AF447 wreckage found
Two's In
Agree with you entirely when you mention cognitive dissonance - it's involved somewhere.
From what I've heard
until you've been involved in an aircraft coming "unglued" you have no idea how quickly your comfy world can turn to a crock of S**** and subsequently just how difficult it can be to metaphorically "step back" and analyse the situation objectively.......
We may well eventually discover what information the AF crew had available to them - we'll sadly never know what they perceived.
From what I've heard
until you've been involved in an aircraft coming "unglued" you have no idea how quickly your comfy world can turn to a crock of S**** and subsequently just how difficult it can be to metaphorically "step back" and analyse the situation objectively.......We may well eventually discover what information the AF crew had available to them - we'll sadly never know what they perceived.
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@ misd-agin
You are fired
As 80% of the pilot considering what is said in the report above :
" The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.
The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable."
Don't think. Nose down.
As 80% of the pilot considering what is said in the report above :
" The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.
The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable."
Don't think. Nose down.
Some points:
> Let's not use the term "deep stall" in reference to this accident. A "deep stall" is a specific kind of stall where the attitude of the aircraft is such that the wings block airflow to the horizontal stabilizer, making elevator inputs useless for recovery. Almost always involves a "T"-tail design, which does NOT include any Airbus aircraft. (oopps - edited to include NOT)
This was a pronounced, possibly extreme, and prolonged stall (it appears), but NOT at any time a "deep stall."
> I find huge fault with an audible stall warning system that cuts out as the AoA gets worse, and then cuts back in again during recovery. Yes, a good pilot should be able to recognize a stall by other means than the audible alert - but an alert that a) stops while the situation is still getting worse and b) begins screaming again when the pilot does the RIGHT thing (lowers AoA for recovery) is just ludicrous.
> Let's not use the term "deep stall" in reference to this accident. A "deep stall" is a specific kind of stall where the attitude of the aircraft is such that the wings block airflow to the horizontal stabilizer, making elevator inputs useless for recovery. Almost always involves a "T"-tail design, which does NOT include any Airbus aircraft. (oopps - edited to include NOT)
This was a pronounced, possibly extreme, and prolonged stall (it appears), but NOT at any time a "deep stall."
> I find huge fault with an audible stall warning system that cuts out as the AoA gets worse, and then cuts back in again during recovery. Yes, a good pilot should be able to recognize a stall by other means than the audible alert - but an alert that a) stops while the situation is still getting worse and b) begins screaming again when the pilot does the RIGHT thing (lowers AoA for recovery) is just ludicrous.
Last edited by pattern_is_full; 28th May 2011 at 21:01.
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Correct method, as always been taught, use rudder to recover a wing drop.
Does anyone else disagree with the above post?
I recall the UK CAA sending out a memo around about the use of rudder in stalls...
Right back to the basics ...
Rudder should be used to maintain balance only...
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Perhaps they reacted to winshear, rather than stall.
Full back stick and TOGA, then hold both until the aircraft flies out of the problem.
Not enough thrust at high level, protections not there so the computer cannot stop the pilot holding the aircraft in a stall.
Mind set on the wrong cause of sudden loss of airspeed.
The dreadful fact seems to be that they had a flyable aircraft that they failed to fly.
Full back stick and TOGA, then hold both until the aircraft flies out of the problem.
Not enough thrust at high level, protections not there so the computer cannot stop the pilot holding the aircraft in a stall.
Mind set on the wrong cause of sudden loss of airspeed.
The dreadful fact seems to be that they had a flyable aircraft that they failed to fly.
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With respect to the "we have no valid indications" comment, is it possible that the crew were just so convinced that they were in a nose-down dive (idle throttle, pulling back on stick) that they simply concluded that any instrument which contradicted this belief (such as attitude indicator pointing up) must be wrong?
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Nose-dive?
The way I read the report it continously stated that the plane was in a nose up attitude. And the airspeed very slow. And it seems to me that they had no control over the stabilizer/elevator.
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Birgen Air flt 301
Just for the record the Captain discovered his airspeed was out in the beginning of the TO roll before V1 but elected to go anyway. It's on the CVR.
The taped static port occurred on the Peruvian 757. Unsure if they were aware of it during take-off.
The taped static port occurred on the Peruvian 757. Unsure if they were aware of it during take-off.
"Mildly" Eccentric Stardriver
I can't help feeling there is a bit of the Eastern 401 problem here. If they were dealing with all sorts of other warnings, was anyone looking at attitude, altimeter, R.O.D.? An additional factor; could the PF be inadvertently holding full nose-up control? Unlikely on a conventional aircraft, but could he have been so busy with the other problems that he didn't realise he was doing it? The call at ten thousand is unusual; surely someone would have reacted to that, unless it was a Pavlovian call in the confusion. I don't think we will be able to know much else until the full CVR is made available.
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757
The maddening part of Birgenair is the Capt merely had to reach forward to his outboard instrument panel and rotate his Air DATA switch from NORM to ALT.
AeroPeru 603 was a through flight from KMIA to Chile. The arriving 727 was grounded for maintenance upon arrival Lima, so they hurriedly pressed the 757 into service. I don't know if it was a dedicated 757 crew, or a crew who normally flew both and was expecting to continue with the 727.
This accident is pretty well covered on wiki. I don't know how many line pilots would have been successful in the same circumstances, but the problem was surely more challenging than AF447.
AeroPeru 603 was a through flight from KMIA to Chile. The arriving 727 was grounded for maintenance upon arrival Lima, so they hurriedly pressed the 757 into service. I don't know if it was a dedicated 757 crew, or a crew who normally flew both and was expecting to continue with the 727.
This accident is pretty well covered on wiki. I don't know how many line pilots would have been successful in the same circumstances, but the problem was surely more challenging than AF447.
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New stall recovery procedure
This is interesting, sorry if posted already:
Revised stall procedures centre on angle-of-attack not power
Very relevant indeed.
Revised stall procedures centre on angle-of-attack not power
Very relevant indeed.
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Deep Stall
Let's not use the term "deep stall" in reference to this accident. A "deep stall" is a specific kind of stall where the attitude of the aircraft is such that the wings block airflow to the horizontal stabilizer, making elevator inputs useless for recovery. Almost always involves a "T"-tail design, which does include any Airbus aircraft.
Last edited by thcrozier; 28th May 2011 at 20:57. Reason: code
I noticed a mistake in my original that you quote - a critical missing "NOT"!
The real key to this accident will be to figure out why the PF thought holding full back stick all the way down was the correct response. I don't jump to a conclusion that it was simply "error." I'd like to see as good a re-creation as possible, from the data, of what the cockpit environment was actually telling the crew (alarms, instruments, ECAM messages, seat-of-the-pants, etc.).
Two of the clues that normally identify a stall would have been missing (airspeed) or perhaps disguised (buffet in the middle of convective turbulence - the pilots clearly were expecting buffets from turbulence, having changed course and warned the cabin). Pitch on the AH is not a trustworthy indicator of AoA (one can be 20° nose-down and still stalled with a 35° AoA).
I can't conceive of holding full back stick for 4 minutes in any aircraft. But I also can't conceive of any other trained pilot doing it unless some outside influence was suggesting such a bad idea was really a "good" idea. So "why"?
The real key to this accident will be to figure out why the PF thought holding full back stick all the way down was the correct response. I don't jump to a conclusion that it was simply "error." I'd like to see as good a re-creation as possible, from the data, of what the cockpit environment was actually telling the crew (alarms, instruments, ECAM messages, seat-of-the-pants, etc.).
Two of the clues that normally identify a stall would have been missing (airspeed) or perhaps disguised (buffet in the middle of convective turbulence - the pilots clearly were expecting buffets from turbulence, having changed course and warned the cabin). Pitch on the AH is not a trustworthy indicator of AoA (one can be 20° nose-down and still stalled with a 35° AoA).
I can't conceive of holding full back stick for 4 minutes in any aircraft. But I also can't conceive of any other trained pilot doing it unless some outside influence was suggesting such a bad idea was really a "good" idea. So "why"?
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In a test : Any pilot that doesn't nose down earing a stall warning should be fired
@ Flight Safety
Thank you for your 20:24
Your link :
"A formal document detailing the rationale for the revision points out: "There have been numerous situations where flight crews did not prioritise [nose-down pitch control] and instead prioritised power and maintaining altitude."
Operational experience has shown that fixating on altitude, rather than the crucial angle of attack, can result in an aircraft stalling."
Try the test : a pilot that doesn't nose down immediately when earing a stall warning has not understood what is a stall : the plane is no longer a plane, it is a cucumber.
If you don't nose down, you are dead within a minute or two.
The trouble is that :
" The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.
The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable."
REPORT on the incident on 24 September 1994 during approach to Orly (94) to the Airb
Thank you for your 20:24
Your link :
"A formal document detailing the rationale for the revision points out: "There have been numerous situations where flight crews did not prioritise [nose-down pitch control] and instead prioritised power and maintaining altitude."
Operational experience has shown that fixating on altitude, rather than the crucial angle of attack, can result in an aircraft stalling."
Try the test : a pilot that doesn't nose down immediately when earing a stall warning has not understood what is a stall : the plane is no longer a plane, it is a cucumber.
If you don't nose down, you are dead within a minute or two.
The trouble is that :
" The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.
The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable."
REPORT on the incident on 24 September 1994 during approach to Orly (94) to the Airb
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The same has unfortunately happened with "FBW".
"Fly-By-Wire", as such, simply denotes using "electrical signalling" (the old-fashioned British term), i.e., using an electrical connection between the pilot's controls and the hydraulic servo-control units that move the flying control surfaces, instead of cables and rods.
Since.... it has become a synonym for hooking up all kind of digital electronic systems between the pilot's controls and the flying control surfaces, leading to the "now why is it doing that !!??" syndrome, and the mistrust, expressed here time and time again, of digital systems and software in general.
The real issue with "FBW" here seems to be with the digital part of the system... in which case reference to the "DAFS" (Digital Air Flight System) would be more appropriate... but I agree, the term "FBW" has now unfortunately become part of the vocabulary.
Concorde used FBW, in the real sense, but all of the rest of the AFCS (AP, A/S, A/THR, A/TRIM, SFC, etc.) was purely analog.
And FBW worked fine all the time... there was a mechanical back-up, which basically was never called on in service.
"Fly-By-Wire", as such, simply denotes using "electrical signalling" (the old-fashioned British term), i.e., using an electrical connection between the pilot's controls and the hydraulic servo-control units that move the flying control surfaces, instead of cables and rods.
Since.... it has become a synonym for hooking up all kind of digital electronic systems between the pilot's controls and the flying control surfaces, leading to the "now why is it doing that !!??" syndrome, and the mistrust, expressed here time and time again, of digital systems and software in general.
The real issue with "FBW" here seems to be with the digital part of the system... in which case reference to the "DAFS" (Digital Air Flight System) would be more appropriate... but I agree, the term "FBW" has now unfortunately become part of the vocabulary.
Concorde used FBW, in the real sense, but all of the rest of the AFCS (AP, A/S, A/THR, A/TRIM, SFC, etc.) was purely analog.
And FBW worked fine all the time... there was a mechanical back-up, which basically was never called on in service.
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Stall Recovery Parachute
I understand if that a stall is not dealt with properly immediately - or incorrectly - it may develop into a unrecoverable stall.
At what stall-angle (angle of atack) will the elevator be virtually useless to lower the nose? 30 og 40degrees?
Will it be possible to recover from 40 AoA stall using alternative methods? (asuming the elevator is not able to get the nose down) Indtroduce rotation /spin /wing-drop using rudder or ailron or single-side engine power.
Also - At high altitude - why would anyone use engine force to recover from a complete stall - concerning the potential disastrous delay it introduces to lowering the nose and AoA.
And would it be a idea to introduce an obligatory "stall recovery parachute" - it would perhaps be the only option to safely get a severely stalled aircraft into back in business.
Are even large passenger planes tested for a severe stall in real life?
At what stall-angle (angle of atack) will the elevator be virtually useless to lower the nose? 30 og 40degrees?
Will it be possible to recover from 40 AoA stall using alternative methods? (asuming the elevator is not able to get the nose down) Indtroduce rotation /spin /wing-drop using rudder or ailron or single-side engine power.
Also - At high altitude - why would anyone use engine force to recover from a complete stall - concerning the potential disastrous delay it introduces to lowering the nose and AoA.
And would it be a idea to introduce an obligatory "stall recovery parachute" - it would perhaps be the only option to safely get a severely stalled aircraft into back in business.
Are even large passenger planes tested for a severe stall in real life?
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High Altitude Operations
It might be useful for some to look at this:
http://www.faa.gov/other_visit/aviat...Operations.ppt
The notes for slide 29 are very interesting.
http://www.faa.gov/other_visit/aviat...Operations.ppt
The notes for slide 29 are very interesting.
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Human factor
@Flight Safety
p29:
An airplane wing can be stalled Any airspeed, any altitude, any attitude
Pilot Tip:
If the angle of attack is greater than the stall angle, the surface will stall. Attitude has no relationship to the aerodynamic stall. Even if the airplane is in a descent with what appears like ample airspeed - the surface can be stalled.
Understand the difference between:
“Approach” to stall recovery
Stall recovery
Dramatic difference in recovery technique
Know the Difference
p43
http://www.faa.gov/other_visit/aviat...Operations.ppt
High altitude - stalls
Could all the pilots on Earth, read that.
p29:
An airplane wing can be stalled Any airspeed, any altitude, any attitude
Pilot Tip:
If the angle of attack is greater than the stall angle, the surface will stall. Attitude has no relationship to the aerodynamic stall. Even if the airplane is in a descent with what appears like ample airspeed - the surface can be stalled.
Understand the difference between:
“Approach” to stall recovery
Stall recovery
Dramatic difference in recovery technique
Know the Difference
p43
http://www.faa.gov/other_visit/aviat...Operations.ppt
High altitude - stalls
- Low speed buffet mistaken for high speed buffet
- Actual full “Stall Recovery”
- Higher altitudes:
- Available thrust is insufficient
- Reduce the angle of attack
- Trade altitude for airspeed.
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Yes, while in alternate law (and with the AA over 40º, abnormal attitude law) auto-trim is disabled.
Airbus Flight Control Laws