Possible cause of AA flight 587 crash...a new thought

Vanity | 11/15/01 | Agent Smith

[Agent Smith]

Up until now, my best guess as to the cause of the 587 crash was defective/substandard bolts used in attaching the vertical stabilizer to the tail and a failure to detect the problem through inspections.

However, I heard on the news last night that the vertical stabilizer was not fabricated from aluminium, but from a carbon fiber composite. This material is very strong and light but can fail catastrophically if a stress fracture/crack develops. Based on the photos of the recovered stabilizer showing that it was cleanly severed from the tail, I now believe that this is the most likely cause of the accident.

The turbulence from the JAL 747 was the straw that broke the camel's back.

[dobbyman]

Oh Sure,

And then we have to believe that we should ignore the odds that this type of carbon fracture failure could have have happened at any of hundereds of other airports in the world - but no it just happened at the NYC airport one of the two regions under terrorist attack now.
You want us to believe the unlikely possibility instead of the more likely possibility that has been demonstrated by prior terrorist actions, new threats of future terrorist attacks against planes, and motivation to continues attacking the prime terrorist targets - the NYC and Wash DC regions!!!

Dobbyman

[Blueflag]

Good point. Could quickly confirm or refute the missile theorists as well.

I can hear them now "but the data were altered!!!"

[Capt. Tom]

However, I heard on the news last night that the vertical stabilizer was not fabricated from aluminium, but from a carbon fiber composite.

When you say carbon fiber it implys what we fishermen call graphite composition.

Here is my advice from my website to fellow fishermen who are looking to pick a good rod for sharkfishing. This was written long before this plane crash.

"Use fiberglass rods. A decent fiberglass rod is practically unbreakable. Graphite is not reliable. We do not have a graphite rod left on the boat. Our charters, and the sharks, have field tested them into pieces. I don't care who makes the rod or how many people swear by them ; if it is graphite it is unreliable, period."

If I thought they were using graphite on structural members of airplanes I wouldn't fly.

Graphite is exceptionally strong but if it gets nicked it fails rather quickly. -Tom

[Blueflag]

Zordas--

To clarify, the evidence is that the VS failed below the attachment point, barely inside the tailcone.

I thought the bolts that held the VS to the empennage were found still in the empenage, and the attachment parts, repaired and original were still there, and 'wheat straw' looking composites were visible there. No matter. Either way, the point is that the VS did not separate at broken or loosened bolts. Structural members failed, at least in part. Could also be that some bolts failed, others didn't, and the remaining tight structures failed. We're just trying to figure out how in the world a VS could fall off an A300, with or without WT.

I look forward to reading more. Thanks.

It's somewhat ludicrous to think that the A-300 was going to catch up to a B-747. The ATC maximums of the altitude/speed restrictions would preclude that.

Agreed. I think the point here is that their departure paths were different, and the A300 "reportedly" intersected the flight path of the 747 about 45 seconds behind the 747. How? The 747 flew a long curve, while the A300 flew a more direct path. You're right that the A300 would not be permitted to catch the 747 in controlled airspace.

[MassLengthTime]

We're both sort of right. The A320 is all FBW (well, except for rudder and rudder trim). The A300-600 series is FBW for secondary control systems only (flaps, slats, spoiler), and earlier A300's are analog.

[okie01]

Thanks for the update.

[Z-28]

Thrust reverser, same as Eqypt Air Flight 990 out of JFK Oct. 31, 1999, southeast of Nantucket Island, a Boeing 767-300 on flight from N.Y. to Cairo crashed into the Atlantic Ocean, killing all 217 aboard.

Flight 587 may end up the worst aviation disaster in U.S. history if more bodies are found on the ground. It's the 2nd worse U.S. aviation disaster in history now at approximately 269 dead.

But you are correct, the tail did fail. The left engine was found .4 mile from the crater, and the verticle stabilizer and rudder .5 mile from the crater (in the water of Jamicia Bay).

This indicates to me that it was the reverser. But the finding of explosive residue could change all this.

[Z-28]

Oh, I forgot to mention that both Flight 990 and Flight 587 were sabotage.

[Blueflag]

I would agree with you that this failure was the culmination of a lot of prior events on that airframe.

To your point, I hope Airbus has good lawyers, AND I hope they improved their engineering and fabrication after the A300.

Last question-- since the rudder was not attached to the VS, how do 'they' know the trim was set to 10 degrees? Was the trim tab found in that position? Was there an indicator in the cockpit? Why was the aircraft that much out of yaw trim? I really don't know.

[discostu]

Interesting stuff. Thanks.

Ken, figured I'd ping you on this thread. It's got a bunch of folks much smarter than myself, if you were learning stuff from me yesterday you'll learn plenty from these guys (I am).

[Agent Smith]

In that case, I think that you are going to have to check out the make, model number, and date of manufacture before you get on board any modern airplane.

[RaceBannon]

This is probably a woven composite, then pressed into a flat sheet, impregnated with resin/glue, then put into a mold to form together with other composites to make the tail. Under no circumstances would this tear in a straight line due to stress cracks.

I used to work in Flight Test/Static test for Kaman Aerospace, and we tested many materials like this for blades and other surfaces, so I saw this stuff first hand. No way it tore on it's own, it would have to be cut or folded mechanically,

OR...It was a bad forming from the start, but that is highly unlikely!

[discostu]

Question (any of the other smart flyers are more than welcome, but BF seems to be leading the charge so I'm picking on him): what about the collateral damage? According to the media, both engines fell off and there was a wing joint fire, that seems like a lot more secondary damage than is normally caused by loss of the tail.

To me the socondary damage is the major flaw in all the theories, sabatoge or poor maintenance the damage path seems very muddy and greatly in excess of what you'd expect from the damage starting in any of the four places we're told were damaged before ground impact. Admittedly I am at best a semi-informed amateur but that's the big issue to me.

Thanks

[Agent Smith]

Hey, sometimes sh*t just happens. That's life.

[HardStarboard]

>>>This could be a plausible scenario for rattling once, rattling again, and departing controlled flight as the VS separated from the airframe.<<<

Yours is the most rational and reasonably factual senario that I have yet seen on the crash. I have breakfast every morning with a former Nam F-4 pilot and we have been searching for a glimmer of sense in how this plane broke up. I can't wait to share your set of fact with him tomorrow.

I think you have nailed it. I nominate you to the NTSB!!

[Agent Smith]

There is an earlier post in this thread that Airbus did infact have to "correct" a manufacturing defect in the vertical stabilizers of the A300.

[Blueflag]

Your questions are what perplex me as well. Normally, TREMENDOUS forces would have to act on the airframe of a commercial airliner to cause it to shed / fling parts the way this one did. IF it was not sabotage, then this aircraft was flying as a near-death experience everytime it took off. If not sabotage, then this was one weak airframe.

The argument becomes ontological-- Why was it weak? Wear? bad materials? bad manufacture? bad maintenance? intentional act? OR, was it blown apart by a series of small charges, just like small charges can collapse a large building?

I have no idea. This is one for the books.