High altitude stall recovery B737

[Judd]

what if the craft is already in high altitude stall? in diving out of that stall how significant is the risk of overspeed and without ASI how to manage that risk?

I would have thought common sense airmanship would apply. You don't have to do a Stuka type dive to un-stall the wings. See: https://en.wikipedia.org/wiki/Junkers_Ju_87


if there is a problem with all three ASI's and you have stalled it as well, then it is not your day
In that event, keep the nose slightly below the horizon for 30 seconds and keep out of buffet then very gently level out. Not forgetting to set cruise power as part of the un-stalling procedure. Count on losing at least 3000 ft in the recovery procedure. There is probably no QRH procedure for that combination of events so you simply have to `wing it`.

[Vessbot]

Originally Posted by Judd

. You don't have to do a Stuka type dive to un-stall the wings.

Well... sometimes you do, though. AF447 was at about 40 deg. AOA for much of its ride down. So to unstall it they'd have had to put the nose down in that vicinity. Let's say 30deg. That might as well be vertical with respect to how it would feel to a pilot only used to conventional attitudes.

[_Phoenix]

Yes, reducing the AOA is imperative and it is the only way out.
I'm still amazed that AOA indicator is not mandatory, as it should be the no. 1 instrument for the recovery of the flying wing.
The incident of Tarom at Orly is a textbook example of recovery from a hairy stall situation.
Here is the video with the actual CVR:
(click watch video on youtube, will work)

You Tube

[phylosocopter]

Originally Posted by Vessbot

Well... sometimes you do, though. AF447 was at about 40 deg. AOA for much of its ride down. So to unstall it they'd have had to put the nose down in that vicinity. Let's say 30deg. That might as well be vertical with respect to how it would feel to a pilot only used to conventional attitudes.

yes AF447 was on my mind when i asked the question, that was a deep stall and I believe a "stuka" dive was the only option that could have saved them from that situation, as to how it would feel? well on a black night and considering falling like a stone and no ASI .... how would it feel? probably like standing still. hence my question how would you know when to pull up, perhaps "count to thirty" is the right answer after all

[Centaurus]

The incident of Tarom at Orly is a textbook example of recovery from a hairy stall situation.

The official incident report shows no evidence of "a textbook example of recovery from a hairy situation." See: https://reports.aviation-safety.net/...310_YR-LCA.pdf


On the contrary, it seems clear from the subsequent investigation that, not only was the captain utterly confused about the gyrations of the aircraft caused by his own incompetence and subsequent over-controlling, but it was only sheer good fortune the aircraft did not crash. It did not help that the co-pilot was also on the controls some of the time without telling the captain. Neither had a clue what was going on following the initial strong pitch up. That was obvious from the CVR

The aircraft virtually fell into an uncontrolled steep dive of its own volition after stalling at an extreme nose high attitude. As it picked up airspeed by virtue of the steepness of its dive, the captain was able to recover by simply pulling back on the stick. There was no evidence in the report that the captain attempted to deliberately roll the aircraft to the nearest horizon in order to get the nose to drop and thus pick up airspeed for recovery.

Good luck - not skill - saved that aircraft from crashing. .

[vilas]

In that event, keep the nose slightly below the horizon for 30 seconds and keep out of buffet then very gently level out. Not forgetting to set cruise power as part of the un-stalling procedure.

If you are cruising at 350 this won't help. It will need at least 4 to 5 degrees below the horizon and once the stall warning stops all the power(which is not much) you have and may be forward trim if you are in it for a while as 447 was. Since there is no speed it will be a journey from low speed buffet to shall I say high speed buffet or rumbling before you recover flight path. Very unnerving to say the least.

[RAT 5]

Centaurus: thanks for that. I had not seen the report, snd it was easy to assume the Tarom pilots were ex-military and let the a/c go with the roll and not fight etc, and thus be a hero.

Regarding stall recovery in steep dives; gentle dives and GPS ground speed can help. Stuka dives might not give an accelerating GPS GSpd. Ha.

[Centaurus]

It will need at least 4 to 5 degrees below the horizon

Vilas. Maybe it all depends on the simulator type? Having done over 50 of these manoeuvers in a Level D FFS 737 simulator, using zero body angle or maybe two degrees below the horizon at the most is sufficient to pick up to a safe recovery speed of around 235 knots depending on weight.

[vilas]

Yes! May be on aircraft type. But I think more on how long been in it. I don't think 447 would have recovered on the horizon.

[recceguy]

Originally Posted by RAT 5

it was easy to assume the Tarom pilots were ex-military and let the a/c go with the roll and not fight etc, and thus be a hero.

What the hell does it mean ? I read and read again - I can only assume you are not ex-"military" (and what does it mean, "military" - fighter pilot ? transport, helicopter pilot ? Air Force, Navy, Army ? UK, Ireland, Luxemburg, North Korea ? somebody who didn't have to pay for his training, and had to go through a selection ? somebody who has University degrees you will never get close ? somebody who had to command hundred of people at war ? )

I'm one of those, and I have done dozens, even hundreds of what you call "stalls" and loss of control in aircraft raging from SEP trainers to fighters and transport aircraft - I have done barrel rolls at night in fighters, and barrel rolls with three types of transport multi-crew aircraft (only in day VFR this time, I must confess) I had my knees shaking in a couple of occasions but I'm still here, and I'm not bragging because you don't know who I am ! so I suppose I'm a hero in your minimal world ?

For those who have been through dozens of stall recoveries in a simulator not designed to replicate that, and did remain alive, I can only suggest a medal.

[_Phoenix]

Centaurus, thank you for the link, first time I see this report. In the past, I discussed about this incident with a romanian friend. He sent me the video link, with the romanian transcript, the pilot said "...oh, l-am scos!", "Oh, I took it out! (from stall), at the moment the aircraft finally pitched down. That made me believe the pilot did something good in there.

[RAT 5]

Touchy. Let's take out the hero bit, then. It seems they were not as much hands on as it was easy to assume. Sorry to have touched a nerve.

My innocent thinking, after watching the recovery profile, was that it was something not taught in a civilian UPT program. I suspect some pilots might have tried to resist the natural momentum of the a/c's pitch & roll. I too have enjoyed aerobatics in a multitude of a/c, and done what was possible in a B738 sim. Nothing like yours in the real thing.

[fdr]

TAROM was a replay of Condor with fewer wash rinse spin cycles. It was very close to CAL #1 Nagoya, and CAL #2 at CKS.

Fighting the AP becomes fun on an A300/310, and the passengers get a free disney ride. Overriding an autopilot would be nice if it led to AP disconnect, however we have seen that also end in tears in the everglades, and various other wild rides where the disconnect gets out of sorts.

Once the aircraft is out of trim with the THS and has an adverse thrust couple, the elevator authority is going to get compromised, and a wild ride often ensures. Pilot training is supposed to make up for deficient design, however that is all well and good until you get cognitive overload from a dynamic event, which the data of TAROm shows was a wild ride. Doing low level aeros is best as an observer sport, or after lots of practice in the box.

Pilots are human, any pilot encountering a compromised pitch condition at low altitude (or anywhere arguably) is going to have a pants load of adrenalin running along. Training mitigates bad design, it doesn't guarantee a positive outcome always.

TAROM like Condor, was lucky. Electrojets can get out of sort too, as USAirs A320 in Reagan, ANZ's A320 @ Perpignan did. The first one got away with it, the second one ended badly in headlines.