What happened
A routine training flight involving navigation and aerial refueling departed Davis-Monthan Air Force Base in Tucson at 0615LT. The mission, which included camera gunnery exercises, proceeded normally until the aircraft completed a fuel transfer of 870 gallons to a KB-29 near Yuma. During the subsequent climb to 20,000 feet, the crew pressurized the cabin and reached an altitude of approximately 17,000 feet.
At roughly 0815LT, the pilot observed a master fire warning light, coinciding with reports from the right scanner regarding flames emanating from the number three engine. The aircraft then experienced three consecutive minor explosions that forced the B-50 Superfortress into a 45-degree right bank. As the right wing caught fire, the bomber entered a steep turn and began to break apart in flight. Out of a total crew of fourteen, only two survivors managed to escape the wreckage. The debris from the accident was distributed across a two-mile area of uninhabited desert.
Findings
Investigations into the incident revealed that the number three engine had been swapped into the aircraft just one day prior to the flight. The fire originated due to a failure of an exhaust clamp on this specific engine, which permitted hot exhaust gases to reach fuel that had leaked past the fire seal. This leakage was attributed to a loose main fuel line located at the inlet side of the engine-driven fuel pump.