Japan Airlines 747 and American Airlines A300 Flew Parallel Trajectories, 1 Minute 30 Seconds apart

Megadata Corporation (Via PRNewswire ^ | 11/15/01

[Steven W.]

These numbers differ from those reported on the 1st day when they said that the plane took off 7 minutes after the previous plane and that NTSB recommendations were 4 minutes.

[DoughtyOne]

By the time you consider the horizontal and vertical distances mentioned here, it appears these craft were anywhere from three quarters of a mile to just under one mile apart in flight paths, plus five miles apart due to the difference in take off times. I don't see a real likelihood of air turbulence playing a role here, but then I'm no expert in these matters.

The one minute and thirty second time frame is considerably less than recommendations, but the distance in flight paths seems to have nulified that, at least in my opinion.

[Blueflag]

For tracks, go here

radar track and time plot

[DoughtyOne]

That could have been based on the Japan plane having taken off from a second runway. I should add, I'm not sure if that is applicable or not.

[Blueflag]

See the post above for a link to time-distance plot data. The planes were a little closer than you surmised, but separation will not ne an FAA issue. Looks like they were 90 second, 400 feet (vertical +/-) and 1/2 to 2/3 lateral apart. Winds blowing to the SE, surface, at 11 kts.

[eno_]

The whole thing is very weird: How could an explosion in the middle of the plane rip the tail off so cleanly? Or, how could air load on the tail cause a "bright flash," "fire," and loud noise near the center of the plane, under the wing? And didn't part of a wing come off, too? The engines certainly did, and not due to them exploding. Also, in how many pieces did it hit the ground? I recall mention of a separate piece of fuselage. Whatever it is it is damn strange.

[discostu]

I haven't heard 7 minutes. I heard 2 minutes 7 seconds, but that was supposedly the delay between the tower giving the two planes clearance (FAA rules for clearance gap are going to vary based on wind conditions since the wind moves turbulence around, still air would make the delay very long). But that was the tower clearance gap, somewhere I saw that the JAL plane wasn't particularly quick on the switch so the take off gap shrunk. I'd trust these figures as their from the big radar box that's supposed to be looking at this stuff, and once airborne the gap between receiving clearance from the tower is pretty immaterial.

[discostu]

over here (see if I did that right) is a thread where we're talking about apparent problem this tail had right from the shipping line. We're still trying to figure out just how FUBAR the tail would have to be to fall off form WT, and have only begun to tackle all the secondary damage (engines, underarm fire). I think the missing wing piece was started by someone misunderstanding the tail piece removed from the bay (understandable, the vert and horz stabilizers on the tail are pretty much just small wings, pretty easy to confuse). But we still have 4 different damage location and the only 2 that look like they could have snowballed from each other are the fire and the nearest engine.

[DoughtyOne]

Thanks for the link. I agree that the vertical was 400 to 1000 feet, but don't forget their flight paths were three quarters of a mile apart. I was taking that into account too. That doesn't even take into consideration the five miles ahead the Japan plane was.

Does that bring us closer to agreement, or am I still missing something?

[John Jamieson]

Fact1: 587 hit the 747 wake (due google search for turbulance reports, most are smaller planes landing behind bigger ones, but a few are taking off. All are scary.

Fact2: Stab broke off about same time, but shouldn't have. (Must have been damaged previously.)

Speculation: Rest of plane suffered spotaneous disassembly when pilots, not knowing what was going on, called for full power on an airplane that was at a crazy angle to the airflow. MIT'67 XVI

[Blueflag]

I'm with you. Plane hit one side of vortex, then the other. (up then down, and/or right then left) Resulting torque forces jar stabiliser loose. (musta been weak already) Pilots apply power to gain altitude (as plane noses over) Plane departs controlled flight. Plane begins flat spin as differntial lift (swept wings) aggravated by yaw forces kicks in. Extreme cross wind stalls compressor on upwind engine, accounting for reported 'pop pop pop'. Rotational forces later sling motors off mounts. Wing shears at root, fuel catches fire. Debris scatters. Plane hits ground. All this in the space of about 15 - 30 seconds near the end.

It could have happened.

But to believe this, I think the airframe had to be near death to begin with.

[okie01]

"But to believe this, I think the airframe had to be near death to begin with."

Not just the composite VS, but the whole magilla?