By: Gavin
E-mail Address: GAVUFO@aol.com

Who's Right?

The ongoing NTSB hearings per regards the TWA 800 explosion has produced a contradiction between Commander Donaldson and a Boeing expert vis a vis the ignition point of Jet A-1. Could you tell me who is correct?

Donaldson says;

I will call your attention to the flammability range (Percentage By Volume) of Jet A-1 vapor contained at enclosure (1). (Pg. 71, Table 8, Handbook of Aviation Fuels Properties, CRC Report 530, 1988) This table also depicts the minimum temperature (closed cup flash point) where a flame introduced into the cup of heated fuel will ignite the minuscule amount of vapor at the surface of the fuel. Because C12H24 produces a very heavy vapor molecule, at aircraft operation temperatures, if it exists at all, it stays very close to the surface of the liquid fuel and does not mix well with air. In other words the table tells us at 53 C or 127 F just enough molecules of C12H24 are energized to break the surface tension, leave the liquid and mix in a 6:994 ratio (.006 Vapor, .994 Air) with air in a thin layer just above the surface. It also means this fuel is so safe a maintenance employee could have taken a smoke break standing in the residual fuel of TWA's tank, reached down and put out his lit match in the fuel without consequence at temperatures up to and including 126 F!

According to the Boeing Fuel Tank Expert testimony this morning (12.9) the flash temp of Jet A is 100 degrees and not 127 degrees.

Thanks for your time. Gavin.

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