Air Crash Hearings Pay Off

This week’s National Transportation Safety Board hearings on the explosion of TWA Flight 800 continue to point out reasonable steps that could be taken to minimize the risk of a similar tragedy. The June 1996 TWA disaster off Long Island, N.Y., killed all 230 passengers and crew members aboard the Boeing 747.

Investigators have dismissed a bomb or a missile as the source of the explosion in the aircraft’s center fuel tank. Speculation is focused on the likelihood that an electrical spark ignited a mixture of air and fuel in the tank, but what created the spark is a mystery.

The exact cause may never be found, but several theories under study could lead to changes to greatly reduce the risk of such explosions. And that’s what this week’s NTSB hearings can produce. Several possible modifications, some tested and used in military aircraft, were detailed Thursday by Robert Ball, a professor of aeronautics and astronautics at the Naval Postgraduate School in Monterey, Calif. Among them: installing low-weight foam or fibrous fillers inside the fuel tanks, introducing a chemical to break down the chain of combustion, venting the fuel tank and using additives to reduce the fuel volatility. These steps would reduce vapors, dilute oxygen content or absorb heat.

Also under consideration is pumping cooler fuel into the tank before takeoff. TWA Flight 800 sat on the ground for three hours before takeoff with its heat-generating air conditioner running. That system is located just beneath the central fuel tank.

Investigators are also probing the possibility that the silicone insulation on some electrical wiring on older 747s may have worn off, creating the possibility of a spark. The Federal Aviation Administration already has proposed a requirement that airlines better insulate or separate certain wiring to decrease the possibility of short circuits.

There’s a final caution here. At the time of the crash, the Boeing 747 was held in such high esteem that aviation experts considered an equipment failure the least likely explanation for the explosion and crash, despite the fact that the TWA airplane was 26 years old. The various versions of the Boeing jet have an enviable safety record in comparison to other large commercial jets, but according to the FAA database, only five 747s had flown more than Flight 800’s 87,000-plus hours or logged more than its 16,000-plus takeoff and landing cycles.

The safety board’s hearings must air and study all possibilities. The flying public demands it.