April 09, 2015; I’m up for a challenge in the next weeks: I’ve been invited to fly an airliner. Having flown 14 aircraft types before it shouldn’t be so big news if it wasn’t for none of those types being close to the aircraft I will fly now, a modern civil airliner.
The previous types were military trainers, fighters and later civil sports and business aircraft. They are all more or less the same. Flying is like cycling and driving a car: it is something one learns and then doesn’t unlearn. So the flying part should be no problem.
It is not what makes me undertake weeks of preparations. It is that other thing, the aircraft’s computerized soul, that expects to be operated in a certain way. The buttons should be pressed and handles moved in the right order or the aircraft will tell me it doesn’t understand what I want.
So now I am reading through thousands of pages and flying civil airliner procedures day and night. We will dwell on how and why in a couple of Bjorn’s Corners.
The differences in flying
In the beginning of flying, it is all the same. You train in the theoretics of aerodynamics, aircraft systems, weather and flying traffic rules. Then on to the aircraft for hands on flying. The civil training aircraft are built to be straight forward to fly, robust and economical. If they are military trainers, you can add safe to take to and beyond normal flying limits to that. Why?
Military flying, especially for fighters, is about flying on the limits. And to learn what to do when you have passed them. Therefore a lot of military basic training is about flying up to and beyond stall, with or without G-load. If you do it with G-load, the aircraft behaves differently, many divert violently in a quick-roll type stall and you are suddenly head down instead of up in a split second.
This is normal. You train it time and time again so that when it happens later in a dog-fight with a real fighter, it is no big deal–you grab the horizon (real or artificial if you stalled in a cloud) and get out of it. Push a little harder at low speed and you can end up in a spin or deep stall. You train for that as well.
Civil flying is different. If we start with sports or business flying, which is what I have done so far (after my military training), it was disappointing to see how shallow the stall training was. Straight stalls, no G’s, no crossed rudders (spin training) and you only went to beginning of stall and backed out immediately. This is no good base for someone that gets all crossed up in, e.g., a real stall in a cloud during bad weather flying.
The things that gets stressed in civil flying, especially when flying in accordance with Instrument Flight Rules, IFR, are the mechanics of flying. Procedures for take-off, climb, cruise, descent and landing. In good weather and bad.
Business flying is like airliner flying in that it follows the same IFR rules, airways and traffic control functions. The difference is that your aircraft is smaller, lighter and has few passengers. It is also less complex from a handling point of view, the check lists are for a simpler environment both system and regulatory wise. This would fit for all but the largest types, these are more like the aircraft we come to next.
Airline flying used to be like business aircraft flying, aircraft with rather simple system with a rather simple autopilot. The autopilot had control of all the aircraft’s axis but no auto-thrust; speeds were kept by the pilots. But the environment has changed. Civil airliner flying today is a highly sophisticated transportation business, with demands for precision and predictability in the finest detail.
Air traffic has and will grow at ever increasing rates. The figure shows a picture of the world’s air traffic during day time. It is of course highly zoomed but shows what we want: civil air traffic is mass transportation of people and goods in the most efficient and safe way possible.
To do that, everyone has to fly to the same rules and procedure, to the same speeds and with the same precision. Doing that hour in, hour out with a two pilot flight crew requires automation on a different level from other sorts of flying.
Initially the flight engineer was part of a team of three that shared the workload of achieving this kind of precision and safety. Then he and a lot of the original pilot tasks got moved to a computerized flight management system, the FMS. Today this is the heart of the flying airliner. It gets filled with key performance, route and weather data for the trip and then computes all the speeds, altitudes, routings and more…., ready to control the flight.
If your FMS is correctly programmed, you are fine to go, if not you will be asked to fly yourself. This is regardless if the aircraft is controlled in a conventional way or controlled by fly-by-wire. The FMS tells the flight director how he wants the aircraft to be flown and the flight director tells the autopilot what he wants to have done. The autopilot in turn tells the flight control system to move control surfaces so the aircraft flies the desired route. In case of engaged autothrust, it controls the engines for desired speeds in all this.
I list the chain of events because it gives a glimpse of the logical complexity of a modern civil airliner. Add now that each of these systems have different modes and if they get degraded back-up modes. It is complex. The question is if it is not too complex. This was all designed to help the pilots with the work load, the results is logical schemes which require long training to understand.
When things go wrong
That something can go wrong is shown by the Asiana crash where mode confusion was the cause of the crash. The aircraft that I will fly has fly-by- wire in addition to the above. Fly-by-wire makes the aircraft easier and safer to fly as it hides aircraft handling complexities (aircraft quirks) and it adds protection from crossing flight borders. The cost is additional system complexity. New modes gets added to the above and there is more for the pilot to learn and keep track of. Once again the question is if it is worth it and how to design it so that it is.
The other danger is that the high level of automation makes one fly on needle and data fitting. In military training this is an absolute no-no; you do all actions on the horizon, never on a needle that is pointing in the wrong way. If you learned to fly on needle/data fitting it will not help you when you break away from a formation in cloud. You haven’t looked at your own instruments for minutes, you bank abruptly and pull 3G to make sure you are clear from the others, how shall you now react to an altitude indicator going spinning? The only way to avoid a mess is staring at the artificial horizon and flying the aircraft virtually only on that until you have a controlled level attitude, then you can start to worry about needles…
Yet the civil automated flight makes you check the needles and data all the time. It is part of your surveying the autopilot, hour in and hour out. Checking the aircraft’s attitude on the artificial horizon is a waste of time; it is always the same–the computer flies it to the millimeter. So when things go wrong, you are wrongly programmed; you fly on the needles/data and not the artificial horizon. This could be what happened at Air France 447…
It will be interesting to fly the airliner after all my training to master the complexity (we will look into this training in the next Corner). I then expect to be able to compare the more difficult aircraft to fly (the old fashioned one) but simpler to operate with the modern aircraft which seems to be the other way around. Only hands on experience will tell which one I will prefer and why.