AF 447 report out
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EMIT, great post!
Very nice example that the shortcomings of AF447 have hardly anything to do with the Airbus general design.
Very nice example that the shortcomings of AF447 have hardly anything to do with the Airbus general design.
However, an accident is a lasting process and even after the initial mistake has been made, there may be some chance to save the aircraft and the lives of the passengers. Or not. It depends on many factors, including the "error tolerance" of the plane, and the amount and quality of feedback given to the pilots:
- The Boeing that was directed by its pilot into a TV tower, was nevertheless built strong enough and had enough backup systems to survive the accident, that at first glance seems to be 100% fatal. But they got lucky and made it back to the airport.
- The Airbus that stalled at high altitude, had trimmed itself into an AOA 40 degrees, with zero chance of recovery and survival. Obviously it was the pilot who put the plane into that condition. However, if the autotrim had not been working, there might have been some, slight, chance of recovery. If the full back sidestick position had been obvious to the PNF, then maybe, just maybe he would have found some confidence to stop the madness without waiting for the captain. Or maybe the captain would have noticed the controls full back and taken action immediately after entering the cockpit. Or, if there had been an AOA indicator, maybe the pilots wouldn't have ignored the stall warning. Etc... Even a slight chance is better than nothing...
Last edited by ap08; 14th Aug 2012 at 15:47.
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I see far more pro Airbus bias here than I see anti Airbus bias. Numerous pilots are obviously pro Airbus, numerous engineers are pro Airbus, numerous techies are obviously pro Airbus.
The majority of pilots are typical pilots (they are willing to blame their fellow pilots) I many pilots expressing disbelief that a professional pilot could have been so incorrect his his actions.
The majority of techies/computer programmers defend Airbus.
The majority of SLF appear to be at least neutral.
The majority of retired pilots are definitely in the "no pro pilot should have ever let that happen" camp.
Which leaves guys like me, pro pilots that don't really care about A vs B, but who are concerned about a far larger issue. That issue being why this legally qualified cockpit crew failed to recognize a problem, and why the airplane offered no more assistance than it did in helping them identify and correct the problem.
I can only speak to the USofA's regulatory environment, but in my opinion the FAA demands that Airbus aircraft pilots be trained and checked to the same standards and maneuvers that were applicable to a DC3. My six month check still requires minutes upon minutes spent watching the autopilot fly a holding pattern or perform a non precision approach, and the training sessions preceding a checking session are nothing more than rehearsals for the checking sessions.
Airline management teams no longer (at least in my experience) give credence to pilots concerns in training and checking. The bottom dollar, (bottom as defined by the FAA mins) rules. Period.
Airline training depts are ruled by money managers and train to the mins.
Regulators are unwilling to demand true "training" because the industry associations spend huge amounts of cash lobbying the government.
Airlines hire pilots on monetary costs vs qualification. and regulators ALLOW the practice.
Manufacturers build machinery with an emphasis on cost of operation. EFIS tubes are cheaper to buy and maintain than mechanical gauges, etc. FBW is lighter, which allows a lighter airframe, which saves fuel.
Inputs to the pilot ( visually interpreted instruments, aural warnings, tactile feel) are sacrificed to the bottom dollar or unnecessary "innovation". Dial type performance instruments gave way to linear for no apparent reason. (If someone has any study that shows an advantage to tapes, please post it) The only reason I can find is that fighter aircraft HUD's used tapes at the perimeter of the HUD display and it looks cool. SS's offer no tactile feedback because it would be far more costly and less reliable (costly to maintain) than nothing more than a spring loaded video game joystick.
The aviators art has been refined over the hundred years since Glen Curtis invented the aileron, aircraft were designed for humans. Now aircraft are designed for computes and humans must adapt, and for what reason? Statistically, airliners were not falling out of the sky because pilots didn't know how to control them. Transport aircraft haven't crashed because pilots don't understand aircraft control for eighty some off years. Transport aircraft crashed because pilots lost SA and flew into a swamp, or focused on fuel and ran into a mountain, or because pilots misread an approach plate land hit a mountain, or because pilots tried to land in thunderstorms. I could go on, but it is plain to me that changing the way a pilot controls the airplane (inputs and outputs) was an answer to a question no pilot was asking.
Pilots are not allowed to practice the craft of aviation, because we can't allow any altitude deviation because we cram too many aircraft into the sky because that's how we make money. Pilots can't practice the craft of aviation because the regulators show absolutely NO mercy on any level of pilot deviation. We end up turning on the A/P asap because we can't feed our children if we get one altitude bust on our record. "you'll never work in this town again"
Which leaves us with inadequately trained (initial and on a recurring basis) pilots, flying an autopilot for the above stated reasons, watching instruments that make perfect sense as long as the A/P is flying. Then, the automation shuts down for whatever reason and those pilots, either with atrophied skills or lacking skills, are faced with the task of making sense what they've never before seen, likely amidst a cacophony of bells/whistles and amongst flashing lights, and translating that into control inputs they've never before made using controls that respond like nothing they've ever felt.
The aircraft should degrade into a state that humans can easily, quickly understand and control. Not the opposite. That's neither an Airbus, nor Boeing, nor Bombardier, nor Embraer comment. It's just what I want to see.
Yes, I do expect it to happen again.
No, I don't like Boeing's modern pilot "interface" any more that I like Airbus.
And, one more time. I strap into an Airbus about thirty times a month and I'm not scared, nor apprehensive.
The majority of pilots are typical pilots (they are willing to blame their fellow pilots) I many pilots expressing disbelief that a professional pilot could have been so incorrect his his actions.
The majority of techies/computer programmers defend Airbus.
The majority of SLF appear to be at least neutral.
The majority of retired pilots are definitely in the "no pro pilot should have ever let that happen" camp.
Which leaves guys like me, pro pilots that don't really care about A vs B, but who are concerned about a far larger issue. That issue being why this legally qualified cockpit crew failed to recognize a problem, and why the airplane offered no more assistance than it did in helping them identify and correct the problem.
I can only speak to the USofA's regulatory environment, but in my opinion the FAA demands that Airbus aircraft pilots be trained and checked to the same standards and maneuvers that were applicable to a DC3. My six month check still requires minutes upon minutes spent watching the autopilot fly a holding pattern or perform a non precision approach, and the training sessions preceding a checking session are nothing more than rehearsals for the checking sessions.
Airline management teams no longer (at least in my experience) give credence to pilots concerns in training and checking. The bottom dollar, (bottom as defined by the FAA mins) rules. Period.
Airline training depts are ruled by money managers and train to the mins.
Regulators are unwilling to demand true "training" because the industry associations spend huge amounts of cash lobbying the government.
Airlines hire pilots on monetary costs vs qualification. and regulators ALLOW the practice.
Manufacturers build machinery with an emphasis on cost of operation. EFIS tubes are cheaper to buy and maintain than mechanical gauges, etc. FBW is lighter, which allows a lighter airframe, which saves fuel.
Inputs to the pilot ( visually interpreted instruments, aural warnings, tactile feel) are sacrificed to the bottom dollar or unnecessary "innovation". Dial type performance instruments gave way to linear for no apparent reason. (If someone has any study that shows an advantage to tapes, please post it) The only reason I can find is that fighter aircraft HUD's used tapes at the perimeter of the HUD display and it looks cool. SS's offer no tactile feedback because it would be far more costly and less reliable (costly to maintain) than nothing more than a spring loaded video game joystick.
The aviators art has been refined over the hundred years since Glen Curtis invented the aileron, aircraft were designed for humans. Now aircraft are designed for computes and humans must adapt, and for what reason? Statistically, airliners were not falling out of the sky because pilots didn't know how to control them. Transport aircraft haven't crashed because pilots don't understand aircraft control for eighty some off years. Transport aircraft crashed because pilots lost SA and flew into a swamp, or focused on fuel and ran into a mountain, or because pilots misread an approach plate land hit a mountain, or because pilots tried to land in thunderstorms. I could go on, but it is plain to me that changing the way a pilot controls the airplane (inputs and outputs) was an answer to a question no pilot was asking.
Pilots are not allowed to practice the craft of aviation, because we can't allow any altitude deviation because we cram too many aircraft into the sky because that's how we make money. Pilots can't practice the craft of aviation because the regulators show absolutely NO mercy on any level of pilot deviation. We end up turning on the A/P asap because we can't feed our children if we get one altitude bust on our record. "you'll never work in this town again"
Which leaves us with inadequately trained (initial and on a recurring basis) pilots, flying an autopilot for the above stated reasons, watching instruments that make perfect sense as long as the A/P is flying. Then, the automation shuts down for whatever reason and those pilots, either with atrophied skills or lacking skills, are faced with the task of making sense what they've never before seen, likely amidst a cacophony of bells/whistles and amongst flashing lights, and translating that into control inputs they've never before made using controls that respond like nothing they've ever felt.
The aircraft should degrade into a state that humans can easily, quickly understand and control. Not the opposite. That's neither an Airbus, nor Boeing, nor Bombardier, nor Embraer comment. It's just what I want to see.
Yes, I do expect it to happen again.
No, I don't like Boeing's modern pilot "interface" any more that I like Airbus.
And, one more time. I strap into an Airbus about thirty times a month and I'm not scared, nor apprehensive.
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studi... Guten tag
From the outset of the DFDR reads, the THS has taken some flack, this is not new. What is unique is the control Law between NORMAL, and DIRECT. Autotrim is not a protection, nor is it a Navaid, nor a required control for stabilized flight.
It is an accomodation to the size of the aircraft, and the economy of its operation. There is no feedback given the pilot, regardless his control inputs. Trim does nothing for recovery of controlled flight from upset or LOC. Whether his elevators are at five degrees deflection, or thirty, his only 'feel' is the instrument he may be using for PITCH ONLY. G does not count, or shouldn't.
In its operation, the HS changes the angle of incidence of the entire aircraft, if you define incidence as angle to airstream in level flight. The elevators change the PITCH, trim follows to make this the new "stable".
As its movement is slow, and measured, one wonders the need for it at all in upset, when inputs might needs be rapid, and opposing, as in roll control here, in the case of 447. It can throw off the scan, since one can lose track of the trim position, especially when in cockpit surroundings as 447....
These pilots had never experienced a STALL in their aircraft, especially not of the variety that led to their impact with the SEA. With full Nose UP trim, the a/c Was in dramatically high AoA. If I can interject here what I tried to say before, with an AoA of 40-50 degrees, full down deflection of the elevator puts them at roughly 70 degrees.....relative to airstream.
I do not focus too terribly much on the post STALL. THIS accident seems to have begun with PF' initial input of NU with Left Roll.
From the outset of the DFDR reads, the THS has taken some flack, this is not new. What is unique is the control Law between NORMAL, and DIRECT. Autotrim is not a protection, nor is it a Navaid, nor a required control for stabilized flight.
It is an accomodation to the size of the aircraft, and the economy of its operation. There is no feedback given the pilot, regardless his control inputs. Trim does nothing for recovery of controlled flight from upset or LOC. Whether his elevators are at five degrees deflection, or thirty, his only 'feel' is the instrument he may be using for PITCH ONLY. G does not count, or shouldn't.
In its operation, the HS changes the angle of incidence of the entire aircraft, if you define incidence as angle to airstream in level flight. The elevators change the PITCH, trim follows to make this the new "stable".
As its movement is slow, and measured, one wonders the need for it at all in upset, when inputs might needs be rapid, and opposing, as in roll control here, in the case of 447. It can throw off the scan, since one can lose track of the trim position, especially when in cockpit surroundings as 447....
These pilots had never experienced a STALL in their aircraft, especially not of the variety that led to their impact with the SEA. With full Nose UP trim, the a/c Was in dramatically high AoA. If I can interject here what I tried to say before, with an AoA of 40-50 degrees, full down deflection of the elevator puts them at roughly 70 degrees.....relative to airstream.
I do not focus too terribly much on the post STALL. THIS accident seems to have begun with PF' initial input of NU with Left Roll.
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Originally Posted by ap08
It is very clear that both accidents started due to horrible pilot error and violation of procedures. I don't think anyone would ever argue with that.
Had the pitots been changed, this accident would never have happened.
@ TTex600
Good post. And hopefully it brings back the discussion about some topics without the A v B bias.
A v B is neither an argument for the one side nor the other. Both designs have proven their value and also their safety, but as always nothing is perfect. To adress some points which are improveable is the task in accident investigation. The BEA final report mentiones some of those points, and it is legal to discuss those points and some others of concern to some people here which were not adressed by BEA. That does not make them to an anti A brigade or A haters, but it shows there interest in understanding what went wrong besides the overall and dominating human factor. I personally find it offending to be thrown in the pit of A haters despite stating numerous times, that i have no axe to grind with Aor B. I think others feel the same.
Yes, i have the same feeling as TTex600, that in most cases the A v B quibble was introduced into ongoing discussions by posters defending A despite the fact, that not A was attacked, but a system of A and the functioning logic of this system was being discussed, but not sentenced yet. Sometimes it looks like holey ground to even start a discussion on a subject, and the then introduced A v B flaming trivializes the further discussion without ending at any usefull result. This result may very well end at the point where everybody recognizes, that the system not only worked as designed, but also that the advantages of a change are bought with aditional unbearable risks. It might also lead to the result, that the system should be improved. We do not know and never will know the outcome of such a discussion, if it leads in A v B bashing or defending before the discussion over the topic even started. And finally it´s not the manufacturer alone who sets the standard for the design, but also regulators and money money money.
What i know for sure is, that such a discussion will improve the knowledge base and the understanding of discussed systems and flying itself significantly, if we stick to facts and do not make things up to serve our own biased mind. There is even a way to learn out of wrong assumptions and failed statements, when its allowed to discuss about those in a civilized manner.
But let me add also that those, who think they know all about their aircraft after a few years of uneventful flying and are not willing and not able to see the necessity to know more and to gain more expierience will hopefully have a lot of luck when running out of knowledge and expierience.
Good post. And hopefully it brings back the discussion about some topics without the A v B bias.
A v B is neither an argument for the one side nor the other. Both designs have proven their value and also their safety, but as always nothing is perfect. To adress some points which are improveable is the task in accident investigation. The BEA final report mentiones some of those points, and it is legal to discuss those points and some others of concern to some people here which were not adressed by BEA. That does not make them to an anti A brigade or A haters, but it shows there interest in understanding what went wrong besides the overall and dominating human factor. I personally find it offending to be thrown in the pit of A haters despite stating numerous times, that i have no axe to grind with Aor B. I think others feel the same.
Yes, i have the same feeling as TTex600, that in most cases the A v B quibble was introduced into ongoing discussions by posters defending A despite the fact, that not A was attacked, but a system of A and the functioning logic of this system was being discussed, but not sentenced yet. Sometimes it looks like holey ground to even start a discussion on a subject, and the then introduced A v B flaming trivializes the further discussion without ending at any usefull result. This result may very well end at the point where everybody recognizes, that the system not only worked as designed, but also that the advantages of a change are bought with aditional unbearable risks. It might also lead to the result, that the system should be improved. We do not know and never will know the outcome of such a discussion, if it leads in A v B bashing or defending before the discussion over the topic even started. And finally it´s not the manufacturer alone who sets the standard for the design, but also regulators and money money money.
What i know for sure is, that such a discussion will improve the knowledge base and the understanding of discussed systems and flying itself significantly, if we stick to facts and do not make things up to serve our own biased mind. There is even a way to learn out of wrong assumptions and failed statements, when its allowed to discuss about those in a civilized manner.
But let me add also that those, who think they know all about their aircraft after a few years of uneventful flying and are not willing and not able to see the necessity to know more and to gain more expierience will hopefully have a lot of luck when running out of knowledge and expierience.
ap08,
The scenario you describe has been thoroughly discussed by some very well-informed posters, (ie, pilots, aeronauticists etc). I think you need to do some reading from previous posters before concluding that there was "zero chance of recovery".
Theoretical recovery possibilities have been studied and are presented here. Sim work is discussed at length throughout threads 6, 7, 8 & 9 - one recent example is my own. Though not driven by actual data, the approximation of aircraft behaviour at and beyond the stall is sufficient to explore recovery possibilities more thoroughly. However, post #457 on Thread #6 from Owain Glyndwr is well worth reading on the topic of the effects of the THS, the subject under discussion.
The Airbus that stalled at high altitude, had trimmed itself into an AOA 40 degrees, with zero chance of recovery and survival.
Theoretical recovery possibilities have been studied and are presented here. Sim work is discussed at length throughout threads 6, 7, 8 & 9 - one recent example is my own. Though not driven by actual data, the approximation of aircraft behaviour at and beyond the stall is sufficient to explore recovery possibilities more thoroughly. However, post #457 on Thread #6 from Owain Glyndwr is well worth reading on the topic of the effects of the THS, the subject under discussion.
Last edited by PJ2; 14th Aug 2012 at 20:11.
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I don't think A pilots are inferior to B pilots. Automation, if required to be used makes all pilots computer monitors. I found it affecting how I flew so corrected it by manually flying to stay proficient. My airline allowed me to do that. AA. AA had it's faults but you could ignore and work around the weird stuff. You can't be the best pilot if you let them make you a robot so don't let them, I didn't.
Originally Posted by Retired F4
Although that post and similar others were not directed to me, i comment on them.
Originally Posted by Retired F4
They are very personal and disrespectful to the adressed poster, do not contribute to the thread and are not necessary at all.
Originally Posted by Lonewolf 50
Wrong answer, amigo.
I used to teach this stuff (to some seriously ego endowed pilots) and had it taught to me (as a seriously ego endowed pilot) while in the Navy. We learned a lot of our CRM from commercial aviation, specifically the airlines.
I used to teach this stuff (to some seriously ego endowed pilots) and had it taught to me (as a seriously ego endowed pilot) while in the Navy. We learned a lot of our CRM from commercial aviation, specifically the airlines.
Originally Posted by Lonewolf 50
CRM 101: if the other pilot is AFU, you have to recognize that and act to make the situation better. This may include actions like taking the controls in those {hopefully} rare occasions that it is necessary. Usually you help him get back into the problem and get back to flying right.
You can't do that unless you assess how well the other pilot is doing if things are not going well, or if he isn't flying right.
You can't do that unless you assess how well the other pilot is doing if things are not going well, or if he isn't flying right.
Originally Posted by Lonewolf 50
I am pretty sure that you know better than that off hand remark you made, in bold, since you do multi-place aricraft flying for a living, and IIRC, are a Captain.
Originally Posted by ap 08
My conclusion: any aircraft with sufficiently high wing loading can potentially enter "deep stall" - a freefall mode, from which it is not possible to recover...
Originally Posted by Carjockey
Why was the automated system not programmed to adequately inform the pilots of their exact situation
Originally Posted by TTex600
They never initiated the UAS procedure. Why? - that is the only real question.
Originally Posted by Lonewolf 50
If you habitually fly with reference to the tapes and airspeeds, I can see a bit of difficulty in wrenching your self out of that mental mode and establishing an alternate scan to keep yourself flying on a stable path and course. Airspeed is a key element of any instrument scan and cross check.
Originally Posted by Retired F4
Therefore in a decreasing speed situation the computers would have ordered a NU command to the elevators and finally also to the THS in order to maintain 1 g flightpath even without the command from the SS.
Originally Posted by Retired F4
But this input didnt worsen the situation imho.
Originally Posted by Retired F4
To recognize an stall when you dont expect it is a very challenging task.
Originally Posted by Retired F4
That´s a oversimplified version of cure. As i assume, that you drive a car, it would equal an advice to stay on the street to avoid hitting a tree along the road.
Originally Posted by studi
I guess most airbus pilots stay away from the discussion because it became some sort of intellectual ma********on.
Originally Posted by Lonewolf 50
One more tool in the tool box, to be used when necessary.
Originally Posted by Lonewolf 50
ONe part of the mishap that concerns me is what looks like a non-trivial CRM breakdown between LH and RH seat.
Originally Posted by ap08
but the system also responded inadequately (autotrim put the airplane in unrecoverable stall;
Originally Posted by ap08
Also, if I understand correctly, autotrim was NOT supposed to work this way.
Originally Posted by TTex600
Does "any other plane" remove power awareness from its pilot with its non moving power levers?
[quote=Dozy Wannabe]You can see the power settings by looking at the "donuts" on the centre MFD - you know this
Wow! I hope I don't get kicked-off the board for pointing out the obvious and the personal, but it will have been worth it. 
The entirety of Clandestino's post was breath-takingly arrogant, not for the first time, eitther. And full of black-and-white thinking. And painfully sarcastic. I'm just stunned. F4, TTex, and several others who were singled-out for belittlement, have made many valuable and thoughtful contributions to these threads over a very long period, and fair-minded people who want to learn will have benefited greatly from their efforts.
I had a brilliant surgeon who was going to work on my eye, but I fired him before he could cut into it due to his utter lack of humanity towards others (me).
The entirety of Clandestino's post was breath-takingly arrogant, not for the first time, eitther. And full of black-and-white thinking. And painfully sarcastic. I'm just stunned. F4, TTex, and several others who were singled-out for belittlement, have made many valuable and thoughtful contributions to these threads over a very long period, and fair-minded people who want to learn will have benefited greatly from their efforts.
I had a brilliant surgeon who was going to work on my eye, but I fired him before he could cut into it due to his utter lack of humanity towards others (me).
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Thanks Organfreak. Not to worry, I'm a Texan and far beyond being belittled. I only worry about what my kids think of me. Besides, in my little world, I'm looking good vs Clandestino. He's the guy that always asks the long question at 430PM on the last day of ground school. That guy is probably right more often than not, but he won't get credit because everybody else understands how to cooperate and graduate.
Originally Posted by TTex600
Airplane that must be flown in a degraded state has no business in the sky.
Originally Posted by author unknown
Whenever we talk about a pilot who has been killed in a flying accident, we should all keep one thing in mind. He called upon the sum of all his knowledge and made a judgment. He believed in it so strongly that he knowingly bet his life on it. That his judgment was faulty is a tragedy, not stupidity. Every instructor, supervisor, and contemporary who ever spoke to him had an opportunity to influence his judgment, so a little bit of all of us goes with every pilot we lose.
Originally Posted by TTex600
Not everyone can be a skygod. It must be good to be you.
Originally Posted by TTex600
Yes, I and most every pilot I know is somewhat above your "average Joe", we just don't wear it on our sleeve.
Originally Posted by Organfreak
The entirety of Clandestino's post was breath-takingly arrogant, not for the first time, eitther.
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Originally Posted by Clandestino
You shouldn't be. I don't. Why do you believe what you read in personal info
Why would one place information on their personal info that is "unbelievable"?
Originally Posted by Clandestino
I'd rather have my posts checked for accuracy than arrogance but I can live with such an evaluation.
Your Honor, this pertains because it speaks to the credibility of the witness.
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In reply to Clandestino:
Maybe so, Sir. But I submit that (some level of) decorum and respect is required before there can be a credible discussion. Those whom you've sneered-at will not be likely to discuss your points objectively.
And now, we return you to our regularly-scheduled program, "Why the Airbus Must Never Be Criticized, Upon Pain of Ridicule."
I'm merely a skytoddler and it really is good to be me, which is not the subject of the thread. Who or what is anyone discussing AF447 has no bearing on the facts of the case, it's just experts can deliver them more precisely.
And now, we return you to our regularly-scheduled program, "Why the Airbus Must Never Be Criticized, Upon Pain of Ridicule."
Last edited by Organfreak; 15th Aug 2012 at 14:39. Reason: typo
Clandestino
I'd rather have my posts checked for accuracy than arrogance but I can live with such an evaluation.
I'd rather have my posts checked for accuracy than arrogance but I can live with such an evaluation.
Clandestino
You can start agreeing. Aeroplane was flightpath stable
You can start agreeing. Aeroplane was flightpath stable
BEA Final report
When the autopilot disconnected, the roll angle increased in two seconds from 0 to +8.4 degrees without any inputs on the sidesticks. The PF was immediately absorbed by dealing with roll
When the autopilot disconnected, the roll angle increased in two seconds from 0 to +8.4 degrees without any inputs on the sidesticks. The PF was immediately absorbed by dealing with roll
Originally Posted by Retired F4
Therefore in a decreasing speed situation the computers would have ordered a NU command to the elevators and finally also to the THS in order to maintain 1 g flightpath even without the command from the SS.
Therefore in a decreasing speed situation the computers would have ordered a NU command to the elevators and finally also to the THS in order to maintain 1 g flightpath even without the command from the SS.
Clandestino
Irrelevant to case we are discussing, too. Stick was not neutral but heftily pulled back.
Irrelevant to case we are discussing, too. Stick was not neutral but heftily pulled back.
DozyWannabe
THS was at 5 degrees NU at apogee. If the crew had levelled off it would have stayed there and reoriented itself.
THS was at 5 degrees NU at apogee. If the crew had levelled off it would have stayed there and reoriented itself.
Clandestino
Let me explain how it works in the real world: loss of control, aeroplane shaking and warning system shouting "STALL STALL STALL" are symptoms of stall.
Let me explain how it works in the real world: loss of control, aeroplane shaking and warning system shouting "STALL STALL STALL" are symptoms of stall.
BEA Final Report
From the previous events studied (see 1.16.2 and 1.16.8.4) it is clear that almost all the crews that heard the stall warning considered it to be surprising and irrelevant. These judgements may be explained by the lack of awareness of the margins in relation to the trigger threshold of the stall warning and by not knowing the triggering conditions of the warning, which are a function of the angle of attack and Mach.
From the previous events studied (see 1.16.2 and 1.16.8.4) it is clear that almost all the crews that heard the stall warning considered it to be surprising and irrelevant. These judgements may be explained by the lack of awareness of the margins in relation to the trigger threshold of the stall warning and by not knowing the triggering conditions of the warning, which are a function of the angle of attack and Mach.
BEA Final report
It should be noted that, during this forty-six second period between the autopilot disconnection and the STALL 2 warning, the C-chord warning sounded for a total duration of thirty-four seconds, thirty-one seconds of which as a continuous alert, and the STALL warning sounded for two seconds. The C-chord alert therefore saturated the aural environment within the cockpit. It was not cancelled by the crew. This aural environment certainly played a role in altering the crew’s response to the situation.
It should be noted that, during this forty-six second period between the autopilot disconnection and the STALL 2 warning, the C-chord warning sounded for a total duration of thirty-four seconds, thirty-one seconds of which as a continuous alert, and the STALL warning sounded for two seconds. The C-chord alert therefore saturated the aural environment within the cockpit. It was not cancelled by the crew. This aural environment certainly played a role in altering the crew’s response to the situation.
BEA Final report
The crew never referred either to the stall warning or the buffet that they had likely felt. This prompts the question of whether the two co-pilots were aware that the aeroplane was in a stall situation. In fact the situation, with a high workload and multiple visual prompts, corresponds to a threshold in terms of being able to take into account an unusual aural warning. In an aural environment that was already saturated by the C-chord warning, the possibility that the crew did not identify the stall warning cannot be ruled out.
The crew never referred either to the stall warning or the buffet that they had likely felt. This prompts the question of whether the two co-pilots were aware that the aeroplane was in a stall situation. In fact the situation, with a high workload and multiple visual prompts, corresponds to a threshold in terms of being able to take into account an unusual aural warning. In an aural environment that was already saturated by the C-chord warning, the possibility that the crew did not identify the stall warning cannot be ruled out.
BEA Final report
On the other hand, in the absence of airspeed information known to be reliable, it is possible that the PF thought that the aeroplane was in an overspeed situation, notably due to his interpretations of several clues:
- ˆˆThe aerodynamic noise,
- ˆˆThe buffeting, that he might have interpreted as being due to high speed,
- ˆˆThe speed trend arrow on the PFD, which at that time indicated acceleration.
On the other hand, in the absence of airspeed information known to be reliable, it is possible that the PF thought that the aeroplane was in an overspeed situation, notably due to his interpretations of several clues:
- ˆˆThe aerodynamic noise,
- ˆˆThe buffeting, that he might have interpreted as being due to high speed,
- ˆˆThe speed trend arrow on the PFD, which at that time indicated acceleration.
Originally Posted by Retired F4
Sometimes it looks like holey ground to even start a discussion on a subject, and the then introduced A v B flaming trivializes the further discussion without ending at any usefull result.
Sometimes it looks like holey ground to even start a discussion on a subject, and the then introduced A v B flaming trivializes the further discussion without ending at any usefull result.
Clandstino
I would count my amusement as an useful result but everyone else is free to disagree.
I would count my amusement as an useful result but everyone else is free to disagree.
Last edited by RetiredF4; 15th Aug 2012 at 15:17.
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I think BEA is to be commended for their perspective, here....
"It should be noted that, during this forty-six second period between the autopilot disconnection and the STALL 2 warning, the C-chord warning sounded for a total duration of thirty-four seconds, thirty-one seconds of which as a continuous alert, and the STALL warning sounded for two seconds. The C-chord alert therefore saturated the aural environment within the cockpit. It was not cancelled by the crew. This aural environment certainly played a role in altering the crew’s response to the situation."
The part that can be overlooked in an emergency situation is that the Stall WARN is not STALL, not YET..... There can be an accomodation made, unconsciously, that allows for the Horn to be forgotten, in favor of a few seconds of "What's That?" addressed to other stimuli.....
"It should be noted that, during this forty-six second period between the autopilot disconnection and the STALL 2 warning, the C-chord warning sounded for a total duration of thirty-four seconds, thirty-one seconds of which as a continuous alert, and the STALL warning sounded for two seconds. The C-chord alert therefore saturated the aural environment within the cockpit. It was not cancelled by the crew. This aural environment certainly played a role in altering the crew’s response to the situation."
The part that can be overlooked in an emergency situation is that the Stall WARN is not STALL, not YET..... There can be an accomodation made, unconsciously, that allows for the Horn to be forgotten, in favor of a few seconds of "What's That?" addressed to other stimuli.....
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In the August 2012 issue of Wired magazine, author Ben Paynter penned an article named, "The Fire Next Time". "The Fire Next Time"s discusses the paradox of the "close call".
I'll summarize since I only have a print issue.
A "near miss", probability wise, is not a success. They are indicators of failure. If a flaw is systemic, it requires only a small twist of fate for the next incident to result in disaster. "Rather than celebrate then ignoring close calls, we should be learning from them and doing our best to prevent their recurrence." ......"most accident investigations work backward to determine the cause. A more effective way to curtail disasters is to get better at spotting the near miss"
Author Paynters article is based on NASA research (in cooperation with MITRE Corp and the FAA).
In context of AF447, and considering the continued emphasis of some board participants on previously successful near misses (thirty something UAS incidents caused by pitot ice), I suggest that we begin to view those previous A330 UAS incidents as omens. Omens that the system failed to heed.
I'll summarize since I only have a print issue.
A "near miss", probability wise, is not a success. They are indicators of failure. If a flaw is systemic, it requires only a small twist of fate for the next incident to result in disaster. "Rather than celebrate then ignoring close calls, we should be learning from them and doing our best to prevent their recurrence." ......"most accident investigations work backward to determine the cause. A more effective way to curtail disasters is to get better at spotting the near miss"
Author Paynters article is based on NASA research (in cooperation with MITRE Corp and the FAA).
In context of AF447, and considering the continued emphasis of some board participants on previously successful near misses (thirty something UAS incidents caused by pitot ice), I suggest that we begin to view those previous A330 UAS incidents as omens. Omens that the system failed to heed.
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You really believe that all folks that keep on promoting views incompatible with the way things really work are interested in serious discussion?
For what it's worth I don't see your contributions as arrogant in the slightest. I see them as understandable exasperation with those who continue to muddy the waters without having a proper grasp of the situation, who nevertheless have a firm belief that they are correct. I'm also more than a little amused at the criticism coming from those who are unaware just how useful and long-standing your active BS-detection and refutation has been.
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In context of AF447, and considering the continued emphasis of some board participants on previously successful near misses (thirty something UAS incidents caused by pitot ice), I suggest that we begin to view those previous A330 UAS incidents as omens. Omens that the system failed to heed.
BEA's investigation is not a systemic approach to accident of AF447
If it was systemic .. BEA should recognize his inability or ability to have drawn the lessons of past events that have been submitted
Last edited by jcjeant; 15th Aug 2012 at 18:30.