Jet Probe Focusing On Bomb Data From Recorders Shows Plane Operating Normally

The flight data recorder on board Trans World Airlines Flight 800 showed that all systems were operating normally until the device suddenly stopped operating - at virtually the same moment the cockpit voice recorder picked up a final, loud noise, federal officials said Friday.

The disclosure appeared to increase the probability that either a bomb or a missile caused the 747-100 to explode and crash into the Atlantic Ocean on July 17, killing all 230 people aboard, law-enforcement authorities said.

But National Transportation Safety Board officials said that a catastrophic mechanical malfunction still could not be ruled out. James Kallstrom, the assistant FBI director for the New York office, said a final determination of the cause probably could not be made until investigators examined more of the wreckage remaining on the ocean floor.

Nevertheless, Kallstrom said, with the new information from the flight data recorder and the absence of conversation on the cockpit voice recorder indicating trouble, investigators are getting closer to determining a cause.

Even without that determination, he added, the bomb and missile scenarios are under intensive investigation.

Officials said the final sound on the cockpit voice recorder was being compared with one on the cockpit tape of Pan Am Flight 103, which was destroyed by a bomb on Dec. 21, 1988, over Lockerbie, Scotland. British investigators, some of whom were involved in the Lockerbie investigation, are coming to New York to help in the TWA inquiry.