TWA Flight 800, bound for Paris from New York-JFK, broke apart roughly 12 minutes after takeoff. All 230 occupants—212 passengers and 18 crew—perished. The National Transportation Safety Board (NTSB) determined the probable cause was an explosion of the center wing fuel tank (CWT), igniting flammable fuel/air vapors. The ignition source was never conclusively identified; the most likely scenario involved a short circuit outside the CWT that transferred excessive voltage into the Fuel Quantity Indication System (FQIS) wiring. Contributing factors included the certification assumption that fuel tank explosions could be prevented solely by eliminating ignition sources, and the placement of air conditioning packs beneath the CWT without means to reduce heat transfer or render vapors non-flammable.