july 17th, 1996, twa flight 800 explodes in flames shortly after takeoff. the fbi rules out a bomb or missile, but it will take a four-year investigation, the most costly and extensive in the ntsb s history, to determine the cause. after pulling debris from the ocean, investigators conclude that the airplane broke apart into three distinct sections. the front section including the cockpit and the first class areas broke off and that just fell to the ground, then much further away you had the rest of the airplane, which seems odd. it was clear that piece of the airplane had to continue some part of the flight for a lot longer. went back and started looking at all the pieces that came off first. they all came out of areas around the wing center fuel tank. so it started becoming apparent that whatever happened happened inside the wing center fuel tank.
unlike gasoline, jet fuel isn t highly flammable. but as this faa test shows, when it s heated, the vapors that are produced can be explosive. as twa flight 800 prepares to take off from new york s jfk airport, the center wing fuel tank, about the size of a two-car garage, is nearly empty. all that was in that fuel tank was basically just residual fuel, just a small amount of fuel sloshing around the bottom of the tank. given the short duration of this particular flight, the operators don t usually use or put fuel into the center fuel tank because they don t need it. the wings hold a sufficient amount of fuel. you can save some money and get better performance by leaving the fuel out of it. with passengers waiting on board flight 800, a delay with baggage is keeping the plane at the gate. it was a hot day in new york, and they ve had the air conditioning packs running to keep the aircraft cool. the air conditioning packs are mounted in close proximity to the center fuel tan
and touch a door knob and the spark you get. less energy than that was necessary to ignite that fuel tank. but there is no clear source of ignition on board twa flight 800. by design, only low voltage wires are used inside the fuel tank. however, those low voltage wires pass in very close proximity to much higher voltage wires in wiring bundles. and as the airplane s age and these wiring bundles chafe, you can have occasion where there s arcing or shorting between these wires, which introduce this high voltage into low voltage wire and now you have an ignition source. we don t have a piece of wire or something that we can hold up and say, this absolutely did it. there s not enough left. the ntsb believes and i believe it s most likely a short circuit of the wiring and that certainly was very possible. you look at all the evidence.
actually generating heat underneath the center wing fuel tank. so the fuel tank was actually getting very warm. so when the airplane takes off, you have this warm fuel vapor. if there was a full load of fuel in that tank, it could absorb that heat with no problem. it was generally believed that fuel tank were not really flammable. they couldn t really even be ignited because the temperature wasn t great enough. and so we took a 747 tested them in very similar conditions, and we were all surprised how hot it got and also it didn t take a lot of energy to ignite these vapors. it s less than you feel if you rub your feet across a carpet
whatever ignited the fuel of the tank was inside the tank. it didn t come from outside. the cockpit voice recorder recovered one week after the crash may provide evidence. the pilot is heard observing a strange reading on a fuel flow gauge. that s probably an indication of some type of short circuit going on. this airplane was old, it was getting ready to be taken out of service. and there are more clues. one second before the cockpit voice recording ends, there are two dropouts in background noise suggesting a possible arc on the cockpit wiring. investigators believe in this moment high voltage enter the center wing fuel tank igniting the warm fuel vapors. that ignition caused overpressurization of the tank that blew out the forward panel of the tank. you can see the indentation where it s very clear on slam down, there s a very clear mark. from that position we had fractures that went down into