Interesting note about AA Airbus crash in NYC
YankeeWhiskey, thank you very much for the link provided. This quote is taken from it:
Now would anyone, please, still clinging to the opinion that there was pre-existing damage and that fin was weakened, please explain to us why does he have problems accepting this factual statement, signed by the NTSB experts, please. Thank you.
Now there are at least two severly tragic facts linked to this accident.
First was pointed out by Hand Solo: hitting the wake turbulence was almost a non-event, inappropriate reaction by pilot flying was what caused the accident. As I have quoted many times before on the PPRuNe: he has bet (although this bet was made unknowingly, in the heat of the moment) his life and life of his crew and passengers that he was doing just the right thing. And lost.
Second is that the main lesson of this crash is not just applicable to A300 pilots but to every pilot of any heavier-than-air fixed wing aircraft, but sadly it seems that almost noone took notice. As I feel it is worth shouting from the rooftops, here it comes again:
NEVER, EVER RAPIDLY CYCLE ANY FLIGHT CONTROL AT ANY FLYING SPEED. YOU MIGHT DIE IF YOU DO.
Yep, you can safely make a full control deflection of any flight control at Va or less but that means just that: to stop and then back to neutral. Not rapidly from stop to stop. Also safely here means: without the risk of the airframe failure, stalling is another matter.
Also AA Advanced manuevering program stressed the use of rudder, when recovering from unusal roll attitudes and never advocated cycling it, but it also never explicitly warned against controls cycling. Either the creators of AMP tought that everyone was aware of dangers associated with it, so there was no need to mention it again, or they were unaware of it too. Chances are we'll never know for sure.
Likewise, the maintenance log shows no problems. Investigators looked for preexisting damage on the vertical stabilizer. This aircraft had been involved in a severe turbulence incident several years before but no damage was found. The NTSB noted that even if there were pre-existing damage to the stabilizer, the structure remained intact until massive overloads were sustained. Aerodynamic and internal stress calculations on the vertical stabilizer computed by Airbus, and independently by the NTSB, show that loading was significantly above the ultimate loads required by certification standards and actually near the structural test loads demonstrated during the certification process.
I imagined that one of the tests during certification, is you could whack on fairly heavy control inputs without bending anything.
First was pointed out by Hand Solo: hitting the wake turbulence was almost a non-event, inappropriate reaction by pilot flying was what caused the accident. As I have quoted many times before on the PPRuNe: he has bet (although this bet was made unknowingly, in the heat of the moment) his life and life of his crew and passengers that he was doing just the right thing. And lost.
Second is that the main lesson of this crash is not just applicable to A300 pilots but to every pilot of any heavier-than-air fixed wing aircraft, but sadly it seems that almost noone took notice. As I feel it is worth shouting from the rooftops, here it comes again:
NEVER, EVER RAPIDLY CYCLE ANY FLIGHT CONTROL AT ANY FLYING SPEED. YOU MIGHT DIE IF YOU DO.
Yep, you can safely make a full control deflection of any flight control at Va or less but that means just that: to stop and then back to neutral. Not rapidly from stop to stop. Also safely here means: without the risk of the airframe failure, stalling is another matter.
Also AA Advanced manuevering program stressed the use of rudder, when recovering from unusal roll attitudes and never advocated cycling it, but it also never explicitly warned against controls cycling. Either the creators of AMP tought that everyone was aware of dangers associated with it, so there was no need to mention it again, or they were unaware of it too. Chances are we'll never know for sure.
Join Date: Dec 2007
Location: Montreal
Age: 92
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
An ounce of prevention.....
There are a number of observations made on this forum following the AAL accident, most of which have value when seen on their own merrits and when seen together. I have learned from it.
The fact the fin broke off at loads exceeding design limits, then the fact that a pilot used the rudder employing full deflections followed by practical advise to pilots NEVER to employ full felections and the POSSIBILITY of a failure mode introduced by water freezing inside a structure etc etc etc.
We have the expert forensic engineer talk from his point of view and the pilots from theirs, not to ignore the non-pilot and the aircraft maintenance engineer on the shop floor, all of whom have made important contributions to these discussions.
Before those of us, so inclined, start throwing more pointed critical evaluations of what some of us are lacking in language or technical knowledge and/or applied seriousness, let's agree that preventing an accident, such as AAL, is what it is all about.
This has been accomplished, in my opinion at least. I know that one operator flying Airbus has taken serious measures at the shop floor and cockpit crew levels to prevent departures of rudders and fins from their aircraft.
I fully agree with all of you where it concerns your earnest desire to prevent accidents from happening in the first place.
One final note; PBL has, apparently, never had to dig into the mud during the early spring to get to a burst PVC waterpipe that had some left over water in it from the previous fall winterization (blowing out the pipes with air). It happens when temps dip into freezing levels that can reach
-45C. I am not making this up, believe me!
The fact the fin broke off at loads exceeding design limits, then the fact that a pilot used the rudder employing full deflections followed by practical advise to pilots NEVER to employ full felections and the POSSIBILITY of a failure mode introduced by water freezing inside a structure etc etc etc.
We have the expert forensic engineer talk from his point of view and the pilots from theirs, not to ignore the non-pilot and the aircraft maintenance engineer on the shop floor, all of whom have made important contributions to these discussions.
Before those of us, so inclined, start throwing more pointed critical evaluations of what some of us are lacking in language or technical knowledge and/or applied seriousness, let's agree that preventing an accident, such as AAL, is what it is all about.
This has been accomplished, in my opinion at least. I know that one operator flying Airbus has taken serious measures at the shop floor and cockpit crew levels to prevent departures of rudders and fins from their aircraft.
I fully agree with all of you where it concerns your earnest desire to prevent accidents from happening in the first place.
One final note; PBL has, apparently, never had to dig into the mud during the early spring to get to a burst PVC waterpipe that had some left over water in it from the previous fall winterization (blowing out the pipes with air). It happens when temps dip into freezing levels that can reach
-45C. I am not making this up, believe me!
Join Date: Sep 2000
Location: Bielefeld, Germany
Posts: 955
Likes: 0
Received 0 Likes
on
0 Posts
IGh,
thanks! I didn't know about AA Flight 1.
Yankee Whiskey, I say again, you need to get to grips with the physics of freezing water. You are persuading me rather well that one cannot learn it just by doing.
Screwball, thanks for the kind words. There is some reason behind it. I actually think airsupport is an impostor. I have had lots of dealings over the years with alternative-explanation theorists. Some of them are right, most of them are clearly wrong (some of them stupidly wrong, like Pierre Salinger). But all of them have been only too glad to provide reams of information, usually far more than one wants or that is useful, about their theories. Airsupport says one thing, expressible in one or two short sentences, and then goes aggressively ad hominem if one asks him for any details. This behavior just doesn't fit type. The guy doesn't appear to have any clue about engineering (I cannot imagine any serious engineer describing a component that failed 30+% over spec strength as "seriously weakened") and acts rapidly to deflect any engineering query. I think he's just trying to spread an internet rumor and chose the wrong forum.
Speaking of alternative-explanation theorists, I would like to mention two in particular.
One is the cluster of people around (was it?) the Boeing wiring lab who were distributing reams of information in 1995 about wiring defects (degradation and so on) in older transport airplanes and no one apparently would listen to them. (One should not forget in this regard the prescient work done by Pat Cahill at the FAA Technical Center.) Then came TWA 800 and the colleagues at the NTSB discovered all about the extent of the problem with aging wiring. Not to denigrate their excellent investigative work, but I do think it was a bit mean not to credit the others who were on the case years previously. I didn't say anything about it, though.
The other is Robert Allardyce, who through doggedness and selective application of the FOIA uncovered some USG data (radar data showing the track over Alaska; data from CIA OTH backscatter radar mid-ocean) which is inconsistent with the ICAO explanation of the nav error undergone by KAL 007. That discrepant data has still to be explained. I don't necessarily buy Allardyce's explanation, but he has done the hard work necessary to get the data. There is some hope that we might learn more in 2008, for that is then 25 years hence and much government information is declassified after 25 years.
PBL
thanks! I didn't know about AA Flight 1.
Yankee Whiskey, I say again, you need to get to grips with the physics of freezing water. You are persuading me rather well that one cannot learn it just by doing.
Screwball, thanks for the kind words. There is some reason behind it. I actually think airsupport is an impostor. I have had lots of dealings over the years with alternative-explanation theorists. Some of them are right, most of them are clearly wrong (some of them stupidly wrong, like Pierre Salinger). But all of them have been only too glad to provide reams of information, usually far more than one wants or that is useful, about their theories. Airsupport says one thing, expressible in one or two short sentences, and then goes aggressively ad hominem if one asks him for any details. This behavior just doesn't fit type. The guy doesn't appear to have any clue about engineering (I cannot imagine any serious engineer describing a component that failed 30+% over spec strength as "seriously weakened") and acts rapidly to deflect any engineering query. I think he's just trying to spread an internet rumor and chose the wrong forum.
Speaking of alternative-explanation theorists, I would like to mention two in particular.
One is the cluster of people around (was it?) the Boeing wiring lab who were distributing reams of information in 1995 about wiring defects (degradation and so on) in older transport airplanes and no one apparently would listen to them. (One should not forget in this regard the prescient work done by Pat Cahill at the FAA Technical Center.) Then came TWA 800 and the colleagues at the NTSB discovered all about the extent of the problem with aging wiring. Not to denigrate their excellent investigative work, but I do think it was a bit mean not to credit the others who were on the case years previously. I didn't say anything about it, though.
The other is Robert Allardyce, who through doggedness and selective application of the FOIA uncovered some USG data (radar data showing the track over Alaska; data from CIA OTH backscatter radar mid-ocean) which is inconsistent with the ICAO explanation of the nav error undergone by KAL 007. That discrepant data has still to be explained. I don't necessarily buy Allardyce's explanation, but he has done the hard work necessary to get the data. There is some hope that we might learn more in 2008, for that is then 25 years hence and much government information is declassified after 25 years.
PBL
Join Date: Sep 2000
Location: Bielefeld, Germany
Posts: 955
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by PBL
I actually think airsupport is an impostor.
Originally Posted by airsupport
And what is that supposed to mean
I do, obviously, have the resources to find that out, should I consider it worth while.
PBL
Join Date: May 2000
Location: Camp X-Ray
Posts: 2,135
Likes: 0
Received 0 Likes
on
0 Posts
I don't think airsupport is an impostor, but I do think he is a different kind of engineer to PBL. To use an analogy, airsupport is like the pit lane engineer in a Formula 1 team. He's seen a new spoiler come out from the design labs and it keeps working loose from the car. It would stand to reason that the design of the spoiler could be at fault as these problems didn't exist before the new spoiler arrived on the car. On the other hand PBL is the aerodynamicist in the wind tunnel looking at the spoiler design. Technically it's perfectly acceptable. There are many reasons the spoiler could be working loose. Perhaps the design really is duff. Or maybe it's the fastenings that are defective. Or maybe the suspension is incorrectly tuned causing resonant vibrations in the fasteners which are then working loose. Or maybe the way the driver is driving the car is overstressing the fasteners. The point is that there is not necessarily much crossover in the way that airsupport and PBL see the problem. Airsupports input into where, when and how the spoiler is coming loose is essential to the investigation, but it cannot be said that just because the spoiler is coming loose the spoiler design must be to blame. It's PBLs job to work out if the spoiler really is to blame or if it's one of countless other reasons. If, after extensive investigation, it turns out that the spoiler design is sound and another factor has caused the failures then we have to accept those findings and not hang on to the belief that because the problem is local to the spoiler then the spoiler must be to blame. Sometimes the analysis goes above our level of expertise and we have to accept the experts findings.
Join Date: May 2002
Location: Brisbane
Age: 77
Posts: 1,406
Likes: 0
Received 0 Likes
on
0 Posts
PBL,
Prior to my recent retirement, I spent over 40 years as an Aircraft Engineer, working all over the World, as I mentioned in New York and also many other parts of the USA including at Boeing, McDonnell Douglas and GE, plus many other Countries too including places like Vietnam and Russia.
Prior to my recent retirement, I spent over 40 years as an Aircraft Engineer, working all over the World, as I mentioned in New York and also many other parts of the USA including at Boeing, McDonnell Douglas and GE, plus many other Countries too including places like Vietnam and Russia.
Join Date: May 2002
Location: Brisbane
Age: 77
Posts: 1,406
Likes: 0
Received 0 Likes
on
0 Posts
Hand Solo,
Your post wasn't there when I was typing my previous one, but yes that would be a fair analogy.
I just get upset when after spending a Lifetime in Aircraft Engineering, someone who doesn't even know me, accuses me of being an impostor, just because I don't agree with him 100%.
Best regards,
airsupport.
Your post wasn't there when I was typing my previous one, but yes that would be a fair analogy.
I just get upset when after spending a Lifetime in Aircraft Engineering, someone who doesn't even know me, accuses me of being an impostor, just because I don't agree with him 100%.
Best regards,
airsupport.
Thread Starter
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,125
Likes: 0
Received 13 Likes
on
8 Posts
Airsupport,
Please stop swearing in your responses. It is only going to get this thread that I started way back when, shut down and it destroys your credibility. While I have lost track of the discussion on this thread, I would suggest that if you have an arguement, to make to use logic and common sense in your replies.
I have had to do this in my disagreement with PBL and his coworkers Joernstu and Bernd on this thread here.
http://www.pprune.org/forums/showthread.php?t=291507
And it works. Its a bit long but worth reading.
Please stop swearing in your responses. It is only going to get this thread that I started way back when, shut down and it destroys your credibility. While I have lost track of the discussion on this thread, I would suggest that if you have an arguement, to make to use logic and common sense in your replies.
I have had to do this in my disagreement with PBL and his coworkers Joernstu and Bernd on this thread here.
http://www.pprune.org/forums/showthread.php?t=291507
And it works. Its a bit long but worth reading.
Last edited by punkalouver; 3rd Jan 2008 at 02:48.
Thread Starter
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,125
Likes: 0
Received 13 Likes
on
8 Posts
In order to try to keep this thread somewhat on topic I am pasting a link to Peter Garrison's writeup on the AA 587 accident. AA587: The Perils of Flying by the Book. He writes about many accidents and his columns are very interesting. And we don't want this thread to end like the Brazilian A-320 thread due to some people childishly argueing and not talking at all about the thread subject.
http://www.flyingmag.com/article.asp...&page_number=1
http://www.flyingmag.com/article.asp...&page_number=1
Last edited by punkalouver; 2nd Jan 2008 at 18:20.
Thread Starter
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,125
Likes: 0
Received 13 Likes
on
8 Posts
In keeping with my desire to stay somewhat on subject, I am pasting a link to an article about a dedication to the victims 5 years after the accident.
http://www.iht.com/articles/ap/2006/...nniversary.php
.
http://www.iht.com/articles/ap/2006/...nniversary.php
.
Join Date: Feb 2002
Location: Elysion
Posts: 195
Likes: 0
Received 0 Likes
on
0 Posts
To be fair, punkalouver, you did walk straight into what was, undoubtedly, well prepared.
I find the focus of a response quite revealing. Often a word or two becomes the entire subject which the responder is addressing. That sort of fixation does seem to imply it is of great importance to the responder. The conclusions to be drawn are of course up to the individual, but I doubt they will differ much.
Speaking of conclusions, I, at least, had the benefit of personal information made readily available. Unless that was not to be taken seriously.
I find the focus of a response quite revealing. Often a word or two becomes the entire subject which the responder is addressing. That sort of fixation does seem to imply it is of great importance to the responder. The conclusions to be drawn are of course up to the individual, but I doubt they will differ much.
Speaking of conclusions, I, at least, had the benefit of personal information made readily available. Unless that was not to be taken seriously.
Thread Starter
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,125
Likes: 0
Received 13 Likes
on
8 Posts
I'm sure it has been published elsewhere previously, but here is the animation and very difficult to see video of the accident. It appears that the fiirst encounter with wake turbulence resulted in aileron movement only which was successfully used to maintain proper attitude. It was on the subsequent encounter that large rudder inputs were used. Probably discussed elsewhere,but interesting to see again.
http://www.ntsb.gov/events/2001/AA587/anim_587.htm
http://www.ntsb.gov/events/2001/AA587/anim_587.htm
Thread Starter
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,125
Likes: 0
Received 13 Likes
on
8 Posts
Once again this info may have already been posted on this forum but here is an interesting link.
http://www.iasa-intl.com/folders/the...87crows-1.html
http://www.iasa-intl.com/folders/the...87crows-1.html
Moderator
Quite amazing ... this is the second thread in about four years which has gone AWOL coincident with my having net problems for a few days ...
If there be further posts of a disciplined nature, we shall let the thread continue ... otherwise it will be locked.
If there be further posts of a disciplined nature, we shall let the thread continue ... otherwise it will be locked.
Join Date: Mar 2006
Location: Choroni, sometimes
Posts: 1,974
Likes: 0
Received 0 Likes
on
0 Posts
Frightening.....
http://a257.g.akamaitech.net/7/257/2...f/E7-24523.pdf
Due to the recalculation of loads for the
Multi Role Transporter and Tanker (MRTT)
aircraft, it has been found that a structural
reinforcement at the aft section of the
fuselage (FR (frame) 87–FR91) is required for
A300–600 aircraft and A310 aircraft with a
Trim Tank installed. * * *
The unsafe condition is the potential
loss of structural integrity in the aft
section of the fuselage between FR87
through FR91, inclusive, during extreme
rolling and vertical maneuver
combinations.
Multi Role Transporter and Tanker (MRTT)
aircraft, it has been found that a structural
reinforcement at the aft section of the
fuselage (FR (frame) 87–FR91) is required for
A300–600 aircraft and A310 aircraft with a
Trim Tank installed. * * *
The unsafe condition is the potential
loss of structural integrity in the aft
section of the fuselage between FR87
through FR91, inclusive, during extreme
rolling and vertical maneuver
combinations.
Moderator
Presumably the design team revisited one of the torsion points and found the RF to be a tad light on with the benefit of hindsight ? Without the details it is not feasible to offer much comment .. however, I wouldn't have thought "frightening" .. this is a normal design governance exercise and occurs from time to time. In any case, the suggested design case is one which is not all that likely to occur in routine operations ...
Join Date: Mar 2006
Location: Choroni, sometimes
Posts: 1,974
Likes: 0
Received 0 Likes
on
0 Posts
The unsafe condition is the potential
loss of structural integrity in the aft
section of the fuselage between FR87
through FR91, inclusive, during extreme
rolling and vertical maneuver
combinations.
loss of structural integrity in the aft
section of the fuselage between FR87
through FR91, inclusive, during extreme
rolling and vertical maneuver
combinations.
