AF 447 report out
Hi DW - yes, there is so much valuable and informed writing in those threads. Yes, it takes effort and time to research, but this isn't an idle discussion about any accident - this is a watershed event in a number of ways, some seen and predicted, many, though, not.
As just one of many observers and part-time contributors who has learnt tremendously from others, I would invite those truly interested by this accident, especially those who manage, train and / or fly transport equipment, to visit or return to those threads and read them from start to finish.
To make best sense of the threads, keep the "long line" in view. Despite meanderings and some rabbit trails, many of which are worth careful thought in themselves, there is a main "story" here and it is really worth pondering.
BTW, I have not set aside the "virtual reality" discussion! Time, and perennial commitments . . . !
Capn Bloggs;
The parameters labeled as such do seem illogical but they are labeled conventionally in flight data work, by their direct result at the point of action, so to speak. So, it isn't Nose-up, it is Tail-down, and the parameter is labeled with a "minus" value; the same is true with the THS, the sidestick parameters and so on.
Regarding the sidestick not spending much time in the NU position, by the data, the sidestick spends most of the 4 minutes from event to impact in the "minus", tail-down, (NU) position, and the elevator spends almost all its time NU:
As just one of many observers and part-time contributors who has learnt tremendously from others, I would invite those truly interested by this accident, especially those who manage, train and / or fly transport equipment, to visit or return to those threads and read them from start to finish.
To make best sense of the threads, keep the "long line" in view. Despite meanderings and some rabbit trails, many of which are worth careful thought in themselves, there is a main "story" here and it is really worth pondering.
BTW, I have not set aside the "virtual reality" discussion! Time, and perennial commitments . . . !
Capn Bloggs;
The parameters labeled as such do seem illogical but they are labeled conventionally in flight data work, by their direct result at the point of action, so to speak. So, it isn't Nose-up, it is Tail-down, and the parameter is labeled with a "minus" value; the same is true with the THS, the sidestick parameters and so on.
Regarding the sidestick not spending much time in the NU position, by the data, the sidestick spends most of the 4 minutes from event to impact in the "minus", tail-down, (NU) position, and the elevator spends almost all its time NU:
Last edited by Jetdriver; 14th May 2013 at 21:54.
Psychophysiological entity
Surely it is possible to use an independent instrument to indicate pitch?
Wings level a $10 spirit level bolted horizontally to the side of the cockpit would do the job...like a slip and turn indicator?
Would it be a good idea to have a simple graphical display of the position of the stick in plain sight, as a means of cross reference between pilots in an emergency?
Wings level a $10 spirit level bolted horizontally to the side of the cockpit would do the job...like a slip and turn indicator?
Would it be a good idea to have a simple graphical display of the position of the stick in plain sight, as a means of cross reference between pilots in an emergency?
Did you guys read the BEA report all the way through. I have.
Do you guys know how to recover from a stall in a transport cat jet in Alternate law at FL370??
It doesn't involve BACK STICK.
Now sod off until you are educated....
A7 really? Who cares about a 1950's carrier fighter jet in this case!!!
Do you guys know how to recover from a stall in a transport cat jet in Alternate law at FL370??
It doesn't involve BACK STICK.
Now sod off until you are educated....
A7 really? Who cares about a 1950's carrier fighter jet in this case!!!
Last edited by nitpicker330; 15th May 2013 at 04:47.
What caused the accident was
1/ iced Pitots
2/ the crews inability to recognize the state the aircraft was in and the fact they applied incorrect side stick inputs during the event exacerbating the problem massively.
END OF STORY FULL STOP----DEAD
Now read the report....
1/ iced Pitots
2/ the crews inability to recognize the state the aircraft was in and the fact they applied incorrect side stick inputs during the event exacerbating the problem massively.
END OF STORY FULL STOP----DEAD
Now read the report....
Last edited by nitpicker330; 15th May 2013 at 04:33.
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5. With the subsequent control law reversion, the aircraft was then doomed to a no-stall-recovery situation with the Stabilizer stuck full up (as the Stab autotrim feature was lost with control law reversion). One of the pilots should have re-trimmed the Stabilizer sufficiently nose down with manual inputs using the pitch trim wheel to allow recovery. This did not happen...why?
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Training
Agree with PJ and Dozy but here's my two-penneth on training;
As a PuT in '83 I was taught spin recovery. Shortly after I qualified it was removed from the syllabus and only incipient spin recovery taught, reasoning: climbing repeatedly to a safe altitude used up too much time.
Two years later as a trainee flying instructor I had to demonstrate spin recovery from the right hand seat. Somehow the sight of the ground rotating towards me ensured I never allowed an A/C to get into a situation whereby I might need that skill.
I believe it's called imprint memory.
As a PuT in '83 I was taught spin recovery. Shortly after I qualified it was removed from the syllabus and only incipient spin recovery taught, reasoning: climbing repeatedly to a safe altitude used up too much time.
Two years later as a trainee flying instructor I had to demonstrate spin recovery from the right hand seat. Somehow the sight of the ground rotating towards me ensured I never allowed an A/C to get into a situation whereby I might need that skill.
I believe it's called imprint memory.
Did you guys read the BEA report all the way through. I have.
Do you guys know how to recover from a stall in a transport cat jet in Alternate Law at FL370??
It doesn't involve BACK STICK.
A7 really? Who cares about a 1950's carrier fighter jet in this case!!!
You agree with him.
Why the attitude?
Last edited by Lonewolf_50; 15th May 2013 at 12:34.
From personal experience, knowing what a fighter pilot in another aircraft is doing with his controls by watching his aircraft bears no resemblance to this scenario. It is far easier to work what is going to happen by watching the controls first. There is no way the PM could have known what the PF was doing with his stick by watching the motion of the aircraft; all he would have been able to see was rapid rolling and pitching with the stall warning blaring on and off. A 200+ tonne, totally stalled airliner does not behave or react like your standard fighter being flown at normal speeds and it is naive to think that the other crew members could ascertain the PF's control inputs with any degree of confidence.
I have no doubt that if AF447 had had conventional control columns, there would have been much better SA amoungst the crew, which includes the captain when he re-appeared, about what was actually being done on the flight controls and so the possibility that one or the other would have taken over much earlier or at least increased the intensity of criticism.
I have no doubt that if AF447 had had conventional control columns, there would have been much better SA amoungst the crew, which includes the captain when he re-appeared, about what was actually being done on the flight controls and so the possibility that one or the other would have taken over much earlier or at least increased the intensity of criticism.
Captain Bloggs, with due regard to your experiences, the performance problem began well before stall, in terms of aircraft performance and sustained pitch error. I think you switched topics in the middle of your point there. Correcting the initial pitch error, and the 3000 foot altitude error is well within reason using performance instruments to detect and call for correction of a flying out of desired parameters.
To address the second part, post stall pitch error: once again, the performance seen by the PM would again be manifested by what was displayed on the attitude indicator. (Based on the report identifying the pitch at various times via the FDR data). Granted, since neither seems to have registered "we are stalled" and latched on to "hmm, nose up, yet we are falling" as an indicator of that condition, any error correction for what is an untrained (recover from actual stall) flight condition relies on putting a number of pieces of the puzzle together. That didn't occur for whatever reason. If you feel lack of seeing the flight control position contributed to that, OK, I'll stop arguing, since most of what I flew was conventional controls, not FBW.
In defense of the PM, and in support of your point, once stalled:
the lack of confidence in airspeed display and possiblly lack of training in stall recovery (rather than the stall prevention) puts the PM behind the aircraft, catching up, and in a night/IMC stall recovery situation that the PF has put him into, and that their collective CRM mis-steps have allowed to happen. The errors are crew errors, not just PF errors.
As PM, even when he realized he is over his head and called the captain, isn't his attitude indicator still showing him pitch errors?
"Lower your nose. Your pitch is too high."
Those are inputs/commands used to advise a PF to correct a pitch error. Even if you don't know what the other stick is doing, you can see what is wrong with the pitch and call for a correction. Is that not pretty basic CRM?
The related topic in re your second point -- why the audio stall warning (a secondary indication of pitch still being wrong) was apparently not factored into his correction inputs to the PF. My original guess was that A/S being whack (both seem to have acknowledged that) leads either or both pilots in the seat discounting mentally a stall warning as spurious ... again, I am guessing on that, but it does fit the SA problem. It gets compounded when they report to the Captain when he arrives. Seems to have provided a bit of misdirection as he tried to make sense of what they were doing, or not doing.
To address the second part, post stall pitch error: once again, the performance seen by the PM would again be manifested by what was displayed on the attitude indicator. (Based on the report identifying the pitch at various times via the FDR data). Granted, since neither seems to have registered "we are stalled" and latched on to "hmm, nose up, yet we are falling" as an indicator of that condition, any error correction for what is an untrained (recover from actual stall) flight condition relies on putting a number of pieces of the puzzle together. That didn't occur for whatever reason. If you feel lack of seeing the flight control position contributed to that, OK, I'll stop arguing, since most of what I flew was conventional controls, not FBW.
In defense of the PM, and in support of your point, once stalled:
the lack of confidence in airspeed display and possiblly lack of training in stall recovery (rather than the stall prevention) puts the PM behind the aircraft, catching up, and in a night/IMC stall recovery situation that the PF has put him into, and that their collective CRM mis-steps have allowed to happen. The errors are crew errors, not just PF errors.
As PM, even when he realized he is over his head and called the captain, isn't his attitude indicator still showing him pitch errors?
"Lower your nose. Your pitch is too high."
Those are inputs/commands used to advise a PF to correct a pitch error. Even if you don't know what the other stick is doing, you can see what is wrong with the pitch and call for a correction. Is that not pretty basic CRM?
The related topic in re your second point -- why the audio stall warning (a secondary indication of pitch still being wrong) was apparently not factored into his correction inputs to the PF. My original guess was that A/S being whack (both seem to have acknowledged that) leads either or both pilots in the seat discounting mentally a stall warning as spurious ... again, I am guessing on that, but it does fit the SA problem. It gets compounded when they report to the Captain when he arrives. Seems to have provided a bit of misdirection as he tried to make sense of what they were doing, or not doing.
Last edited by Lonewolf_50; 15th May 2013 at 15:26.
The Stab autotrim feature was never lost in AF447.
It was a nice design touch to make life easy when everything is going normally, but when the sh1t hits the fan, the first thing that is forgotten is...the thing that you never touch in normal operation. Great idea that...
I wonder, had there been no autotrim, if the PF would have manually trimmed all the way back into the stall... I somehow doubt it.
Originally Posted by Bubbers
Yes, seeing a Boeing with the control wheel full back would alert any pilot at high altitude that we can't fly this way...
Originally Posted by Dozy Wannabe
Birgenair 301 and Northwest 6231 show that's not true.
Read page 30 and 31 of the CVR transcript of 447. It's pretty obvious there was confusion ("Get the wings horizontal", "I’m at the limit… with the roll"; "Climb climb climb climb", "But I’ve been at maxi nose-up for a while") that would not have existed had the PNF and captain been able to see the "control columns" moving in unison.
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Further.
Is it not true that the correct response to stall in a bus is full power and full aft stick?
Is it not true that the correct response to stall in a bus is full power and full aft stick?
Have I missed something here? That is NEVER the correct response to a stall in any aeroplane!
What the OP is likely referring to is that, in NORMAL LAW and @ TAKEOFF, this was the published the Airbus procedure, and was taught thus. Please correct me if I'm wrong, everybody.
Last edited by Organfreak; 15th May 2013 at 15:58.
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Originally Posted by Organfreak
this was the published the Airbus procedure, and was taught thus.
Hazelnuts39, I had the same reaction as you. As I understand it, that response is to a stall warning (warning of impending stall) and the remedy implies that
1. you aren't yet stalled and
2. following that should get you out of trouble and keep you from stalling when all protections are in play.
When stalled reducing AoA is typically the correct response.
I predict that the "why is there no AoA indicator" hamsterwheel begins in 3, 2, 1 ...
1. you aren't yet stalled and
2. following that should get you out of trouble and keep you from stalling when all protections are in play.
When stalled reducing AoA is typically the correct response.
I predict that the "why is there no AoA indicator" hamsterwheel begins in 3, 2, 1 ...
In all fairness to Capn, the THS would have trimmed nose down if the PF would have commanded nose down with his stick forward for whatever time constant the computers use. I beg all the "new" folks I have seen this past week to go thru the thousand posts on the other thread.
The THS implementation was discussed at length, and several of us agreed that it did not help things if the pilot continued to hold aft stick. Otto tries to reduce your stick position to achieve one gee corrected for pitch attitude, even in some of the reversion modes. 'Direct law" is a different story, and the AF crew never got there.
I shall continue to argue that seeing or feeling the other guy's stick or column or whatever was not the primary contributing factor to the crash. Tried to explain this, but I guess some folks don't understand.
The THS implementation was discussed at length, and several of us agreed that it did not help things if the pilot continued to hold aft stick. Otto tries to reduce your stick position to achieve one gee corrected for pitch attitude, even in some of the reversion modes. 'Direct law" is a different story, and the AF crew never got there.
I shall continue to argue that seeing or feeling the other guy's stick or column or whatever was not the primary contributing factor to the crash. Tried to explain this, but I guess some folks don't understand.
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Originally Posted by nitpicker330
Supercooled water droplets exceed the capability of the older Pitots
Some examples are shown here. How does one test pitots to ensure they are able to deal with such variety? Is it really sufficient to quantify icing conditions in terms of IWC (ice water content) and mean particle size?
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I wanted to post this a while back, but didn't have a chance to . . .
But as long as this thread is seeing activity again, there are two things I wanted suggest as things I see as factors in AF447 - and both of them are design related.
The first has been discussed many times (including just recently) before, and that is I think there needs to be some form of mechanical feedback between the control inputs (whether actual or simulated). People are inherently tactile beings and they very much - despite training to overcome it - depend on haptic feedback when the brain is processing higher level intellectual tasks. Look at touch keyboards, musicians, even surgeons using robotic instruments. While they can function without it, people work better with it.
The second may have been mentioned, but I might have missed it in the thousands of posts on this thread. And that is the way that the stall annunciator logic operates. It is pretty clear that the audible "stall, stall" means just that - you are stalling. But in the Airbus, the stall annunciation can be silenced by either recovering from the stall, or in the case of AF447, when the system loses key data inputs (the pitot tubes clogged), yet the system does indicate which.
While the actual cause for the silencing of the warning could have been deduced from various other indicators, in a rapidly changing and unusual system, I think it would be easy for the mind to get into the wrong feedback loop. Warning=on, I'm stalled. Warning=silent, I have recovered from stall. I think that is exactly what happened on AF447 (read the transcript of CVR).
If the system was designed something like, warning="stall", you have stalled; warning=silent, you have recovered and the system knows it because it is fully functional; warning="stall warning suppressed", you can no longer rely on the stall annuciator for the status of your aircraft, I think the outcome may have been different.
Just my thoughts.
The first has been discussed many times (including just recently) before, and that is I think there needs to be some form of mechanical feedback between the control inputs (whether actual or simulated). People are inherently tactile beings and they very much - despite training to overcome it - depend on haptic feedback when the brain is processing higher level intellectual tasks. Look at touch keyboards, musicians, even surgeons using robotic instruments. While they can function without it, people work better with it.
The second may have been mentioned, but I might have missed it in the thousands of posts on this thread. And that is the way that the stall annunciator logic operates. It is pretty clear that the audible "stall, stall" means just that - you are stalling. But in the Airbus, the stall annunciation can be silenced by either recovering from the stall, or in the case of AF447, when the system loses key data inputs (the pitot tubes clogged), yet the system does indicate which.
While the actual cause for the silencing of the warning could have been deduced from various other indicators, in a rapidly changing and unusual system, I think it would be easy for the mind to get into the wrong feedback loop. Warning=on, I'm stalled. Warning=silent, I have recovered from stall. I think that is exactly what happened on AF447 (read the transcript of CVR).
If the system was designed something like, warning="stall", you have stalled; warning=silent, you have recovered and the system knows it because it is fully functional; warning="stall warning suppressed", you can no longer rely on the stall annuciator for the status of your aircraft, I think the outcome may have been different.
Just my thoughts.
Last edited by areobat; 15th May 2013 at 21:47. Reason: typo
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UAS checklists on any airliner do not include pull full back. Depending on altitude and weight you select an attitude and power setting which is quite simple and is in your check list. All pilots should be able to do this easily.