Posted on 11/16/2001 1:06:50 PM PST by dead
Flight 587 from New York to Santa Domingo had just taken off and was arcing into the clear autumn sky when the co-pilot, Sten Molin, felt a violent shaking.
What followed was the final 37 seconds for all 260 people on board, revealed in chilling detail by the cockpit voice-recorder of the airliner that speared into a New York suburb on Monday.
The American Airlines A300 Airbus had been aloft for just 1 minute 47 seconds when the flight recorder captured what had startled First Officer Molin - described by investigators as an "airframe rattling noise".
Seven seconds later, the jet pitched in the sky as if tossed by a tidal wave of turbulence.
The black box records Mr Molin as saying he fears the plane has crossed into the jet stream of a Japanese Air 747, which took off 2 minutes 7 seconds earlier.
The normal separation time between flights from John F. Kennedy, one of the world's busiest airports, is two minutes.
Another seven seconds later, just 2 minutes 1 second into the flight, a second, more violent rattle can be heard on the cockpit recorder.
Mr Molin's voice increases in volume and anxiety. He calls for the captain, Edward States, to apply "maximum power" in the hope that he can fly out of what he thinks is extreme turbulence.
It is suspected that it was at this point that the rear tail fin, or stabiliser, came off as the plane flew over Jamaica Bay towards the Rockaway peninsula.
The tail fin and rudder would be found in the bay later on Monday, about 750 metres from where the plane crashed.
At 2 minutes 7 seconds on the cockpit recorder, the two pilots are heard saying that they have lost control of the plane.
Witnesses say that at this point the Airbus lurched violently to the right and left, as if the pilots were battling desperately to keep it flying straight.
The black box does not record what was happening among the terrified passengers as the plane pitched hopelessly on its way to now certain disaster.
Soon after the pilots lost control, both engines broke away from the wings and plunged to the ground.
One landed in a boat parked in the backyard of Kevin McKeon's house. The other slammed into a service station driveway just metres from where Ed DeVito huddled under his truck - narrowly missing a petrol bowser and even greater devastation.
The pilot of a United Airlines flight heading for John F. Kennedy Airport at the time said he believed he had heard the pilot's last words - "We're having a mechanical ..."
At 2 minutes 24 seconds after take-off, the cockpit recording ends. Flight 587 had spiralled, nose-first into the middle of four houses in Rockaway in Queens, exploding in an orange fireball and killing all on board and at least five on the ground.
Investigators from the National Transportation Safety Board (NTSB) released details of the voice recording to a stunned and silent media conference.
Soon after, they revealed that the plane's other black box, containing the flight data recorder, had been recovered.
The investigators hope that this information will provide answers to what caused the shaking that Mr Molin first reported and the second, more violent, shudder that apparently caused the plane's tail fin to snap off.
The NTSB chairwoman, Ms Marion Blakely, maintained that the evidence pointed to a "catastrophic mechanical failure", but FBI agents said they had not ruled out a bomb or sabotage.
A lead NTSB investigator, Mr George Black, said that he did not know of any precedent for a tail fin snapping off an Airbus during turbulence.
The recorded separation time between the doomed flight and the preceding Japanese Air 747, if accurate, was considered within safety guidelines and not so close as to create the extreme turbulence that would cause a following aircraft to break apart.
Amid the heightened sensitivity after the attacks on the World Trade Centre and Pentagon, the Airbus crash has reignited a furious debate over the level of baggage screening.
Airport authorities have conceded that just 2 per cent of all bags that are checked at the counter are screened for bombs before they go on board a plane.
As Congress continues to debate legislation that would tighten the regulations on baggage screening, the US airline industry remains crippled by an acute loss of consumer confidence and a rush of flight cancellations.
The cancellations are expected to keep coming as the flying public learns more about the horrifying last seconds of Flight 587.
I thought they earlier said the black box showed everything was normal.
Huh? Who’s “they”? Are you aware that this black box came from a plane that crashed? Do many pilots consider their plane falling apart in flight "normal"?
I'm no expert on any of this, but I find this explanation for the crash plausible. I suspect that in certain conditions jet streams persist longer than usual, and it's been said that the jet stream from a 747 is more dangerous than from a smaller plane. I also suspect that the 2 minute interval may be cutting things a bit short, because if they extended it busy airports would have to cut back on the number of flights. In other words, maybe 2 minutes is enough 99.999% of the time, but there's that occasional instance when the jet stream persists longer than usual.
What I do know about turbulence and vibration is that they are very complicated, hard to analyze and predict. My cousin, a British engineer, made destructive turbine vibration his specialty; he solved the problem many years ago having to do with Rolls Royce jet engines on the Lockheed Electra which had caused several catastrophic failures.
What the NTSB had said earlier was that there was no indication of abnormality until the final seconds of the flight (from the CVR). This IS consistent with the information released yesterday, which details the final seconds of the flight.
As to wake turbulence - the JAL 747 was a good 8 miles ahead of AA587, plenty of spacing for dissipation of wake turbulence in a 5 mph crisp breeze. You want to see close "heavy" spacing? Park at the GA terminal on the south side of LAX and watch the heavies (AC +350,000 GW) arrive and depart with under 2 mi. separation. Or go to the 9th floor lobby of the Airport Hilton across the I-70 fwy from STL in Saint Louis and watch heavies depart, then other a/c departing less than 3 miles in trail. Happens every day at every airport across the land where you have heavies departing.
AA587 is NOT a wake turbulence incident.
Michael
It can when it's YOUR 37 seconds...
Wake turbulence references wingtip vortices generated at the tip of the wings by an aircraft. The heavier and slower the aircraft, the more pronounced the vortices. So it sounds like a likely culprit, right?
No, and here's why. The vortices are not generated until the aircraft leaves the ground, that is, when the wings are supporting the weight of the airplane. Once generated, they sink at a rate of roughly 1000 ft. per second. They don’t just linger there in the airspace once occupied by the generating craft -- they descend.
With a separation of over two minutes, the wing-tip vortices of the departing JAL 747 would have been over 2000 ft lower than its flight path. The A-300 has both a shorter takeoff roll and a higher rate of climb than the 747. This means that even if the two aircraft took off within seconds of one another, the AA flight would have lifted off at a point on the runway before the 747 began to generate vortices and would have remained on a flight path higher than that of the previous airplane.
Since vortices descend, and do not climb, it would be necessary for the AA flight to be below the flight path of the proceeding 747 to encounter it's wake; a very unlikely situation.
In addition, there was a good breeze that day at JFK. (Evidence - the smoke from the fires) Vortices move through the column of air that they are in. At this point in an airplanes flight, they are on a predetermined departure procedure flying over ground references that do not move (waypoints, navaids, etc). To encounter the wake turbulence of the 747 the AA flight would need to be 2000 ft. low and off-course, just the right amount in the direction of the wind.
So, something happens which causes the tail section of the aircraft to fall off. Corrosion makes sense. So does tampering. Interesting to see where this leads. the AC in question had an 'a-check' the day prior with no problems found....
These journalists make half this stuff up, or interview unnamed "authorities" who know nothing, just to get a quote.
It looks like it was likely accidental from what we know so far, but we don't know everything yet. Something went seriously wrong with this aircraft very quickly. The pilot certainly didn't suspect a bomb, but sabotage is also a possibility.
You have confused miles with minutes, I believe. The separation has consistently been reported as at least two minutes (by regulation), perhaps a bit more (seven seconds as it turns out).
That separation in time translates to a difference of 7 or 8 miles distance in the air (both distances have been reported).
I've seen this for myself coming in and out of LAX.
It's hard to believe AA587 is turbulance without an additional cause. I have no problem believing the engines tore themselves loose from the aircraft before impact after loss of the vertical stablizer.
I was commenting about this statement from "they" in an earlier post: "Authorities said the voice recorder, which was found soon after the Monday crash, didn't indicate any problems aboard the airliner." Seems odd that at first "they" said it did not indicate any problems and now it is chilling and shows desperate struggle.
We have always been at war with Eastasia... :)
("He who controls the present controls the past. He who controls the past controls the future.")
Which I think everybody had figured out without the NTSB's help, given that the plane was only in the air for about three minutes. Like, tell us something we don't know. If you read the the quotes from officials, they were classic misdirection, just like the misdirection we've been seeing for weeks now in the handling of the anthrax situation. Basically, you need to take every government statement, parse it carefully, ask yourself, "What is this trying to get me to believe, or get the headline to be?" and then "What is the substantive content of the statement?" Otherwise, you will remain clueless, like the people on this forum who deluded themselves for weeks about the anthrax (naming no names, but they know who they are).
IF the vertical stabilizer was to fall off the airplane, for whatever reason, then the entire structural integrity of the aircraft would have been compromised beyond any design limits. It is not unreasonable to think that the forces generated once the tail section fell off were of such a nature as to cause separation of the engines.
Once airplanes begin to break up in flight, they tend to REALLY break up.
Well, if some sort of metal fatigue or corrosion is involved, that'll be easily identified. As for the engines, I suppose a sudden uncontrolled yaw - or the steep spinning dive that immediately followed - could snap the mounts. Either way, it's pretty clear that the tail came off first. Have there been any cases of airliners losing the entire vertical tail and rudder and successfully landing?
Yes, but the Electra had problems with whirl mode, and this accident with the Airbus isn't that. Lockheed goofed by sticking turboprops on mountings orginally designed for piston props. A little stiffening solved the problem once they saw how the vibrations were coupled through the engine cowling and pylon to the wings.
The clean break along the lower edge of that stabilizer just cries out for some kind of study of brittle fracture, if the stabilizer in fact did break off and cause the accident. Its just too neat. Ductile fracture would leave a much more ragged edge, since it involves a substantial amount of plastic deformation and energy absorption before failure. Its time course is just too long. This looks like a quick failure, which brittle fracture would be.
Time for you to get new glasses.
BTW I hope your mother-in-law responds and recovers quickly.
...or a manufacturing defect, or metal fatigue, or a screwup during maintenance, or...
And yes, it could be sabotage. But it's foolish to say it "surely must be" at this point.
I have to wonder what sort of activities that type of inspection involves, and whether it's possible that some thing(s) had been loosened or removed for inspection, and then mistakenly put back together improperly (or not at all).
There was a case a decade or two ago where several aircraft of a certain type went down, until it was discovered that it was possible to accidentally REVERSE two control wires when reassembling a part after routine inspection/replacement. This caused the rudder (or maybe it was the ailerons, it's been a while) to act *opposite* of the pilot's instructions, resulting in a quick crash after takeoff.
This is edging into tinfoil hat terroritory.
I could buy sabotage of the tail (although I have to wonder just how hard it would be to get to the bolts INTERIOR to the tail section in order to loosen them).
But implied sabotage of the tail AND both engines strikes me as ludicrous as the JFK assassination theories that postulate multiple shooters from all over the plaza. It's just too baroque, AND unnecessary.
If I were sabotaging a plane by loosening components, I'd pick one critical item (tail OR left engine OR right engine), then fiddle with it and scoot. First, one is enough. Three is insane overkill. Second, sabotage to more components means more time spent farting around with the plane when you might get caught. Finally, it means you've tripled the odds of something failing prematurely on the ground, during taxiing, or during the launch down the runway, which would cause the plane to be grounded before it could take off and actually crash.
I'll bet large sums of money that whatever caused the first failure, the following failures were simply a chain-reaction and not due to sabotage at multiple locations.
Tails do not come off because of wake turbulance. Something else caused the rudder to come off the AB300. However, with a tailess jet it is easy to imagine extreme areodynamic forces and torque cauing the engines to depart from the plane after the flight characteristics were shot to hell and the 300 exceeded the flight envelope. After departing normal flight and exceeding the stress levels the plane was doomed. It is also fly by wire and the computers were not designed to trim a tailess jet with no yaw control or stability and with a nose heavy aircraft with a dangerous forward center of gravity after tail departure and hydrualic problems as well unless shut off valves were activated.
My initial impression is that a bomb in the baggage compartment took out a wing spar, the wing separated, and the resulting abnormal aerodynamic forces tore the vertical stabilizer off. Just an initial educated guess from available information.
It seems the vortex shed off the leading edge extension set up an unexpected flutter oscillation.
Result: no more V-Stab.
With all due respect, you will not find, anywhere in the US, tight spacing like that coming out of Memphis Airport late at night (actually early morning) when the FedEx planes hit the skies.
FedEx planes have special seperation rules from the FAA. I can't remember the number but it's well under 120sec.
First one gets up, takes a hard right; left one left, next one straight out and up, next one right, etc...
Watching them arrive, on a clear night - their lights dotting the horizon, is pretty awesome too.
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