NTSB looks for answers from the military at crash hearing
BALTIMORE (AP) _ The National Transportation Safety Board is looking to the military for ways to make fuel tanks incapable of exploding.
During Thursday’s session of the NTSB’s weeklong hearing into the crash of TWA Flight 800, witnesses said U.S. jet fighters have survived bullets and missile hits since the 1950s because liquid nitrogen and foam were added to the tanks to keep fuel temperatures safely low.
Ralph Lauzze II, director of live fire testing and evaluation at the Air Force Research Laboratory, showed a photograph of a wing that was almost sheared off by an explosive during the Gulf War. Still, the plane returned safely to its base.
``The point is, the bottom line is, foam works,″ he said.
The hearing, which was to conclude today, was intended to gather information. The NTSB isn’t expected to release a probable cause until late next year; the FBI has concluded the crash was not the result of a criminal act.
The chief suspect in the Flight 800 disaster is a combination of events involving damaged wires and corrosion on a fuel measuring rod that could have introduced a spark or flame into the Boeing 747′s center fuel tank.
All 230 people aboard the plane were killed when the tank exploded July 17, 1996, after it left Kennedy International Airport for Paris.
Another witness, NTSB engineer George Anderson, said his research discovered that Russia during World War II managed to suppress fires in its ground attack planes by venting exhaust gases into the fuel tanks.
Some engineers have argued that the best way to eliminate fuel tank explosions is to cut out any possible ignition sources, such as faulty wires. But witnesses here said even maintenance programs can damage aircraft.
``One of the most probable causes for damage to wires is the maintenance activity,″ said Bill Crow, a Federal Aviation Administration supervisor. ``Where there’s no symptomatic cause of a problem, you can cause more damage than there was in ... the aircraft.″
Crow’s view was supported by George Slenski, lead engineer for electronic materials at Wright Laboratory in Dayton, Ohio. He said he agreed maintenance was a threat to wiring.
``One problem with inspection is every time you disturb that bundle, you can do damage. In the process of inspection, you can do more damage,″ he said.
Questions arose as to whether wiring should be replaced at a certain age, but Robert Vannoy, chief of the 747 Fleet Support at Boeing, said wiring should last as long as the airplane.
Boeing’s designs have long relied on keeping possible ignition sources away from flammable fumes and vapors in fuel tanks. The company says it will now focus on ways to eliminate or reduce flammability within the tanks.