TWA Flight 800. 1/4-Scale Center Wing Tank Jet A Explosions

Applied Research Associates, Inc. (ARA) and the California Institute of Technology (Caltech) are key members of the team of experts conducting research for the National Transportation Safety Board (NTSB) in the investigation of the July 1996 explosion of TWA Flight 800. ARA and Caltech conducted 30 (1/4-scale) tests of the Center Wing Tank (CWT) during the past year. A 1/4-scale model of the large center fuel tank assembly, thought to be the source of the explosion, was constructed and instrumented for the experimental tests. As an empty CWT fuel tank (747-100) contains approximately 55 gallons of fuel, the fuel vapors generated during ground and flight operations may be susceptible to ignition sources located within the tank structure. The vapor ignition sensitivity would be enhanced due to external heating caused by the environmental control units which are located beneath the CWT structure. This vaporized fuel could be ignited by a suitable ignition source resulting in a fuel-air deflagration or detonation. ARA and Caltech conducted the 30 tests at ARA's Rocky Mountain Division's test site located Southeast of Denver. The tests were designed to provide controllable surrogate vapor mixtures and Jet A liquid fuel to understand flame combustion phenomenology and its effect on the scale tank pressures and temperature across the various fuel tank compartments. The explosive effects and internal partition response were documented by high-speed and SVHS video cameras. The ignition source locations were varied to replicate possible ignition sources on Flight 800. The instrumentation suite measured the quasi-static pressure, temperature, flame speed, and partition movement. Special photography was employed to document the combustion front and flame propagation through the tank compartments. Data analysis from this test series is on-going with results expected within the next year. See also ADM001002. Published in the Proceedings of the DoD Explosives Safety Seminar (28th) Held in Orlando, FL on 18-20 August 1998.