Tests Tied to TWA Flight 800 Crash Start

A jumbo jet wired with sensors on its fuel tanks took off from John F. Kennedy International Airport on Monday in the first of a series of test flights that could help unlock the mystery of what destroyed TWA Flight 800 a year ago this week.

Each flight is designed to re-create one or more of many variables investigators suspect led to the July 17, 1996, explosion, which is believed to have originated in the near-empty center fuel tank.

For example, one flight will take off after the plane has sat for an hour with its air-conditioning running full blast. The air conditioners in a 747 are directly beneath the center fuel tank, and investigators believe that they may have heated fuel vapors inside the tank, increasing their volatility.

“We want to know what goes on inside those center fuel tanks: How hot it gets, and whether or not it shakes in flight,” said Bernard Loeb, director of aviation safety for the National Transportation Safety Board.

While investigators have not ruled out a bomb or a missile, they have raised the possibility a mechanical malfunction ignited the fuel tank.

The test flights will take place over the next 10 days to two weeks.

The crash of Flight 800 shortly after the plane took off from Kennedy Airport for Paris killed all 230 people aboard.

Loeb said it is coincidental that the flights are taking place so near the anniversary. He said it would be impossible for investigators to re-create the precise weather conditions of last July 17 and there will be no attempt to have the test flights take off at the same time of day as Flight 800.

“We will probably not be able to replicate precisely the flight of TWA 800,” Loeb said. “We will come close enough to be able to gather sufficient information to be able to draw some conclusions.”

While investigators have ruled out a big bomb, it is possible that a small, well-placed charge sparked the explosion, NTSB Chairman James Hall said. He also said that although a direct hit by a missile has been ruled out, a charge from a missile that exploded prematurely could have caused the blast.

Four possible mechanical sources of the igniting spark are under consideration: faulty wiring, static electricity, a fuel measuring rod inside the center tank, or a fuel pump. The last is considered an unlikely source, Loeb said; all indications are that the fuel pump was off at the time of the crash.

The plane’s center fuel tank exploded as the 747 climbed to around 13,700 feet on a mild, calm evening. The jumbo jet then dropped to about 9,000 feet, before exploding in a fireball off Long Island.