Fuel Tank Inerting and TWA Flight 800
The FAA issued requirements for adding to commercial jets, fuel tank inerting systems. These systems replace potentially explosive fumes in fuel tanks with "nitrogen enriched air." Aircrafts of most concern to the FAA are those that sometimes fly with heated and near-empty tanks, where the potential for explosive vapors exists. Federal investigators determined fuel vapors exploded aboard TWA Flight 800 before it crashed in 1996.
The National Transportation Safety Board (NTSB) investigated the Flight 800 crash. Though never isolating the explosion's ignition source, the NTSB closed the case naming an electrical spark the most likely catalyst and dismissing eyewitness accounts of a missile.
During the Flight 800 investigation, the NTSB requested the FAA to consider “design modifications, such as nitrogen inerting systems” for aircraft fuel tanks. The FAA’s plan to add these systems to commercial jets addresses one of the NTSB’s “Most Wanted” Safety Recommendations.
Fuel tank inerting is widely used in military aircraft, such as the F-16, that rely on these systems during combat to help prevent fuel vapors from igniting after sustaining damage from a missile or anti-aircraft shell.
The terrorist missile attacks on an Israeli charter flight in Kenya has brought fears normally reserved for military pilots to the flying public. Without inerting systems, many commercial aircraft remain dangerously vulnerable to terrorist missile attacks. Although the shoulder-launched missiles used in Kenya were relatively small, they could have caused catastrophic structural failure had either hit a fuel tank containing explosive vapors.
The official investigation into the crash of TWA Flight 800, though controversial, resulted in a recommendation to preclude an unnecessary vulnerability within aircraft fuel tanks. The FAA's rollout of fuel tank inerting system requirements for certain aircraft will add a level of safety that is in step with world events.