Split second of sound may solve TWA crash mystery

July 27, 1996
Web posted at: 1:00 a.m. EDT

From Correspondent Ann Kellan

ATLANTA (CNN) -- A fraction of a second may be all it takes for investigators to determine what caused TWA Flight 800 to burst into a ball of fire.

As investigators continue to search for bodies and debris, they are examining a loud, abrupt noise heard at the end of an audio tape from the cockpit voice recorder.

Investigators are convinced a "catastrophic explosion" occurred, but why the plane blew up is not yet known. The July 17 crash off Long Island killed 230 people.

"Even a half second could still lead to some important information, so it really depends on the true length of this sound," said Michael Hecker, a forensic acoustics consultant.

According to Hecker, the audio will most likely be digitized onto a computer designed for voice and sound analysis. Investigators will then dissect the tape into milliseconds, or thousandths of a second, Hecker said.

He said an "immediate and catastrophic power failure" may have occurred on the plane. (345K AIFF or WAV sound) Ken Evans with the College of Aeronautics also believes something "catastrophic and instantaneous" ripped through the Boeing 747. (320K AIFF or WAV sound)

If a bomb did cause the explosion, Hecker said it would have sent shock waves through the plane and produced two types of sounds: one through the body of the aircraft and the other through the air.

The audio tape may or may not reveal such information. Investigators are listening for wave patterns similar to those from Pan Am 103 that exploded by bomb over Lockerbie, Scotland, in 1988.

National Transportation Safety Board Vice Chairman Robert Francis has said a brief sound was recorded just before the cockpit tape stopped, about 11 minutes into the flight.

"All four CVR channels recorded a brief fraction-of-a-second sound just prior to the end of the tape," Francis said.

The tape also indicates a routine pre-flight preparation, takeoff and departure from John F. Kennedy International Airport in New York, Francis said.

Sound experts from Britain and experienced pilots are helping to analyze the noise, as well. It may take days for the results, authorities said.

CNN-Time Magazine Special TWA Flight 800 Sunday, July 28, 9p.m. EDT/6 p.m. PDT

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