Your answer that the NIST 8:46:30 time is based upon video evidence is not entirely correct. The video evidence referenced, and assumed to have a true timestamp, is associated with fraud. This post explains why:
http://forum.physorg.com/index.php?s=57070... However,
NIST's accepted revised LDEO seismic time of 8:46:29 (plus or minus 1 second, which NIST supposedly used to corroborate the video evidence and published as 8:46:30), is real and accurate.
Your understanding of the 8:46:40 from the 9/11 Commission, and radar in particular, is not complete. Here is why.
The FAA issued an approximate time of 8:46:40 because this was
the time of the last primary radar return. However, it is "approximate" only because of the sweep of the radar antennae, which means it could have been up to six seconds after 8:46:40, but
it could not have been before 8:46:40 because that was the time of the return.
This final radar return is visible on the page 4 graph from the NTSB report:
http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB... The return is also magnified in the paper on the top of page 7.
(Thanks for the broken link to the paper; here is one that works that goes to the Journal of 9/11 Studies.)
http://journalof911studies.com/volume/2006... The "approximate" aspect you mentioned, which I have explained above, is verified by former ATC Robin Hordon (who used to work out of the actual Boston station that tracked AA Flt 11) here in this post:
http://www.studyof911.com/forum/index.php?... Mr. Hordon writes: "Therefore, if the NORAD/FAA/Military collected radar data shown in your work is to be trusted, it is exactly as it is...
:46:40 or later for the collision, and, it should relate accurately to the seismic readings because they too are using the exact same GMT time reference."
In addition, all the radar tracks for all four flights were synchronized to the 84th RADES radar track, which had the complete radar data (from beginning to end) for all four flights, and thus all were synched to UTC.
http://www.911myths.com/Recorded_Radar_Dat... Therefore, 8:46:40 and 8:46:30 are both accurate.
So:
What caused/was the 8:46:40 time?
Answer:
The plane crash.
What caused/was the 8:46:30 time?
Answer:
Explosions in the WTC1 sub-basements, which many witnesses experienced and confirmed.
If you must argue, do so with these facts and witnesses.
Regards,
Craig T. Furlong
THE FEAR OF THE LORD IS THE BEGINNING OF WISDOM
