From: Hal Finney (hal@rain.org)
Date: Thu Mar 13 1997 - 12:49:23 MST
I only speak a little French, but with all the news coverage on this
story I have tried to understand what the Paris Match magazine is
saying about the radar images.
http://www.parismatch.tm.fr/actualite/twa800/framedepart.html has 9 photos
(purportedly) from the radar image which show activities in the minutes
surrounding the accident.
http://www.parismatch.tm.fr/actualite/twa800/twa1.html shows one big and
three small images from about the same period.
The TWA flight is shown on the screen in the big picture as follows:
TWA800
/ BET*37 H
C
This has the flight number, TWA800; a designation of its departure route,
BET; a speed indication, 37, for 370 knots; and the H for "heavy", standard
designation for large airliners. In the later images the BET is replaced
by an altitude indication, for example 137 for 13,700 feet. I believe the
actual location of the plane is at the "C".
The images on the page with four pictures has the above geometry,
while the page with nine pictures has a slightly different one, with
the label to the left of the "C" rather than to the right:
TWA800 \
129 37 H \
C
This suggests to me that the two pages are taken from different data sets,
since the time of their images overlaps, but they consistently have these
two different label formats. There are also differences in the scale and
the position of some other labels. The relative plane positions are
consistent between the two series of images, though.
Large circles on the display are 10 (nautical) miles apart, I believe;
this is how the FAA typically lays out controlled airspace, and it is
consistent with the indicated speed of TWA800 and how far it travels
between images.
There are four objects marked on the various pictures. The red circle
shows a USAir flight which to the south and higher than TWA800. The
yellow circle shows a US Navy P3 Orion plane, which is apparently not
in communication with the FAA ATC system. The USAir and Orion blips
approach each other, and they almost touch at the exact moment that
TWA800 explodes. This is apparently just a coincidence; they are two
or three miles from flight 800, and presumably the planes are all at
different altitudes.
The page with the nine photos also shows two other objects. A light green
circle marks the unidentified object which I think is supposed to be the
"missile". It only appears on two of the images, west of TWA800, and
doesn't look to me to be moving very quickly. There is also a later
object marked with a blue square a few minutes after the explosion,
a Navy helicopter.
The explosion occurs at 00 h 31 min 17 sec (according to one of the
pages), which is the 6th picture in the 9-picture sequence. The
green-circled object appears on two images, one 41 seconds before the
explosion and one 34 seconds before. One question is whether it is
moving fast enough and in the right direction to reach TWA800 at the
moment it explodes. My impression is that it is not. It is hard to
be certain given the small scale of the images, but the object appears
to be about 6 or 7 miles west of TWA800 in the first picture, and
still 6 or 7 miles west 7 seconds later. In fact, I measured with a
piece of paper and it is slightly farther from the "C" indicating the
position of flight 800 in the second picture than in the first. So it
doesn't appear to be catching up to TWA800 at all.
It would be very dramatic and exciting if it turned out that there were
a big conspiracy to cover up an accidental missile hit, but the radar
pictures which Paris Match is displaying don't make the case as far as
I can tell.
Hal
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