What happened
The incident occurred during a routine training exercise in the vicinity of Barmouth, Wales. At the time of the accident, the crew was piloting a twin-engine aircraft at a cruising altitude of approximately 1,000 feet. While flying over the area, the aircraft collided with the slope of Mt Bwlch y Llan. The force of the impact resulted in the total destruction of the airframe. All 4 occupants on board were killed in the crash.
Findings
The source material identifies the victims as members of the 9th Air Fighting Unit (AFU). The fatalities included the pilot, two navigators, and a wireless operator who also served as an air gunner. No specific mechanical failures or human error factors are detailed in the provided text beyond the collision with terrain.