AF447 wreckage found
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Machinbird;
First three sentences: Yes. On the other hand, I was mainly interested in the motion of the airplane, and did not work out the "seat of the pants feel". The lift coefficient and hence alpha is based on the acceleration normal to the flight path.My data do not go beyond alphamax, so anything beyond that should be taken with the appropriate grains of salt.
First three sentences: Yes. On the other hand, I was mainly interested in the motion of the airplane, and did not work out the "seat of the pants feel". The lift coefficient and hence alpha is based on the acceleration normal to the flight path.My data do not go beyond alphamax, so anything beyond that should be taken with the appropriate grains of salt.
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- the absence of appropriate actions to correct the stall of the aircraft
Hi
to fill some emptiness (no job presently) I started to build a model into x-plane, a simuator game that claim to calculate air forces mostly correct.
I did a blended wing, during flight tests i got severe problems to recover high altitude stalls. I figured out a reliable procedure for x-plane to recover from such a stall.
First let my say all what is reported here about that behavior looks reasonable to me. The 7000ft/min compares perfect to the trim setting. (What is not fully correct the trimsetting is corret for the speed 60-80 IAS, but the vvi is looking good for the flight maneuver.)
The stall speed is independent from altitude regarding IAS as long no oblique shock or vortex occurs.
My problem was after the stall the ACFT reached a stable position with 20-30 degrees AoA what i not could not terminate. After many crashes I decided to fly the stall what mean not try to recover early by pressing the yoke forward. I pulled gently until the rear stop was reached, power idle, engine secured by igniter, while gamble to keep wings leveled, checked the horizontal trim settings (I found best was take off trimm working). When reached that carefully move the yoke forward to reach more than 30 degrees downwards but not more than 60 degrees. While dive let the speed increase, just a little below maneuver speed bring pitch to the horizon. Reset power.
This is not the procedure for reacting for a stall warning alarm, what still is just add power. It is for my little blended wing in x-plane. I never lost more than 10000 feet but thats better than an impact.
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What the pilot might have felt
Speaking of brains and our human response to various stimuli -- computer aided or not -- what would the "seat of the pants" part of the pilots' brains be experiencing?
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.
But in this case, if the aircraft stalled at less than a G, the speed would be lower and there may not have been any or much buffetting. If that is the case, the PF may not have felt enough of a stall or break to make him think he had actually stalled it. Stall horns go off when you approach stall, not after you stall.
What very well could have happened is that as the stall warning started and the PF applied TOGA. The aircraft didn't buffet, shake or break into a conventional stall, it stopped flying and started falling at a lower speed.
Absent the break or buffett, when the stall horn stopped the PF likely thought that he flew out of the approach to stall and was flying again. All speculation, of course, but if that is what happened it would offer an explanation of what the PF thought and would explain a lot better his actions.
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engine-eer,
Engine-eer,
Sounds like a very plausible scenario to me, i.e. non-recognition of the full stall at the start (after intial nose-down following recognized impending stall) for reasons stated. But what is so baffling is that the PF (and others) would persist in such a belief in the face of a rapid and continuing descent for 30K ft with the stick full aft and substantial nose-up attitude (even if credibility in IAS never returned). [Assumes all relevant data provided by BEA, skeptical icon ...]. Of course a continuing stall alarm would have helped greatly one assumes but really, at some point reality should have dawned, leading to forward stick +/- power, i.e. at least an attempt at recovery.
Sorry to bring the discussion back to this issue but for me it's the most troubling one in a way. Let's hope the CVR will reveal much more about state-of-mind of some or all involved.
<returns to piston gallery>
Sounds like a very plausible scenario to me, i.e. non-recognition of the full stall at the start (after intial nose-down following recognized impending stall) for reasons stated. But what is so baffling is that the PF (and others) would persist in such a belief in the face of a rapid and continuing descent for 30K ft with the stick full aft and substantial nose-up attitude (even if credibility in IAS never returned). [Assumes all relevant data provided by BEA, skeptical icon ...]. Of course a continuing stall alarm would have helped greatly one assumes but really, at some point reality should have dawned, leading to forward stick +/- power, i.e. at least an attempt at recovery.
Sorry to bring the discussion back to this issue but for me it's the most troubling one in a way. Let's hope the CVR will reveal much more about state-of-mind of some or all involved.
<returns to piston gallery>
Last edited by SDFlyer; 5th Jun 2011 at 20:49.
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Trim wheel motion
I thought "traditionally" the pitch trim wheel went "ping, ping, ping" like a bicycle bell?
Easily distinguished from just about everything else.
Easily distinguished from just about everything else.
A while ago on earlier threads, PJ2 briefed that the A330/340 trim wheel moved silently.
Don't know why they made that decision at Airbus, but I think they need to revisit it.
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I'll have to check, or ask friends to check.
If even to an ancient as myself that was "obvious", one does wonder why it was changed.
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Hi,
I think pprune can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful.
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.
I think pprune can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful.
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.
Since PPRune never speaks with one voice the media only use PPRune to incite questions.
So let's just carry on with our multiple theories based on what scraps of fact are fed to us
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jcjeant
Red section...what are you suggesting?
The transcript of the CVR needs to be complete. Otherwise how do we know AF447 maintained a sterile flight deck? The Buffalo incident is a good example of non-sterile environment to the point of distraction in my humble opinion. Lest those lessons never be learnt.
Transparency is the only way forwards. Otherwise who do you suggest should erase parts of the transcript, AF, BEA, French Judiciary...?
Hi,
I think PPRuNe can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful.
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.
I think PPRuNe can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful.
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.
The transcript of the CVR needs to be complete. Otherwise how do we know AF447 maintained a sterile flight deck? The Buffalo incident is a good example of non-sterile environment to the point of distraction in my humble opinion. Lest those lessons never be learnt.
Transparency is the only way forwards. Otherwise who do you suggest should erase parts of the transcript, AF, BEA, French Judiciary...?
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"Transparency is the only way forwards."
I agree. Nothing good will ever come from secrecy, whether it be from a group, organisation, authority or society.
A certain European country learnt it's lesson last century. Their equivalent of parliament now has a glass dome for a roof.
I agree. Nothing good will ever come from secrecy, whether it be from a group, organisation, authority or society.
A certain European country learnt it's lesson last century. Their equivalent of parliament now has a glass dome for a roof.
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Trouble is, any advertising/PR guy will tell you that first impressions last a long time - and, in many peoples' minds, for ever......
Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA:-
So we're really no further forward as to what caused the stall in the first place?
But BAE's repeated mentions of 'noseup inputs' later on appear to have put over an impression that the pilot caused the whole thing?
My own position is that the BAE would have been 'within its rights' not to publish the CVR this early in the investigation. Alternatively it could have published the whole of it. But just publishing a few isolated quotes is, in my view, plain wrong.
And its also clear that, from the rest of the text, with its descriptions of control movements, power settings etc., they've already analysed quite a lot of the FDR information too. Again, I'd have preferred 'all or nothing.'
Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA:-
"The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left. The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees."
But BAE's repeated mentions of 'noseup inputs' later on appear to have put over an impression that the pilot caused the whole thing?
My own position is that the BAE would have been 'within its rights' not to publish the CVR this early in the investigation. Alternatively it could have published the whole of it. But just publishing a few isolated quotes is, in my view, plain wrong.
And its also clear that, from the rest of the text, with its descriptions of control movements, power settings etc., they've already analysed quite a lot of the FDR information too. Again, I'd have preferred 'all or nothing.'
Last edited by RWA; 6th Jun 2011 at 04:57.
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Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA:-
The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).
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Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA
Controversial, moi?
....would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.
The transcript of the CVR needs to be complete. Otherwise how do we know AF447 maintained a sterile flight deck?
I read this thread for amusement and for the occasional gem like post #1208.
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Zorin 75:
What's depressing is how easy the recovery could have been by trading altitude for speed. That requires putting to nose well down in such circumstances followed by a judicious application of power.
That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky
aterpster: what I found most striking in the MD82 event was that the nose trim kept going up ... similar to what AF447 has.
Nose drop to lower AoA. Speed up. Watch RoD decrease.
I've been watching the comments on round versus strip gauges and personally agree: the strips don't give me the same "feel" as round gauges. Thanks to mimpe for a bit of an explanation on that.
Nose drop to lower AoA. Speed up. Watch RoD decrease.
I've been watching the comments on round versus strip gauges and personally agree: the strips don't give me the same "feel" as round gauges. Thanks to mimpe for a bit of an explanation on that.
Quote:
That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky
The lack of a distress call (or actually any call) from AF447 has never been resolved. Wonder if this was a conscious decision ?
That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky
The lack of a distress call (or actually any call) from AF447 has never been resolved. Wonder if this was a conscious decision ?
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There was some discussion on the 'Trim Running' aural alert, but no conclusion. Some thought it was 'ding ding' bell. (Never heard of that for trim.) Others a traditional 'trim clacker' - which you'd sort of expect. Someone suggested a clacker that only sounded after several seconds of trim running. Whatever it is, it should be on the CVR - but what is it?