What happened
The incident occurred during a routine training sortie where the crew was conducting a simulation of a bombing attack. During the exercise, a bomb stored under one of the wings failed to release properly as intended. The aircraft continued its approach and touched down on the runway. Upon landing, the unreleased ordnance detonated. The force of the explosion caused the airframe to disintegrate completely. All three members of the crew were killed in the accident.
Findings
The official investigation determined that the immediate cause of the disaster was the explosion of the bomb at the moment of touchdown. The failure of the release mechanism during the simulated attack allowed the live munition to remain attached to the aircraft until it made contact with the ground.