Incident
A heavy bomber departed Davis-Monthan AFB in Tucson at 0615LT for a routine training mission involving navigation, aerial refueling, and camera gunnery training. After transferring 870 gallons of fuel to a KB-29 over Yuma, the crew pressurized the cabin and began climbing to 20,000 feet. While climbing through 17,000 feet at approximately 0815LT, the master fire warning light suddenly illuminated on the pilot's instrument panel. Simultaneously, the right scanner reported a fire streaming from Number 3 engine. Three successive minor explosions occurred, rolling the bomber into a 45-degree right bank. With the right wing engulfed in flames, the aircraft fell into a steep right turn and began to disintegrate.
Escape
As the bomber broke apart in the sky, only two of the fourteen crew members were able to escape: the copilot, Lieutenant William Gentry, and the bombardier, Captain John Lee. The wreckage was spread over a two-mile area of remote desert terrain.
Investigation
The investigation revealed that Engine Number 3 had been replaced the prior day. The cause of the fire was determined to be a failed exhaust clamp on Engine Number 3, which allowed hot exhaust gas to ignite fuel that had seeped past the fire seal into the engine section. The source of the fuel was likely from a loose-fitting main fuel line at the inlet side of the engine-driven fuel pump.