High altitude stall recovery B737

[binzer]

Piratepete. Read the thread title if you want to talk about low alt stalls start a new thread. You are calling people's comment stupid. I think you are making yourself look that way.

[piratepete]

Binzer.Agreed.But in 28 years of simulator training I have seen various TRIs and trainees only apply one type of recovery.Unlike Trump, I CAN read.However it is very important to consider the WHOLE issue not just one aspect.Perhaps im stupid but im still a TRE and treat this issue with great care.Too much emphasis on one method only has a lot of risk attached.Sometimes powering out is the better method, of course at altitude primarily unstalling the wing is correct technique.Have an open mind Sir.

[Check Airman]

Originally Posted by piratepete

Sometimes powering out is the better method, of course at altitude primarily unstalling the wing is correct technique.

1. AF447 was unable to power out of the situation. CJC3407 was also unable to power out of the situation.

2. We'll agree that at altitude, unstalling the wing is primary. What's the primary concern in a stall at low altitude?

[vilas]

piratepete

But in 28 years of simulator training I have seen various TRIs and trainees only apply one type of recovery. Unlike Trump, I CAN read. However it is very important to consider the WHOLE issue not just one aspect. Perhaps im stupid but im still a TRE and treat this issue with great care. Too much emphasis on one method only has a lot of risk attached. Sometimes powering out is the better method, of course at altitude primarily unstalling the wing is correct technique. Have an open mind Sir.

I hope you read my post 44 and 59. Out of the 28 years at least twenty years powering out of stall was taught. Only now the procedure is changed. The new procedure asks you to unstall irrespective of altitude. Your concern of ground contact at lower altitude is correct but for recovery from stall it is not the altitude but whether the aircraft has stalled or is on the verge of stall with stall warning is important. If the aircraft has stalled you cannot power out of it. Stall warning is not stall. To give you airbus figures stall warning is set at alpha max+4 degrees and stall occurs even later. It will depend on rate of change of AOA also. So if you are on the verge you may succeed in powering out of it because you haven't lost control yet but if you are in full stall it will not work. It cannot be taught as an alternate method. Yes! after unstalling you may have to begin recovery of flight path sooner.

[galaxy flyer]

Pirate Pete,

Are we talking about a stall or an “approach to stall” where buffet begins, IAS numbers go red, etc? Big difference.

[Goldenrivett]

GF,

Not any more - there is just one procedure now for both.

"The traditional APPROACH TO STALL training is characterized by
a controlled deceleration to stall warning, followed by a power
recovery with minimum altitude loss
• The difference between an APPROACHING STALL and an
ACTUAL STALL is not easy to determine, even for specialists
• In numerous accidents, the APPROACH TO STALL procedure
was applied whereas the aircraft was actually stalled."

http://www.ukfsc.co.uk/files/Safety%...une%202010.pdf

"Approach To Stall Recovery
A single procedure has to be defined
focusing on AoA reduction
• Classical Approach to stall procedure focuses:
On thrust application
Minimum loss of altitude
• It is NOT appropriate for EVERY stall condition:
Possible inability to reduce AoA with the TOGA thrust
application
Recovery may require thrust reduction
Recovery from a stall may require altitude loss."

[Vessbot]

Originally Posted by piratepete

Gents.You cannot solely consider the issue of stall recovery from the position of "high altitude".In a comprehensive pilot training module for this very serious issue it is quite important that pilots of modern jet airplanes are trained in both "terrain is a factor" also when it is not.The recovery methods necessarily differ.This can be life or death.

What's different? Why is it any less important to unstall the wing at low altitude, than it is at high altitude? Again, if terrain is a factor then unstalling the wing ASAP is the only action that will give me a flyable wing and any chance of pulling out and away from that terrain.

Many TRIs emphasize that minimum altitude loss is the key to a "correct" recovery.

And incorrectly so, with the trail of carnage to show for it. At both low and high altitude.

Sometimes powering out is the better method, of course at altitude primarily unstalling the wing is correct technique.Have an open mind Sir.

There is actually no such thing as "power out" of a stall. It goes much further than being bad technique, it doesn't exist. It's a fundamental misconception.

[Avenger]

High Altitude stalling is always a consequence of poor energy management, that is to say flying in the "T" thrust limited zone or "B" Buffet limited zone with a lack of situational awareness for the conditions, perhaps without the benefit of real time bank angle protection( No LNAV) or flying to close to "maximum" and then hitting turbulence or increasing warmer air and basically not descending, or limiting the bank. Mr Boeing,bless him says:

STALL RECOVERY.
In all upset situations, it is necessary to recover from a stall before applying any other recovery actions. To recover from the stall, angle of attack must be reduced below the stalling angle. Nose-down pitch control must be applied and maintained until the wings are unstalled. Under certain conditions, on airplanes with underwing-mounted engines, it may be necessary to reduce some thrust in order to prevent the angle of attack from continuing to increase. Once unstalled, upset recovery actions may be taken and thrust reapplied as needed.

Ref: Aerodynamic Principles of Large-Airplane Upsets

[RAT 5]

In this thread there has been a confusion in the discussion by some people advocating the recovery from approach to stall and others answering with recovery from full stall techniques; and vice versus. Some back & forth has not been apples & apples, hence some agitation. If the topics were separated then perhaps clarity would prevail.

IMHO the only opportunity power might be used to aid recovery is if the wing is not aerodynamically stalled. I can't see how brawn can overcome brains.

Many TRIs emphasize that minimum altitude loss is the key to a "correct" recovery.

I doubt SFI/TRI/TRE's made the rules. Was it not that they were instructed by XAA's to do so? If so, where did the error lie?

The bit about 'ground contact being a threat' always tickled me. Having been a crop sprayer being close to the ground meant 'at most times on the job', without hitting it. i..e 3-5m depending on the application. Doing pipeline surveillance it could mean 200-500' as allowed.
Recovery from approach to stall at 500' on finals full flaps IMHO does not mean maintaining 500'; it means recovery from your predicament without hitting the ground, and not making it doubly difficult by entering a secondary stall, which often meant you stood a better chance of doing so. It was a delicate manoeuvre where low kinetic energy needed to be increased and if there was some potential, energy to help you do so, why not use it with finesse? Do you fail the tick in the box if you recover and fly away safely at 200' from 500', or must you achieve the same sweating success above 400'? In real life they both pass.
At 200' the dices are loaded and more delicacy & finesse are required. In the days of real training in the sim it was nice to do both, and the crews loved it. Sadly time has been stolen from real training.

When Boeing FCTM said "recovery from stick shaker (low level) was apply thrust and reduce attitude" I interpreted that not as apply thrust 1st then reduce attitude; I considered it as both at the same time, and if the student pressured the elevator before thrusting the levers by a split second there was no admonishment. But if they did it the other way round, and secondary stalled, there was.

It's taken a longtime but I think common sense has woken up a little; not enough. Why should there be only one size fits all? We have other recall procedures that need quick decision making; we are supposed to be intelligent trained professionals. Or is this one size fits all a reflection on what the opinion is of the standard of professionals. Only time to think of one thing, when as a pilot we should be able to choose the best applicable. IMHO.

With that question I lump the new Unreliable Airspeed procedure introduced a few years ago. It took 2 minutes and 8 check items to tell me what I already knew to do; by which time the a/c had transitioned from its last steady state and needed to be returned to it. That has been discussed previously, and I don't which to open that debate. I think the debate is much deeper about the true depth of professional pilot training and what is expected of us.

I've run out of tin hats.

[Vessbot]

"Aerodynamic Principles of Large-Airplane Upsets"

[piratepete]

If you are in the "approach to stall" and near the ground then powering out can be ONE option.If you are near the ground and FULLY STALLED you are basically finished.However at altitudes a long way from the ground then YES there is only one correct method.Unstall the wing, thats about it except watch out for other aircraft especially in RVSM.

[piratepete]

Vesspot.
I dont know your background but for years and years TRIs have been teaching incorrectly that your performance in an approach to stall exercise was to POWER OUT with minimum loss of altitude.Of course this is wrong and could be fatal.I hope this has stopped but STILL hear of it being taught this way.

[Check Airman]

Piratepete, the point we're trying to make is that regardless of altitude, there is only one way to recover from a stall, and it has nothing to do with power.

As someone pointed out earlier, even the flight test engineers sometimes find it difficult to say when the actual stall takes place- and they're deliberately doing it. Throw in the startle factor of the crew that stalls inadvertently, and the less than accurate sim representations, would you risk treating it as an approach to a stall?

We accept that if you're close to a stall, then you can probably power your way out of it. That's pretty much a rejected landing, or low level GA.

The reason we're here trying to show you the difference is because there have been many crews who were improperly trained to maintain altitude, and that training simply gets them into more trouble when poop really hits the fan.

[italia458]

In real life they both pass.
At 200' the dices are loaded and more delicacy & finesse are required.

I agree with your general point. And so I would argue that you’d require more finesse to recovery at 400’!

By recovering at 400’ you’re riding a fine line between unstalling enough to be effective while not entering a secondary stall but also recovering from the altitude loss sooner. In this case, you’re closer to stalling AoA which is why I’d argue it requires more finesse.

[RAT 5]

There are also times when pilots have to that rare of tasks calling piloting.

You Tube

But I do wish ATC would have shut up.

[vilas]

Let's take real life situation. Even at low altitude what does one do when the stick shaker sounds? Off course without thinking push the nose down. Everything else comes after that.

[misd-agin]

At altitude you’re not ‘powering out’ of a slow speed event. Decades ago the Captain slowed to FMC holding speed number at FL390 despite my comment “I don’t think we’re supposed to be this slow.” His reply “it’s ok, I’ve done it before.” No buffet. ATC said “normal speed” and power went to continuous where it basically had already been. Stuck. Zero acceleration. We had to descend. Captain “I don’t know why it didn’t work. It worked last time.” I asked “how heavy were you and what altitude?” “I don’t remember.”

25W brain in a 100W world.

[misd-agin]

Originally Posted by vilas

Let's take real life situation. Even at low altitude what does one do when the stick shaker sounds? Off course without thinking push the nose down. Everything else comes after that.

The nose doesn’t have to go down as much as at least have a slight reduction in back pressure. Minor unloading has a big effect on AOA. Even at .95 G, which is barely noticeable, the plane will fly at less than it’s expected stall speed.

On the 727 it wasn’t a shock to get stick shaker if you were flying at the minimum flap speeds, especially while turning even using the increased minimum flap speed required while turning. Slight roll out, or slight back pressure reduction, and the stick shaker stopped. Completely unnoticeable by passengers.

At low altitude, in normal flight attitudes, minor AOA excursions require minor adjustments. At altitude, with more significant AOA/speed excursions, the airplane will need large corrections in AOA with resulting larger pitch changes.

[RAT 5]

One time I saw power overcome aerodynamics. It was a Sukhoi 29S do a torque roll. Until then I think, in our type of a/c, I play by the law of physics and aerodynamics. KISS>

You Tube

[Stuart Sutcliffe]

Originally Posted by RAT 5

One time I saw power overcome aerodynamics. It was a Sukhoi 29S do a torque roll.

Just to be clear, the video link shows a radio-controlled model, not a full size aircraft.