New Theory and Speculation On AA A300 Crash In New York
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The last I heard, the FDR cannot determine weather the pilot caused full deflection of the rudder or if the rudder deflection caused a feed back to the peddles. Given the history of rudder problems on the A300-600 it gives credibility to the latter scenario.
The last I heard, the FDR cannot determine weather the pilot caused full deflection of the rudder or if the rudder deflection caused a feed back to the peddles. Given the history of rudder problems on the A300-600 it gives credibility to the latter scenario.
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Hey there, 747FOCAL, you say.....have been thru 500 stalls (not in aircraft)....this must have been in the Sim. Yes?
What makes you think the sim actually demonstrates actual stall conditions? Are you a test pilot or what?
You sound like an amateur to me. Or, to give you the benefit of the doubt, misinformed. <img src="rolleyes.gif" border="0">
What makes you think the sim actually demonstrates actual stall conditions? Are you a test pilot or what?
You sound like an amateur to me. Or, to give you the benefit of the doubt, misinformed. <img src="rolleyes.gif" border="0">
....or perhaps he/she's a Flight Test Observer/Engineer and has been involved with testing although not at the controls him/herself? Incidentally, the term 'breaking' in his/her post refers to a +Gz 'break' at the stall, not structural failure, and a 'wind up' is a manoeuvre incolving increasing +Gz and angle of bank in level flight untilthe point of stalling is reached - rather him/her than me in a large aeroplane!
I suspect he/she is far from being an 'amateur' as you have suggested, 411A.
[ 08 January 2002: Message edited by: BEagle ]</p>
I suspect he/she is far from being an 'amateur' as you have suggested, 411A.
[ 08 January 2002: Message edited by: BEagle ]</p>
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747FOCAL, you stated
´I doubt there is any input a pilot could do that should make control surfaces or the tail or engines come off a plane if it satisfies all FAR requirements for structural integrity.´
Just look at FAR 25.361 and you shurely believe a pilot can overstress a plane´s tail :
14 CFR 25 Sec. 25.351 Yawing conditions.
The airplane must be designed for loads resulting from the conditions specified in paragraph (a) of this section. Unbalanced aerodynamic moments about the center of gravity must be reacted in a rational or conservative manner considering the principal masses furnishing the reacting inertia forces:
(a) Maneuvering. At speeds from VMC to VD, the following maneuvers must be considered. In computing the tail loads, the yawing velocity may be assumed to be zero:
(1) With the airplane in unaccelerated flight at zero yaw, it is assumed that the rudder control is suddenly displaced to the maximum deflection, as limited by the control surface stops, or by a 300-pound rudder pedal force, whichever is less.
(2) With the rudder deflected as specified in paragraph (a)(1) of this section, it is assumed that the airplane yaws to the resulting sideslip angle.
(3) With the airplane yawed to the static sideslip angle corresponding to the rudder deflection specified in paragraph (a)(1) of this section, it is assumed that the rudder is returned to neutral.
(b) [Reserved]
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 35 FR 5672, Apr. 8, 1970; Amdt. 25-46, 43 FR 50595, Oct. 30, 1978; Amdt. 25-72, 55 FR 29775, July 20, 1990; 55 FR 37608, Sept. 12, 1990; 55 FR 41415, Oct. 11, 1990; Amdt. 25-86, 61 FR 5222, Feb. 9, 1996]
So just apply full rudder (FAR 25.361 (1)), wait for maximum sideslip angle (FAR 25.361 (2)), dont just return rudder to neutral as specified in (FAR 25.361 (3)) but apply full opposite rudder and you shurely overstess your airframe. And in this case the yawing speed is not even accounted for, for a plane wich such a long aft fuselage it produces another amount of effective tail fin angle of attack. Additionally the maximum dynamic sideslip angle is much larger than the static one, so it is easyly possible to produce about twice the angle of attack dynamically and apply rudder in the direction that increases aerodynamic forces. European JAR 25.361 is just the same as the FAR requirement.
As my structural design professor always said : It is impossible to design a plane that can not be destroyed by wrong pilot control inputs at the right speed and flight attitude. (might not be true for fighter airplane where the physical capabilities of the pilot are the limiting factor and the pilot rather kills himself before breaking the airframe)
There are some more paragraphs important for structural design of the fin like lateral gustloads and single engine failure loads, so it is not clear if the 25.351 yawing condition is the most critical for a specific airplane. But it is for shure possible to exceed the loads specified in this paragraph.
´I doubt there is any input a pilot could do that should make control surfaces or the tail or engines come off a plane if it satisfies all FAR requirements for structural integrity.´
Just look at FAR 25.361 and you shurely believe a pilot can overstress a plane´s tail :
14 CFR 25 Sec. 25.351 Yawing conditions.
The airplane must be designed for loads resulting from the conditions specified in paragraph (a) of this section. Unbalanced aerodynamic moments about the center of gravity must be reacted in a rational or conservative manner considering the principal masses furnishing the reacting inertia forces:
(a) Maneuvering. At speeds from VMC to VD, the following maneuvers must be considered. In computing the tail loads, the yawing velocity may be assumed to be zero:
(1) With the airplane in unaccelerated flight at zero yaw, it is assumed that the rudder control is suddenly displaced to the maximum deflection, as limited by the control surface stops, or by a 300-pound rudder pedal force, whichever is less.
(2) With the rudder deflected as specified in paragraph (a)(1) of this section, it is assumed that the airplane yaws to the resulting sideslip angle.
(3) With the airplane yawed to the static sideslip angle corresponding to the rudder deflection specified in paragraph (a)(1) of this section, it is assumed that the rudder is returned to neutral.
(b) [Reserved]
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 35 FR 5672, Apr. 8, 1970; Amdt. 25-46, 43 FR 50595, Oct. 30, 1978; Amdt. 25-72, 55 FR 29775, July 20, 1990; 55 FR 37608, Sept. 12, 1990; 55 FR 41415, Oct. 11, 1990; Amdt. 25-86, 61 FR 5222, Feb. 9, 1996]
So just apply full rudder (FAR 25.361 (1)), wait for maximum sideslip angle (FAR 25.361 (2)), dont just return rudder to neutral as specified in (FAR 25.361 (3)) but apply full opposite rudder and you shurely overstess your airframe. And in this case the yawing speed is not even accounted for, for a plane wich such a long aft fuselage it produces another amount of effective tail fin angle of attack. Additionally the maximum dynamic sideslip angle is much larger than the static one, so it is easyly possible to produce about twice the angle of attack dynamically and apply rudder in the direction that increases aerodynamic forces. European JAR 25.361 is just the same as the FAR requirement.
As my structural design professor always said : It is impossible to design a plane that can not be destroyed by wrong pilot control inputs at the right speed and flight attitude. (might not be true for fighter airplane where the physical capabilities of the pilot are the limiting factor and the pilot rather kills himself before breaking the airframe)
There are some more paragraphs important for structural design of the fin like lateral gustloads and single engine failure loads, so it is not clear if the 25.351 yawing condition is the most critical for a specific airplane. But it is for shure possible to exceed the loads specified in this paragraph.
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Supposing there was an uncommanded rudder 'hard-over' (like in the 737's) - it still does not explain the break-up? Those 737's didn't break up, and at cruising altitude they would have been flying much faster than this A300 was on departure.
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First 411A- Why would you think simulator since I refered to feeling and hearing sounds that most pilots will never encounter or whatever I said? I only said I wasn't doing the flying. Of course they were in a real airplane. Been sitting in the cockpit of a 727 when the pilot took it down to 85 kts at 18,000 ft. He said it was probably wrong as we were at such an attitude that the pitot tubes were not getting proper airflow. In a simulator, thats rich. I can barrel roll a 747-400 at 875,000 in the sim, bet I couldn't do it in real life. <img src="eek.gif" border="0">
[ 08 January 2002: Message edited by: 747FOCAL ]</p>
[ 08 January 2002: Message edited by: 747FOCAL ]</p>
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"As my structural design professor always said : It is impossible to design a plane that can not be destroyed by wrong pilot control inputs at the right speed and flight attitude. (might not be true for fighter airplane where the physical capabilities of the pilot are the limiting factor and the pilot rather kills himself before breaking the airframe)"
He said "right speed and flight attitude" This airplane was way below it's design maximum speed. And was not at an attitude that was out of cert limits. Of course if you dive to mach 1 and pull back hard at step on one rudder pedal hard the wings and tail will come off. I been in flutter tests as well.
"As my structural design professor always said : It is impossible to design a plane that can not be destroyed by wrong pilot control inputs at the right speed and flight attitude. (might not be true for fighter airplane where the physical capabilities of the pilot are the limiting factor and the pilot rather kills himself before breaking the airframe)"
He said "right speed and flight attitude" This airplane was way below it's design maximum speed. And was not at an attitude that was out of cert limits. Of course if you dive to mach 1 and pull back hard at step on one rudder pedal hard the wings and tail will come off. I been in flutter tests as well.
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Your profile indicates that you are an Aero Engineer so I am hardly in a position to argue with you in this field, but does part 25 take in to account aircraft with rudder limiting systems designed to negate the large inputs that could cause the vertical stab to fail?
If it was so easy to cause a vertical stab to fail then the world would be littered with aircraft aluminum. I just don't buy it.
Your profile indicates that you are an Aero Engineer so I am hardly in a position to argue with you in this field, but does part 25 take in to account aircraft with rudder limiting systems designed to negate the large inputs that could cause the vertical stab to fail?
If it was so easy to cause a vertical stab to fail then the world would be littered with aircraft aluminum. I just don't buy it.
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BEagle- Thanks for your support. You are correct I am a flight test engineer among other things. It is fun to do that stuff, but I am glad I don't do it everyday. 4 hours of stalling and your head feels all swollen up. doesn't hurt just feels different from your brain bouncing around in the the brain bucket. 
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Well 747FOCAL, suggest you keep to engineering and leave the "piloting" to....actual pilots (or flight test pilots).
And...stick to KILOS so our European friends understand.
And...stick to KILOS so our European friends understand.
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411A- You must be daft. Then again this isn't the first thread I have seen your rantings. I think I hear the Guv calling........ How is that live in Hey Boy thing going anyway?
ps. to convert lbs to kilos divide by 2.2 and you should be close enough for that C152 they let you motor around your backyard.
[ 09 January 2002: Message edited by: 747FOCAL ]</p>
ps. to convert lbs to kilos divide by 2.2 and you should be close enough for that C152 they let you motor around your backyard.
[ 09 January 2002: Message edited by: 747FOCAL ]</p>
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747
like you I am a pilot and an engineer. Surely you should have enough experience to know that we have no idea which way a particular aircraft type will react to certain stresses in certain conditions. History has proven time and time again that 'foolproof' systems have a way of failing. Imagine the bridge buiders shock who built indestuctable bridges when they were confronted by 'resonance' and found a moderate wind could knock their bridges down. I am amazed that you cannot accept that a structural problem caused by control input in certain conditions resulted in this accident.
Of course it may not have been, but JFK conspiracy theories do not lie around EVERY corner in life. History has proven that aircraft crash investigators do a pretty good job and are reasonably honest (thank God). How likely is it that they are trying to cover something up or that they are barking up the wrong tree and that a 500 stall man is correct. Unfortunately I have to say my money goes on the investigators. No offense intended but I think you need to accept that history will probably prove you wrong. Of course there is a chance that what you say is correct and I accept that and welcome discussion on it, but I think you are a bit brazen to shoot down the proven experts based on your lower level of experience in crash investigation (I assume you are not an experienced crash investigator because I'm sure you would have added it to your CV)
like you I am a pilot and an engineer. Surely you should have enough experience to know that we have no idea which way a particular aircraft type will react to certain stresses in certain conditions. History has proven time and time again that 'foolproof' systems have a way of failing. Imagine the bridge buiders shock who built indestuctable bridges when they were confronted by 'resonance' and found a moderate wind could knock their bridges down. I am amazed that you cannot accept that a structural problem caused by control input in certain conditions resulted in this accident.
Of course it may not have been, but JFK conspiracy theories do not lie around EVERY corner in life. History has proven that aircraft crash investigators do a pretty good job and are reasonably honest (thank God). How likely is it that they are trying to cover something up or that they are barking up the wrong tree and that a 500 stall man is correct. Unfortunately I have to say my money goes on the investigators. No offense intended but I think you need to accept that history will probably prove you wrong. Of course there is a chance that what you say is correct and I accept that and welcome discussion on it, but I think you are a bit brazen to shoot down the proven experts based on your lower level of experience in crash investigation (I assume you are not an experienced crash investigator because I'm sure you would have added it to your CV)
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I don't care what any of you engineers or crash investigators say. Tails are NOT supposed to fall of transport catagory airplanes due to wake, control input, composites, or anything else.. .There is at least 50 years of design experience with aluminum flight control surfaces and all but maybe 10 with composites. I hate to throw this out, but has anyone considered the fact that Airbus may have screwed it up on this one?
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I was reading an article (I think from Flight International) that indicated the data from the flight was, in fact, filtered internally.
Would this tend to hide the sudden transients and control extremes that are being talked about here?
If the data extremes can not be determined from the FDR, then what course of action can the investigators take apart from some intelligent guesswork ?
The same article also refers to the testing of a fin assembly identical to the one from the destroyed aircraft.
Would this tend to hide the sudden transients and control extremes that are being talked about here?
If the data extremes can not be determined from the FDR, then what course of action can the investigators take apart from some intelligent guesswork ?
The same article also refers to the testing of a fin assembly identical to the one from the destroyed aircraft.
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If my memory is correct there was a 707 that was involved in a midair breakup, in the early days of the jets, which was attributed to overcontrol in turbulence, and that aircraft was built like a brick outhouse.. .regards
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Correcto Steamhead............Over Mt. Fuji in Japan. In that area you can get CAT that will shake your teeth out. I have been in 170 knot winds in that area. But that is a whole lot different than being 5 miles behind a B 747.
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Can any of you try this out, as a thought experiment?
Put 10 oz of semtex pressed in a somewhat shaped charge ( as someone pressing their shoes against the AC fuselage would shape a charge), perhaps in the rear head or last few seats in the plane, and then discharge this bomb on 587.
Can you come up with the sudden gyrations and loss of control resulting in the tail falling off, along with the AC breakup, to fit the crash of 587 when you consider this charge? The size of the charge is small, so would that keep it off of the sound recorder? Would such a charge actually be shaped, such that if in the rear of the aricraft it would be similar to a small rocket thrust, violently moving the read sidewais similar to a flat spin?
Or can a stinger be fired with out a tail being noticed?
My thoughts initially raised ire and condescending platitudes from most of you, but it is near humorous (but for the fact that this is a most terroble tragedy) now in observing the contortions most of you are going through trying to figure out why a perfectly good AC dropped out fo the sky when piloted by a senior pilot during optimal flying conditions. It seems most are starting to come to an Airbus conspiracy coverup assisted by the NTSB, or soemthing similar. (A NTSB coverup of a bomb to avoid total implosion and panic of the airline industry is more likely.)
In times of war, on a clear beautiful day with little or no normally occuring exogenous forces or events identified, a large AC will usually fall from the sky from an act of war. Makes sense to me. Why do you refuse to take the Occum's Razor approach?
I am very impressed with the majority of "ostrich" like views here that refuse to try on the thought model above, despite all the terrible things that have happened since 9/11 and most importantly since Reid.
Why dont you guys wake up? We are at war.
Come on, as a public service, use your professional skills and engineering ability to proof out how such a bomb charge model can fit the event. Try hard. Then , and only after that effort, should you discard an act of war as the reason. Most of you have it totally ass backwards and will be forced to consider the bomb after losing much personal credibility by trying out incredible contortions first.
Rescue your professional consderations and reputations.
Try the thought experiment.
Put 10 oz of semtex pressed in a somewhat shaped charge ( as someone pressing their shoes against the AC fuselage would shape a charge), perhaps in the rear head or last few seats in the plane, and then discharge this bomb on 587.
Can you come up with the sudden gyrations and loss of control resulting in the tail falling off, along with the AC breakup, to fit the crash of 587 when you consider this charge? The size of the charge is small, so would that keep it off of the sound recorder? Would such a charge actually be shaped, such that if in the rear of the aricraft it would be similar to a small rocket thrust, violently moving the read sidewais similar to a flat spin?
Or can a stinger be fired with out a tail being noticed?
My thoughts initially raised ire and condescending platitudes from most of you, but it is near humorous (but for the fact that this is a most terroble tragedy) now in observing the contortions most of you are going through trying to figure out why a perfectly good AC dropped out fo the sky when piloted by a senior pilot during optimal flying conditions. It seems most are starting to come to an Airbus conspiracy coverup assisted by the NTSB, or soemthing similar. (A NTSB coverup of a bomb to avoid total implosion and panic of the airline industry is more likely.)
In times of war, on a clear beautiful day with little or no normally occuring exogenous forces or events identified, a large AC will usually fall from the sky from an act of war. Makes sense to me. Why do you refuse to take the Occum's Razor approach?
I am very impressed with the majority of "ostrich" like views here that refuse to try on the thought model above, despite all the terrible things that have happened since 9/11 and most importantly since Reid.
Why dont you guys wake up? We are at war.
Come on, as a public service, use your professional skills and engineering ability to proof out how such a bomb charge model can fit the event. Try hard. Then , and only after that effort, should you discard an act of war as the reason. Most of you have it totally ass backwards and will be forced to consider the bomb after losing much personal credibility by trying out incredible contortions first.
Rescue your professional consderations and reputations.
Try the thought experiment.
Dozens of Pilots Want American to Ground A300. .By John Crawley
WASHINGTON (Reuters) - Dozens of pilots at American Airlines want the carrier to ground its fleet of Airbus A300s, saying too many unresolved safety questions have been raised since one of the airliners crashed in New York in November.
"Are we completely comfortable putting our friends and family on an A300? If the answer to that question is not a resounding yes, then logic would lead a well-trained pilot to conclude that no one should be flying on them either,'' according to a recent open letter initially signed by a dozen American A300 pilots in New York, Boston and Miami.
About 60 pilots have signed the letter, which was also circulated to other crew members.
American, a unit of AMR Corp. has about 400 pilots who fly the carrier's 34 wide-body A300s, the company said.
The airline and Airbus SAS said on Thursday there were no plans to ground the fleet, stressing that safety officials investigating the crash of Flight 587 have found no reason to do so.
That plane, An A300-600 crashed shortly after takeoff from New York's John F. Kennedy International Airport, killing all 260 aboard and five people on the ground.
Investigators are looking at a possible mechanical problem, a structural defect with the composite materials that make up the aircraft's tail fin, or actions by the crew to explain the disaster.
No other U.S. commercial carrier other than American offers A300 service, but cargo airlines Fedex Corp. and United Parcel Service operate them.
The letter was not linked to the pilots union at American, the Allied Pilots Association. In fact, the union said it did not back the demand.
"We are not advocating a grounding of the A300 fleet at this point,'' spokesman Gregg Overman said.
The pilots who signed the letter are unhappy that investigators, the manufacturer and the airline have yet to develop a clear idea of why the jetliner's tail fin, or vertical stabilizer, and rudder fell off before the A300 crashed into a residential neighborhood.
"At this point, safety experts and our own safety and fleet people have agreed that no test exists to definitively check the structural integrity of the vertical stabilizers on our remaining 34 aircraft,'' the letter said.
After the crash, the Federal Aviation Administration (news - web sites) ordered American and the cargo carriers to conduct visual checks of the A300 tail section. All reported no safety problems.
Aside from the focus on the carbon-reinforced plastic composites that make up the thick tail fin, investigators are looking closely at three sharp, unexplained rudder deflections just before the plane crashed.
It has not been determined whether these rudder movements were commanded by the crew, or if there was a glitch in the Airbus systems associated with the flight control components.
The safety board is looking into a handful of flight control mishaps over the past several years involving the A300. One involved the ill-fated American jet in 1994.
Investigators confirmed on Thursday they were examining a report that an uncommanded rudder movement prompted the pilot of an American A300 to return to Caracas, Venezuela, shortly after takeoff on Jan. 17. That plane was bound for Miami.
WASHINGTON (Reuters) - Dozens of pilots at American Airlines want the carrier to ground its fleet of Airbus A300s, saying too many unresolved safety questions have been raised since one of the airliners crashed in New York in November.
"Are we completely comfortable putting our friends and family on an A300? If the answer to that question is not a resounding yes, then logic would lead a well-trained pilot to conclude that no one should be flying on them either,'' according to a recent open letter initially signed by a dozen American A300 pilots in New York, Boston and Miami.
About 60 pilots have signed the letter, which was also circulated to other crew members.
American, a unit of AMR Corp. has about 400 pilots who fly the carrier's 34 wide-body A300s, the company said.
The airline and Airbus SAS said on Thursday there were no plans to ground the fleet, stressing that safety officials investigating the crash of Flight 587 have found no reason to do so.
That plane, An A300-600 crashed shortly after takeoff from New York's John F. Kennedy International Airport, killing all 260 aboard and five people on the ground.
Investigators are looking at a possible mechanical problem, a structural defect with the composite materials that make up the aircraft's tail fin, or actions by the crew to explain the disaster.
No other U.S. commercial carrier other than American offers A300 service, but cargo airlines Fedex Corp. and United Parcel Service operate them.
The letter was not linked to the pilots union at American, the Allied Pilots Association. In fact, the union said it did not back the demand.
"We are not advocating a grounding of the A300 fleet at this point,'' spokesman Gregg Overman said.
The pilots who signed the letter are unhappy that investigators, the manufacturer and the airline have yet to develop a clear idea of why the jetliner's tail fin, or vertical stabilizer, and rudder fell off before the A300 crashed into a residential neighborhood.
"At this point, safety experts and our own safety and fleet people have agreed that no test exists to definitively check the structural integrity of the vertical stabilizers on our remaining 34 aircraft,'' the letter said.
After the crash, the Federal Aviation Administration (news - web sites) ordered American and the cargo carriers to conduct visual checks of the A300 tail section. All reported no safety problems.
Aside from the focus on the carbon-reinforced plastic composites that make up the thick tail fin, investigators are looking closely at three sharp, unexplained rudder deflections just before the plane crashed.
It has not been determined whether these rudder movements were commanded by the crew, or if there was a glitch in the Airbus systems associated with the flight control components.
The safety board is looking into a handful of flight control mishaps over the past several years involving the A300. One involved the ill-fated American jet in 1994.
Investigators confirmed on Thursday they were examining a report that an uncommanded rudder movement prompted the pilot of an American A300 to return to Caracas, Venezuela, shortly after takeoff on Jan. 17. That plane was bound for Miami.