AF447 final crew conversation - Thread No. 1
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That said, even with the trim the way it was, the extreme attitude was being held with the elevators - letting go should have brought the nose down to some degree
The elevators have some influence, but the THS and the pitch up moment from the engines' thrust hold the trump cards.
The PF didn't actively hold the nose on the level flight pitch attitude when he took control and all bad things flowed from that.
When the nose tried to fall through at the stall, the PF actively fought it and that is the reason for most of his nose up input after the stall. Do you agree?
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Nothing of the sort - Capt. Burkill himself says that all he did was raise the flaps while his F/O tried to keep the aircraft as on track as he could - no "oversteering", no disabling of the protections.
The Air Transat Azores incident proved that you can deadstick an A330 quite handily too.
@Machinbird, agreed - to be clear the nose coming down "to some degree" means exactly what you're describing - not enough to change the situation in itself, but the FCU would not be trying to hold the elevators in place if the PF let go.
The Air Transat Azores incident proved that you can deadstick an A330 quite handily too.
@Machinbird, agreed - to be clear the nose coming down "to some degree" means exactly what you're describing - not enough to change the situation in itself, but the FCU would not be trying to hold the elevators in place if the PF let go.
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Maintain altitude, full (or 'enough') power, indicated at approach to STALL.
Use back stick to maintain level.
TOGA, PITCH 15 degrees NOSE UP, indicated at Wind Shear.
Full back stick, full power, CFIT recovery.
All published, all trained, all wrong. Everything is in the "Stick". And the stick is 'invisible'. Without full disclosure, this gets stuck on myth, and bias. Or on a guess at the Pilot's thinking. Excellent way to improve safety, eh?
Use back stick to maintain level.
TOGA, PITCH 15 degrees NOSE UP, indicated at Wind Shear.
Full back stick, full power, CFIT recovery.
All published, all trained, all wrong. Everything is in the "Stick". And the stick is 'invisible'. Without full disclosure, this gets stuck on myth, and bias. Or on a guess at the Pilot's thinking. Excellent way to improve safety, eh?
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Let's have a look at the DFDR traces:
Dozy,
The PF released (sort of) back-pressure on the sidestick between 02:12:15 and 02:12:30, without any change in the elevator (full nose-up). When he then moved the SS forward, the elevator moved away from the up stop, pitch attude decreased, and lift (normal acceleration) increased. Similar but slightly lesser responses between 02:13:45 and 02:14:00.
Machinbird,
The traces show similar responses in pitch when thrust is reduced between 02:11:45 and 02:12:15.
Dozy,
the FCU would not be trying to hold the elevators in place if the PF let go.
Machinbird,
The traces show similar responses in pitch when thrust is reduced between 02:11:45 and 02:12:15.
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Lyman,
I am constantly amazed at what I perceive to be total fabrication and mis-statement. Their is absolutely no indication that the PF acted in any logical or correct manner. He was totally incorrect in his actions and the PM knew it but for some reason did not take control of the plane.
I am constantly amazed at what I perceive to be total fabrication and mis-statement. Their is absolutely no indication that the PF acted in any logical or correct manner. He was totally incorrect in his actions and the PM knew it but for some reason did not take control of the plane.
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As an ancient engineer, and one not fully familiar with all the Airbus FCS subtleties, I hesitate to bring this up once again....
But, wasn't there a suggestion, early in one of the earliest threads, that AB pilots are 'not encouraged' to use manual trim (except after full reversion to "mechanical")?
Not to mention the absence of a "bicycle bell" while autotrim was winding the THS to full nose-up, contributing to a lack of "configuration awareness"?
Is "trim" still being taught, or is it now left to George entirely?
But, wasn't there a suggestion, early in one of the earliest threads, that AB pilots are 'not encouraged' to use manual trim (except after full reversion to "mechanical")?
Not to mention the absence of a "bicycle bell" while autotrim was winding the THS to full nose-up, contributing to a lack of "configuration awareness"?
Is "trim" still being taught, or is it now left to George entirely?
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Maybe I'm missing something here, but I fail to understand how none of the pilots recognised (or mentioned anyway), that the plane was stalling. As far as I know the vertical speed/altimeters and attitude indicators were functioning correctly. Once the plane was in a rapid descent despite the fact the nose was pitched up, I'm sure most trainee pilots or even aviation enthusiasts could tell you the aircraft had stalled.
Basic training used to emphasise the importance of not only recovering from a stall but also to recognise it. As MU99 says, slow speed, high nose att, RoD all give it away. I feel that these guys were disorientated, they had forgotten their basic flying training and were engulfed by the wrong mental model. As a general principle, if an aeroplane does not respond as you expect, reduce the AoA and try again. That's good for anything that you put in the air, fast or slow.
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Emergency Action
Maybe I'm missing something here, but I fail to understand how none of the pilots recognised (or mentioned anyway), that the plane was stalling. As far as I know the vertical speed/altimeters and attitude indicators were functioning correctly. Once the plane was in a rapid descent despite the fact the nose was pitched up, I'm sure most trainee pilots or even aviation enthusiasts could tell you the aircraft had stalled.
It's clear to me, after having read everyone's input here, that there is a fundamental difference between 'A and B,' and that difference amounts to: to fly B, you need to be a thoroughly-trained pro. To fly A, you don't need to be unless the poop hits the fan. And so, they all died. So far, without complete information, there will be plenty of blame to go all around.
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When he then moved the SS forward, the elevator moved away from the up stop, pitch attude decreased, and lift (normal acceleration) increased. Similar but slightly lesser responses between 02:13:45 and 02:14:00.
@CJ - As I recall, it was only 1 poster, Svarin IIRC, who stated that his airline were very strict about their Airbus crews not touching the manual trim wheel. This is worrying to me because even if autotrim is there more than 99% of the time, you still need to know how to recover the aircraft if it isn't - so it should be trained for regardless. The trim "whooler" was deleted from the A320 onwards, probably because it would be an annoyance with autotrim active during turbulence - it would be sounding almost constantly. Maybe a compromise with the whooler sounding if the trim goes beyond a certain limit could be looked into?
I was referring to aviation accident investigation terminology, in which "structural failure" and "adverse meteorological conditions" are considered distinct and separate.
Last edited by DozyWannabe; 19th Oct 2011 at 18:54.
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Originally Posted by DozyWannabe
Nothing of the sort - Capt. Burkill himself says that all he did was raise the flaps while his F/O tried to keep the aircraft as on track as he could - no "oversteering", no disabling of the protections.
Originally Posted by ChristiaanJ
But, wasn't there a suggestion, early in one of the earliest threads, that AB pilots are 'not encouraged' to use manual trim (except after full reversion to "mechanical")?
- It is not trained or 'encouraged' to use manual trim in Normal or Alternate Law.
- Manual trim is used in Direct Law, and trained for.
- Manual trim and thrust are the only way to 'control' pitch in Mechanical Backup, and 'trained' for.
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I'm still not convinced by your arguments on the Hudson incident either - but I'm not going to argue the point.
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Self Loading Freight in Arizona.
You have some ironclad conclusions. You are without doubt basing these on what you read here. What the Pilot did, and did not do, was undoubtedly based on what he made of his situation. It turned out badly.
For you to extrapolate beyond that makes you one who parrots what is readily available here, in great quantity.
Oddly, someone as yourself might easily take the opposite tack. I don't presume to know how what happened, happened. I think you do. Is there an explanation for what the PF did? Without doubt. I am baffled. As you are not, I defer to your report of the accident.
What you see as fabrication I present as "what ifs". If you do not suss the difference, no harm, no foul.
Don't choose fish.
What some here do not get, is that this a/c is a known quantity, and has a diary that shows what she did and did not do. The pilots are human, and have to pay for their individuality in knee jerk condemnation because the BUS has a pedigree, a huge fan base, and has her own recorders to cement her reputation. The interpreters of said recorders are her friends.
The pilots are "unquantifiable", to some extent, and that looms large when one's jury is engineers who reject a challenge to their sense of the World as it "is". What bonus, advantage, or future consideration is worth the open mind? None, as they see it.
Human factors are not the same, and instantly put dead men on the defensive.
You have some ironclad conclusions. You are without doubt basing these on what you read here. What the Pilot did, and did not do, was undoubtedly based on what he made of his situation. It turned out badly.
For you to extrapolate beyond that makes you one who parrots what is readily available here, in great quantity.
Oddly, someone as yourself might easily take the opposite tack. I don't presume to know how what happened, happened. I think you do. Is there an explanation for what the PF did? Without doubt. I am baffled. As you are not, I defer to your report of the accident.
What you see as fabrication I present as "what ifs". If you do not suss the difference, no harm, no foul.
Don't choose fish.
What some here do not get, is that this a/c is a known quantity, and has a diary that shows what she did and did not do. The pilots are human, and have to pay for their individuality in knee jerk condemnation because the BUS has a pedigree, a huge fan base, and has her own recorders to cement her reputation. The interpreters of said recorders are her friends.
The pilots are "unquantifiable", to some extent, and that looms large when one's jury is engineers who reject a challenge to their sense of the World as it "is". What bonus, advantage, or future consideration is worth the open mind? None, as they see it.
Human factors are not the same, and instantly put dead men on the defensive.
Last edited by Lyman; 19th Oct 2011 at 19:19.
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Originally Posted by DozyW
I don't need to tell you that hydraulically-assisted controls need a few seconds to respond to demand now, do I?
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Lyman
Help me out here, guys. Is it me, or are Lyman's posts increasingly odd?
It doesn't matter a damn what the aeroplane is. How crude or sophisticated. You do NOT pull the stick hard back when the autopilot disconnects at altitude. You fly attitude, attitude, and attitude. Then, you fly attitude.
It doesn't matter a damn what the aeroplane is. How crude or sophisticated. You do NOT pull the stick hard back when the autopilot disconnects at altitude. You fly attitude, attitude, and attitude. Then, you fly attitude.
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Aileron Drag
AD, no, you are quite on target. His approach is often skewed from physical reality.
But sometimes he has his points. Just pick and choose what you want to actually consider and ignore the rest.
Help me out here, guys. Is it me, or are Lyman's posts increasingly odd?
But sometimes he has his points. Just pick and choose what you want to actually consider and ignore the rest.
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@HN39 - I must confess I'm a little confused. At approx 2:10:07, the pitch attitude trace registers nose-up in response to the initial pitch-up command from the sidestick. The aircraft is at normal cruising speed at this point, so the elevator deflection only needs to move very slightly to effect a significant result.
I thought we were taking about the later traces at 02:12:15 to 02:12:30, when the aircraft is stalled and the PF makes a 1-2s "blip" forward on the sidestick, whch triggers a very small deviation in the elevator trace, followed by the 2:12:31 to 2:12:45 traces where the stick spends most of it's time either neutral or forward, with the corresponding elevator movement, and the 02:13:45 to 02:14:00, where the PNF's inputs achieve the same thing.
I thought we were taking about the later traces at 02:12:15 to 02:12:30, when the aircraft is stalled and the PF makes a 1-2s "blip" forward on the sidestick, whch triggers a very small deviation in the elevator trace, followed by the 2:12:31 to 2:12:45 traces where the stick spends most of it's time either neutral or forward, with the corresponding elevator movement, and the 02:13:45 to 02:14:00, where the PNF's inputs achieve the same thing.
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Lyman . . .
One should look for proof that PF was causing the climb to 38. Not the aircraft.
...FDR at 2h 10min 51 "the P/F continued to make nose-up inputs." What difference would it make if he was commanding the climb or trimming into it ....when he should have been commanding nose-down and if trimming at all, then nose-down.
Tell us: With A/P switched off, could the A330-200 climb and trim itself into a 3000' climb without manual inputs?