INVESTIGATORS ARE analysing a brief sound on the cockpit-voice-recorder (CVR) tape recovered from the wreckage of Trans World Airlines Flight 800, looking for clues as to why the Boeing 747-100 exploded soon after take-off from New York Kennedy on 17 July, killing all 230 on board.
Initial CVR analysis indicates that the pre-flight, take-off and departure phases of Flight 800 were routine, according to the US National Transportation Safety Board (NTSB). About 11.5min into the flight, the recording ended abruptly. All four CVR channels recorded "a brief, fraction-of-a-second, sound just prior to the end of the tape", says the NTSB.
The CVR and flight-data recorder (FDR) were found among wreckage lying more than 100ft (30m) under water, by divers and a remotely operated vehicle from the recovery ship USS Grasp. They displayed moderate impact damage, but had sustained no fire damage, says the NTSB. The "last few seconds" of data from the 19-parameter FDR were contaminated by its immersion, but will be recovered, the Board maintains.
Investigators are looking for information to determine whether the 747 was downed by a bomb, a surface-to-air missile, or mechanical failure. Tests for traces of explosive on the first pieces of wreckage recovered have proved inconclusive, while analysis of radar tapes and satellite photographs have failed to find evidence of a missile.
The NTSB says that priority is being given to recovery of the victims. A week after the accident, only 126 bodies had been recovered. A major debris field had been located, including an 18m-long section of fuselage. Two engines have also been located and were being recovered as Flight International went to press. The aircraft came down 19km (10nm) off Long Island.
Meanwhile, US President Bill Clinton announced on 25 July that a major tightening of airline security is being pushed through. Among the measures are more hand-searching and screening of luggage and preflight inspections of any aircraft flying to or from the USA.
Coincidental to the crash was initiation of a review of aviation security by the Aviation Security Advisory Committee. Made up of federal officials and aviation-group representatives, the committee will evaluate security regulations and practices, including passenger screening, terrorist profiling and explosive detectors.
Source: Flight International
