Radar plots with times. Per NTSB
20:31:48:94 — ~2,800 ft. - 36.94 sec Eighth post IE radar return. - Shortly after the Flight TWA800 falls below the radar horizon and no further radar returns are received.
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It looks like the last radar return from JFK was at 20:32:10. Are you sure you aren’t using the radar returns from ISP? It looks like your timeline could be in serious trouble.