Numerous pieces of Trans World Airlines Flight 800, mostly from the Boeing 747’s midsection, have been sent to the FBI’s Washington lab for indepth analysis after showing possible traces of explosive residue in preliminary tests, a senior investigator said Friday.
However, none of the pieces tested thus far has been positive when subjected to the more rigorous analysis conducted in Washington. Investigators are still awaiting results from other fragments that appeared to bear elements of explosives in initial tests conducted at a hangar in Calverton, N.Y., according to the source, who spoke on the condition of anonymity.
The stream of field tests that have shown positive results then fallen short in Washington has confounded investigators and led to renewed doubts about whether the plunge of the jumbo jet and its 230 passengers into the Atlantic Ocean was caused by a bomb or a missile.
National Transportation Safety Board investigators have often seen initial crash theories evaporate under the weight of evidence. And they have always given equal weight to the possibility that something mechanical or structural brought down the plane. Now many law enforcement officials who pressed a bomb theory in the early days after the July 17 crash are having second thoughts.
Nonetheless, many other law enforcement officials remain convinced a criminal act is involved in the crash, and that they merely have not found the necessary evidence.
“We still don’t think we have the right parts of the plane,” the source said.
Sources close to the investigation said the FBI apparently has tested far more of the wreckage than has been indicated.
Now, new pieces of wreckage are arriving from the plane’s lower fuselage section around the center fuel tank that might provide the evidence for which they are looking.
Robert Francis, the safety board’s vice chairman, said Thursday that investigators are reconstructing the lower section of the fuselage from just ahead of the wing to just behind the wing. This “wing box” section, which also contains the center fuel tank, shows signs of major fire damage.
Sources close to the investigation said there is preliminary evidence the tank exploded, although there is no way now to determine whether it initiated the crash sequence or exploded as a result of something else. A bomb, for example, could have provided a hot, penetrating spark, igniting fumes in the tank.