RAPID CITY, S.D. (AP) — An Air Force report says a mechanical malfunction that started a fuel leak caused the crash of an Ellsworth Air Force Base B-1B bomber during an August training exercise over southeastern Montana.

The report released by the Air Combat Command Accident Investigation Board concluded that about 7,000 pounds of fuel leaked into the aircraft and was ignited by hot ductwork, leading to a series of detonations in the plane

The plane crashed Aug. 19 near Broadus, Mont. The four crew members safely ejected and escaped serious injury. No one on the ground was hurt.

The report says there is no evidence that human error contributed to the crash that destroyed the $318 million aircraft.

The plane and crew were assigned to the 34th Bomb Squadron, 28th Bomb Wing, at Ellsworth.

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