PPRuNe Forums

Go Back   PPRuNe Forums > Flight Deck Forums > Tech Log
Forgotten your Username/Password?

Tech Log The very best in practical technical discussion on the web


Closed Thread
 
Thread Tools
Old 13th Oct 2011, 23:58   #1 (permalink)
 
Join Date: Nov 2002
Location: UK
Posts: 301
AF447 final crew conversation - Thread No. 1

'Damn it, we're going to crash, it can't be true!': Terrified final words of pilot on doomed Air France jet | Mail Online

The crew sound pretty confused about how to deal with the situation.

Very sad.
seafuryfan is offline  
Old 14th Oct 2011, 00:33   #2 (permalink)
Psychophysiological entity
 
Join Date: Jun 2001
Location: Tweet Rob_Benham Famous author. Well, slightly famous.
Age: 75
Posts: 3,705
Quote:
France's air accident investigation unit, the BEA, reacted angrily to the publication of the book, with a spokesman saying printing the conversation showed a 'lack of respect to the memory of the crew who died'.
It may be hard for the ones left behind, but transparency is the only course to take in accidents like these. Providing of course, that 'facts' are facts.


There's an valid comment in the thread below the article. The translation would need some latitude in interpretation to have the real feel of what he meant.
Loose rivets is offline  
Old 14th Oct 2011, 01:01   #3 (permalink)

 
Join Date: Sep 2000
Location: England
Posts: 302
disbelief is the thief of time

You really cannot blame the crew.
They experienced (i.e. quietly slipped into) a pitch-up (and thrust-) induced, and very insidious, deep-stall entry at high altitude - a straight unapparent and unremarkable entry into a very high descent rate, featuring a quite misleading and almost normal pitch attitude.
It's a bizarre phenomenon that's unique to the environment and only possible due to automation (especially the auto-trimming of the horizontal stabilizer) – but perhaps also due to the pitch-up effect of applying full power to underslung wing-mounted engines…... an Air France SOP (as with many other airlines).
In the deep stall:

a. the stall warning trigger threshold "cooks off" at a LOWER AoA and remains silent at deep-stall AoA's (i.e. any attempt to stick fwd [and thus lower the nose] triggers a quite deterrent aural stall warning – so any prudent pilot unstalling actions are thwarted).
.
b. All the normal audible and airframe vibrational cues of a stall are absent (i.e. wing-induced turbulence does not impinge upon the tail surfaces) - so the ensuing stalled flight condition is quite uncharacteristically "smooth" (for a stalled state).

c. prior training is irrelevant to the point of being misleading (including the aural exhortations to "Pull UP")

d. time is simply not available to resolve what's happening, particularly against a background cacophony of aural alarms and visual alerts.

e. auto-rotational wing-drop trends are "managed" by the flight control system - so there is no "give the game away" tendency towards spin entry. Once any bank component becomes part of the attitude presentation, a pilot may be inspired to take an Unusual Attitude (i.e. “upset”) recovery action. However in this case the bank remained well within limits and the pitch attitude was around what one would expect. One tends to think of that soubriquet “sucked in” when considering the AF crew’s dilemma once in deep-stall territory, i.e. a propos automation “set-ups” and confidence tricks.

f. pilot sidestick inputs are always hidden from the other pilot and any unseated observer

g. engine thrust increases tend to induce (or sustain) the pitch-up into the high AoA stall attitude (around 40 degrees AoA) and helps "mask" the stall by approximating a level flight attitude.

h. disbelief is the thief of time

It is just one of the "late to the party" Achilles Heels of automation.


THE FINAL MOMENTS
Marc Dubois (captain): 'Get your wings horizontal.'
David Robert (pilot): 'Level your wings.'
Pierre-Cedric Bonin (pilot): 'That's what I'm trying to do... What the... how is it we are going down like this?'
Robert: 'See what you can do with the commands up there, the primaries and so on…Climb climb, climb, climb.'
Bonin: 'But I have been pulling back on the stick all the way for a while.'
Dubois: 'No, no, no, don't climb.'
Robert: 'Ok give me control, give me control.'
Dubois: 'Watch out you are pulling up.'
Robert: 'Am I?'
Bonin: 'Well you should, we are at 4,000.'
As they approach the water, the on-board computer is heard to announce: 'Sink rate. Pull up, pull up, pull up.'
To which Captain Dubois reacts with the words: 'Go on: pull.'
Bonin: 'We're pulling, pulling, pulling, pulling.'
The crew never discuss the possibility that they are about to crash, instead concentrating on trying to right the plane throughout the final four minutes.
Dubois: 'Ten degrees pitch.'
Robert: 'Go back up!…Go back up!…Go back up!… Go back up!'
Bonin: 'But I’ve been going down at maximum level for a while.'
Dubois: 'No, No, No!… Don’t go up !… No, No!'
Bonin: 'Go down, then!' (a poorly expressed exhortation to lower the nose?)
Robert: 'Damn it! We’re going to crash. It can’t be true!'
Bonin: 'But what’s happening?!'

The recording stops.


Read more: 'Damn it, we're going to crash, it can't be true!': Terrified final words of pilot on doomed Air France jet | Mail Online

Last edited by TheShadow; 18th Oct 2011 at 01:12.
TheShadow is offline  
Old 14th Oct 2011, 01:42   #4 (permalink)
 
Join Date: Nov 2010
Location: FR
Posts: 457
Gentlemen, there already is an AF447 thread in the tech log.
Mods, if you merge topics, feel free to erase this as well
AlphaZuluRomeo is offline  
Old 14th Oct 2011, 02:13   #5 (permalink)
 
Join Date: Aug 2005
Location: fl
Posts: 2,514
I know they were new pilots but why couldn't they figure out what was happening to them? pulling back for 3 and a half minutes goes against all of our survival instincts.
bubbers44 is offline  
Old 14th Oct 2011, 02:24   #6 (permalink)
 
Join Date: Aug 2000
Location: northwest england
Posts: 20
Gentlemen, as a former military pilot who has had the benefit of a surfeit of sim instructors who love to play the “he’s doing ok, but how would he cope with this…..” game, I can only stand back and be glad I did not experience these confusing events for real. However, I find it difficult to understand the misidentification of the stall, I can remember trying to setup many a stalling sequence only to have the first indication of the stall being the high rate of descent with no other definite signs other than my own expectation due to control inputs.

I admit I am lucky, I have only flown older aircraft that do not have modern automation, I have not had to sacrifice physical feedback to the demands of efficiency, but perhaps, even given erroneous readouts, the pilots should have had enough overall awareness of there situation that a stall should have been self evident. If the throttles are back and you are losing height then who cares if the system says pull up, it is nose forward and power on time …..

I know that I speak from a legacy viewpoint but the current fear that manual flying skills will atrophy as systems take more of a role appears to be valid. Until recently I would have been of the opinion that that the perseverance of inclusion of human fallibility in the flying system was detrimental to overall safety, now I sit confused; there is now doubt that increased automation has improved safety but the major accidents I can think of recently, in the western world, have been in spite of automation or directly/indirectly caused by it.

Perhaps we need, as an industry and as a fraternity, to invest more in operator input at the design stage. Perhaps all pilots under training should make themselves available for 2 weeks of simulator testing at industry expense, not for the benefits of the pilots but for the benefit of the designers, let them see what an inexperienced pilot will do, not a 20,000 hr test pilot would. It is oh so easy to sit in the sim expecting trouble but it is rare in life to find ourselves outside of the norms. I am not criticising modern training techniques, I am certainly not suggesting we go back to fully manual control systems, rather, I suggest that we all need to spend more time in the sim being surprised as opposed to just knocking out the stats, even if this means more expense. Longer scenarios and more insidious errors combined with long scenarios with sudden error would be useful although I would never suggest a reduction in the current training, this would be as well as not instead of.

Thoughts?
Burnswannabe is offline  
Old 14th Oct 2011, 03:09   #7 (permalink)
 
Join Date: May 2000
Location: USA
Posts: 2,530
Quote:
You really cannot blame the crew.
They experienced (i.e. quietly slipped into) a pitch-up (and thrust-) induced, and very insidious, deep-stall entry at high altitude - a straight unapparent and unremarkable entry into a very high descent rate, featuring a quite misleading and almost normal pitch attitude.
Sorry, but that response may be valid for the first 15 seconds, but not the last 3 minutes. The pitch attitude was definitely NOT normal or even "almost normal" with 10+ deg nose up at 30,000'+!

The Airbus software may have contributed to the confusion with the on-again, off-again stall warnings, but an experienced pilot should have recognized the reality within a minute or less by the attitude and [lack of] airspeed.


Another thought just came to me...

What would have happened if the pilots just took their hands off the stick altogether. What would the computer have done? Has anyone tried this in a [lab] simulator?
Intruder is online now  
Old 14th Oct 2011, 03:11   #8 (permalink)
 
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,122
Confusion came from entering an unknown land, a regime of which there was no knowledge, least of all experience. The accident began when the autopilot stopped. Perhaps some several seconds earlier. The Shadow, as is his wont, has laid it out explicitly.

The only aircraft system that may have had a part to play in the Stall was the THS, and it is completely unknown if the crew could have recovered with the Trim Back at 3. I think they could have, but they should not have climbed at the outset, and that climb is not well understood.

I am sorry this has leaked out, after the apex of the climb, nothing of value is to be captured by reading their last few comments.

If under some circumstances an aircraft can STALL whilst carrying passengers, it needs to be trained, not ignored, at the altar of self serving "mastery" of the craft. We are all buffoons, some more culpable than others, but it is an industry abdication of responsibilty that this happened.
Lyman is offline  
Old 14th Oct 2011, 05:59   #9 (permalink)
 
Join Date: Jun 2010
Location: Noyb
Posts: 63
So there was an aurall warning of pull up during the descent??

Last edited by dlcmdrx; 14th Oct 2011 at 06:34.
dlcmdrx is offline  
Old 14th Oct 2011, 07:47   #10 (permalink)
 
Join Date: Aug 2007
Location: The sky
Posts: 159
Of course there was, from the GPWS as they closed in on the sea. Nothing to do with Fly By Wire and probably too low to recover from a stall by then anyway.
Locked door is offline  
Old 14th Oct 2011, 08:24   #11 (permalink)
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,680
Quote:
Originally Posted by TheShadow
e. autorotational wing-drop trends are "managed" by the flight control system - so there is no "give the game away" tendency towards spin entry.
- I am puzzled by this - do you know that for sure? I cannot believe the software was designed to REVERSE aileron response OR apply rudder in a fully stalled condition? I would have expected the 'managed' response (if there was one) to worsen the wing drop.
BOAC is offline  
Old 14th Oct 2011, 10:00   #12 (permalink)
 
Join Date: Aug 1999
Location: U.K.
Posts: 405
n
Now retired and never having flown fly by wire, I still wonder if the mode of operation of the side-stick contributed. With a traditional column if it is back past a certain point the wing is stalled, and it is pretty obvious that the a/c is being held in a stall, ie the stick position gives a idea of attitude.
Croqueteer is offline  
Old 14th Oct 2011, 10:40   #13 (permalink)
 
Join Date: Oct 2004
Location: York
Posts: 405
These words should never have been made public. What on earth is the point??

Just so ghouls and idiots like amos can pontificate in the luxury of utter ignorance?? In all my years of flying, I have learned that people like amos are EXACTLY the kind of person you never want to be at the controls. Whether you are sitting next to them, or down the back! (He doesn't even know it's possible to stall an A320 in normal law. The type he claims to fly!!)

Deepest sympathies to all affected.
4468 is offline  
Old 14th Oct 2011, 10:44   #14 (permalink)
 
Join Date: Jul 2007
Location: UK
Posts: 136
Burnswannabe, possibly the most erudite and sensible post on this subject. Unfortunately due to cost it will never be implemented. Pax will not pay realistic prices for a ticket and a huge proportion of modern pilots would never reach the required standard to leave the simulator, leading to massive pilot shortages. Even with the current recruiting and training systems too many people with genuine natural flying ability and enthusiasm never get near an aeroplane.
windytoo is offline  
Old 14th Oct 2011, 11:12   #15 (permalink)
 
Join Date: Nov 2007
Location: england
Posts: 75
I believe that self regulation in the Training dept is not the way forward. It's too self serving. Some depts are ineffective due to an old boys club feel where checkers are 'looking after' their buddies regardless of their output. Others are quite happy to accept minimum standards with no wish to spend any extra cash on more education, whilst other depts are simply inept and are run by politicians that were never any good in the right seat never mind the main training management positions. The way forward is for an externally delivered LPC (regulator) every 3 yrs covering all the normal items plus any number of potential items. Let's get back to 'hard, firm and fair' training and checking.
in my last airline is offline  
Old 14th Oct 2011, 11:16   #16 (permalink)
 
Join Date: Feb 2011
Location: Oslo
Age: 49
Posts: 15
Burnswannabe: "If the throttles are back and you are losing height then who cares if the system says pull up, it is nose forward and power on time ….."


Is it that simple?
Skipskatta is offline  
Old 14th Oct 2011, 11:31   #17 (permalink)
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,680
Indeed - it is a strange quote and could confuse some Flt Sim folk
BOAC is offline  
Old 14th Oct 2011, 11:38   #18 (permalink)
 
Join Date: Feb 2010
Location: waad
Posts: 12
Ok children, back to the topic with one question for all?
How often have you all practiced unusual attitude/unreliable airspeed scenarios?

Please go on right now and without looking it up, answer to yourself with honesty, at what indications you will have during climb or any flight regime due to a blocked pitot tube, or static port or a combination of both.
How would you recognise it and how would you manage it?The size of a modern flight deck, the eyes have a long distance to travel across all instruments and make the right right diagnosis in such a pressured situation with coupled with the vast data available.

So its easy to sit in your comfy chair and slate the actions of others forgetting that we are all human and often enough react just the same!

(except for amos2 and mates of course 'cause they are super humans)

Recognising one's own deficiencies(or telling the truth) are the most difficult of all demands that face adult humans.
wet vee two is offline  
Old 14th Oct 2011, 11:44   #19 (permalink)
Psychophysiological entity
 
Join Date: Jun 2001
Location: Tweet Rob_Benham Famous author. Well, slightly famous.
Age: 75
Posts: 3,705
Quote:
Gentlemen, there already is an AF447 thread in the tech log.
Mods, if you merge topics, feel free to erase this as well

I fell this thread started out very well. It's very specific to one aspect and time-band of the accident. There have been two superb posts - some points I didn't agree with, but they had me thinking, which is what it's all about. However, other points really were thought-provoking.

My comment about transparency. It would be ideal to let concerned professionals know those last words, while not allowing them to stab at the sensibilities of families and friends. It really is important we know - those words reveal so much.

I've mentioned this before, but there must have been an absence, or at least a major reduction, of white noise. Ten degrees or more nose up would have had me feeling uneasy, but had been coupled with the kind if silence they must have been in, I would like to think I'd have taken that into account as a major factor. Remember, by now they must have known much of their normal information was suspect, and should have been looking outside the box for other clues. The cockpit noise from way back on the drag-curve, to a good flying speed is chalk and cheese.
Loose rivets is offline  
Old 14th Oct 2011, 11:52   #20 (permalink)
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,680
The 'new' quoted 'lines' add nothing to the pot over the 4000' quote except to confirm that even the Captain did not appear to recognise a stalled situation which should be another cause for concern in AF.
BOAC is offline  
Closed Thread
 
 
 


Thread Tools


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT. The time now is 04:25.


vBulletin® v3.8.7, Copyright ©2000-2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
© 1996-2012 The Professional Pilots Rumour Network