Interesting note about AA Airbus crash in NYC

[airsupport]

He most certainly IS a bully, to anyone that dares to question his version of what happened, to the extent now that when Yankee Whisky dared to enter the discussion and didn't agree with him, he belittled his use of grammar.

I understand from looking at his web site that this PBL has a vested interest in what he is pushing, his academic qualifications would be less thought of if his theory is wrong, however I will try one last time to explain MY position.

I have no problem with this theory of the Pilot using too much rudder, even though I don't really understand it, and IF you all want to blame the dead Pilot that is up to you.

HOWEVER, I do KNOW from personal first hand experience IN New York ON these A300s of the water problem AND the lack of detailed inspections, things that were ignored until AFTER the AA tradegy.

Although I cannot OF COURSE prove it, YES if you are asking me straight out I DO believe it may well have CONTRIBUTED TO (not caused) the tragedy, to the extent I often wonder if we should have been more forceful in bringing it to people's attention before the AA tradegy, but I cannot believe that people in the Industry (not PBL) but Pilots etc are unable to admit that it was even POSSIBLY a contributing factor.

[Hand Solo]

The problem as I see it airsupport is that you are a long way behind the curve when it comes to accident investigation. Pilots almost certainly were able to accept that it might have been a contributory cause. Unfortunately we're a conservative bunch and when our lives are at stake, might have is not enough. We need to know if it was, or if it wasn't, with a much greater degree of certainty. For this we trust the manufacturer to a partial extent, and accident investigation bodies to a greater extent depending on their reputations. The NTSB is a body which on the whole is very highly respected and has proven it's ability to expose safety related findings in the face of considerable political and commercial pressure to do otherwise. That is why we rely on their extensive expertise to analyse all the data available from before, during and after an accident and come to a conclusion as to what caused it and how to prevent a recurrence. The NTSB looked at the possibility of water ingress being a contributory factor and concluded it was not. I don't believe that saying "Look again, look again, look again" will materially alter the facts of the accident, reveal sensational new information or change the conclusions. The experts have looked at it and given their best judgement on the causes.

Pilots do not instinctively wish to blame their colleagues for a mistake. There is no benefit for us in hiding structural or mechanical failures behind the pilots. However sometimes one has to accept that a human made an error, and the actions of the AA pilot on that day were a serious error. No experienced pilot should even dream of handling their aircraft like that, and the loads the aircraft experienced were way beyond their design limits. Whether or not he should have been able to stress the aircraft to that degree or it was a design weakness has been addressed by the NTSB. Your contention, as I understand it, is that had there been water in the assembly it may have weakened it and caused it to fail early. That issue has also been addressed by the NTSB and they found that that was not the case.

I've no reason to dispute that you have water in A300s where it shouldn't have been, or that there have been calls for increased inspections since the accident. However it is not reasonable to link the two. Accident reports frequently reveal failings in aircraft that are unrelated to the accident but require further monitoring. There is nothing like a crash to subject a fleet of aircraft to a level of scrutiny unseen since the types initial certification. It is inevitable that after an accident you'll find something less than ideal in an aircrafts operation but it is important to identify what is a contributory factor in the accident and what is incidental. The NTSB experts believe that the water issue is incidental, and that is probably enough for the vast majority of professional pilots.

[airsupport]

Okay, IF all of you Pilots are quite happy to put the blame totalling on this now dead Pilot, who was just trying to save his Life and those of all the other souls on board, I will force myself to believe that.

It will help actually, I have spent many sleepless nights worrying if we should have done more prior to this tragedy, like being more forceful about getting a fix and new inspections, or even grounding the Aircraft until we got an answer.

I will leave it as let's all blame the dead guy.

[Hand Solo]

We're not putting all the blame on the dead guy. If you read the accident report you'd know that the Airbus design was criticised due to the variable feedback provided through the rudder pedals and the operator was criticised for their training program. You are still well behind the curve here. We talk about "human factors" these days, not "pilot error". We look at why somebody made an error, not just what the error was. The NTSB report addresses these human factors. However that doesn't mean that we should attempt to hide human factors failings behind some spurious mechanical data.

Why the pilot did what he did is a combination of innappropriate training, design flaw and maybe some poor piloting skills. That doesn't get us away from the fact that he did something no pilot outside of AA would consider sensible and as a direct result of those actions he overstressed the vertical stabiliser and caused it to fail. Accident investigations often reveal unpleasant truths and sometimes one has to bite the bullet and accept the findings no matter how unpalatable they are. That is the hallmark of a mature approach to flight safety.

[airsupport]

Sorry if my terminology offends you now.
I am retired now, after more than 40 years in the Industry, and still think in old terms sometimes, certainly NOT into political correctness, I had a gut full of that when I lived in New York.
I mean NO offence to anyone, not even PBL, and as I said let's just all blame the dead guy.
But now you say

a direct result of those actions he overstressed the vertical stabiliser and caused it to fail

, all I was saying is that YES he MAY HAVE overstressed the already weakened vertical stabiliser and caused it to fail.
However, I am now trying to forget that possibility, and go along with all you guys, so I will be able to sleep at night instead all thinking of all those dead souls.
Really PLEASE just forget it, THANKS.

[Hand Solo]

With respect airsupport I don't think you are grasping the difference between cause and blame. Did the pilot cause the accident? Almost certainly! Had he not made those extreme inputs the aircraft would have recovered from the wake turbulence encounter using conventional techniques and the whole incident would be a non-event. Is the pilot to blame? Almost certainly not. He acted in accordance with his training and nothing more should be expected of him. The blame rests largely with AA's training program and to a lesser extent with the rudder feedback design. Your terminology doesn't offend me but it does highlight that you are not familiar with human factors thinking and the distinction between cause and blame in aircraft accidents. It's very noble to try to prevent the pilots being blamed but it's counter-productive to try so hard that you end up hiding the true cause.

Perhaps the stabiliser was weakened by water. The investigators don't think so, and even if it was, it still withstood substantially more than the design loading. If we blame water ingress for the failure above design loading then we could also blame many other things. Perhaps if the weather had been better when the stab was built it would have more strength. Perhaps if the composite fibres had been fractionally thicker the stab would have had more strength. There are a whole load of ifs and buts, but thats not the point. The point is that all aircraft components are designed to a limit, and nobody should ever intentionally take those components outside those limits. Once you exceed that limit all bets are off. If you took every vertical stabiliser on every A300 in the world and tested them to destruction they'd all fail at slightly different levels. Are all but the strongest fins defective because they have failed at lower stress levels? Of course not! Will they all fail above the designated design strength? Almost certainly! If I take a random A300 out and try to break it, is the aircraft to blame if I've got one of the lower failing fins instead of one of the higher failing fins? Hardly! The issue is that any strength above the design strength is a bonus and shouldn't be relied on. Airbus could have quite legitimately designed that assembly to fail at 1% above the design criteria and it would all be quite acceptable. That is why any water ingress in the fin in question is irrelevant. It still failed way above the design criteria. The cause of the accident is that the aircraft was handled in a way that took it outside reasonable operating limits into the realm of structural guesswork.

[airsupport]

I do know that it takes quite a bit to rip the tail off an A300/A310, this one did NOT come off even after all this damage, also in New York.

Air Jamaica A310 had a disagreement with one of the hangars at JFK.

[PBL]

Airsupport,

you aren't helping your argument (such as it is) by supporting the contribution of someone, Yankee Whiskey, who is obviously confused about basic physics. What are we to think about your engineering judgement?

PBL

[twistedenginestarter]

Airsupport
I can't see anywhere where you dispute that the estimation that the fin failed well beyond its design limit, is wrong. So we have a curious situation. Let's say the fin was weakened, and let's say it was because of water ingress. That would mean, to start with, it was much stronger than planned, and had degraded to the estimated strength when the accident happened. Now let's take a hypothetical fin that had been built to exactly the planned limit, and had not degraded at all. Now we fly the two planes into the accident situation. Unfortunately they both fail. Now you feel guilty about the 'strong' one because you thing you could have shouted more about the water. What's your position about the undegraded but weaker one? All your self-doubt doesn't help in the slightest. If we want to save lives we must accept the relevant, and ignore the distractions.

[airsupport]

Airsupport
I can't see anywhere where you dispute that the estimation that the fin failed well beyond its design limit, is wrong. So we have a curious situation. Let's say the fin was weakened, and let's say it was because of water ingress. That would mean, to start with, it was much stronger than planned, and had degraded to the estimated strength when the accident happened. Now let's take a hypothetical fin that had been built to exactly the planned limit, and had not degraded at all. Now we fly the two planes into the accident situation. Unfortunately they both fail. Now you feel guilty about the 'strong' one because you thing you could have shouted more about the water. What's your position about the undegraded but weaker one? All your self-doubt doesn't help in the slightest. If we want to save lives we must accept the relevant, and ignore the distractions.

twistedenginestarter,
You don't see it anywhere because I don't dispute it.
Also as I have pointed out many times, I am not a Pilot and don't really understand what the Pilot did wrong, but I believe from reading all the reports and what is posted here, that he did do something wrong although probably in a desperate attempt to save himself and everyone else on board.
My ONLY concern in all this, as I have tried to explain many times, is that after this terrible tragedy happened I was concerned that this water COULD have contributed to the tragedy, and sadly maybe myself and others that were aware of this prior to the AA tragedy should have pushed harder for a fix of the problem and more stringent inspections, things that were done after the tragedy.
Best regards,
airsupport

[Hand Solo]

that he did do something wrong although probably in a desperate attempt to save himself and everyone else on board.

As a pilot let me explain why that is incorrect. The aircraft encountered wake turbulence from a preceeding aircraft. It's no big deal, we've all encountered wake turbulence. There was no risk to life. The correct procedure to handle it is to use some aileron to control the roll and ride it out. You do not respond to it by whacking full opposing rudder inputs. There was no risk to life until that was done.

A suitable analogy would be you driving your car at low speed and you hit a small patch of ice. The correct response would be to ease off the gas, maybe brake gently and wait until the wheels have more traction before continuing. The incorrect response is to put the handbrake on, spin the steering wheel and try to do a high speed 180 and power your way out of the ice. You may genuinely believe that the latter is the correct way to handle the situation, but if you lose control of the car and it skids into a wall killing the passengers is it a design flaw in the car or the innappropriate driving that caused the accident? If you did the latter then you turned a simple low risk situation into a catastrophe and that is exactly what happened in the AA accident.

[Yankee Whisky]

Fins, fins, fins,fins !!

I, not being a linguist like PBL, am more inclined to understand the reasoning of "Hand-Solo" who, obviously, shows his experience in looking at the reality of a problem in greatly more depth and understanding of the many possible faces of truth related to a failure.
When a person with experience on the shop floor, like "Airsupport" expresses an opinion, I am inclined to listen carefully and not attack his competence.
PBL also knows that when water fully occupies a space between skins and ribs, expansion will cause damage ! Airsupport mentions more than 20 liters of water and this could mean that, before inspections of drainholes was mandated, the possibility existed and that is all we are saying. In this particular case there was, unfortunately, a coming together of many truths and the pilot was in the inenviable position of proving Airbus design and pilot manual deficiencies/oversights.
Another thing to remember is that we are in a relatively early stage of accumulating experience with carbon fibre aircraft structures and this,
in itself, is open to much scrutiny, both at the manufacturing and user levels.
To suspect what CAN happen is to be prepared for prevention.

[twistedenginestarter]

I am not a Pilot and don't really understand what the Pilot did wrong

I'm not a pilot of large transports, and I was very surprised when I first heard of this incident. I imagined that one of the tests during certification, is you could whack on fairly heavy control inputs without bending anything. As I recall, one of the problems is that many pilots thought the same, partly because the aircraft they had flown before were more resilient. This problem was compounded by AA giving suspect advice. I don't think this was anything to do with carbon fibre or water. This was to do with the particular ways to handle finely honed big jets and how clearly that was being promulgated.

[Yankee Whisky]

Explanatory article

http://www.aopa.org/asf/asfarticles/2003/sp0301.html

This article explains in understandable language, some of the events leading to the AAL fin failure. It certainly explains why there is a need for the use of rudder deflection limiters which, I am given to understand, were not incorporated in this aircraft.
I understand full deflection of a rudder plus the enertia present in wings full of fuel can cause an aircraft to go into a slip overriding the stabilizing affect of the vertical fin, thereby increasing the loads on the fin required to reverse the motion.
All the more reason to "ride it out" ,which is where I joined in on the discussion.

[PBL]

When I started contributing to this thread, I was actually hoping for some discussion about the AA587 accident and associated matters.

To that end, I was also hoping that some contributors might have read the many hundreds of pages in the NTSB docket, and have formed their own views of related safety matters, would be willing to read my resume of the accident, and other related material.

I find that I am in discussion with someone who considers a primary flight structure that failed at over 1.9 Design Load, indeed at 30% over Ultimate Load, to be "severely weakened". And with someone else who considers it plausible that freezing water in the fin? rudder? contributed to the failure of this structure on AA587, because "When a person with experience on the shop floor, like expresses an opinion, I am inclined to listen carefully". But when experienced forensic engineers express an opinion, and it is investigated at length, and reported in detail in the accident investigation docket, apparently this person is not so inclined to accept what they conclude.

And the one likes to call me a "bully" for asking him a series of technical questions which he declines to answer.

Yankee Whiskey says

PBL also knows that when water fully occupies a space between skins and ribs, expansion will cause damage ! Airsupport mentions more than 20 liters of water

And how many liters of water does it take to "fully occupy" the space in the vertical stabilizer of an A300?

He says further

Originally Posted by Yankee Whiskey

Another thing to remember is that we are in a relatively early stage of accumulating experience with carbon fibre aircraft structures

Well, sure, the A300 has been flying for only thirty years now, and other composite primary structures for only ten years or so longer than that. Forty years is only, say, 80% of the entire history of jet transports.

This doesn't approximate to any kind of serious discussion. This is just silly stuff.

I am still one of those internet idealists who imagines one can get together on fora with like-minded people who are interested in discussing and technically competent to discuss subjects of mutual interest. I still hope.

PBL

[airsupport]

Thank you very much to Hand Solo, Yankee Whisky and twistedenginestarter for your intelligent and unbiased comments, much appreciated.

[Yankee Whisky]

No hard feelings, the Canadian way.

Quote from PBL

This doesn't approximate to any kind of serious discussion. This is just silly stuff.

I am still one of those internet idealists who imagines one can get together on fora with like-minded people who are interested in discussing and technically competent to discuss subjects of mutual interest. I still hope.

PBL

I am glad we have agreed to disagree. It depends on what one reads in the texts through the looking-glasses of one's own opinions, no?
I can guarantee that I have flown in rotors severe enough to scare the b'j's out of me and I have written based on practical flying experience and the use of methods I described saved my skin.
If that's not technical or serious enough, then I don't know what is! Small airplanes break up in mid-air just as readily as big ones and even if only two, or three, lives are involved in my flying experience, it is serious!
Good bye and no bad feelings, I hope?

[PBL]

Originally Posted by Yankee Whiskey

I am glad we have agreed to disagree.

We have not agreed on anything. You need to do your homework and also think about what you are saying if you want to join in a serious discussion.

Originally Posted by Yankee Whiskey

It depends on what one reads in the texts through the looking-glasses of one's own opinions, no?

No, it doesn't. Go and perform that experiment with the glass of water that I suggested. The outcome does not depend on anyone's "opinion", it depends rather on physical facts about water and ice and glasses. Then reconcile the outcome of that experiment with your published "opinion" about the effects of freezing water on composite fins. Then when you've done that, go and read the results of the investigations of the tail strength of AA587 performed in the wake of the accident. Then we'll be at a place at which we can have a reasonable discussion.

Originally Posted by Yankee Whiskey

I can guarantee that I have flown in rotors severe enough to scare the b'j's out of me...

Congratulations.

Originally Posted by Yankee Whiskey

If that's not technical or serious enough, then I don't know what is!

No, flying airplanes through rotors does not automatically qualify you as an astute observer of structural engineering matters - obviously.

What might qualify you is to take in your hand a piece of kit that has failed and been retrieved from an accident, and to try to explain how and in what way that structure failed, and back your reasoning up in such a way that other engineers who do that kind of thing enter into discussion with you about it.

Airsupport obviously does not and has not done that kind of thing, and neither have you. Both of you are ignoring the well-founded public reasoning of people who do. It's fine to indulge in that kind of word play as a hobby if it gives you kicks, but if you want to be taken at all seriously by forensic engineers, you have to participate in a different kind of discussion; one that talks about how things break and backs it up with reasons when asked. In particular I advise against saying stupid things in public about water and ice and pressure as you did (we can all be stupid at times, but some of us try not to make it a centerpiece of our public writing).

Originally Posted by Yankee Whiskey

Good bye and no bad feelings, I hope?

I am not going. I am just hoping out loud that the thread will not continue in this silly vein.

PBL

[PBL]

Airsupport,

The word "that" in the phrase you quoted has a reference. Here is what it referred to.

Originally Posted by PBL

take in your hand a piece of kit that has failed and been retrieved from an accident, and to try to explain how and in what way that structure failed, and back your reasoning up in such a way that other engineers who do that kind of thing enter into discussion with you about it

Have you ever done that? It would be very hard for me to believe you had, because you have conspicuously failed to do it in this forum with your hypothesis about AA587, despite much prompting from myself and others.

A simple yes or no answer would suffice, if you can write a sentence without using the word "bully".

PBL

[PBL]

Airsupport,

I take it that is your way of saying no, you haven't actually got any experience with forensics.

Congratulations in managing to avoid the word "bully"!

PBL