Stalling in an Airliner

[BarbiesBoyfriend]

As a humble line pilot, no one has ever trained me to get my current (or any of my six previous) type (s), out of a stall.

On the other hand, on my FIRST type, it was hammered into me and subsequently reinforced by full spin training.

I see a few stall/ spin events recently ( Turkish, Colgan, maybe AF447)

Why not train fully developed stall in the sim?.....at least.

Can't be that expensive surely?

Well, at least compared to the Turkish, Colgan maybe AF447 accidents. What did they cost?

Frankly, if I continue at the rate I'm going, I'll soon no longer be able to fly an aeroplane without an autopilot.

Will I still be a pilot?

[Smilin_Ed]

Why not train fully developed stall in the sim?.....at least.

Probably because the flight control system is supposed to keep the plane from stalling in the first place so no one has deliberately tried it in a real airplane. Until someone tries it in a real airplane, they won't know exactly how to program the sim. Maybe the flight recorder traces from AF447 will give them a clue as to how to do it.

:OEd

[parabellum]

Not so very long ago, (well, 1980!), I seem to remember stall recovery was one of the 'boxed' items on an 1179 type rating, i.e. had to be done in the actual aircraft. I recall doing stalls in a B737-200 somewhere over Essex with the late Chuck Thrower during my UK rating for the B737.

[aviatorhi]

Stalls are done as part of the certification process for a new type, they used to also be done in house after heavy checks before putting the airplane online. The "hold [pilots] by their hands" and "don't do anything 'risky'" mentality that has taken over at most airlines today prevents any real flying or knowledge of the airplane outside of the normal flight envelope from occurring/developing.

As a side note, at my carrier we train to a full stall (with break) in the simulator. It's not part of checking, but it is part of recurrent training.

Probably because the flight control system is supposed to keep the plane from stalling in the first place

Well the engines aren't supposed to quit, we're not supposed to bank past 30, cabins not supposed to go above 10K etc. etc., but we train/demonstrate all of that (not necessarily check). Any carrier that doesn't train to a full stall and any aircraft that hasn't been stalled as part of certification should not be in the air.

[ross_M]

On a similar note, what about water ditching training? Is that part of the simulator protocol yet? After the textbook ditching on the Hudson I'd assume there's some motivation there?

[Graybeard]

DC-10s have been in deep enough stalls to wrinkle the ailerons and tear the elevator counterbalance horns off. Yeh, they flew home afterward.

[wallybird7]

The FAA only requires training for "an approach to the stall". Same as AF. And AB.

[aviatorhi]

The FAA only requires training for "an approach to the stall". Same as AF. And AB.

What the FAA requires and what is a good idea are usually 2 different things. Last I heard they are in the process of changing that requirement to a full stall series in the wake of 'Captain stall the q400 into the ground' (Colgan crash in Buffalo) and the two equally "intelligent" beings at Pinnacle who stalled from FL410 (by flying outside of the performance limit of their airplane). Those two went even further and didn't push over far enough to attain enough airspeed to relight the engines (which had compressor stalled and flamed out). People who can do both of those things should have never been let into aircraft in the first place, though I bet they were "professional" (image wise) and said the right things to appease the HR cronies. Training to a full stall and recovery is a good idea, and as I said, if an air carrier is not doing it they should not be in the air. Knowing how to fly/recover the airplane past the limit is where the men are separated from the boys.

[Bergerie1]

BB asks:- Why not train fully developed stall in the sim?.....at least.

If you are going to do this you need to be very clear as to what are the limitations of your simulator. The simulator is programmed with the test data from the manufacurer's stall tests which are reasonable extensive, and this data is then extended using wind tunnel data and aerodynamic formulae.

For example, there is no reliable data for stalls at high altitude, at high Mach No, at very high AoAs, or with large amounts of sideslip. When using simulators, trainers need to remain close to the 'relatively normal' flight envelope. If they get much outside this the simulator is probably not reproducing accurately the responses of the real aircraft and the conclusions the trainers and their pupils may draw could be very misleading. Yes, I believe that stall training for airline pilots in simulators should be rather more extensive than it seems to be at the moment but beware the limitations.

No test pilot will have ever put a large civil aircraft willingly into the very high AoA experienced by AF447 - it would be far too dangerous.

[Centaurus]

DC-10s have been in deep enough stalls to wrinkle the ailerons and tear the elevator counterbalance horns off. Yeh, they flew home afterward.


Reminds me of the Australian designed Wirraway trainer (same basic design as the Harvard). A power on landing flap stall was indeed a vicious beast which caused aileron snatch and rapid wing drop. The control column would whip side to side and belt the pilot on the knees. Yeh, we also flew home afterwards..:ok:

[BarbiesBoyfriend]

OK

For clarification, please let me re-state my point more clearly.

If it's vitally important to learn how to recover your Cessna 150 from a full stall while in initial training with only the two of you onboard....

Why is not even worth looking at when you've got an aircraft full of fare paying?

And perleeease, don't say "cos it aint going to happen"!

I realise the limitations of the sim, etc but don't tell me such training can not be done. Surely, this is precisely, what sims are there for?

[PLovett]

BBf, I understand exactly where you are coming from as there appears to a distressing trend emerging that supposedly competent pilots with "appropriate" training are stalling their aircraft.

However, surely the purpose of stalling the C150 is to show you what happens so that you will avoid doing so in the future. It would seem that some pilots have forgotten that lesson.

[BarbiesBoyfriend]

P Lovett

Sure. But different aircraft react in different ways when stalled.

Surely the point of a 'Type conversion' is to learn about these differences?

Loss of control' is becoming the new Gotcha. Recovery at the shaker is all very well, but surely there is a trend emerging here, and it's one that could be dealt with synthetically!

[ross_M]

For example, there is no reliable data for stalls at high altitude, at high Mach No, at very high AoAs, or with large amounts of sideslip.

Why not? Because these operations are too dangerous even for a test flight?

No test pilot will have ever put a large civil aircraft willingly into the very high AoA experienced by AF447 - it would be far too dangerous.


Are there any projects to try pilot-less testing, at least for certain dangerous flight tests? With everything being fly-by-wire and the experience with pilot-less drones this seems reasonable.

Might get us a lot more data of the edge-of-envelope sort.....

[cwatters]

Perhaps you need one of these..

YouTube - ‪rc airliner A340‬‏

although I doubt you could persuade him to fly it with the CoG as far back as required.

[john_tullamarine]

Good idea for a coffee discussion but a number of problems -

(a) typical sim is a big PC in drag on steroids. The software perambulations are either

(i) within defined boundary conditions derived from FT or wind tunnel work and should have some correlation with reality. Otherwise -

(ii) playing in the box can only be based on guesswork extrapolation. Probably not too bad for controlled flight within a small delta from the certificated envelope but generally GIGO when it comes to post stall departure regimes. Just what training value might be obtained is moot. I, for one, wouldn't waste time in the box on such activities as there are many far more useful playtime uses of benefit to the guys and gals in the front seats.

(b) certification stall practices have varied over the years so one cannot reliably extrapolate one's experience on a light GA trainer to big iron without a lot of homework and access to well-placed folks in the game.

(c) one might hope that the OEM will have done some beyond-certification requirements post stall departure investigation but don't expect it to be described explicitly in the pilot documents. Furthermore, in the civil arena, cost is a major driver and playtime FT can be very costly.

Best to have pilots who can recognise an impending stall environment and remove the aircraft from the situation before things get even remotely exciting ... and, at the risk of being controversial, perhaps it might be a good idea for pilots to do a bit more hand flying (on raw data in 0/0 conditions) and useful playtime work in their sim sessions ?

[Bergerie1]

BB - Recovery from a full stall can be done (and is done during conversion training) on the simulator, and is reasonable representative of the aircraft.

However, what JT says about GIGO is absolutely right. The point I was trying to make is, if you go outside what the simulator is programmed to do, the response of the simulator is likely to be inaccurate and therefore the instructor might well be training the wrong response. One has to be very careful not to indulge in what I used to call 'anti-training', i.e. pilots must not come away from a training session with the idea that the aircraft will behave in a benign way in certain extreme conditions when, in reality, it might exhibit some vicious characteristics.

Yes, training should be done to demonstate the approach to the stall, the recognition of this condition, the flight characteristics at the stall and how to recover with minimum height loss. But pilots should also be trained in the recovery from a full stall, i.e. immediately to reduce AoA and then gently to apply power. They also need to know that applying power too vigorously might cause engine(s) on one side to spool up too quickly causing sideslip and a departure into an 'untested' region of the flight envelope Even more important, they need to know that in many unintentional stalls the situation is likely to be compounded by a severe nose-up trim condition. If they are also flying an aircraft with underslung engines and they apply too much power too quickly the nose-up pitching moment, combined with the out of trim condition, might leave them with too little elevator authority to recover. This latter problem can be demonstrated accurately on the simulator, and it should be done.

But I still caution that all instructors MUST know the limitations of the simulator and not try to draw conclusions from manoeuvres which are outside what has been accurately programmed.

[Mad (Flt) Scientist]

Two regulatory activites are currently underway which are related to this.

There's an Industry-FAA Stall/Stick Pusher Working Group which is looking at both training norms and at simulation capabilities. That's supposed to wrap up this month, IIRC. Recent FAA movement on the applicability of the Practical Test Standard "minimizing altitude loss" comes at least in part from this activity.

There's also an Aviation Rulemaking Advisory Committee task assigned to the Avionics Systems Harmonization Working Group to:
provid[e] information that will be used to develop standards and guidance material for low speed alerting systems. This information may result in
standards that complement existing stall warning requirements.
They are wrapping up for rules for all-new aircraft (phase 1), the next phase will be to consider retroactive requirements for existing aircraft.
(ARAC tasking notice published in the Federal Register on April 2, 2010 (75 FR 16902).)

[ChristiaanJ]

Mad (Flt) Scientist,
The Brits are also looking at this.
I suppose you've already seen the links.

[grounded27]

The "hold [pilots] by their hands" and "don't do anything 'risky'" mentality that has taken over at most airlines today prevents any real flying or knowledge of the airplane outside of the normal flight envelope from occurring/developing.

Drivers do not have the deep pockets airlines and manufacturers do, airlines do not want the liability so mr airbus and boeing will continue to automate stall protection as a marketing tool. Neither want you ever to have one of their aircraft out of the normal flight envelope.

[Mr Optimistic]

Stall characteristics may also be too 'chaotic' to be programmed, that is the behaviour is very sensitive to multiple t=0 parameters.

[macdo]

Did sim full stall training for initial type rating and have done it again every few years. Last year did fully developed a320 spin in the Altheon sim at LGW. I was surprised at the 'classic' spin that developed and how easily it recovered using the standard technique. I think we lost about 7000'. Good to know how much respect has to be given to the rudder on these a/c.

[john_tullamarine]

I was surprised at the 'classic' spin that developed and how easily it recovered using the standard technique

You don't think that this might be just a standard equation spin generated for generic interest .. and of no particular relevance to the A320 ? What validation description was provided by Alteon ?

[RetiredF4]

Disregarding the fact, that until now i never heard, that reliable flight tested post stall / spin data are available for the Airbus i think you flew in wonderland environment.

Or are you just talking about the altitude loss starting with the recovery, disregarding the altitude loss from upset until start of first recovery inputs?

At what level did the procedure start?

I did spin training in the T37 trainer, altitude needed from entry to recovery to S&L again between 5.000 to 9.000 feet for a fully developed spin.

franzl

[Machinbird]

Pan Am B707-120 / 25Feb59 N709PA suffered in-flight separation of the #4 engine during a training mission north of Paris France. An PAA instructor pilot was demonstrating minimum control speeds at 8000 feet, the B707 stalled at an estimated speed of 120 KIAS and started into a right spin. The plane lost 2000 feet of altitude, before a violent recovery maneuver tore the engine and pod mount from the wing. Aircraft flew to London. Engine recovered in pasture near Pioneis on the Brest Peninsula.

With only 2000 feet of altitude loss, this could not have been a fully developed spin.
Sounds more like a post-stall departure.
Demonstrating Vmca at 8000 feet sounds a bit foolish, but those were the bad old days.