Interesting note about AA Airbus crash in NYC

[AirRabbit]

Originally Posted by hetfield

Yes, but AFTER this tragic accident!

Uh ... only partially correct. It is what the NTSB found after the accident. But, as you can read for yourself in the posts preceding yours (by almost a year), the regulator and the airplane manufacturer, joined by another airplane manufacturer, wrote a memo to AA some 4 years prior to the crash, in which they described the problems that may be encountered by "rudder reversals such as those that might be involved in dynamic maneuvers created by using too much rudder in a recovery attempt..." pointing out that such rudder use could "...lead to structural loads that exceed the design strength of the fin and other airframe components."

I know that hind-sight is always 20-20, but here it looks very much like a very clear concern went unheaded ... or at least taken to be applicable in one set of circumstances (windshear) and not another (wake turbulence). While any accident is tragic, I think this one was for more than one reason.

[hetfield]

Sorry, working for a large european carrier and flying the A300/310 since many moons, I didn't get such a note.

Yes, like I said, after the accident.

[PBL]

Originally Posted by PBL

which is what the NTSB found and against which AI, Boeing and the FAA had warned.

Originally Posted by hetfield

Yes, but AFTER this tragic accident!

No. 20 August 1997. As I say on p14 of my paper.

PBL

[hetfield]

How DO YOU know, how I have may be warned/informed?

[PBL]

Originally Posted by hetfield

How DO YOU know, how I have may be warned/informed?

I think it is for you not to misinterpret what I say, rather than for me to conform to your misinterpretation.

PBL

[blueball]

Having flown the A300 as Captain for a few years, I can tell you it is a simple to fly and forgiving aircraft. Just please only use the rudder pedals for X-wind landings, single-engine, and nose wheel steering on the ground. Period!

[AirRabbit]

Originally Posted by hetfield

Sorry, working for a large european carrier and flying the A300/310 since many moons, I didn't get such a note.
Yes, like I said, after the accident.

Originally Posted by hetfield

How DO YOU know, how I have may be warned/informed?

Perhaps the reason you and a gazillion other pilots around the world didn't get copied on the notice sent to American in 1997 was that you and the vast majority of the other gazillion pilots were not involved in the American Airlines Advanced Maneuver Training, that seemed to call for the liberal use (at least, some thought it to be liberal use) of the rudder when attempting recovery from specific airborne encounters, like windshear and wake turbulence.

Airbus, Boeing, and the FAA were concerned about what was being taught in that particular program - at least to the extent that they drafted and sent the referenced memo. I'd suggest taking a look at PBL's post, above, in which he provided a link to a paper he did on this particular accident. Give it read. I have. It's good stuff.

[airsupport]

Maybe, but whatever the problems were, they obviously didn't have much to do with why the tail broke off AA587.

In YOUR opinion.
As someone personally involved with maintaining THESE Aircraft IN this environment, in my opinion it had a lot to do with it.

[hetfield]

@AirRabbit

Having three kids and still enjoying living , be sure I've read the mentioned publication as well as RUDDER AND LOADS by AIRBUS and a similar brochure by BOEING.

regards

[PBL]

Originally Posted by PBL

Maybe, but whatever the problems were, they obviously didn't have much to do with why the tail broke off AA587.

Originally Posted by airsupport

In YOUR opinion.
As someone personally involved with maintaining THESE Aircraft IN this environment, in my opinion it had a lot to do with it.

Yes, in my opinion, for what it may be worth, second hand.
Is my opinion worth anything? Well, that would depend on how I derived it. Not all opinions are worth the same (as you suggest with your emoticon).

I derived my opinion from the published opinions of most of the structural engineers who spent tens of person-years investigating this very point over three years, as well as from structural engineers who know that work and that airplane in more detail than I. Their opinions are worth a lot, because they actually derived first-hand knowledge. And NTSB valued what they discovered. They have structural engineers of their own, and can judge the worth of the work. And this view ended up being the NTSB's opinion also.

It is what we might call a consensus expert opinion.

Let's look at your opinion, that the tail broke because it was "seriously weakened". First, we may observe that it contradicts the consensus expert opinion; that is, it contradicts both the opinions of those engineers that investigated this failure first-hand as well as the opinions of those who performed extensive computer modelling of the dynamics of the oscillation, a task which turned out to be very hard, but which was accomplished to the professional satisfaction of those structural engineers involved in assessing the failure.

So what is your opinion worth? Well, since you are one person (or maybe you and a couple of colleagues) contradicting all those who were tasked to investigate the failure first-hand, your opinion is not worth much yet until you can tell us what the mistakes were that all those engineers made (the ones who investigated the failure itself, as well as those who performed the computer modelling of the dynamics of failure). For if they reached opinions contrary to yours, then either you are plain wrong or they must have made serious mistakes.

So, are you one of those people who just sticks to what his hunch says no matter what weight of engineering argument contradicts him? (In which case, I would judge your opinion on this matter to be worth nothing.) Or are you actually prepared to show us how the board and all their supporting research was wrong? (In which case I would read your information with interest.)

PBL

[PBL]

Originally Posted by hetfield

be sure I've read the mentioned publication as well as RUDDER AND LOADS by AIRBUS and a similar brochure by BOEING.

Then I look forward to substantial contributions by you to the discussion, rather than the usual load of miserly grumbling

PBL

[hetfield]

Having flown the A300 as Captain for a few years, I can tell you it is a simple to fly and forgiving aircraft. Just please only use the rudder pedals for X-wind landings, single-engine, and nose wheel steering on the ground. Period!

@blueball

I totally agree. Anyhow if I had asked a check airman or even the chief pilot in my company BEFORE AA587, if it would do any harm to the aircraft moving the rudder from one side to the other (for whatever reason) but well within VA, the answer would most probably have been NO.

[airsupport]

Yes, in my opinion, for what it may be worth, second hand.
Is my opinion worth anything? Well, that would depend on how I derived it. Not all opinions are worth the same (as you suggest with your emoticon).

I derived my opinion from the published opinions of most of the structural engineers who spent tens of person-years investigating this very point over three years, as well as from structural engineers who know that work and that airplane in more detail than I. Their opinions are worth a lot, because they actually derived first-hand knowledge. And NTSB valued what they discovered. They have structural engineers of their own, and can judge the worth of the work. And this view ended up being the NTSB's opinion also.

It is what we might call a consensus expert opinion.

Let's look at your opinion, that the tail broke because it was "seriously weakened". First, we may observe that it contradicts the consensus expert opinion; that is, it contradicts both the opinions of those engineers that investigated this failure first-hand as well as the opinions of those who performed extensive computer modelling of the dynamics of the oscillation, a task which turned out to be very hard, but which was accomplished to the professional satisfaction of those structural engineers involved in assessing the failure.

So what is your opinion worth? Well, since you are one person (or maybe you and a couple of colleagues) contradicting all those who were tasked to investigate the failure first-hand, your opinion is not worth much yet until you can tell us what the mistakes were that all those engineers made (the ones who investigated the failure itself, as well as those who performed the computer modelling of the dynamics of failure). For if they reached opinions contrary to yours, then either you are plain wrong or they must have made serious mistakes.

So, are you one of those people who just sticks to what his hunch says no matter what weight of engineering argument contradicts him?

I will try one last time, then give up, as you obviously are just so closed minded.

I have said all along that there is probably more than one cause of this terrible disaster, there always is.

I am happy to concede that the Pilot input to the controls may have been one factor, however from being personally involved in detailed Engineering Inspections of these tails in New York, I truly believe the tail structure being weakened by all this trapped water may well have POSSIBLY been another factor.

You on the other hand, with no first hand knowledge of the problem, just say NOT POSSIBLE.

Now you say other Engineers AFTER the tragedy spent much time theorising what might have been, but they did not actually see this problem first hand, and although officially they say it is not possible, these same Engineers remote from the tragedy have ensured that the problem is no longer there, and the Maintenance Inspections have been greatly increased, why IF there was no problem?

These changes to the Maintenance Manuals have according to you been done at great expense for NO reason, while the ONLY cause according to you was FIXED by a letter to Pilots.

[411A]

Anyhow if I had asked a check airman or even the chief pilot in my company BEFORE AA587, if it would do any harm to the aircraft moving the rudder from one side to the other (for whatever reason) but well within VA, the answer would most probably have been NO.

If you had added the word 'rapidly' to your question...most likely correct.
Your CP or fleet manager more than likely would not be old enough to appreciate the problems caused by large rapid movements of a powered rudder at higher speeds...sadly this was known long ago, but all the old guys have died off or retired long ago...except yours truly, and a very few others.

Now you know

[PBL]

Airsupport,

I am trying to get some information out of you on what you think the problem is and why, and all that's happening is you're calling me names. That may make you happy, but it doesn't give me, or anyone else, any good reason to give credence to anything you say.

I did ask you for your evidence. You could give it directly, rather than making us infer what it might be.

I take it your evidence consists in having seen trapped water inside composite structures on A300/A310 aircraft. Have you also seen disbondment? Have you and your colleagues investigated the disbondment to see why it might have occurred? What were your results?

The primary thinking on disbondment is that it has been caused by contamination with hydraulic fluid, not necessarily water/ice damage. Could you shed some light on why you think trapped water is a greater problem than contamination with hydraulic fluid?

Do you have anything more to say about this that we can find, say, in the recently published report on the Air Transat rudder loss at http://www.tsb.gc.ca/en/reports/air/...7/a05f0047.asp or in the various articles published by Flight International on their Flightglobal WWW site at or linked from http://www.flightglobal.com/transat?

The NTSB also appears to be worried that in-flight separation of the rudder in this scenario could overstress the vertical stabiliser beyond Ultimate Load:

Originally Posted by flightglobal article

Further examination of the vertical stabiliser determined that its two rearmost attachment lugs were damaged due to the high stresses associated with the rudder failure and separation.”

The NTSB also warns: “These high stresses may have been dangerously close in magnitude to those that caused the inflight separation of the vertical stabilizer during the 12 November, 2001 accident involving American Airlines flight 587” which resulted in the death of all onboard.

“A subsequent inspection of the vertical stabiliser noted the aircraft’s rearmost attachment lugs were damaged due to stresses associated with rudder failure and separation,” notes the US safety regulator. “The Board believes that this urgent recommendation, if acted upon quickly, will go a long way to prevent a catastrophic failure of the rudder,” says NTSB acting chairman Mark Rosenker

Originally Posted by airsupport

I have said all along that there is probably more than one cause of this terrible disaster, there always is.

Nobody has disputed this; neither have they disputed that you said it all along.

Originally Posted by airsupport

from being personally involved in detailed Engineering Inspections of these tails in New York, I truly believe the tail structure being weakened by all this trapped water may well have POSSIBLY been another factor.

Lots of other people inspected those tails, knew and know of the associated phenomena, and considered in detail that "all this trapped water may well have possibly been another factor". And then concluded that it wasn't. Can you shed any engineering light on why they concluded that it wasn't and you concluded that it was?

Originally Posted by airsupport

You on the other hand, with no first hand knowledge of the problem, just say NOT POSSIBLE.

I didn't say "NOT POSSIBLE". I said "wasn't the case". That's the straw man thing.

Originally Posted by airsupport

Now you say other Engineers AFTER the tragedy spent much time theorising what might have been, but they did not actually see this problem first hand

Actually, lots of them did.

Originally Posted by airsupport

while the ONLY cause according to you was FIXED by a letter to Pilots

Here's the straw man thing again. I have never said or published anything so remotely contrary to fact as this.

As any lawyer can tell you, if you want to trash someone's views, you can only do so effectively by paying close attention to what those views actually are.

PBL

[airsupport]

I will try one last time, then give up

Okay, you still don't seem to understand, so this is definitely the last time, I am sick of trying to explain it.

The problem with the trapped water in the tail, which I dealt with first hand in New York, has now ONLY after this tradegy thankfully been rectified and at GREAT expense, this large amount of money was (reluctantly) spent for a reason and the timing of the modifications was NOT a coincidence.

I am NOT SURE what caused this tragedy, however I have NO doubt at all that this continually trapped water COULD have been a contributory factor, however IF you still think that it could NOT have even been a contributory factor then I am not going to waste any more time explaining it, sorry.

[AirRabbit]

A man in a jail in a small town was broken out of that jail when some of his buddies slipped a chain through the bars on the window in the man’s cell, bolted the two ends of the chain together and looped one end of the chain over a bracket on a bull dozer. By simply driving the dozer away from the building, the window was pulled out and the man escaped through the now-open window.

Upon inspection of the scene, the detectives noticed that the back door to the jail was not locked and that the keys to the jail cell were conspicuously left hanging on a peg next to the jail door. The sheriff made the appropriate corrections to these “faults;” a new locking mechanism was placed on the rear door that was always locked and could be opened only with a key, and the keys to the jail cells were moved to a locked safe.

They did find these other errors when they inspected the fact that escape was allowed by the jail cell window being pulled from the wall, and these other errors were corrected. Is it likely that the contributing cause to this jail-break was the unlocked rear door and the conveniently hung jail cell key? I think not. Just because something else was found and corrected doesn’t necessarily link the two circumstances together.

Until 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.

[airsupport]

A man in a jail in a small town was broken out of that jail when some of his buddies slipped a chain through the bars on the window in the man’s cell, bolted the two ends of the chain together and looped one end of the chain over a bracket on a bull dozer. By simply driving the dozer away from the building, the window was pulled out and the man escaped through the now-open window.

Upon inspection of the scene, the detectives noticed that the back door to the jail was not locked and that the keys to the jail cell were conspicuously left hanging on a peg next to the jail door. The sheriff made the appropriate corrections to these “faults;” a new locking mechanism was placed on the rear door that was always locked and could be opened only with a key, and the keys to the jail cells were moved to a locked safe.

They did find these other errors when they inspected the fact that escape was allowed by the jail cell window being pulled from the wall, and these other errors were corrected. Is it likely that the contributing cause to this jail-break was the unlocked rear door and the conveniently hung jail cell key? I think not. Just because something else was found and corrected doesn’t necessarily link the two circumstances together.

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.

[PBL]

Originally Posted by airsupport

Okay, you still don't seem to understand, so this is definitely the last time, I am sick of trying to explain it.

Yes, please feel free to give up if you have nothing more to say than what you have said already.

You say you've "explained" something but you haven't explained anything. You have repeated the assertion that you have seen trapped water and this could have been a problem. So we can skip that part, because I have read it a number of times.

I have asked you a number of direct questions and apparently you can't answer any of them. I take it the reason that you're contributing at all to a forum about these things is that you want to tell people something and have them take that something seriously. Well, they might do that or they might not, depending on how good you are at justifying what you assert. How do you think you're doing so far?

Reasoning about causes can be extremely difficult, and for every one insightful analyst there are a thousand one-sentence ponies with their favorite "cause" who promote it blindly. So, which are you?

Originally Posted by airsupport

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

Please, please don't tell me you are a conspiracy
theorist as well! That is going to give yourself zero credibility. Any suggestion that that people involved in that investigation, who were at each other's throats so hard that they prompted the Chairman of the NTSB to complain in public about it were actually conspiring with each other is laughable.

PBL

[airsupport]

Yes, please feel free to give up

Sadly I will, much as I hate to give in to a bully, it is just not worth it trying to have a sensible professional discussion with bullies like you on the site.

Anyone else here that has an open mind, read what I have posted earlier, it is all true.

The rest of you including PBL just keep blaming ONLY the dead Pilot who sadly cannot post here to defend himself.