BALTIMORE — The largest hearing in National Transportation Safety Board history begins here today in an effort to learn more about what triggered the fiery fuel tank explosion that hurled TWA Flight 800 into the sea last year, killing all 230 on board.
Last month, after 15 months of investigation that included more than 7,000 interviews and cost nearly $50 million, the FBI concluded that no bomb, missile or other criminal act was responsible for the crash of the Boeing 747 off Long Island, N.Y.
That means static electricity or some mechanical problem--defective wiring or a malfunctioning electrical device--probably generated a spark that touched off the volatile fumes in the nearly empty center fuel tank.
The exact source of that spark may never be known.
Static electricity leaves no trace, and the explosion that tore apart the center fuel tank was so powerful that many of its components were blasted into oblivion.
About 96% of the wreckage, more than 1 million pieces, has been recovered from the ocean floor, reassembled in a hangar and studied by some of the top air crash experts from around the world. But the crucial fragment that could tell investigators precisely what happened--if there is one--has never been found.
The NTSB said the weeklong hearings that start today are intended, in large part, to tell the world what has been learned thus far and explain how it was learned.
Scores of tests have been conducted in an effort to duplicate the conditions under which Flight 800 crashed, and the results of those tests will be discussed this week.
Dozens of experts from the federal government, from the manufacturers of the jetliner and its components, and from research facilities like Caltech and the Christian Michelsen Institute in Norway will offer their insights as to what happened to Flight 800 a few minutes after taking off for Paris from New York's John F. Kennedy International Airport on July 17, 1996.
Some of the testimony will focus on whether the jet's electrical systems--and the insulation materials that were supposed to keep them from shorting out--were deteriorating with age. The 747-100 that crashed was built in 1971.
A year ago, the NTSB asked the Federal Aviation Administration to order a series of "urgent" design changes in hundreds of airliners, including all 747s, that would preclude the volatile buildup of fuel-and-air mixtures at temperatures high enough to permit ignition in the event of a spark.
Last week, the FAA formed a technical group that has been asked to report in six months on ways to lessen the chances of fuel tank explosions. However, the FAA rejected the NTSB's recommendations for short-term fixes.
NTSB investigative documents showed that of the 202 victims of the TWA crash whose remains were complete enough to draw forensic conclusions, 183 suffered injuries that killed them instantly and 15 others may have been killed instantly. Unstated is whether those injuries were sustained in the initial explosion or between then and the impact with the water more than a minute later.
Only eight victims--seven of them seated over the center fuel tank--suffered burns, none of which was severe.
To accommodate the more than 1,000 people expected today, the NTSB is holding the event in Baltimore's convention center.