Interesting note about AA Airbus crash in NYC
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Originally Posted by airsupport
Now that is NOT the true story.
A man did in fact escape from that jail, by walking out the unlocked door, and those defects were found afterwards.
Those defects were fixed on that jail, and every similar jail in the World so a similar escape could never happen again.
This cleared the peole that built the jail of any responsibility, and a story was put out to the press (the one you said) to cover it up, and as the prisoner and his buddies were sadly killed just after he left the jail there was nobody left alive to disagree with the findings, so most people believed the story.
A man did in fact escape from that jail, by walking out the unlocked door, and those defects were found afterwards.
Those defects were fixed on that jail, and every similar jail in the World so a similar escape could never happen again.
This cleared the peole that built the jail of any responsibility, and a story was put out to the press (the one you said) to cover it up, and as the prisoner and his buddies were sadly killed just after he left the jail there was nobody left alive to disagree with the findings, so most people believed the story.
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Well, I finally went back to read all the thread - and found Dozywannabe and Clandestine (thanks, guys!) quoting a longish note of my to the safety-critical systems list at York on this accident. It predates my longer paper, which I linked in my note of 17th December, by a few weeks.
If I remember rightly (and it has only been a few minutes, so there is some chance), the big issues discussed have been
* Rudder actuation design
* Whether the PF actually moved the controls
* Whether the turbulence encounter was unusual in any way
* How AAMP advocated use of rudder in recovering from upsets
* How and when to use the rudder on a large transport airplane
* Whether people knew that arbitrary control inputs could break commercial transports at less than manoeuvring speed
* How APC (Airplane-Pilot Coupling, to use the National Research Council's term for it in their decade-old report) occurs and how it can occur more easily with rudder than with other flight controls on a transport airplane
* Whether the vertical fin on AA587 was strong enough
These are all well addressed in the docket (not just the report, but significant additional material) as well as in my article.
But there is one relevant point which was not raised, concerning sensitivity of the rudder controls. It is in my paper (p13). Rudder pedal displacement measured from the FDR during the episode shows at one point 2 inches and at another 2.5 inches. This compared with a travel to the stops of only 1.3 inches. AI engineering estimated it would take 130-140 lbs of pressure to achieve this. With those kinds of forces, any rudder on any airplane with a variable-stop design would have been taken to the limits, no matter what its sensitivity in terms of break-out-force vs. full-travel force. This makes the sensitivity point moot as a causal factor. It is of course appropriate to address sensitivity in the investigation, for the point of an investigation is to illuminate any safety issues that might arise, not only those deemed to be causal to the accident.
I also took up airsupport's challenge to go back and read all his posts. He says
* Water used to get trapped in the fin of such airplanes
* This may have been (not was, but may have been) a factor in the accident
In other words, just what he has been saying this time around, plus:
* An airplane should be built such that any application of control inputs like this should not break it
Now this further point is easily answered, of course, and was, by Mad (Flt) Scientist. I shall not repeat the answer here. John Tullamarine also stepped in with some comments. airsupport responded with the by-now customary deprecations.
This time around he says
which leads me to wonder whether we attribute the same meaning to the phrase "sensible professional discussion", just as I wondered earlier whether we attribute the same meaning to the phrase "seriously weakened".
PBL
If I remember rightly (and it has only been a few minutes, so there is some chance), the big issues discussed have been
* Rudder actuation design
* Whether the PF actually moved the controls
* Whether the turbulence encounter was unusual in any way
* How AAMP advocated use of rudder in recovering from upsets
* How and when to use the rudder on a large transport airplane
* Whether people knew that arbitrary control inputs could break commercial transports at less than manoeuvring speed
* How APC (Airplane-Pilot Coupling, to use the National Research Council's term for it in their decade-old report) occurs and how it can occur more easily with rudder than with other flight controls on a transport airplane
* Whether the vertical fin on AA587 was strong enough
These are all well addressed in the docket (not just the report, but significant additional material) as well as in my article.
But there is one relevant point which was not raised, concerning sensitivity of the rudder controls. It is in my paper (p13). Rudder pedal displacement measured from the FDR during the episode shows at one point 2 inches and at another 2.5 inches. This compared with a travel to the stops of only 1.3 inches. AI engineering estimated it would take 130-140 lbs of pressure to achieve this. With those kinds of forces, any rudder on any airplane with a variable-stop design would have been taken to the limits, no matter what its sensitivity in terms of break-out-force vs. full-travel force. This makes the sensitivity point moot as a causal factor. It is of course appropriate to address sensitivity in the investigation, for the point of an investigation is to illuminate any safety issues that might arise, not only those deemed to be causal to the accident.
I also took up airsupport's challenge to go back and read all his posts. He says
* Water used to get trapped in the fin of such airplanes
* This may have been (not was, but may have been) a factor in the accident
In other words, just what he has been saying this time around, plus:
* An airplane should be built such that any application of control inputs like this should not break it
Now this further point is easily answered, of course, and was, by Mad (Flt) Scientist. I shall not repeat the answer here. John Tullamarine also stepped in with some comments. airsupport responded with the by-now customary deprecations.
This time around he says
Originally Posted by airsupport
it is just not worth it trying to have a sensible professional discussion
PBL
Last edited by PBL; 19th Dec 2007 at 10:44. Reason: I have finally read all the thread
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This piece of information may well be buried somewhere in this thread, but just where did the pilot get the idea that repeated and full deflection of the rudder would correct any apparent or real upset caused by wake vortex? If it was from AA training dept. then you have to wonder who dreamed up such a scheme in the first place.
If you encounter an unexpected skid situation in your car, perhaps caused by icy conditions and worn tread of the tyres, do you repeatedly apply full steering inputs, first in one direction and then in the other, or do you apply slight and gentle inputs in the direction of the skid?
I know which action is likely to lead my safe recovery and which is liable to end up wrapped around a tree some way off the road.
The pilot was either badly trained, misinformed or plain silly. Either way, he was the major contributor to the accident.
The ice and the tyres contributed to the initial event but did not cause the subsequent crash.
If you encounter an unexpected skid situation in your car, perhaps caused by icy conditions and worn tread of the tyres, do you repeatedly apply full steering inputs, first in one direction and then in the other, or do you apply slight and gentle inputs in the direction of the skid?
I know which action is likely to lead my safe recovery and which is liable to end up wrapped around a tree some way off the road.
The pilot was either badly trained, misinformed or plain silly. Either way, he was the major contributor to the accident.
The ice and the tyres contributed to the initial event but did not cause the subsequent crash.
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Originally Posted by rubik101
This piece of information may well be buried somewhere in this thread, but just where did the pilot get the idea that repeated and full deflection of the rudder would correct any apparent or real upset caused by wake vortex? If it was from AA training dept. then you have to wonder who dreamed up such a scheme in the first place.
If you encounter an unexpected skid situation in your car, perhaps caused by icy conditions and worn tread of the tyres, do you repeatedly apply full steering inputs, first in one direction and then in the other, or do you apply slight and gentle inputs in the direction of the skid?
I know which action is likely to lead my safe recovery and which is liable to end up wrapped around a tree some way off the road.
The pilot was either badly trained, misinformed or plain silly. Either way, he was the major contributor to the accident.
The ice and the tyres contributed to the initial event but did not cause the subsequent crash.
If you encounter an unexpected skid situation in your car, perhaps caused by icy conditions and worn tread of the tyres, do you repeatedly apply full steering inputs, first in one direction and then in the other, or do you apply slight and gentle inputs in the direction of the skid?
I know which action is likely to lead my safe recovery and which is liable to end up wrapped around a tree some way off the road.
The pilot was either badly trained, misinformed or plain silly. Either way, he was the major contributor to the accident.
The ice and the tyres contributed to the initial event but did not cause the subsequent crash.
Using your analogy it would be like the driver encountering an icy road with little tire tread, starting a skid and handling it perfectly and then seconds later encountering a situation that wasn’t quite as icy, and having the driver go “nuts” with the wheel and brakes.
Originally Posted by Hand Solo
Yes it did come from the American Airlines training department. They were taught to do it, even though Airbus told them it was a bad idea.
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Finally we are getting closer to the truth.
December 19, 2007
The rudders of about 420 older Airbus jetliners are being subjected to repetitive ultrasonic and other enhanced inspections, the first time airlines and safety regulators have resorted to such recurring, high-tech procedures to determine the integrity of composite parts on airliners already in service.
The stepped-up inspection program, recommended by Airbus months ago and then reaffirmed by the European Aviation Safety Agency through a mandatory directive, calls for the first enhanced rudder checks to be completed within six months or 500 flights. Some inspections on certain planes must be repeated every 1,400 flights, a relatively short compliance schedule for checking structural integrity of primary flight structures.
The enhanced inspections, including ultrasound, X-rays and other techniques, stem from a March 2005 incident in which an Air Transat Airbus A310 suddenly lost its rudder over the Caribbean while flying from Cuba to Quebec. There were no injuries, and the plane returned safely to Cuba. But as a result, the plane's manufacturer, Canadian air-safety investigators and European regulators began investigating what, if any, additional inspection requirements were necessary to safeguard the integrity of such rudders used on early model Airbus aircraft.
While the changes primarily affect a relatively small number of older twin-engine A300s and A310s, they nevertheless represent a significant break from longstanding Airbus-developed maintenance standards for composite materials. Before the incident, Airbus, a unit of European Aeronautic Defence & Space Co., and European regulators maintained that simple visual inspections, combined with a mechanic's manually tapping on the surface of the composite rudders, were adequate to detect any potentially hazardous internal flaws or structural weaknesses.
But now for the first time, high-tech inspections methods are being required -- and must be repeated during the life of a what Airbus described as a "limited number" of Airbus jets -- to assure long-term rudder integrity. A spokesman for Airbus U.S. operations said only a small number of affected aircraft are flown by U.S. carriers. Spokesman Clay McConnell said about 400 A300 and A310 aircraft are covered by the added inspections, along with 20 wide-body Airbus A330 and A340 jetliners. Mr. McConnell said Airbus changed its rudder-manufacturing process before the 2005 incident.
The rudders of about 420 older Airbus jetliners are being subjected to repetitive ultrasonic and other enhanced inspections, the first time airlines and safety regulators have resorted to such recurring, high-tech procedures to determine the integrity of composite parts on airliners already in service.
The stepped-up inspection program, recommended by Airbus months ago and then reaffirmed by the European Aviation Safety Agency through a mandatory directive, calls for the first enhanced rudder checks to be completed within six months or 500 flights. Some inspections on certain planes must be repeated every 1,400 flights, a relatively short compliance schedule for checking structural integrity of primary flight structures.
The enhanced inspections, including ultrasound, X-rays and other techniques, stem from a March 2005 incident in which an Air Transat Airbus A310 suddenly lost its rudder over the Caribbean while flying from Cuba to Quebec. There were no injuries, and the plane returned safely to Cuba. But as a result, the plane's manufacturer, Canadian air-safety investigators and European regulators began investigating what, if any, additional inspection requirements were necessary to safeguard the integrity of such rudders used on early model Airbus aircraft.
While the changes primarily affect a relatively small number of older twin-engine A300s and A310s, they nevertheless represent a significant break from longstanding Airbus-developed maintenance standards for composite materials. Before the incident, Airbus, a unit of European Aeronautic Defence & Space Co., and European regulators maintained that simple visual inspections, combined with a mechanic's manually tapping on the surface of the composite rudders, were adequate to detect any potentially hazardous internal flaws or structural weaknesses.
But now for the first time, high-tech inspections methods are being required -- and must be repeated during the life of a what Airbus described as a "limited number" of Airbus jets -- to assure long-term rudder integrity. A spokesman for Airbus U.S. operations said only a small number of affected aircraft are flown by U.S. carriers. Spokesman Clay McConnell said about 400 A300 and A310 aircraft are covered by the added inspections, along with 20 wide-body Airbus A330 and A340 jetliners. Mr. McConnell said Airbus changed its rudder-manufacturing process before the 2005 incident.
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These defects were discovered on these A300s in New York, by us and other Engineers, back in 1999.
Nothing was done to rectify the problem, OR to call up for more than just an external visual inspection at the time, ONLY after the AA tragedy.
Now this comes out, but as he says the changes were made BEFORE this Air Transat incident in 2005, what he does NOT say is they were made AFTER the AA tradegy.
Of course, no connection.
Nothing was done to rectify the problem, OR to call up for more than just an external visual inspection at the time, ONLY after the AA tragedy.
Now this comes out, but as he says the changes were made BEFORE this Air Transat incident in 2005, what he does NOT say is they were made AFTER the AA tradegy.
Of course, no connection.
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Airsupport,
I thought you had announced that you would give up. Apparently not so.
I don't think anyone disagrees that disbondment of structures on composite tails is a concern.
However,
1. It was not a causal factor in the AA587 crash, because the fin failed at 30% above the load to which it was designed not to fail.
2. The suggestion concerning Air Transat is that disbondment is due to interaction with hydraulic fluid, not with trapped water.
Those are the facts with which you appear to disagree, and that is what the discussion is about.
PBL
I thought you had announced that you would give up. Apparently not so.
I don't think anyone disagrees that disbondment of structures on composite tails is a concern.
However,
1. It was not a causal factor in the AA587 crash, because the fin failed at 30% above the load to which it was designed not to fail.
2. The suggestion concerning Air Transat is that disbondment is due to interaction with hydraulic fluid, not with trapped water.
Those are the facts with which you appear to disagree, and that is what the discussion is about.
PBL
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As an impartial observer with a scientific background I wouldn't describe the debate here as bullying in any way. It is simply that one person in the debate has a very reasoned, analytical approach to assessing the information available, validating it's merits, discarding that which is without merit and verifying the results. The other person is working on a hunch with little or no scrutiny of the evidence available. The possibility that water in the tail could have caused weakening/seperation of the fin has been investigated and dismissed by all of the investigators. Why continue to flog the dead horse? Do you really think that either they all missed the evidence, or that all the investigators are conspiring to hide the truth?
The rudders of about 420 older Airbus jetliners are being subjected to repetitive ultrasonic and other enhanced inspections.
The vertical stabilizer of AA587 failed, rendering the aircrat both unstable and uncontrolable.
Had the rudder failed before the vertical stabilizer did, chances are this thread would be much shorter and we'd be talking about lucky escape and not accident. And I'm definitively not advocating make-rudders-weaker-than-fins here.
I wonder whether is this mix-up of rudders and fins malicious or just plain ignorant.
The vertical stabilizer of AA587 failed, rendering the aircrat both unstable and uncontrolable.
Had the rudder failed before the vertical stabilizer did, chances are this thread would be much shorter and we'd be talking about lucky escape and not accident. And I'm definitively not advocating make-rudders-weaker-than-fins here.
I wonder whether is this mix-up of rudders and fins malicious or just plain ignorant.
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IF people here only believe the findings put out after the event, by so called "experts" who never even saw this problem, and will not even consider the first hand experience of someone who dealt with this problem on a daily basis on these Aircraft in New York, then I really do give up. 
You all deserve each other.
Hopefully one day the truth will finally come out.
You all deserve each other.
Hopefully one day the truth will finally come out.
This is a link to the EASA airworthiness directive for A300 rudder inspections.I believe that a number of inpections have discovered some delamination.
http://www.ucl.cz/download/pdf_ads/easa_2007_0266_e.pdf
http://www.ucl.cz/download/pdf_ads/easa_2007_0266_e.pdf
IF people here only believe the findings put out after the event, by so called "experts" who never even saw this problem, and will not even consider the first hand experience of someone who dealt with this problem on a daily basis on these Aircraft in New York, then I really do give up.
Your 's don't add up.
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You are, in essence, asking us to overturn almost the entire concept of scientific analysis. If we were to follow your lead we could forget about probabilities and likelihoods, we could forget about causality. Just about the only link between the water ingress and the fin seperation is they both occurred in roughly the same part of the aircraft. Unfortunately proximity doesn't really count when it comes to attributing blame, there's got to be something else, otherwise we can falsely attribute all manner of failures in one component to the failure of something else simply because it's close by.
Just because you have seen a repeated incidences of water ingress doesn't mean it played a part in an incident when the PF managed to impose loads way beyond the design failure level (and remember that the design failure level is typically 50% greater than that which should ever experience in normal flight). If you bend the aircraft hard enough it'll always break, and as a professional pilot I know that if I kick full opposing rudder movements into the system on my aircraft then I am probably going to break something, and we don't even have a water ingress problem.
Perhaps we do all deserve each other, but I'm willing to take the risk that the experts are actually correct and not corrupt and in the pocket of the government and Airbus Industrie. I'm sufficently confident that the NTSB (but not the FAA) know what they are doing. If they say that water ingress was not the cause of the accident and mishandling of the aircraft was then that sits comfortably with me, and probably most of the scientific community worldwide.
Just because you have seen a repeated incidences of water ingress doesn't mean it played a part in an incident when the PF managed to impose loads way beyond the design failure level (and remember that the design failure level is typically 50% greater than that which should ever experience in normal flight). If you bend the aircraft hard enough it'll always break, and as a professional pilot I know that if I kick full opposing rudder movements into the system on my aircraft then I am probably going to break something, and we don't even have a water ingress problem.
Perhaps we do all deserve each other, but I'm willing to take the risk that the experts are actually correct and not corrupt and in the pocket of the government and Airbus Industrie. I'm sufficently confident that the NTSB (but not the FAA) know what they are doing. If they say that water ingress was not the cause of the accident and mishandling of the aircraft was then that sits comfortably with me, and probably most of the scientific community worldwide.
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airsupport:
...and POSSIBLE contributory causes gained from first hand detailed experience with these Aircraft in NY.
...and POSSIBLE contributory causes gained from first hand detailed experience with these Aircraft in NY.
So in your experience, the composite A300 vertical stabiliser and rudder unit retains water, which has to be drained. Great, you've put forward another factor that might be relevant and I'm sure that's appreciated.
However, you then go on to push it as a major cause despite the evidence to the contrary - for example, if the vertical stabiliser on AA587 failed at a load that was considerably in excess of what it was designed for, then it looks like the structural integrity of the tail was not significantly weakened.
The tests in the wake of the Air Transat accident are to check for presence of a disbonding problem caused by corrosive hydraulic fluid - *not* water. However there is a possibility that these tests may show that the constant freezing and unfreezing of water does cause a problem, but we're not going to find out until the tests are finished.
So feel free to elaborate on your idea and engage in the debate, but it's a bit of a stretch to say that you're being bullied, when all that is happening is that other posters are saying the evidence they've seen points to the contrary of your theory - that's just debate. No-one's denigrating you or dismissing your ideas as irrelevant, just that they disagree, given the evidence they've seen. From my point of view, I do have an open mind about both incidents, but the fact that both major manufacturers were concerned about the AA training program and issued bulletins to that effect suggests that pilot input concerns are at least as relevant as your concerns about materials used in construction.
I know that there's a significant number of people on here and in aviation that reflexively distrust composites, but aside from the weight benefits inherent in using them the fact is that aluminium is a finite resource, so we're going to have to find a way of making aircraft from other materials at some point, if we want to continue to fly.
Anyway, I hope you don't disappear entirely, because this is an issue that you're obviously passionate about and your experience is useful in these discussions. But the folk on here are all intelligent and passionate people so a thick skin is sometimes necessary.
All the best and have a great Christmas.
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Originally Posted by airsupport
so called "experts" who never even saw this problem, and will not even consider the first hand experience of someone who dealt with this problem on a daily basis on these Aircraft in New York
As any forensic engineer knows, just because one has seen something doesn't mean one has any clue as to its importance in structural engineering terms. I have asked you many times to provide the engineering argument, and you have declined to do so, which likely means you don't have one.
Originally Posted by airsupport
I really do give up.
PBL
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Plastic rudders
til someone says differently (and to my knowledge, at the present, no one has) the fact that water/ice that had been known to find its way into the tail section of at least some A300/310 aircraft (has it ever been confirmed that ALL A300/310 aircraft had water collecting in the tail prior to the “fix?”) had no contribution to the fact that the tail of AA587 separated in flight as a result of massive sideslip and multiple, rapid, and complete rudder applications and reversals.It only takes one to set up a failure when forces are exceeding REMAINING strength and write off the lot of them!
I refer you all to the Airtransat rudder failure out of Cuba where the final incident report refers to another AT aircraft having "20 liters of water in the bottom of the rudder due to drain holes becoming plugged...."
It does not take much imagination what will happen when this water turns to ice and the expansion will, no doubt, put pressure on skin "glue" joints and, eventually cause delamination. Perhaps the riveted rudders were more resiliant to this?
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Originally Posted by Yankee Whiskey
[84 words in the sentence and no main verb]
Originally Posted by Yankee Whiskey
It does not take much imagination what will happen when this water turns to ice and the expansion will, no doubt, put pressure on skin "glue" joints and, eventually cause delamination
It does not take much imagination to put a glass of water outside in freezing weather to see what will happen when this water turns to ice and the expansion will, no doubt, ...... well, what does it do exactly?
Hint: it doesn't break the glass. Why not? The answer may help you understand why your imagination has led you into fantasy.
PBL
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He's not a bully, he just wants to know what your evidence is, like all the rest of us.
Au contraire! You repeatedly rubbish the expert opinions that say water ingress was not an issue and you accuse these experts of covering up the water ingress issue in some conspiratorial way. As you simply don't believe that water ingress was eliminated a factor the only logical conclusion is that you do believe it was a contributory cause. That means you're not pretending to know what caused this accident, you're saying, in an obtuse way, that water ingress was instrumental in the crash. If you allude to something like that then you simply have to back it up with evidence. It's no good saying
when everything you have said before that indicates that you think you do know what caused it and absolutely will not be persuaded otherwise.
Let me put a question to you. Is there any way you could be persuaded that water ingress was not a factor in this accident? If so, who would be able to persuade you? If not, why do you think you we should consider you reasonable?
I on the other hand do NOT pretend to KNOW what caused this tragedy
I do NOT know what caused this tragedy, however I have NO doubt that this COULD have MAYBE been a contributory factor.
Let me put a question to you. Is there any way you could be persuaded that water ingress was not a factor in this accident? If so, who would be able to persuade you? If not, why do you think you we should consider you reasonable?