AF447 wreckage found
Trash du Blanc
Joined: Mar 2001
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From: KBHM
I haven't studied all the released evidence, so someone correct me if I'm wrong, but it appears that:
1. Level at FL 350, the PF got in an unusual attitude as a result of pitot failures,
2. He climbed to FL 375 - 380 before stabilizing,
3. Once at FL 375, he was flying but above service ceiling,
4. The aircraft therefore slowed to a stall even with TOGA power,
5. A stall was entered,
6. The PF held nose-up controls for quite some time,
7. At some point, the Captain took the left seat and took the controls, at which point the PF relinquished control to him.
Is that the consensus?
1. Level at FL 350, the PF got in an unusual attitude as a result of pitot failures,
2. He climbed to FL 375 - 380 before stabilizing,
3. Once at FL 375, he was flying but above service ceiling,
4. The aircraft therefore slowed to a stall even with TOGA power,
5. A stall was entered,
6. The PF held nose-up controls for quite some time,
7. At some point, the Captain took the left seat and took the controls, at which point the PF relinquished control to him.
Is that the consensus?
Joined: Dec 2008
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From: Netherlands
Hi Phil,
I have had several briefings this year on stall events. In most cases the workload was very high and the pilots had difficulties in assessing the whole situation. When the speed becomes unreliable in a modern jet aircraft you can get overwhelmed by all the different warnings. Without more detailed info on the AF event I would not suggest yet that this could be a factor. However, I would not be surprised.
I have had several briefings this year on stall events. In most cases the workload was very high and the pilots had difficulties in assessing the whole situation. When the speed becomes unreliable in a modern jet aircraft you can get overwhelmed by all the different warnings. Without more detailed info on the AF event I would not suggest yet that this could be a factor. However, I would not be surprised.
Joined: May 2008
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From: UK
'nuff said.
When the speed becomes unreliable in a modern jet aircraft you can get overwhelmed by all the different warnings.
I'm rather disturbed that far from applying the pitch/power memory items, he chose to pitch up instead whilst encountering STALL warnings no less!!!
I'm not making judgement on the pilot(s) here, just trying to figure just WTF was going through their minds to do that.
My username is rather ironic right now.
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Joined: Mar 2009
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From: Phoenix, AZ USA
Again in an unusual attitude/impending stall condition is not the initial step to unload the airframe? From that position further recovery (nose down/power settings etc) steps occur....at it's simplest airmanship is an understanding of cause and effect. It literally begins to become ingrained the moment you take the controls....by 10 to 20 hrs you have a fundamental understanding. Most solo endorsements come at the 10-15 hour range of initial training.
If fundamental airmanship wasn't relatively easy to absorb we'd have a lot more 152's planted in folks backyards....
If fundamental airmanship wasn't relatively easy to absorb we'd have a lot more 152's planted in folks backyards....
Joined: Aug 2004
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From: Earth
All this will probably come down to crew composition, very high workload, in adverse weather conditions, having to manually hand fly an aircraft which found it self in alternate law due to spurious information being fed to not only the flight display computers but also the flight control protection and guidance computers, simultaneously.
When something of this magnitude happens you are not only dealing with conflicting airspeed info, you are also presented with multiple spurious ecam warnings and cautions which is sometimes hard to ignore, also depending on the alternate law protection loss which itself can be further divided in two categories, or even direct law which would mean direct side stick to flight control input without any load protection leading to control overload.
Also when it comes to high speed protection, should this crew received wrong airspeed info indicating high speed situation, you have protection where once Mmo + few kts has been exceeded you will get an auto pitch up to try and maintain Mmo + few knots, so should this happen at slow actual airspeed, it will not be too hard to see why the pilot continued to pull back and continue increasing the pitch angle.
Direct law is there to give the pilot more direct control of the aircraft but it still has some protection to offer at the same time the protection on offer is only as good and accurate as the information provided to the computers involved.
Much more info is needed before one can create a picture on what went wrong when it comes to the decisions the pilots made in the last few minutes of the flight.
RIP all lost.
When something of this magnitude happens you are not only dealing with conflicting airspeed info, you are also presented with multiple spurious ecam warnings and cautions which is sometimes hard to ignore, also depending on the alternate law protection loss which itself can be further divided in two categories, or even direct law which would mean direct side stick to flight control input without any load protection leading to control overload.
Also when it comes to high speed protection, should this crew received wrong airspeed info indicating high speed situation, you have protection where once Mmo + few kts has been exceeded you will get an auto pitch up to try and maintain Mmo + few knots, so should this happen at slow actual airspeed, it will not be too hard to see why the pilot continued to pull back and continue increasing the pitch angle.
Direct law is there to give the pilot more direct control of the aircraft but it still has some protection to offer at the same time the protection on offer is only as good and accurate as the information provided to the computers involved.
Much more info is needed before one can create a picture on what went wrong when it comes to the decisions the pilots made in the last few minutes of the flight.
RIP all lost.
Joined: Mar 2002
Aviation Qualifications: ATPL
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From: Seat 1A
I don't see anything that indicates the captain took back its seat.
Edit: Oz ABC News saying "The captain did not retake the controls, with the co-pilots flying the plane until the end, the investigators said during a conference call."
Joined: Sep 2004
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From: SLF, living somewhere East in the West
In alternate law - is the amount of warning signals reduced to the bare minimum necessary to keep the tube flying? I.e. you don't need a warning that the lights in the toilets aft aren't working while stalling...?
Joined: Dec 1997
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From: Penarth South Wales
Food for thought:-
The blocked pitot system resulted in the autothrust applying thrust to stop the " apparent" speed decay. Similarly, the autopilot applied nose up trim for the reducing speed. When it reached the limit, the autopilot gave up, and the handling pilot now had an aircraft with full nose up trim and full power. by the time he reached the apex of the " bunt" (around 38000ft), the aircraft was in a deep stall with a forward speed of around 60kts and a high angle of attack...resulting in the 10,000ft + Rate of descent. In Direct law, which they may now have been in, holding the stick back will maintain the stall.
I really hope the DGAC /Air France/ Pitot Heat manufacturers don't use the get out clause of " Pilot Error" to wriggle out of their contribution to this crash.
Edited to acknowledge Robssupra's post above, which appeared whil I was writing.
The blocked pitot system resulted in the autothrust applying thrust to stop the " apparent" speed decay. Similarly, the autopilot applied nose up trim for the reducing speed. When it reached the limit, the autopilot gave up, and the handling pilot now had an aircraft with full nose up trim and full power. by the time he reached the apex of the " bunt" (around 38000ft), the aircraft was in a deep stall with a forward speed of around 60kts and a high angle of attack...resulting in the 10,000ft + Rate of descent. In Direct law, which they may now have been in, holding the stick back will maintain the stall.
I really hope the DGAC /Air France/ Pitot Heat manufacturers don't use the get out clause of " Pilot Error" to wriggle out of their contribution to this crash.
Edited to acknowledge Robssupra's post above, which appeared whil I was writing.
Joined: Aug 2005
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From: fl
Huck, step 2 is a bit questionable as well as 7. The nose up pitch by the sidestick probably caused the plane to stall between FL375 and 380, not stabilizing. Wasn't the stall warning activating at that time?
Last edited by bubbers44; 27th May 2011 at 15:06. Reason: altitude error
Joined: Aug 2004
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From: Earth
Hamrah,
With the little info we have to work with you are on the money with your statement.
Lets wait until we have more to work with and hopefully we will all learn something from this and hopefully no more lives lost, whatever the lesson here might be.
And Hambleoldboy, no one has mentioned the FPV flight path vector yet until you did, all one has to do, and it is recommended that you do, when hand flying an aircraft. Select TRK-FPA and you will get the bird, which will represent the actual flight path of the aircraft. But than again will you get an accurate information from the FPV when you have your pressure sensors iced over?
With the little info we have to work with you are on the money with your statement.
Lets wait until we have more to work with and hopefully we will all learn something from this and hopefully no more lives lost, whatever the lesson here might be.
And Hambleoldboy, no one has mentioned the FPV flight path vector yet until you did, all one has to do, and it is recommended that you do, when hand flying an aircraft. Select TRK-FPA and you will get the bird, which will represent the actual flight path of the aircraft. But than again will you get an accurate information from the FPV when you have your pressure sensors iced over?
Last edited by Robssupra; 27th May 2011 at 15:27.
Joined: Jan 2006
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From: eu
So in my opinion the solution to the situation these two pilots found themselves in was:
- Nail the attitude at 2 degrees nose up
- Fix the throttles at the known cruise EPR
- Switch to FPV and keep the symbol on the horizon...
Simples Messieurs!
- Nail the attitude at 2 degrees nose up
- Fix the throttles at the known cruise EPR
- Switch to FPV and keep the symbol on the horizon...
Simples Messieurs!
Joined: Nov 2010
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From: FR
@ hambleoldboy : Good point. Would not a dedicated AoA meter be more "readable", though ?
About the FPV : I think they went inop during the last minutes... Memories from ACARS messages...
[edit] having check : FPV disappeared (triggering ACARS message @ 2:11). Most likely because of an IAS below 60kt. But FPV would have re-appeared as soon as the IAS came above 60kt.
About the FPV : I think they went inop during the last minutes... Memories from ACARS messages...
[edit] having check : FPV disappeared (triggering ACARS message @ 2:11). Most likely because of an IAS below 60kt. But FPV would have re-appeared as soon as the IAS came above 60kt.
Joined: Jan 2006
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From: eu
I would think that the FPV symbols are generated by the IRU's therefore unaffected by unreliable air data inputs...?
In an upset they must surely be an essential indication as they show exactly where the aircraft is going.
In an upset they must surely be an essential indication as they show exactly where the aircraft is going.
Trash du Blanc
Joined: Mar 2001
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From: KBHM
I think they spent a bit of time at FL 375 - 380, thus must have recovered for awhile. The wording is difficult:
The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees.
From 2 h 10 min 50, the PNF tried several times to call the Captain back.
At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.
Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.
From 2 h 10 min 50, the PNF tried several times to call the Captain back.
At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.
Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.
Joined: May 2008
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From: UK
hambleoldboy couldn't agree more!
I don't see why the AP pitched UP due to reducing airspeed. Worse still, it seems clear to me that the pilots had several STALL warnings after AP disengagement and prior to it actually dropping like a brick. What is even more perplexing is given that the pilot arrested the 7000 ft rate of climb, why he then proceeded to apply aft stick input and raise the nose?
Were the altimeters functional? It would appear they were; if so, why didn't this tell them they were actually stalling? As for the THS taking over a minute to get to +13 degrees, suggests the pilot held aft stick input throughout. I'm struggling to comprehend just why he would do that.
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I don't see why the AP pitched UP due to reducing airspeed. Worse still, it seems clear to me that the pilots had several STALL warnings after AP disengagement and prior to it actually dropping like a brick. What is even more perplexing is given that the pilot arrested the 7000 ft rate of climb, why he then proceeded to apply aft stick input and raise the nose?
Were the altimeters functional? It would appear they were; if so, why didn't this tell them they were actually stalling? As for the THS taking over a minute to get to +13 degrees, suggests the pilot held aft stick input throughout. I'm struggling to comprehend just why he would do that.
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