THE FATE OF FLIGHT 800: THE OVERVIEW;Flight 800 Flew for 24 Seconds After the Initial Catastrophe

Radar records show that T.W.A. Flight 800 apparently continued to fly for at least 24 seconds after the cataclysmic event that doomed it, raising the possibility that some of the passengers and crew may have been alive and conscious in the last horrifying seconds before the crippled jet broke apart in a fireball, investigators said today.

The radar information does not give a clue as to whether the cockpit crew had any functioning controls to work with after the plane was disabled at 13,700 feet by either a a bomb, a missile or a mechanical failure -- investigators still do not know which. But the investigators said the records indicated that the jetliner's engines probably continued to run as it moved over the water at more than 400 miles an hour. The plane was also descending rapidly, and by the time it reached about 8,500 feet, a fireball erupted, fed by the jet fuel that investigators presume was gushing from the plane's tanks. The scenario, based on information from a radar dish at Islip, L.I., that takes 12 seconds to make a 360-degree sweep of the planes in its sector, did not make investigators any more certain of the cause of the problems. But it did help establish the framework for the sequence in which the failures occurred.

According to the investigators, the radar made two sweeps after the initial event in which the plane appeared to be basically intact. But by the time the radar made its third 12-second sweep, two pieces of the plane became visible on radar.

Officials said that there were no signs of problems on either the flight data recorder or cockpit voice recorder except for a loud noise at the end of the voice recorder, and the obvious fact that both quit working a fraction of a second after the noise was heard. As a result, law enforcement officials said, the possibility that a mechanical malfunction caused the crash was growing more remote. Investigators also said they had found two of the plane's four engines. But they said they had decided to delay raising them -- which could provide clues -- because doing so would delay the recovery of bodies.

According to the National Transportation Safety Board, the last moment of normal functioning was at about 8:31:12 P.M., when the plane was climbing toward 15,000 feet. Within 12 seconds of then, the beacon that broadcasts the plane's identity and altitude failed. About the same time, possibly at the same instant, power was cut to the flight data recorder and the cockpit voice recorder. Sometime around then the pilots' radios probably ceased to function.

But the plane was in the air for another 2.5 nautical miles, another 41 seconds. For at least 24 of those seconds, the jetliner continued at a more or less constant speed over the water, but its speed through the air was apparently rising rapidly, because it was descending quickly. An airliner normally descends at about 1,500 feet per minute; this would have been about five times faster.