Name one time when a commerical jet aircraft exploded spontaneously because of a spark incuded explosion of fuel vapor. I have not heard of any other explosions other than the mythical explosion of TWA 800 in the "official" cover-up report. I'll see if I can find you a link to the articles on the military labs testing of jet fuel. Their conclusion was that they couldn't get the fuel to explode at any actual operating temperature in a 747.
It is a myth propogated by conspiracy theorists that fuel vapor in aircraft is not explosive and that such explosions have never happened before TWA 800. Ironically, (or maybe not) one of the sister aircraft to TWA 800 (another 747-131 built for the Iranian Air Force) was destroyed while airborne due to an explosion of fuel vapor in its #1 fuel tank. The aircraft was struck by lightening while in a descent. The lightening strike triggered an electrical surge which resulted in a spark igniting vapor in its empty #1 fuel tank.
But in total there have been at least 19 incidents of aircraft exploding due to fuel vapor igniting for various reasons. Here is a link detailing each....19 Fuel Vapor Explosions