AF 447 Thread No. 9
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lyman;
I don't! You've grabbed the wrong quote.
"J’ai aucune indication" has been translated as, "I have no displays" which can also be interpreted as, "I've no information".
He did not. How do you get "Je ne comprends pas" from "J'ai riens vitesses?"
"J’ai aucune indication" has been translated as, "I have no displays" which can also be interpreted as, "I've no information".
Quote:
Originally Posted by Retired F4 (out of BEA Final Report)
No clear mention of the buffet phenomenon is ever made.
Originally Posted by Retired F4 (out of BEA Final Report)
No clear mention of the buffet phenomenon is ever made.
Clandestino
Is pre-stall buffet really so exotic it warrants special mention in the manuals of the aeroplanes possessing it or we perchance require the aeroplanes lacking it to be equipped with artificial means of its simulation?
Is pre-stall buffet really so exotic it warrants special mention in the manuals of the aeroplanes possessing it or we perchance require the aeroplanes lacking it to be equipped with artificial means of its simulation?
Quote:
Originally Posted by Retirred F4 (out of BEA Final Report)
The combination of the ergonomics of the warning design, the conditions in which airline pilots are trained and exposed to stalls during their professional training and the process of recurrent training does not generate the expected behaviour in any acceptable reliable way.
Originally Posted by Retirred F4 (out of BEA Final Report)
The combination of the ergonomics of the warning design, the conditions in which airline pilots are trained and exposed to stalls during their professional training and the process of recurrent training does not generate the expected behaviour in any acceptable reliable way.
Clandestino
You are overgeneralizing, which is understandable as you choose to disregard the cases of A330 /340 UAS where crews either reacted properly to stall warning, or at very least did nothing. So survived.
You are overgeneralizing, which is understandable as you choose to disregard the cases of A330 /340 UAS where crews either reacted properly to stall warning, or at very least did nothing. So survived.
Are you in disagreement here with BEA?
Quote:
Originally Posted by Retired F4
How could he know?
Originally Posted by Retired F4
How could he know?
Clandestino
Why should he know? WIWOA*, drill was to treat every degradation to alternate law as the worst case. What difference would make if it were ALT1? Low speed stability is overridable, especially so with full back stick.
Why should he know? WIWOA*, drill was to treat every degradation to alternate law as the worst case. What difference would make if it were ALT1? Low speed stability is overridable, especially so with full back stick.
Well, BEA is adressing this matter again, and you disagree here again?
BEA Final report
There is however no explicit indication, apart from the red SPD LIM flag next to the speed tape (on the ECAM for example), of the level of alternate law that the aeroplane is in. The ECAM message associated with the reconfiguration to alternate law, of whatever type, indicates “PROT LOST”. However, not all of the protections are lost, since the load factor protection remains available, and reduced protections can also exist. The precise identification of the consequences of a reconfiguration in alternate law is thus complicated.
There is however no explicit indication, apart from the red SPD LIM flag next to the speed tape (on the ECAM for example), of the level of alternate law that the aeroplane is in. The ECAM message associated with the reconfiguration to alternate law, of whatever type, indicates “PROT LOST”. However, not all of the protections are lost, since the load factor protection remains available, and reduced protections can also exist. The precise identification of the consequences of a reconfiguration in alternate law is thus complicated.
Last edited by RetiredF4; 30th Jul 2012 at 05:49.
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"The subtile changes to the PFD, as pointed out in the BEA's report, do not appear to have warranted a comment by either pilot. The PF may have conceded this point when he made the comment, "I have no more displays". But I suspect he really was inferring that he couldn't interpret what was being displayed."
How do you get from "I have no displays", or, "I have no information" that he does not understand what he sees?
Really?
How do you get from "I have no displays", or, "I have no information" that he does not understand what he sees?
Really?
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Hi TD
"The latest in stall recovery: The current fighters (F-22, F-35) "enter and leave" the deep stall region routinely using engine thrust vectoring."
The A330 in 447 was using thrust to keep themselves (or augment) Stalled.
Unfortunately thrust was symmetrical, and limited as to vector, except for value. Utilizing thrust to recover was available. Unfortunately, again, it was not utilized. Pulling back the levers and pushing forward the stick......but that is not the issue. Once STALLED, the argument is wallowing in irrelevancy.....
Maybe gums could put together a syllabus for recovery from Unusual entry, Stall. Or...
From the outset, for me, this accident happened in twenty seconds, and again, for me, BEA is holding back some cards. From the outset, partisans have been comparing 447 to the other UAS. To me, that is preposterous. Each accident has a unique signature, and basing a conclusion on the similarities to improve safety is arse about. What makes us go forward with new knowledge is to assess what is different.
"The latest in stall recovery: The current fighters (F-22, F-35) "enter and leave" the deep stall region routinely using engine thrust vectoring."
The A330 in 447 was using thrust to keep themselves (or augment) Stalled.
Unfortunately thrust was symmetrical, and limited as to vector, except for value. Utilizing thrust to recover was available. Unfortunately, again, it was not utilized. Pulling back the levers and pushing forward the stick......but that is not the issue. Once STALLED, the argument is wallowing in irrelevancy.....
Maybe gums could put together a syllabus for recovery from Unusual entry, Stall. Or...
From the outset, for me, this accident happened in twenty seconds, and again, for me, BEA is holding back some cards. From the outset, partisans have been comparing 447 to the other UAS. To me, that is preposterous. Each accident has a unique signature, and basing a conclusion on the similarities to improve safety is arse about. What makes us go forward with new knowledge is to assess what is different.
Confiture
According to the BEA, the electric stop was at 11 degrees up.
But DozyWannabe, who sat once in a A320 simulator, pretends the A320 airplane has a limitation for the autotrim at 3 degrees. Maybe he knows after all ... but better if he produces the Reference.
True that not everything is black on white in the Airbus documentation dedicated to the pilot ...
According to the BEA, the electric stop was at 11 degrees up.
But DozyWannabe, who sat once in a A320 simulator, pretends the A320 airplane has a limitation for the autotrim at 3 degrees. Maybe he knows after all ... but better if he produces the Reference.
True that not everything is black on white in the Airbus documentation dedicated to the pilot ...
At 15 h 45 min 15, the flight control laws, which were in normal law, passed to direct law. Bank angle reached 50° to the right. The Captain’s lateral input was still at the left stop. The rudder pedal reached a 22 degrees left position. At the same moment, the Captain’s longitudinal input changed to the forward pitch down stop position. Pitch was 11 degrees, the speed 100 kt and the altitude about 2,580 ft.
Auto-trim
From 15 h 44 min 30 the automatic trim function displaced the stabiliser as far
as the electric nose-up thrust stop (- 11 degrees). The stall warning sounded at 15 h 45 min 05. The nose down commands applied by the Captain on the sidestick brought the elevators, due to the load factor, to the neutral position, without however pushing them to the stops(25). Consequently, the trimmable stabilizer did not move even though the flight control law was normal. From 15 h 45 min 15 until the end of the flight, the automatic trim function remained unavailable. In fact, the direct law was active from 15 h 45 min 15 to 15 h 45 min 40 and the Abnormal attitude law phase 1 (without auto-trim) remained active till the end of the flight.
Auto-trim
From 15 h 44 min 30 the automatic trim function displaced the stabiliser as far
as the electric nose-up thrust stop (- 11 degrees). The stall warning sounded at 15 h 45 min 05. The nose down commands applied by the Captain on the sidestick brought the elevators, due to the load factor, to the neutral position, without however pushing them to the stops(25). Consequently, the trimmable stabilizer did not move even though the flight control law was normal. From 15 h 45 min 15 until the end of the flight, the automatic trim function remained unavailable. In fact, the direct law was active from 15 h 45 min 15 to 15 h 45 min 40 and the Abnormal attitude law phase 1 (without auto-trim) remained active till the end of the flight.
The trim went to 11° NU in normal law, stopped operating at 15h 45m 15 s when direct law started and remained inop when at 15h 45m 40s abnormal law was latched until the end of the flight (as designed).
Last edited by RetiredF4; 30th Jul 2012 at 07:58.
Lyman
Franzl:
Do you have advice on the abnormal responses (unusual) in this regard? It is why I brought up the possibility that PNF may have been referring to bug speeds lost? Eg. "we've lost the speeds"
Franzl:
Do you have advice on the abnormal responses (unusual) in this regard? It is why I brought up the possibility that PNF may have been referring to bug speeds lost? Eg. "we've lost the speeds"
Turbine D
Lots of talk about stalls:
Lots of talk about stalls:
2.1.3.2 Exit from the flight envelope
The STALL 2 warning triggered at 2 h 10 min 51 but did not elicit any response from the crew. Even though the stall warning had been sounding for 9 seconds, the aeroplane climbed above the propulsion ceiling with the vertical speed still high, and with a flight path speed that was dropping as a result of this vertical speed. At this point, only descent of the aeroplane through a nose-down input on the sidestick would have made it possible to bring the aeroplane back within the flight envelope.
The rapid reduction in speed was accompanied by an increase in the angle of attack. The lift ceiling, at the Mach at which the aeroplane was flying at that time, was broken a few seconds after breaking through the propulsion ceiling. Due to its momentum, the aeroplane continued to climb: the aeroplane’s kinetic energy was converted into potential energy until the point was reached when the aeroplane unavoidably started to descend. The PF was still applying nose-up inputs and the angle of attack continued to increase. Even with the engines at the TOGA thrust setting, the drag generated by this high angle of attack was so high as to prevent the aeroplane from accelerating.
Subsequently, the position of the sidestick, maintained in its nose-up or neutral position, continued to exacerbate the situation and made the recovery uncertain, even impossible.
The STALL 2 warning triggered at 2 h 10 min 51 but did not elicit any response from the crew. Even though the stall warning had been sounding for 9 seconds, the aeroplane climbed above the propulsion ceiling with the vertical speed still high, and with a flight path speed that was dropping as a result of this vertical speed. At this point, only descent of the aeroplane through a nose-down input on the sidestick would have made it possible to bring the aeroplane back within the flight envelope.
The rapid reduction in speed was accompanied by an increase in the angle of attack. The lift ceiling, at the Mach at which the aeroplane was flying at that time, was broken a few seconds after breaking through the propulsion ceiling. Due to its momentum, the aeroplane continued to climb: the aeroplane’s kinetic energy was converted into potential energy until the point was reached when the aeroplane unavoidably started to descend. The PF was still applying nose-up inputs and the angle of attack continued to increase. Even with the engines at the TOGA thrust setting, the drag generated by this high angle of attack was so high as to prevent the aeroplane from accelerating.
Subsequently, the position of the sidestick, maintained in its nose-up or neutral position, continued to exacerbate the situation and made the recovery uncertain, even impossible.
2.1.3.5 End of the flight
At about 2 h 12, descending though FL 315, the aeroplane’s angle of attack was established around an average value of about 40 degrees. Only an extremely purposeful crew with a good comprehension of the situation could have carried out a manoeuvre that would have made it possible to perhaps recover control of the aeroplane. In fact, the crew had almost completely lost control of the situation.
Up until the end of the flight, no valid angle of attack value was less than 35°.
At about 2 h 12, descending though FL 315, the aeroplane’s angle of attack was established around an average value of about 40 degrees. Only an extremely purposeful crew with a good comprehension of the situation could have carried out a manoeuvre that would have made it possible to perhaps recover control of the aeroplane. In fact, the crew had almost completely lost control of the situation.
Up until the end of the flight, no valid angle of attack value was less than 35°.
There is reason behind that statement, also it is not specified by BEA what this reason is. Reading through the posts of 9 threads shows, that most of the dedicated and expierienced posters (pilots, engineers...) have simple solutions for recovery, some reference their expierience in the sim as proof for simple managable recovery techniques, engineers come up with their math-model of flying.
Who are we going to trust on this matter, BEA or the other opinions?
Just for clarification, AF447 never should have encountered this situation firsthand, as correct recognition of the failures and the subsequent aplication of the procedures would have prevented the exit of the flightenvelope. Even in the first phase of the exit of the flight envelope recognition of the impending stall and the aplication of the correct procedure would have saved the day.
Why does BEA state, that after descending through FL 315 "Only an extremely purposeful crew with a good comprehension of the situation could have carried out a manoeuvre that would have made it possible to perhaps recover control of the aeroplane."
Last edited by RetiredF4; 30th Jul 2012 at 10:55.
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Originally Posted by RF4
Who are we going to trust on this matter, BEA or the other opinions?
EDIT: In this type of accident the main problem is that the crews do not understand the situation. Maybe there is merit in developing a system that reliably detects a stall and announces that condition unequivocally to the crew. Would an AoA indicator be sufficient?
Last edited by HazelNuts39; 30th Jul 2012 at 10:08.
HazelNuts39
Is there a conflict? The crews that performed the recovery in the simulator did have "a good comprehension of the situation" and of the "manoeuvre that would have made it possible to perhaps recover control of the aeroplane." The engineers that calculated the manoeuvre did make BEA's caveat.
EDIT: In this type of accident the main problem is that the crews do not understand the situation. Maybe there is merit in developing a system that detects a stall and announces that condition unequivocally to the crew. Would an AoA indicator be sufficient?
Is there a conflict? The crews that performed the recovery in the simulator did have "a good comprehension of the situation" and of the "manoeuvre that would have made it possible to perhaps recover control of the aeroplane." The engineers that calculated the manoeuvre did make BEA's caveat.
EDIT: In this type of accident the main problem is that the crews do not understand the situation. Maybe there is merit in developing a system that detects a stall and announces that condition unequivocally to the crew. Would an AoA indicator be sufficient?
Concerning the AOA indication BEA made a point:
Angle of Attack Measurement
The crew never formally identified the stall situation. Information on angle of attack is not directly accessible to pilots. The angle of attack in cruise is close to the stall warning trigger angle of attack in a law other than normal law. Under these conditions, manual handling can bring the aeroplane to high angles of attack such as those encountered during the event. It is essential in order to ensure flight safety to reduce the angle of attack when a stall is imminent. Only a direct readout of the angle of attack could enable crews to rapidly identify the aerodynamic situation of the aeroplane and take the actions that may be required.
Consequently, the BEA recommends:
€€that EASA and the FAA evaluate the relevance of requiring the presence of an angle of attack indicator directly accessible to pilots on board aeroplanes.
The crew never formally identified the stall situation. Information on angle of attack is not directly accessible to pilots. The angle of attack in cruise is close to the stall warning trigger angle of attack in a law other than normal law. Under these conditions, manual handling can bring the aeroplane to high angles of attack such as those encountered during the event. It is essential in order to ensure flight safety to reduce the angle of attack when a stall is imminent. Only a direct readout of the angle of attack could enable crews to rapidly identify the aerodynamic situation of the aeroplane and take the actions that may be required.
Consequently, the BEA recommends:
€€that EASA and the FAA evaluate the relevance of requiring the presence of an angle of attack indicator directly accessible to pilots on board aeroplanes.
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Only a direct readout of the angle of attack could enable crews to rapidly identify the aerodynamic situation of the aeroplane and take the actions that may be required.
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Lyman ...
How do you get from "I have no displays", or, "I have no information" that he does not understand what he sees?
Really?
How do you get from "I have no displays", or, "I have no information" that he does not understand what he sees?
Really?
Per Ardua ad Astraeus
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Originally Posted by Franzl
Why does BEA state, that after descending through FL 315
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I think BEA is saying that, if this was a movie you had been watching, at this point you would give up all hope of a happy ending.
EDIT: What was lacking was 'a good understanding of the situation'. With that they should have known what to do about it, and would not need a 'purpose' to do it. The quote is from the part of the BEA report that is "mainly based on the results of the work of the Human Factors group". IMO it speaks more of the HF than of airframe technicalities.
EDIT: What was lacking was 'a good understanding of the situation'. With that they should have known what to do about it, and would not need a 'purpose' to do it. The quote is from the part of the BEA report that is "mainly based on the results of the work of the Human Factors group". IMO it speaks more of the HF than of airframe technicalities.
Last edited by HazelNuts39; 30th Jul 2012 at 12:59.
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Hi mm43...
You say..."Quote:
Lyman ...
How do you get from "I have no displays", or, "I have no information" that he does not understand what he sees? Really?
Well you had better explain how the PF got into the situation where he said, "I have no displays/information" if all along he understood what he saw.
*
Thanks for the reply... French is not my forte. Un peu possible...
From the English translation I understand that the PF has said he has no flight data visible on his screen. I have believed that from the first reading. The FDR has not recorded his RHS fully.
You say he is telling us that he does not understand what he sees. Either way, something is very wrong, n'est-ce pas? Do you say he is too dumb to understand the data he sees? That is not possible? If it's comprehension, I would say he is qualified, but that the data makes insufficient sense?
There is no visual record of what either pilot saw, contrary to the claims of one poster. So we have his record to inform us!
When Captain says "What are you doing?" you will need to explain to me what he might mean? In my business experience with French people in California (food business) I have developed a sense of the vernacular, for what it might be worth.
"Er, What are you doing?" is borderline insulting... French men are sensitive to their work, and much care is taken to not offend or challenge one whose work is in progress. So for me, Captain is very stressed, and is most upset with Bonin.
Now this exchange has taken place after the flight path is abnormal, it is upset, so Captain has basis for his piqué.
You say..."Quote:
Lyman ...
How do you get from "I have no displays", or, "I have no information" that he does not understand what he sees? Really?
Well you had better explain how the PF got into the situation where he said, "I have no displays/information" if all along he understood what he saw.
*
Thanks for the reply... French is not my forte. Un peu possible...
From the English translation I understand that the PF has said he has no flight data visible on his screen. I have believed that from the first reading. The FDR has not recorded his RHS fully.
You say he is telling us that he does not understand what he sees. Either way, something is very wrong, n'est-ce pas? Do you say he is too dumb to understand the data he sees? That is not possible? If it's comprehension, I would say he is qualified, but that the data makes insufficient sense?
There is no visual record of what either pilot saw, contrary to the claims of one poster. So we have his record to inform us!
When Captain says "What are you doing?" you will need to explain to me what he might mean? In my business experience with French people in California (food business) I have developed a sense of the vernacular, for what it might be worth.
"Er, What are you doing?" is borderline insulting... French men are sensitive to their work, and much care is taken to not offend or challenge one whose work is in progress. So for me, Captain is very stressed, and is most upset with Bonin.
Now this exchange has taken place after the flight path is abnormal, it is upset, so Captain has basis for his piqué.
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Franzl.
Thank you for your post. I am beginning to believe PNF has said that the speeds he lost might have been his limit speeds! "bugs". With three ADR kaput, the Stall bug goes away, for example.
And thank you for posting the BEA report about the Stall. I had not read that part of the report. Needless to say, I think it is an excellent description of what happened. For me, even though the pilots were responsible for venturing into that dangerous domain, it explains how they may have missed the Entry to Stall, and how the aircraft and the Airline, and the manufacturer are responsible for the Stall, and some of the difficulty of understanding this situation. It remains to determine how and to what extent the THS affected the entry and capture of STALL. I do not think it is that important, I still believe the crash was a foregone conclusion within fifteen seconds after loss of autopilot.
I have done that type of Stall, and it is exciting...I never thought we were in any danger, and I learned a lot about energy, and rapid descent. I have done these and held nose up, it is exhilarating the excursions in altitude. I do not wish to demean these pilots, the circumstances were as buckwheat to bullets.
Thank you for your post. I am beginning to believe PNF has said that the speeds he lost might have been his limit speeds! "bugs". With three ADR kaput, the Stall bug goes away, for example.
And thank you for posting the BEA report about the Stall. I had not read that part of the report. Needless to say, I think it is an excellent description of what happened. For me, even though the pilots were responsible for venturing into that dangerous domain, it explains how they may have missed the Entry to Stall, and how the aircraft and the Airline, and the manufacturer are responsible for the Stall, and some of the difficulty of understanding this situation. It remains to determine how and to what extent the THS affected the entry and capture of STALL. I do not think it is that important, I still believe the crash was a foregone conclusion within fifteen seconds after loss of autopilot.
I have done that type of Stall, and it is exciting...I never thought we were in any danger, and I learned a lot about energy, and rapid descent. I have done these and held nose up, it is exhilarating the excursions in altitude. I do not wish to demean these pilots, the circumstances were as buckwheat to bullets.
Clandestino, (#836) "If the safe conduct of the flight is impacted".
I repeat; this phrase requires interpretation, which you make in hindsight. We do not know what the crew understood and decided.
The CVR / report suggest that the crew observed the loss of airspeed information but did not understand the implications, and possibly did not consider any association with UAS. Previous events reported difficulty in associating the situation with UAS.
Assuming that the PF’s subsequent control activity was based on a conscious decision (local rationality), then this may have just been poor handling skills in maintaining level flight, or an ill-judged attempt to achieve a specific goal, - either an inappropriate UAS pitch value or stall recovery as in the ‘alternative view’ (#816).
At best we only have a small snapshot of what occurred in the flightdeck, and can only speculate on the crew’s mental activity. Such speculation could be made to fit many views of the big picture. My alternative considers one of these, particularly in association with previous events, and enquires if there is anything which the safety of our industry might benefit from.
A single view of the situation may not have this advantage and thus is perhaps disadvantaged in future thought and action.
RetiredF4, (#828), thanks. The ‘alternative view’ aligns with the report when the stall is established; the point of difference / interest is the crew’s mental model and choice of action which resulted in the stall.
With either view, the effects of surprise on situation awareness, and background knowledge, flight and CRM skills (including time management) all appear to be significant contributors to this accident.
I repeat; this phrase requires interpretation, which you make in hindsight. We do not know what the crew understood and decided.
The CVR / report suggest that the crew observed the loss of airspeed information but did not understand the implications, and possibly did not consider any association with UAS. Previous events reported difficulty in associating the situation with UAS.
Assuming that the PF’s subsequent control activity was based on a conscious decision (local rationality), then this may have just been poor handling skills in maintaining level flight, or an ill-judged attempt to achieve a specific goal, - either an inappropriate UAS pitch value or stall recovery as in the ‘alternative view’ (#816).
At best we only have a small snapshot of what occurred in the flightdeck, and can only speculate on the crew’s mental activity. Such speculation could be made to fit many views of the big picture. My alternative considers one of these, particularly in association with previous events, and enquires if there is anything which the safety of our industry might benefit from.
A single view of the situation may not have this advantage and thus is perhaps disadvantaged in future thought and action.
RetiredF4, (#828), thanks. The ‘alternative view’ aligns with the report when the stall is established; the point of difference / interest is the crew’s mental model and choice of action which resulted in the stall.
With either view, the effects of surprise on situation awareness, and background knowledge, flight and CRM skills (including time management) all appear to be significant contributors to this accident.
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Safetypee;
Your post #816:
The stall warning resulted from the pull on the sidestick, added to light turbulence. It was real. Stall warning does not occur in normal law, only in alternate or direct law.
Your post #858:
You seem to be making a distinction between "loss of airspeed information" and UAS. Do you mean they did not associate the UAS procedure with the UAS situation?
Your post #816:
The crew had not detected the UAS situation, but with ADC dropout/changeover the (unwarranted?) stall warning was taken as real.
Your post #858:
The CVR / report suggest that the crew observed the loss of airspeed information but did not understand the implications, and possibly did not consider any association with UAS.
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Clandestino
Here: "The rapid reduction in speed was accompanied by an increase in the angle of attack. The lift ceiling, at the Mach at which the aeroplane was flying at that time, was broken a few seconds after breaking through the propulsion ceiling. Due to its momentum,the aeroplane continued to climb: the aeroplane’s kinetic energy was converted into potential energy until the point was reached when the aeroplane unavoidably started to descend.
Here is BEA definition of the depart. Do you see any reference to STALL? The aircraft has climbed after the lift ceiling was passed, it was converting energy to altitude without benefit of aerodynamic lift, IOW, Ballistic. There was no drastic increases in drag, in fact drag was decreasing, due to the lessening of velocity.
Neither was there Stall Buffet sufficient to announce STALL onset. And the Nose remained UP.
These two markers are required by the certifying authority to allow the 330 a waiver for additional STALL warning. Stall is demonstrably available in ALTERNATE LAW, the 330 is no different than any other aircraft in this regard, and yet the requirement was waived? STALL WARN is dependent on Mach plus AoA so the certificate requires the 330 to warn always before BUFFET. Mach is not available in transient UAS, so the 330 is violating its certificate in this entry.
Other aircraft would shake in this regime, yet the Bus gets a pass...
HazelNuts39
Howdy.. You say: You seem to be making a distinction between "loss of airspeed information" and UAS. Do you mean they did not associate the UAS procedure with the UAS situation?
This is not even a nit pick... There is a profound difference between "loss of..."
And "Unreliable...."
Something I will repeat unto the door of no return, "We have lost the speeds."
That means, in it's most probable iteration, that the display of airspeed is.....GONE.
In the part of the CVR that does not exist in our reality, but is present in the reality of BEA and AIRBUS, there will be discussion between all three pilots of the loss of the visual data from the instrumentS.
Here: "The rapid reduction in speed was accompanied by an increase in the angle of attack. The lift ceiling, at the Mach at which the aeroplane was flying at that time, was broken a few seconds after breaking through the propulsion ceiling. Due to its momentum,the aeroplane continued to climb: the aeroplane’s kinetic energy was converted into potential energy until the point was reached when the aeroplane unavoidably started to descend.
Here is BEA definition of the depart. Do you see any reference to STALL? The aircraft has climbed after the lift ceiling was passed, it was converting energy to altitude without benefit of aerodynamic lift, IOW, Ballistic. There was no drastic increases in drag, in fact drag was decreasing, due to the lessening of velocity.
Neither was there Stall Buffet sufficient to announce STALL onset. And the Nose remained UP.
These two markers are required by the certifying authority to allow the 330 a waiver for additional STALL warning. Stall is demonstrably available in ALTERNATE LAW, the 330 is no different than any other aircraft in this regard, and yet the requirement was waived? STALL WARN is dependent on Mach plus AoA so the certificate requires the 330 to warn always before BUFFET. Mach is not available in transient UAS, so the 330 is violating its certificate in this entry.
Other aircraft would shake in this regime, yet the Bus gets a pass...
HazelNuts39
Howdy.. You say: You seem to be making a distinction between "loss of airspeed information" and UAS. Do you mean they did not associate the UAS procedure with the UAS situation?
This is not even a nit pick... There is a profound difference between "loss of..."
And "Unreliable...."
Something I will repeat unto the door of no return, "We have lost the speeds."
That means, in it's most probable iteration, that the display of airspeed is.....GONE.
In the part of the CVR that does not exist in our reality, but is present in the reality of BEA and AIRBUS, there will be discussion between all three pilots of the loss of the visual data from the instrumentS.
Last edited by Lyman; 30th Jul 2012 at 15:49.
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The A330 in 447 was using thrust to keep themselves (or augment) Stalled.
Utilizing thrust to recover was available. Unfortunately, again, it was not utilized.
Pulling back the levers and pushing forward the stick......but that is not the issue.
Once STALLED, the argument is wallowing in irrelevancy
From the outset, for me, this accident happened in twenty seconds
BEA is holding back some cards.
From the outset, partisans have been comparing 447 to the other UAS. To me, that is preposterous. Each accident has a unique signature, and basing a conclusion on the similarities to improve safety is arse about.
What makes us go forward with new knowledge is to assess what is different.