very useful. The multiplicity of small islands down below reveal that we are initially drifting right to the tune of 5 degrees on the driftmeter, as is consistent with a westerly wind. But quite quickly we are not, because the driftmeter now shows a drift of 1 degree left. Clearly we have now picked up the forecast easterly winds. I adjust the aircraft heading to what I hope is the correct one and wait for the star shot in the vicinty of ICO13, quite a long wait. In the meantime we have lost the islands but the driftmeter seems to operate not too badly on clouds and strongly suggests that the easterly wind is holding. If we were doing things strictly by the book I would now go to the appropriate website from the FS9 kneeboard and look up three suitable stars with their elevations and azimuths. However, the sextant gauge will work perfectly well if one simply pretends there are stars where one wants them to be, and as this is very much an experiment I decide to take the easy option. Thus I take one shot at an imaginary star directly off the starboard beam, another at one almost dead ahead and a third of one at an azimuth of 225 degrees. It is important with these shots to centre the stars in the sextant bubble accurately, because if one does not the resultant position will be inaccurate, possibly seriously so. However, the signs are good. The first shot places me only 5nm from my assumed position and the three together cross each other at a fairly definite point - if the crossing forms a distinct triangle something has probably gone slightly wrong. ICO13 is at N59 54 W12 18 and the sextant tells me that the plot has produced N60 20 W11 60 (the latter I take to mean W12 00). Plotting these coordinates on my physical chart (see the illustration of that chart above) shows that I have gone slightly too far north and am a little too far east, but not by very much at all. I turn the heading of the aircraft to port by what I guess is the right amount and wait for the plot at ICO10, a plot which is never made. Why? Because the stars are obscured by clouds, just as they might be in real life. All I can do is wait, and wait I do until I suddenly see the ADF needle jump into action and hear the welcome beeps which tell me that we have picked up the NDB at Vestmannaeyjar. The needle is about 5 compass points to the left of where it should be. After that everything is straightforward, although ATIS comes in rather late and tells me that landing is on Keflavik Runway 11 rather than 24, as one might have expected from the fact that the wind is about 5 knots from 241 degrees. I resist the temptation to land on 24 anyway and go round for 11, making a good landing on a clear night. After the long taxi in (Keflavik is a big place) and engine shut down there are 3,420 lbs of fuel left from the 15,084 lbs originally loaded. Flight time 4 hours and 7 minutes.
Then I take the cover off the monitor to look at the Plan G track, which generally confirms what I think has happened.
After Barra we held the course pretty well until the NDB gave out but then drifted east fairly slowly. In future I shall take shots more frequently than every 250 nm, although in this case that distance was effectively reduced by the use of the Barra NDB. The Plan G track only turns left some way after ICO13 but that is probably because it took me some minutes to take the star shots, get the result, plot it on my physical chart and work out what to do. If I had been able to take shots at ICO10 I would have been very near it, but as it was went slightly too far west until I picked up the Vestmannaeyjar NDB. Have I been navigating? I think so.
To be continued (perhaps).
Addendum: This is part of the night sky at Keflavik at 17:21 on 21st December, 1956, as seen in FS9 with the stars by Juergen Haible. I have identified them by setting the same time and location in the program Stellarium. Constellations in red. An experienced navigator must have been able to recognise them at a glance, but what the novice is looking for is easily recognisable patterns. Altair, for example, is the central one of a distinctive group of three stars which I have often noticed without knowing what it was. Near it is the distinctive grouping of the constellation Delphinus.