NTSB Briefing, NTSB claiming .3 to .8 g wake encounter caused crash?!?!?!

CNN | 11/15/2001 | me

[nevergore]

"I did my bit for the economy at Kohl's 50 percent off sale."

Good start! Now go buy a car!

NeverGore

[Zorobabel]

I saw the same photos of the bolt assembly that secures the verticle stabilizer to the fusilage, and it was plain that the VS had broken off cleanly ABOVE the bolts. So apparently loose bolts were not a factor. I also heard that when the plane was delivered in 1988 there was a delamination problem with the VS that was repaired by the manufacturer. Looks like this could be some kind of composite failure.

[MindBender26]

You are right, but you will convince no one here. When PIC went to full throttle, engines probably responded somewhat asymetrically, causing thrust imbalance, compounding problem

S/MEL COMM/INST 2200 hrs, inc .5 in Airship America!!!

[L_Von_Mises]

Maybe a dumb question but I am wondering how they came up with the figures of 0.3g and 0.8g in the first place. Does the flight data recorder capture this info or is it obtained from some type of radar? They don't appear to be arbitrary figures so are they figures that were calculated to be the ones necessary to fit the asumed scenario?

Maybe someone more familiar with either ATC or flying in general can provide this info for me.

[MindBender26]

One more thing. Composites are great, very light weight, very strong... but they do not bend, they do not give. Strong, rigid, but when overloaded, they fracture without warning!

[Interesting Times]

One wonders if something like this might have happened. The aircraft encountered the wake and the data recorders measured the 0.3 to 0.8 acceleration. This acceleration is insufficient to cause separation of the stabilizer and is consistent with other information about how the vortex may tend to throw the aircraft out of the wake. However, the vortex impinging upon the rudder caused it to begin to oscillate. The computer read this as some kind of unusual situation and began to send a series of counter commands at high rate. This might cause a high amplitude, high frequency vibration to be transmitted to the structure connecting the stabilizer to the tail inducing a failure in these connectors. There could even be some kind of a feed back loop that might persist after the aircraft exited the wake. In effect, what I'm saying is that the computer might have gone nuts when it encountered something outside it's program.

Worth a bump. After all, both engines came off as well as the tail, and eyewitnesses described the plane as "wobbling" in the air. There seem to be few if any precedents for a commercial airliner coming so completely unglued. A violent, computer-driven oscillation certainly seems like a possibility.

[Doe Eyes]

There is another way to look at this. Suppose the tail, because it has a large surface area perpendicular to the fuselage, is most affected by the wake (localized high velocity airflow) created from the 747. The airflow is normal to the surface of the tail creating a force on the tail. It is that force that results in the 0.8 g recorded by the aircraft. Then the question becomes, how much force on the tail would it take to produce a 0.8 reaction on the rest of the aircraft. The force on the tail would created a moment (torque) about the attachment point to the aircraft, where it broke loose.

[MindBender26]

G load transducer in A/C. Problem is, can't find anyone else who saw this, can find data at other site, etc.

?????

[PSYCHO-FREEP]

You should learn more about a subject before you spew..

The NTSB was merely giving technical data that came from the flight data recorder onboard the aircraft. The aircraft has sensors and meters located throughout the airframe that monitor certain conditions. The data may be false or only partial because of the failure. Many variables are involved.

By the way, take it easy on these people who investigate....it's a crumby job, and they are no different than those firemen who work at the WTC.

As far as your Evil Gubbermint Conspiracy theory goes, shame on anybody who spews such blind hate.....If you don't like it here, then roll up your sleeves and pich in and help change it. Ranting about it over this forum won't do it.

[Tarakotchi]

"they're pushing theories in our faces that sound as kooky and far-fetched as any of the anti-government conspiracy theories I've been reading about it."

Really, what kooky and far-fetched anti-government conspiracy theories have you been reading about the crash? On FreeRepublic? Many people feel because of the timing and locale and airline it may have been another act of terrorism, is that a kooky and far-fetched conspiracy theory?

[oprahstheantichrist]

Spoke yesterday with a relative who's a flight attendant for another carrier. She's going with the wake turbulance theory without a shred of doubt, and is not at all surprised it happened. Swears the Airbus is pure junk. Flying (usually) trash, although that wasn't quite the adjective, and every pilot that's ever flown one knows it. They hate to fly 'em, and the flight attendants hate them as well.

She also remarked that wake turbulance is very scary in a decent plane, let alone an A300, 320, 340, or whatever.

[Fred25]

But I did stay at a Holiday Inn last night!

[Map Kernow]

The posibility of this actually being an accident is not what most of the tinfoil commandos want to hear. Their minds are already made up so don't confuse them with facts...

Grow up, you cliche' freak. Facts are what I and others WANT to hear, not some preprocessed theory about how the plane "shook itself apart."

The latest I have seen is that the grafite composite and alloy structure above the attach points (considered non-critical structure) has failed.

Wrong. It came apart cleanly at the attach points.

Nothing more, nothing less. A bomb would have caused a much different wreckage than what we are seeing, especially the vertical stabilizer.

Depends on where the bomb was, genius. Also, ruling out a bomb doesn't mean you've ruled out sabotage.

Some form of separation has occured between the G-composite and the metal alloy conjoined with it.

Meaningless gobbledygook.

The Airbus is a radical new design and they more than likely are beginning to show their weaknesses.

This is an outright lie. The Airbus has been around for thirty friggin' years and it's considered a safe aircraft. What's so "radical" about the design??

The vertical stabilizer failing caused the aircraft to become so unstable that the airframe literally shook itself apart. Another error is when the Copilot went to full power with both engines which compounded the problem.......

Oh, CRAP. Even I know that losing a vertical stabilizer, while absolutely not a good thing, doesn't necessarily cause a plane to "shake itself apart."

You lost every ounce of credibility with me when you tried to push a theory that the Fl. 587 engines had deployed reverse thrust on take-off. Lose your stupid tinfoil hat cliches and leave this thread to someone who knows what he's talking about.

[aruanan]

Gee, what a co-incidence after 9-11 and in NY even! What are the odds? Since odds of probably no longer apply in this universe maybe I will win the lottery 5 times in a row! I better start buying tickets.

You're comparing the wrong things. Odds can be figured for multiple instances of the same thing, such as winning the lottery 5 times in a row but not for different things of different origins. In any one place there are always things happening simultaneously which you'd be hardpressed to predict, but they happen anyway. It doesn't mean their occurrence was improbable, just unpredictable. Improbability and unpredictability are two different things. Since they are not occurring through the same mechanism, their relative frequency of happening singly or in unison is not described in terms of probability.

[clintonh8r]

Right after the incident I bought tin foil futures.

[PSYCHO-FREEP]

You are very close.

Like I said earlier, the Vertical Stabilizer controls the vertical axis. When the aircraft lost it, it went into a condition of "positive static instability" The engines aggrivated that condition.

The oscillations were from wing forward/rearward pivoting on the center of gravity of the fusalage.(witnesses reported the wings as moving rapidly forward and backward from the ground before it broke apart)

Oscillations will increase in magnitude and frequency when positive static instability is present.

(Just basic physics 101) The engines fell off because the struts could not handle the stress the oscillations......

[sweetliberty]

There is definitely something "fishy" about the whole thing, and I think there is likely quite a bit we are not being told. I ran across this article last night and found it interesting, but definitely not evident in the bulk of the reporting on the crash:

Air Authorities Monitored Terrorist Threats After Downing of Flight 587

[MindBender26]

You should learn more about a subject before you spew.. The NTSB was merely giving technical data that came from the flight data recorder onboard the aircraft. The aircraft has sensors and meters located throughout the airframe that monitor certain conditions. The data may be false or only partial because of the failure. Many variables are involved. By the way, take it easy on these people who investigate....it's a crumby job, and they are no different than those firemen who work at the WTC. As far as your Evil Gubbermint Conspiracy theory goes, shame on anybody who spews such blind hate.....If you don't like it here, then roll up your sleeves and pich in and help change it. Ranting about it over this forum won't do it.

I think you sent this to the wrong guy, or is FR misdirecting again......

I am far from the person you post about. S/MEL COMM/INST 2200HRS