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AA587 - Tail Separation Initiated Breakup?  
User currently offlineSpacecadet From United States of America, joined Sep 2001, 3624 posts, RR: 12
Posted (12 years 9 months 3 weeks 1 day 1 hour ago) and read 2538 times:

I think the media and a lot of people here have been looking at this the wrong way. The tail fin was found intact in Jamaica Bay - a mile *behind* the main wreckage and two engines. The NTSB just said they've found no evidence of uncontained engine failure, no evidence of birdstrike, and no sound of any kind of explosion on the cockpit tape or any talk of engine problems. In fact, what they heard was airframe shuddering and talk of wake turbulence 20 seconds before the crash.

I think the tailfin somehow ripped off the plane and initiated the breakup process. With no tailfin, the plane would go into an uncontrolled yaw that would put aerodynamic loads on the engines that they were not designed for, possibly ripping both of them off. This is the only explanation that really explains the distribution of the debris field, and it's supported by the CVR tape.

Anyone else agree? It's looking to me like, once again, initial speculation has turned out to be dead wrong in this crash. Of course, this still doesn't explain how the tail tore off, but I think that's where the crash originated, not from the engines.



I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
57 replies: All unread, showing first 25:
 
User currently offlineAWA22 From , joined Dec 1969, posts, RR:
Reply 1, posted (12 years 9 months 3 weeks 1 day 1 hour ago) and read 2271 times:

I just heard on MSNBC during the NTSB news conference that on the cockpit voice recorder the pilots are talking about wake turbulence from another aircraft. A JAL 744 took off right before the A300. Maybe the wake turbulence had something to do with the accident. The FDR has also been found.

User currently offlineVoodoo From Niue, joined Mar 2001, 2074 posts, RR: 0
Reply 2, posted (12 years 9 months 3 weeks 1 day 1 hour ago) and read 2259 times:

And where have we had a tail fin separation before?
That JAL 747 that flew around afterwards barely in control before hitting a mountain.
What caused that? A crack in the pressure dome
after a faulty maintanance after a tail strike (correct me if wrong) on the runway.
But that blew out at a higher altitude due to pressurization.
So *if* this is at all similiar: what caused a rear fuselage blast?



` Yeaah! Baade 152! Trabi of the Sky! '
User currently offlineIkarus From United Kingdom, joined Jan 2001, 3524 posts, RR: 2
Reply 3, posted (12 years 9 months 3 weeks 1 day 1 hour ago) and read 2243 times:

Don't forget to mention that you are just speculating, too. Based on very little information.

I disagree on your theory. Even without tailplane, there is no immediate reason why the plane should go into so powerful a yaw that the engine pylons cannot withstand the stress - a scenario I find hard to imagine anyway. True, lateral stability would be lost. But how should that cause structural damage of this degree?

You mention that there is claimed to have been "talk of wake turbulence 20 seconds before the crash". If that is correct, the real question might boil down to "What effect that can be perceived as wake turbulence by a pilot can cause a fatal accident of this nature?"

And frankly, I have no idea. Let's just wait until the investigators come up with verifiable theories, shall we?

Regards

Ikarus


User currently offlineIkarus From United Kingdom, joined Jan 2001, 3524 posts, RR: 2
Reply 4, posted (12 years 9 months 3 weeks 1 day 1 hour ago) and read 2199 times:

Voodoo: The 747 in question lost its tailfin. It also lost all hydraulics and therefore all control over the control surfaces - the only means of control left was alternating thrust on the LHS and RHS engines.

In this case, if the tailfin was indeed lost before the breakup, there is still no viable explanation why it should cause the engines to separate, or structural breakup. Loss of control - yes. But loss of engines? How?

Regards

Ikarus


User currently offlineAWspicious From , joined Dec 1969, posts, RR:
Reply 5, posted (12 years 9 months 3 weeks 1 day 1 hour ago) and read 2187 times:

Could an aircraft of that size break apart due to aerodynamic stress from only 2800 feet?

User currently offlineVoodoo From Niue, joined Mar 2001, 2074 posts, RR: 0
Reply 6, posted (12 years 9 months 3 weeks 1 day ago) and read 2166 times:

Ikarus, I am not sure which is more liable to the double separation we have seen:
i.e.
a) fin, then engine or
b) engine, then fin.

But since the planes are designed to cope with the latter i.e. engine separation and not the former,
then it does seem possible that the fin came off, then the engine.



` Yeaah! Baade 152! Trabi of the Sky! '
User currently offlineMika From Sweden, joined Jul 2000, 2881 posts, RR: 4
Reply 7, posted (12 years 9 months 3 weeks 1 day ago) and read 2147 times:

Put into the account that they were travelling at max 250 knots if they were below 10.000 feet. I find it hard to believe that any part of the plane (aside from the vertical stab. maybe) couldn't withstand such forces.

But then again, i'm no physics expert. just my 2 cent's worth.


User currently offlineTAA_Airbus From Australia, joined Nov 1999, 726 posts, RR: 0
Reply 8, posted (12 years 9 months 3 weeks 1 day ago) and read 2136 times:

Maybe, and just maybe, the plane was a flying bucket of sh*t, and infact was an accident waiting to happen.

Who knows.


User currently offlineSpacecadet From United States of America, joined Sep 2001, 3624 posts, RR: 12
Reply 9, posted (12 years 9 months 3 weeks 1 day ago) and read 2134 times:

Ikarus: There's nothing wrong with informed speculation. This is a discussion board, not a "shut up and let the professionals do their work" board. My point in writing this post was to get people thinking on a possible track that I think is much more likely than the one dominating other threads here. We've got 46 messages and counting in a birdstrike thread, when there's absolutely no evidence of that whatsoever.

A wake vortex should never be severe enough to sheer off a tailfin, but it *could* be severe enough to put a following plane *without* a tailfin into a progressively worsening yaw. I also mentioned on another thread that it was a pretty windy morning yesterday (I live in Queens), so even without the wake turbulence there was plenty of wind to knock a plane missing a tail fin around.

With no means to correct such a yaw, the sideslip would only continue to get worse as airspeed increased during descent. The engines were found *close* to the main wreckage - just a couple blocks away - which suggests that they were detached just prior to the plane's crash, probably when it was traveling at a high rate of speed and at maximum sideslip. The fin, however, was found a mile behind the main wreckage, and was more than likely a separate event.

Voodoo: The JAL 747 you speak of had a rear pressure bulkhead failure that was clearly audible on the CVR tape and that blasted the entire rear end of the plane off the fuselage. It was not a clean break as was the case in this crash (about half of the fin was still on the plane, the metal torn and jagged - you can see this in pictures of the flight). It also happened at a much higher altitude where the pressure inside the fuselage was much greater. AA 587's tail fin looked like it had just come off the assembly line when they fished it out of the water - it didn't get blown off the plane or otherwise ripped off by external debris. Seems like two different kinds of failures to me.



I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
User currently offlineLuckySevens From , joined Dec 1969, posts, RR:
Reply 10, posted (12 years 9 months 3 weeks 1 day ago) and read 2090 times:

I still think this looks like the Lauda Air incident.
The reverser deployed and the plane self-destructed mid-air.


User currently offlineRedngold From United States of America, joined Mar 2000, 6907 posts, RR: 44
Reply 11, posted (12 years 9 months 3 weeks 1 day ago) and read 2062 times:

I wondered if the vertical stabilizer could have been "blown away" from the plane by the impact but now see that the ensuing damage from that type of explosion did not occur. It seems the vertical stabilizer came off first.

redngold



Up, up and away!
User currently offlineJfs9900 From United States of America, joined Dec 2000, 8 posts, RR: 0
Reply 12, posted (12 years 9 months 3 weeks 1 day ago) and read 2041 times:

LuckySevens - If the reverse thrusters had been deployed wouldn't the pilots have had some indication of this and may have mentioned it in their conversations? Unless.. (and this theory is probably off completely) one or both of the pilots intentionally deployed them? This would most certainly show up on the FDR It cause of the crash seems more complex.

User currently offlineGreenArc From United States of America, joined May 2000, 78 posts, RR: 1
Reply 13, posted (12 years 9 months 3 weeks 1 day ago) and read 2026 times:

Rudder hard over? Rudder is completely missing from vertical stabilizer. Vertical stabilizer broken off at factory join.

Just wondering aloud.

GreenArc


User currently offlineHeavymetal From , joined Dec 1969, posts, RR:
Reply 14, posted (12 years 9 months 3 weeks 1 day ago) and read 2027 times:

Interesting theories folks but you're ignoring the obvious....a lost tailfail wouldn't damage the engines in the slightest. And given the aircraft's speed and altitude I just can't see how an engine would have seperated based on the lateral forces that would accompany a gradual uncontrolled flight.

I'm still inclined to believe something really bad happened out on that engine, something mechanical...but I'm just as concerned at this point that if there was ANY kind of foul play involved, that it's being withheld in the interests of the airline industry and the economy.......


User currently offlineIainhol From , joined Dec 1969, posts, RR:
Reply 15, posted (12 years 9 months 3 weeks 23 hours ago) and read 2025 times:

The reverser deployed and the plane self-destructed mid-air

The Lauda accident the aircraft was crusing, so when the revers thrust deployed there was incredible stress on the aircraft. I highly doubt that a reverse thrust deploying at such a slow speed would cause such structual damage!
Iain


User currently offlineGreenArc From United States of America, joined May 2000, 78 posts, RR: 1
Reply 16, posted (12 years 9 months 3 weeks 23 hours ago) and read 2027 times:

>>Tuesday November 13, 6:01 pm Eastern Time<<

>>American 587 engines show no internal failure-NTSB

NEW YORK, Nov 13 (Reuters) - A preliminary inspection of the engines from doomed American Airlines(NYSE:AMR - news) Flight 587 showed no evidence of internal failure, investigators looking into what caused the airliner to crash, killing up to 265 people, said on Tuesday.

``Initial inspection shows no evidence of any sort of internal failure of engines. They all appear to be in one piece,'' said NTSB member George Black at a news conference.<<

>>At the news conference, Black said initial analysis of the cockpit voice recorder revealed that the plane rattled loudly twice before pilots lost control.<<


User currently offlineTWA717_200 From , joined Dec 1969, posts, RR:
Reply 17, posted (12 years 9 months 3 weeks 23 hours ago) and read 1993 times:

The Lauda accident the aircraft was crusing, so when the revers thrust deployed there was incredible stress on the aircraft. I highly doubt that a reverse thrust deploying at such a slow speed would cause such structual damage! Exactly what I was thinking. For once, Iain and I agree on someting.  Smile

As for Spacecadet's theory, it's certainly as plausible as any. Especially for the amount of information that has been released.


User currently offlineGyro From , joined Dec 1969, posts, RR:
Reply 18, posted (12 years 9 months 3 weeks 23 hours ago) and read 1975 times:

Correct me if I'm wrong, but the Lauda incident was during climb, not cruising!!! If memeory serves me correct it crashed against a mountain.

User currently offlineWoodsboy From United States of America, joined Mar 2000, 1031 posts, RR: 3
Reply 19, posted (12 years 9 months 3 weeks 23 hours ago) and read 1963 times:

Sounds very likely to be related to wake-turbulance and a failure or upset of the tail.

Too bad the media are already holding funeral services for the GE CF6 engine, they are "flying death pods" dont ya know.

If anybody wants a good laugh, go see what the Yahoo message board looks like regarding the news of the Cockpit Voice Recorder. People are soooooo retarted, its embarrasing.


User currently offlineGyro From , joined Dec 1969, posts, RR:
Reply 20, posted (12 years 9 months 3 weeks 23 hours ago) and read 1965 times:

"Shortly after takeoff, a REV ISLN message appeared on the aircraft's EICAS system alerting the crew that there was a malfunction with the thrust reverser isolation valves. The crew opted to continue the flight, and as the aircraft approached FL310, the no.1 engine thrust reverser engaged. The incredible force on the aircraft caused the airframe to break apart within several seconds."

Sorry, my bad...


User currently offlineKlaus From Germany, joined Jul 2001, 21442 posts, RR: 53
Reply 21, posted (12 years 9 months 3 weeks 23 hours ago) and read 1945 times:

GreenArc: ``Initial inspection shows no evidence of any sort of internal failure of engines. They all appear to be in one piece,'' said NTSB member George Black at a news conference. [...] At the news conference, Black said initial analysis of the cockpit voice recorder revealed that the plane rattled loudly twice before pilots lost control.

That would still leave the engine pylon fatigue issue in the game.

By the way, one eyewitness explicitly said she saw the plane go down "in one piece, fuselage, wings and tail". She didn´t mention the engines, if I remember correctly, but she might be right in what she said.

I could imagine the tailfin being tossed a few meters into the water on impact.

But with the flight data recorder recovered (and hopefully intact), I´m pretty sure we´ll know much more very soon. An engine separation would be very noticeable. Especially if it came with no previous vibration or other irregularity.


User currently offlineTWA717_200 From , joined Dec 1969, posts, RR:
Reply 22, posted (12 years 9 months 3 weeks 23 hours ago) and read 1940 times:

By the way, one eyewitness explicitly said she saw the plane go down "in one piece, fuselage, wings and tail". She didn´t mention the engines, if I remember correctly, but she might be right in what she said.

Another witness said that he saw the entire wing fall off before impact. One saw this, one saw that.


User currently offlinePilot1113 From United States of America, joined Aug 1999, 2333 posts, RR: 11
Reply 23, posted (12 years 9 months 3 weeks 23 hours ago) and read 1932 times:

The tail is bolted on to the rest of the plane. It's quite possible that the bots didn't get torqued properly during the last maintenance check.

That JAL 744 was 8 miles ahead of the A300, so wake turbulance couldn't have been a problem.

It's very possible that the tail came off shortly after takeoff leading to unstable flight. During the wild yaws, the copilot called for max thrust and increased the loads on the engines causing them to come off.

The Wall Street Journal is saying there is evidence of FOD, which I think can be attributed to other parts coming off and getting ingested, thereby increasing the loads even more.

It really doesn't take much for an engine to come off. Anyone remember that NWA 727 that lost an engine after getting repeadily hit by ice chunks from the leaky lavatory?

- Neil Harrison


User currently offlineRayChuang From United States of America, joined Jun 2000, 8003 posts, RR: 5
Reply 24, posted (12 years 9 months 3 weeks 22 hours ago) and read 1896 times:

It's beginning to sound like that the structural design of the A300B4-600R could be at fault.  Sad

Remember, these planes were built in time when structural parts being bonded together with adhesives were still a relatively new idea. There has been quite a lot of concerns from mechanics about the quality of the adhesive joins in the long run. It's small wonder why Boeing has not really used adhesive joins until the 777 program, more or less.

I think there's a possibility that structural failure of the vertical tail--which ripped it off the plane--caused the plane to undergo severe aerodynamic yawing and structural stress, which eventually broke up the plane.

It appears that Airbus may have to issue an immediate directive to all A300/A310 operators start inspecting all structural joins very closely.


25 Spacecadet : We know the engines came off; that's not an issue. The point is that they both came off 2 blocks from the crash site. The fin came off a mile from the
26 Treg : But hey, look at the picture. The tail is virtually cut off. Pure and clean cut. No damage what-so-ever. It is impossible that there was some foreign
27 Voodoo : Differing from the earlier A300B4, the A300-600R has the tail structures of the A310. Do these have a fuel tank in the fin and or stabs? Did the stabs
28 Dauphine : I haven't seen any info on regarding the condition/location of 587's horizontal stabs, and I've been looking everywhere. The video of that pristine ve
29 Houstondallas : I'm guessing that the tail section seperated from the aircraft. The rattling that was heard on the CVR was probably the fuse shaking like crazy due to
30 Heavymetal : "It's very possible that the tail came off shortly after takeoff leading to unstable flight. During the wild yaws, the copilot called for max thrust a
31 EWR757 : >>The video of that pristine vert stab is really troubling, though.
32 Dauphine : I'm not an expert, but I did notice that immediatley as well. Talk about cold shivers.
33 Prebennorholm : I don't think that the A300/A310 have a wet fin. But the clean cut: The A300-600 (and A310) fin is mostly made of carbon fibre, while the fuselage is
34 Gregg : One thing many people are missing... The forces on a plane going 250 knots at sea level are probably higher then one cruising at 40,000 feet at cruis
35 Aa737 : If the tailfin fell off, for what ever reason, could the wake turbulence of the JAL 744 ahead been the cause of the AA plane nose diving into the grou
36 Spacecadet : In the NTSB briefing tonight, they commented that two pilots on other airplanes saw the crash and said it went into a spin before hitting the ground.
37 Notar520AC : I heard something about an engine failure...?
38 Guillermo : This aircraft (N14053 if I am not wrong) suffered severe clear air turbulence (passengers injured) near PR on 11/28/94 (FAA 19941128043499C incident r
39 Positive rate : What if one of the thrust reversers deployed on one engine only??? This would certainly produce enough force to rip an engine off, rip the tailplane o
40 Spacecadet : Positive rate: That's not how the Lauda Air crash happened. What happened was the reverser deployed, causing increased drag on that wing, which stalle
41 Post contains links T prop : I think Space cadets is theory is the most plausible here so far. By the pictures shown on the news, it appears that the fasteners securing the vertic
42 Mika : I'm guessing that the tail section seperated from the aircraft. The rattling that was heard on the CVR was probably the fuse shaking like crazy due to
43 Chiawei : I also believe that it has to be similar to lauda air accident. 1. Assume that AA587 was flying close to its max 250knots below 10,000 feet. This is s
44 Pilot1113 : >>Can you achieve thrust loads on the engines with >>the throttles that would cause the engines to come >>off? I'm fairly certain you can't. In normal
45 Cyberflyer : I think it was sabotage. None of this makes sense. The tail of the plane is too pristine-leading me to believe that somone got "to it". You never, eve
46 VS744 : How would someone "get to it" wouldnt you require access behind the rear toilets on the -300 to do this?
47 XXXX10 : I read an ntsb report about an AA A300 that suffered an engine fire (I think out of MIA) and for some reason the warning failed so the pilots didn't r
48 Rhino4ever : Has anyone found out why this flight had an hour and 15 minute maintenance delay at JFK?
49 Braniff727 : One thing that I thinkis interesting is on the CVR the NTSB reported hearing the First Officer asking for "full power" seconds before the crash. That,
50 Rhino4ever : This one is quite the mystery. At the altitude of this event there wouldn't have been enough differencial pressure for a explosive decompression.
51 BigO : Ok, here's the only way this could have taken place. Soon after takeoff they lose one engine. The continue with full thrust on the other engine as per
52 Mcdougald : AA737 wrote: "Could the wake turbulence of a 744 be strong enough to flip a widebody A300?" Or strong enough to cause the failure of a tail weakened b
53 VS744 : Would a 777 give off more wake than a 744?
54 Houstondallas : I doubt an engine failed before the tail separation. I'm sure the pilots probably would have mentioned it but there doesn't seem to be a reported reco
55 A300 American : Hey All, McDougald, I hear ya big time on the wake vortices on the proposed A380. I sure wouldn´t want to be behind that Bohemith sized airplane. I´
56 Post contains links VirginFlyer : (?´(x?e loss of vert stab theory holds more water than the thrust reverser one. Why? Well, if the thrust reversers had have been deployed accidenta
57 VirginFlyer : Um, I am not quite certain what happened in my post there, but where it says (?´(x?e it should say From the available evidence so far, in particular
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