The DM said that, during the accident airplane’s departure, as the airplane rotated for takeoff, if water was present in the bottom of the nacelle tank, it would shift aft covering the fuel intake port to the engine. This “slug” of water would then flow to the engine’s 14 fuel nozzles, where it could extinguish the engine’s fire; the engine would stop producing power and its propeller would move from coarse to fine pitch.  

Subsequently, jet fuel would follow the water, and the engine’s internal heat would likely be sufficient to relight the atomized fuel. The engines were equipped with auto ignition systems, and if they were in the on position, they may also have been triggered to relight the engine. The DM believes that the two pops he heard were attempts by the engine to relight the reintroduced fuel. He said that each pop would have been accompanied by grayish white smoke. 

The DM also said that water found in airplane fuel tanks does not necessarily come from contaminated fuel trucks. Airplane refueling trucks have stringent checks and documentation requirements of their filters and are subject to regular tank sump sampling. He believes that the biggest source of introduced water into fuel tanks is daily temperature variations and atmospheric temperature variations. That is, if a fuel tank is not completely full, there is a cavity of air above the fuel, and due to the tank’s venting system, the air in that cavity will move in and out as daily temperature rise and fall, or as the airplane climbs to cruise altitude and descends at its destination. 

The United States Air Force has a fuels engineering research laboratory located at Wright-Patterson Air Force Base. One of their Senior Research Engineers stated that “the cavity above fuel in a partially filled fuel tank is vulnerable to aircraft fuel tank breathing through its vent system.