AMR 587 Airbus Crash (merged)
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and that ridiculous PA announcement the FO makes approaching the gate when he/she should be watching the ramp for equipment.
As SLF who once had gold status on AA (125,000+ miles in one year), I think that AA's announcement helps keep the idiots in back in their seats until the plane stops. I can't count the number of times I've seen pax on UA and DL stand up prematurely and nearly topple over when the aircraft finally comes to a stop.
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Belgique is "too kind" in his disclaimer.
Just as some banks are "too big to fail" because they are so key to their industry, so also are a couple of airframe manufacturers...... or three, if you want to count NASA.
Does that mean that problems are swept under the carpet and never fixed? I don't know, but a first guess would be that barrels of midnight oil have been and are being burnt in trying to identify possibly related problems, cover them up, and then gracefully phase in changes that finesse-fully remove the "theoretical" faults.
Just as some banks are "too big to fail" because they are so key to their industry, so also are a couple of airframe manufacturers...... or three, if you want to count NASA.
Does that mean that problems are swept under the carpet and never fixed? I don't know, but a first guess would be that barrels of midnight oil have been and are being burnt in trying to identify possibly related problems, cover them up, and then gracefully phase in changes that finesse-fully remove the "theoretical" faults.
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did I pick this up correctly from the BBC programme ....... 4 inches of pedal movement on the ground gives full rudder deflection ...... one and a quarter inches of pedal movement in the air gives full rudder deflection ......
I thought that once airborne and with increasing velocity that pedal movement is progressively restricted with a corresponding limit on rudder deflection (to structurally protect the rudder/fin)
this was not mentioned at all in the programme?
I thought that once airborne and with increasing velocity that pedal movement is progressively restricted with a corresponding limit on rudder deflection (to structurally protect the rudder/fin)
this was not mentioned at all in the programme?
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I just watched that BBC programme on the loss of AA587. If (-BIG if) the programme was right in portraying AA as promoting the use of rudder to recover from extreme attitudes - and there appeared to be training video supporting this - then surely this must be the crux of the issue.
I've been flying the A300 for the last 11 years, and the 737 before that. I was always trained since basic flying that the rudders in flight were foot rests only, apart from an engine failure or the first/last 5 seconds of the flight. I can think of no other circumstances where I would use rudder - A300 roll input is perfectly adequate. Shortly after the crash Boeing also issued a notice pointing out that their rudders were not designed to be used in this way.
I recall a cross-wind approach some years ago when the PF reverted to his previous turboprop type and applied rudder in the last 500'. There was a sickening, uncomfortable wing-drop as well as a most unusual noise before I clamped my feet on the pedals.
The one thing that continues to puzzle me is the wake turbulence. The A300 easily outclimbs a 747, and vortices move downward. How could AA587 have encountered JAL's wake ?
I've been flying the A300 for the last 11 years, and the 737 before that. I was always trained since basic flying that the rudders in flight were foot rests only, apart from an engine failure or the first/last 5 seconds of the flight. I can think of no other circumstances where I would use rudder - A300 roll input is perfectly adequate. Shortly after the crash Boeing also issued a notice pointing out that their rudders were not designed to be used in this way.
I recall a cross-wind approach some years ago when the PF reverted to his previous turboprop type and applied rudder in the last 500'. There was a sickening, uncomfortable wing-drop as well as a most unusual noise before I clamped my feet on the pedals.
The one thing that continues to puzzle me is the wake turbulence. The A300 easily outclimbs a 747, and vortices move downward. How could AA587 have encountered JAL's wake ?
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I Just watched the same on the beeb.Quite unusual for the hacks to get a few of the facts straight for a change.
I don't have quite so much experience on the bus as the previous poster but I have to agree on the rudder inputs though.
I was also told that during the certification of any aircraft, the design load factors are based on only one full control deflection, not on several..........
I don't have quite so much experience on the bus as the previous poster but I have to agree on the rudder inputs though.
I was also told that during the certification of any aircraft, the design load factors are based on only one full control deflection, not on several..........
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I was under the impression that in flight full rudder pedal movement would give you less and less rudder deflection, for obvious reasons.
I fly boeings. I cannot imagine that what was said in the programme was right.
Why would an aircraft be designed so that if you accidentally bumped the pedal that you would get full rudder deflection? It's just nonsense!
I fly boeings. I cannot imagine that what was said in the programme was right.
Why would an aircraft be designed so that if you accidentally bumped the pedal that you would get full rudder deflection? It's just nonsense!
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Rudder use
Excuse me for being naive...im relatively new to flying, and possess a ppl(sep) licence......would someone please explain why the rudder isn't used in flight in the large passenger jets......i understand that with greater velocity less movement would be required...but it sounds like the rudder shouldn't be used at all........plus.......on x-wind lands.....surely it has to be used to line up the aircraft just before touchdown.........i also understand that it doesn't apply to my 152 (or so i've been taught). Please dont jump down my throat, this is an innocent question. Thanks.
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Of course it is possible that sabotage was involved. An small explosive charge in the tail would have done it. The plane had just come out of service. Funny how they didn't release the actual voice recordings of the last few seconds of the flight, or even the supposed warnings of wake turbulence before take off, yet they did release the take-off clearance. Why only the transcripts for these other times? Call me a conspiracy thoerist, but you can bet your bottom dollar that if there was any information pointing towards this, it would have been extremely well covered up, given the timing after 9-11, to avoid national panic. Things are often simpler than they seem!
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"Call me a conspiracy thoerist, but you can bet your bottom dollar that if there was any information pointing towards this, it would have been extremely well covered up, given the timing after 9-11, to avoid national panic."
OK, so lets say that they did cover the "sabotage" up so it would avoid national panic, why don't they now release the information about their being a small explosive device, America is now past 9/11 (relatively speaking). The only reason i can think of is because there was no explsive device
if there actually was foul play involved the FBI and not forgetting the bush administration would have been onto it like flies on......well you know what. It would have been great propaganda for the admistration and would have further strengthened there war on terror campaign.
OK, so lets say that they did cover the "sabotage" up so it would avoid national panic, why don't they now release the information about their being a small explosive device, America is now past 9/11 (relatively speaking). The only reason i can think of is because there was no explsive device
if there actually was foul play involved the FBI and not forgetting the bush administration would have been onto it like flies on......well you know what. It would have been great propaganda for the admistration and would have further strengthened there war on terror campaign.
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As a mere laymen and PPL I read the responses with interest. The program seems somewhat sensationalist to me,If you and other flyers of other aircraft are aware of this, the program made no attempts as implying its generally known that "rudders are merely foot rests for the majority of the flight" The program gives a somewhat unbalanced view. Perhaps a few interviews with pilots from other airlines flying all sorts of aircraft having the same views would have balanced up the program somewhat.
Perhaps if such program makers were aware of this site they could get some more INFORMED opinion as to the facts from avaitors across the board, and produce a less sensationalist piece that appeared somewhat black and white. To members of the public this program must be somewhat alarming without the full facts..
Fundi Ya Ndege are you saying that designers of aircraft fail to build in factors to cater for the situation where a pilot "wrestles" for control requiring full multiple control inputs in order to restore balanced flight in say a windshear/wake turbulance situation? As an engineer that to me seems somewhat odd
Perhaps if such program makers were aware of this site they could get some more INFORMED opinion as to the facts from avaitors across the board, and produce a less sensationalist piece that appeared somewhat black and white. To members of the public this program must be somewhat alarming without the full facts..
Fundi Ya Ndege are you saying that designers of aircraft fail to build in factors to cater for the situation where a pilot "wrestles" for control requiring full multiple control inputs in order to restore balanced flight in say a windshear/wake turbulance situation? As an engineer that to me seems somewhat odd
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AA 587 /rudder use
Re various FAQs on 587 -
The reason the rudder was so sensitive is that unlike the current Boeings that use variable rudder ratio systems (full travel produces progressively less actual surface movement as speed increases) airbus dropped that system with the A300-600 and subsequent and use a variable stop. the gearing is constant but the load increases, and the maximum travel decreases with increasing speed. The effect of this when breakout forces are taken into account is that it would be very difficult to modulate such a control - but of course no one ever thought that pilots would use the control in that way... see various Aviation Week articles by the excellent Michael Dornheim.
Re jshg's query about why the A 300 didn't easily outclimb the 747 - it did, but then accelerated from 1000ft while the 747 didn't begin its acceleration and clean up until at least 2000ft, so the A300 was at one point below and downwind of the 747. Actually the wind necessary to bring the vortices into play has been quoted as only 28kt (from memory) but this refers to the component at right angles to the flight paths, and means that the total wind necessary might have been higher...unless these vortices were left lying around from some previous departure! The point is not that the vortex upset was particularly strong, but that it triggered this wholly inappropriate and uniquely AA response with the aggressive rudder inputs.
There has been a lot of puzzlement along the lines of 'I thought i could apply full control up to Max manoeuvre speed' Well, you can though whether you should really want to is debatable, but what happens with the reversals is that the aircraft yaws and overshoots the equilibrium position, so achieves a higher than normal sidleslip; if you then reverse the control, the fin load is now much higher than the either of the two design cases. These are: max deflection at zero sideslip (ie one bootful from straight and level) and max rudder in a sustained sideslip, and it is easy to see how the reversal loads will be higher. Should we all have been expressly warned of this? Well, my car handbook doesn't spell out for me what would happen if I decide to slam the shift into reverse at max speed, because they don't believe I would want to do that, and it has been the same for the aircraft builders. Of course in a country that tells you your coffee is hot, things may be different.
The reason the rudder was so sensitive is that unlike the current Boeings that use variable rudder ratio systems (full travel produces progressively less actual surface movement as speed increases) airbus dropped that system with the A300-600 and subsequent and use a variable stop. the gearing is constant but the load increases, and the maximum travel decreases with increasing speed. The effect of this when breakout forces are taken into account is that it would be very difficult to modulate such a control - but of course no one ever thought that pilots would use the control in that way... see various Aviation Week articles by the excellent Michael Dornheim.
Re jshg's query about why the A 300 didn't easily outclimb the 747 - it did, but then accelerated from 1000ft while the 747 didn't begin its acceleration and clean up until at least 2000ft, so the A300 was at one point below and downwind of the 747. Actually the wind necessary to bring the vortices into play has been quoted as only 28kt (from memory) but this refers to the component at right angles to the flight paths, and means that the total wind necessary might have been higher...unless these vortices were left lying around from some previous departure! The point is not that the vortex upset was particularly strong, but that it triggered this wholly inappropriate and uniquely AA response with the aggressive rudder inputs.
There has been a lot of puzzlement along the lines of 'I thought i could apply full control up to Max manoeuvre speed' Well, you can though whether you should really want to is debatable, but what happens with the reversals is that the aircraft yaws and overshoots the equilibrium position, so achieves a higher than normal sidleslip; if you then reverse the control, the fin load is now much higher than the either of the two design cases. These are: max deflection at zero sideslip (ie one bootful from straight and level) and max rudder in a sustained sideslip, and it is easy to see how the reversal loads will be higher. Should we all have been expressly warned of this? Well, my car handbook doesn't spell out for me what would happen if I decide to slam the shift into reverse at max speed, because they don't believe I would want to do that, and it has been the same for the aircraft builders. Of course in a country that tells you your coffee is hot, things may be different.
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Bootlegger,
After years of being told to use the rudder in the turn to stop adverse yaw, particularly in something like a glider or seneca which does not turn much without it, I am now boll*** by the training captain every time i touch it, other than x wind landings or engine out.
I think the reasons are a much bigger roll -yaw couple on a swept wing jet than on a light a/c making it not needed, also it upsets the yaw damper as it trys to correct for your rudder input giving an uncomfortable swing in the back.
please correct me if wrong or there are other reasons.
it's also interesting that when correcting for wing drops etc in light a/c the rudder is used, in a difficult situation it might be easy to revert to this, though not the correct procedure in a jet
After years of being told to use the rudder in the turn to stop adverse yaw, particularly in something like a glider or seneca which does not turn much without it, I am now boll*** by the training captain every time i touch it, other than x wind landings or engine out.
I think the reasons are a much bigger roll -yaw couple on a swept wing jet than on a light a/c making it not needed, also it upsets the yaw damper as it trys to correct for your rudder input giving an uncomfortable swing in the back.
please correct me if wrong or there are other reasons.
it's also interesting that when correcting for wing drops etc in light a/c the rudder is used, in a difficult situation it might be easy to revert to this, though not the correct procedure in a jet
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Simon Brown- Fair points but unfortunately TV/ Journos will always go for "sensational" over "accurate".
Never let the truth get in the way of a good story!
Captf- Excellent post, well done, says it all really.
Never let the truth get in the way of a good story!
Captf- Excellent post, well done, says it all really.
Union Goon
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Captf,
Recent information has come out from Airbus (withheld at the hearing...) about the rate of change of the rudder load limiter as well.
The rudder load limiter basically uses a jack screw to retard movement of the pedals, thereby reducing movement of the rudder. . If you get the airspeed trend arrow on the PFD more than 10 knots long (IOW if you will be going more than 10 kts faster in 10 seconds than you are now) YOU ARE OUT RUNNING THE RUDDER LOAD LIMITER, and you can break the aircraft. The max rate of change on the rudder load limiter is 1 knot per sec. The A300605R particularly at low levels accelerates MUCH faster than this.
So anytime you see the trend arrow greater than 10 knots long pointed up you are not protected by the rudder load limiter.
As to AA;s training. They never advocated anything other than cooridinated rudder. There was a long discussion about crossover speed and high angle of attack and rudder inputs (VERY RELEVENT to loss of control crashes in the 737) but nobody was advocating stomping rudders.
The airplane is a trap for a Pilot induced oscilation in the yaw access at certain speeds.
Cheers
Wino
Recent information has come out from Airbus (withheld at the hearing...) about the rate of change of the rudder load limiter as well.
The rudder load limiter basically uses a jack screw to retard movement of the pedals, thereby reducing movement of the rudder. . If you get the airspeed trend arrow on the PFD more than 10 knots long (IOW if you will be going more than 10 kts faster in 10 seconds than you are now) YOU ARE OUT RUNNING THE RUDDER LOAD LIMITER, and you can break the aircraft. The max rate of change on the rudder load limiter is 1 knot per sec. The A300605R particularly at low levels accelerates MUCH faster than this.
So anytime you see the trend arrow greater than 10 knots long pointed up you are not protected by the rudder load limiter.
As to AA;s training. They never advocated anything other than cooridinated rudder. There was a long discussion about crossover speed and high angle of attack and rudder inputs (VERY RELEVENT to loss of control crashes in the 737) but nobody was advocating stomping rudders.
The airplane is a trap for a Pilot induced oscilation in the yaw access at certain speeds.
Cheers
Wino
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Regarding the Horizon programme and according to my searches, which I cannot personally verify as accurate :-
[1] -- There was no mention of the comments of senior American Airlines pilot, John Lavelle, who told the NTSB that five years ago, while flying with Molin (the co-pilot in the crash and the pilot in control during the incident), he noticed that Molin used the rudder too aggressively during a takeoff.
[2] -- There was no mention that in 1997 an American Airlines pilot, David Tribout, expressed concerns about the way his company's pilots were being trained to use rudders, saying what they were being taught was potentially dangerous.
[3] -- There was no mention that in 1998, reacting to a turbulence incident involving another A300 flown by American, Airbus warned the NTSB in a memo that rapid back and forth movements of the rudder could lead to structural loads that exceed the design load of the fin.
Can anyone verify the above ?
If they are accurate, then why were these not mentioned in the Horizon programme ? Or did I miss them ?
[1] -- There was no mention of the comments of senior American Airlines pilot, John Lavelle, who told the NTSB that five years ago, while flying with Molin (the co-pilot in the crash and the pilot in control during the incident), he noticed that Molin used the rudder too aggressively during a takeoff.
[2] -- There was no mention that in 1997 an American Airlines pilot, David Tribout, expressed concerns about the way his company's pilots were being trained to use rudders, saying what they were being taught was potentially dangerous.
[3] -- There was no mention that in 1998, reacting to a turbulence incident involving another A300 flown by American, Airbus warned the NTSB in a memo that rapid back and forth movements of the rudder could lead to structural loads that exceed the design load of the fin.
Can anyone verify the above ?
If they are accurate, then why were these not mentioned in the Horizon programme ? Or did I miss them ?
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Please excuse rookie question from a non-pilot.
According to the program, about an inch and a half of travel on the rudder pedals causes full deflection of the rudder at high speed. This seems very little - a pilot sneezing or coughing could in theory be enough to cause this kind of movement, which while not catastrophic, might make for an uncomfortable ride down the back.
Have I missed something obvious here? (like pilots feet aren't on the pedals at all during cruise maybe?).
Thanks for any response. Without knowing enough to be sure, it struck me as a balanced and fair assesment of the problem shown in the program. Airbus sure make it tough to love them, especially in the current climate of admiration for the French!
According to the program, about an inch and a half of travel on the rudder pedals causes full deflection of the rudder at high speed. This seems very little - a pilot sneezing or coughing could in theory be enough to cause this kind of movement, which while not catastrophic, might make for an uncomfortable ride down the back.
Have I missed something obvious here? (like pilots feet aren't on the pedals at all during cruise maybe?).
Thanks for any response. Without knowing enough to be sure, it struck me as a balanced and fair assesment of the problem shown in the program. Airbus sure make it tough to love them, especially in the current climate of admiration for the French!
'nough said
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Purely as a layman I thought the program was a tad biased against Airbus - i.e. the accident happened because it was an Airbus - so it's interesting to see that Boeing released a memo advising against using the multiple rudder reversal procedure on their planes too (as stated in a post above).
I also had the feeling that there was something missing from the program and that maybe the producers knew something that they were not allowed to broadcast (maybe for legal reasons) - it was the kind of feeling when you watch a film that ends open-ended and you kinda of go "and then what happened"? Did anyone else get that feeling?
I also thought it was a nice sensitive gesture not to broadcast the actual voice recordings as the plane was about to go down - it's not nice to listen to and should be kept private for the families and investigators involves, imho.
May they rest in peace.
I also had the feeling that there was something missing from the program and that maybe the producers knew something that they were not allowed to broadcast (maybe for legal reasons) - it was the kind of feeling when you watch a film that ends open-ended and you kinda of go "and then what happened"? Did anyone else get that feeling?
I also thought it was a nice sensitive gesture not to broadcast the actual voice recordings as the plane was about to go down - it's not nice to listen to and should be kept private for the families and investigators involves, imho.
May they rest in peace.
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I’m a bit uncomfortable with the use of rudder to recover from upsets. The usual technique for recovery from unusual attitudes is unload, speed, roll, pitch. In other words reduce the G-load, control the speed trend with power bearing in mind the pitch/power couple, idle thrust for nose low, mid to full thrust for nose up, roll to the horizon, then pitch. Use of speed-brake should be cautiously considered against its effect of reducing available lift and compromising the roll authority of the spoilers.
I’m afraid I can’t think of any primary role for the rudder in this. Unlike the wings or the horizontal stabiliser, it is not built to withstand high manoeuvring loads. The rudder is primarily for achieving longitudinal balance in flight and counteracting moderate out of trim loads in the event of engine failure. Yes, the secondary effect of rudder is roll, but it has only a very limited application in the recovery from upset scenario. If yaw is required then assymetric thrust would be far quicker.
In all the years I’ve been flying big aeroplanes, I cannot remember any procedure that required me to rapidly apply full rudder followed by an immediate reversal. I have been conditioned to avoid the use of large rudder deflections at high speed. In many years on the 767, from memory the failure of the rudder ratio system after a hydraulic system loss (can’t remember which one) specifically mentions the necessity to avoid large rudder inputs to avoid structural failure.
Hindsight is a wonderful thing, but we do all need to analyse the actions of the unfortunate crew involved in case there’s anything we can learn. To do anything less would be to dishonour their untimely deaths. I’ll leave blame to the lawyers and suits, that’s about all they’re good at.
I’m afraid I can’t think of any primary role for the rudder in this. Unlike the wings or the horizontal stabiliser, it is not built to withstand high manoeuvring loads. The rudder is primarily for achieving longitudinal balance in flight and counteracting moderate out of trim loads in the event of engine failure. Yes, the secondary effect of rudder is roll, but it has only a very limited application in the recovery from upset scenario. If yaw is required then assymetric thrust would be far quicker.
In all the years I’ve been flying big aeroplanes, I cannot remember any procedure that required me to rapidly apply full rudder followed by an immediate reversal. I have been conditioned to avoid the use of large rudder deflections at high speed. In many years on the 767, from memory the failure of the rudder ratio system after a hydraulic system loss (can’t remember which one) specifically mentions the necessity to avoid large rudder inputs to avoid structural failure.
Hindsight is a wonderful thing, but we do all need to analyse the actions of the unfortunate crew involved in case there’s anything we can learn. To do anything less would be to dishonour their untimely deaths. I’ll leave blame to the lawyers and suits, that’s about all they’re good at.
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I can vouch for the fact that good ole Captain Van.d.B advised using aggressive rudder inputs having seen the video of the AA symposium when it was first mooted as part of company training.
The difference is that these inputs were only advised during LOSS OF CONTROL resulting in an unusual attitude ie up to actually inverted.
The relatively minor controllability problems caused by wake turbulence as shown on the Beeb should not have necessitated these inputs, the A300 is not a 172.
The CRM aspects of being spring loaded or predisposed towards a particular scenario were barely covered.
The difference is that these inputs were only advised during LOSS OF CONTROL resulting in an unusual attitude ie up to actually inverted.
The relatively minor controllability problems caused by wake turbulence as shown on the Beeb should not have necessitated these inputs, the A300 is not a 172.
The CRM aspects of being spring loaded or predisposed towards a particular scenario were barely covered.