As a historic National Transportation Safety Board hearing got under way here yesterday, expert witnesses and safety investigators sought to put to rest continued speculation that a bomb or missile brought down TWA Flight 800 off Long Island, New York.
Even though a missile could have reached the Boeing 747 as it climbed to 15,000 feet, the reconstructed aircraft showed virtually no signs of high-velocity impact caused by a missile warhead, witnesses testified. Likewise, none of the 230 bodies had injuries typical of a bomb explosion, they said.
"There was no evidence of a bomb or missile-type phenomenon," testified Barrie Shabel, a retired Alcoa scientist who was hired as an independent consultant by the FBI. The FBI spent more than a year investigating the possibility of sabotage before ruling it out last month.
Investigators say the 747's center fuel tank exploded just minutes after the Paris-bound aircraft took off from John F. Kennedy International Airport on July 17, 1996.
Witnesses also discounted the possibility that a dud missile failed to detonate but struck the aircraft hard enough to cause the explosion or, an even less likely theory, that a missile exploded near the aircraft causing the nation's second worst air disaster.
The first day of the weeklong hearing -- the largest and most costly in the NTSB's history -- drew several hundred spectators, reporters and media technicians outnumbering the NTSB's entire staff and dozens of victims' relatives who met with FBI Assistant Director James K. Kallstrom.
After a two-hour meeting, Kallstrom said most of the families had accepted the FBI's findings, though several thought the agency was withholding something.
"I tried to convince them that nobody knows the answer to this tragedy," he said.
So far, the 17-month investigation has failed to pinpoint any mechanical or electrical source that sparked the highly volatile vapors in the nearly empty tank.
Interest is 'intense'
"The mystery of Flight 800 has generated intense public interest," NTSB Chairman James E. Hall said yesterday, adding that his office had received 500 letters offering theories ranging from a lighted cigarette in the lavatory to a malfunctioning fuel pump.
"While the shock of this event has slowly abated, the horror has not," Hall said.
He said the NTSB ultimately hopes to not only learn what sparked the explosion but to find a way to reduce the likelihood that explosive vapors will accumulate in airliner fuel tanks. "In the final analysis, had the vapors in TWA Flight 800's fuel tank not been explosive, this accident would not have occurred, no matter what the ignition source," the NTSB chairman said.
This week's hearing is not expected to determine the cause of the explosion. The event is being held in Baltimore because of the size of the convention center, the availability of affordable hotel rooms and the city's central location in the Mid-Atlantic region.
Fuel tank will be topic
In today's session, the NTSB will examine evidence about the 747's fuel tank, the fuel pumps and wiring and discuss little-known issues about fuel volatility.
The TWA flight was an hour late taking off because a piece of luggage seemed to be on board without the passenger. Tests have shown that temperatures in the tank may have reached dangerously high levels while the plane sat on the runway.
A transcript of the cockpit voice recorder (CVR), released yesterday, revealed a normal flight with no sign of trouble as the flight crew chatted routinely.
At one point in the transcript, the captain said, "Look at that crazy fuel flow indicator there on number four." But the NTSB report appeared to dismiss the significance of the sticky fuel flow gauge, a common occurrence in the 747.
Unusual sound at end
At the end of the transcript, there was a unusual sound, believed to be vibrations from the center fuel tank explosion.
Immediately, the CVR and flight data recorders ceased within a fraction of a second of one another -- 12 seconds after 8: 31 p.m. -- when electrical power was lost. The two critical pieces of evidence were recovered by Navy divers a week after the crash.
The remains of 99 victims were recovered floating on the surface of the ocean. Others were recovered by divers in what the NTSB said was the largest underwater recovery operation since the space shuttle Challenger exploded in 1986.
Forensic medical experts, who examined the remains of all 230 victims, also discounted the possibility of a bomb exploding in the passenger cabin.
"Bodies can tell many stories about what happened during a crash," said Col. Dennis F. Shanahan, a senior medical consultant.
Such an explosion, Shanahan said, would leave certain injury patterns such as tearing rather than lacerations, powder discoloration or metal fragments penetrating the bodies.