TWA Probe Nearing End
NTSB: Investigators expect final report in December
By Lauren Terrazzano
ZEROING IN ON exactly what sparked the explosion of TWA
Flight 800, investigators said they plan to issue a final report and a
probable cause of the crash as early as December, National
Transportation Safety Board officials said yesterday.
Several months of testing lie ahead, but one scenario they are
aggressively pursuing is that electrical energy migrated from one wire
to another to the rear bay of the aircraft's center tank, using the plane's
fuel-measuring system as a pathway.
Even though the NTSB has said that a massive fuel-tank explosion
brought down the plane, investigators have had a harder time
pinpointing the actual ignition source because they would have to
prove a complicated chain of events.
The Boeing 747 crashed off Long Island on July 17, 1996, killing all
230 people aboard. Last month, NTSB chairman Jim Hall pledged to
Congress that the agency would do everything in its power to resolve
the lingering mystery, putting an end to what has shaped up to be a
$35 million investigation.
''We are just as certain today as we were at the time of the hearing
that we understand basically what happened, a fuel-air explosion
brought the airplane apart,'' said Bernard Loeb, the NTSB's director
of aviation safety. ''What we have been working on since the public
hearing almost exclusively is trying to determine if we can identify the
source of ignition. ''
Boeing spokesman Russ Young said yesterday that the company
continues to ''support the investigation, in terms of pursuing all of those
possible theories . . . It's our role to show them the safeguards we've
now built in to prevent such occurrences.'' TWA spokeswoman Julia
Bishop said the airline would not comment on what is still an ongoing
While a team of investigators still toils at the delicate clues of the
wreckage, testing at various laboratories around the country may soon
put an end to the nearly 3-year-old puzzle.
Cal Tech and Sandia National Laboratories are home to fuel-testing
and computer-modeling programs that are re-creating points of ignition
that tell investigators how the flame traveled through to the tank.
Sources said they are particularly interested in a fuel bay in the rear of
the center wing tank - known as Bay 2 - where a host of wires
The fuel-measuring system, which runs from the cockpit to the fuel
tank, consists of hundreds of feet of wire connected to long aluminum
probes. The system carries a low current, too small to cause an
explosion. But investigators have also found damaged wiring in the fuel
system of the crashed plane and on inspections of three other 747s
that may or may not have helped the spark travel through the tank.
Loeb said investigators are also pursuing other possibilities such as an
external electromagnetic field that could have caused the plane's tank
to ignite. Investigators have also considered that residual metal
shavings - possibly from a repair job before the plane's crash - fell into
wire bundles and somehow created a path for electrical energy.
NTSB officials said there is little or no evidence currently to support
those theories, but have checked local radar trackings at airports and
on boats to see if there could have been radar interference the night of
Even though the investigation appears to be winding down, officials
said they were still unclear what safety recommendations, if any, would
emerge from the final report on the disaster.
Meanwhile, the NTSB plans to move the plane next year from the
Calverton hangar where it is housed to a site in either Queens or to
Loudon County, Va., where it could be used as a tool in aviation
NTSB's managing director Peter Goelz said the 94-foot reconstruction
could be separated into sections and transported by barge or truck to
its ultimate destination. ''It was a tremendous effort by the NTSB, FBI
and other party members. If we can use it as a teaching tool to help us
prevent future tragedies, maybe something good can come from this