What happened
The Boeing B-30 Liberator departed RAF Heathfield in Prestwick during the evening for a scheduled service to Montreal-Saint Hubert Airport. The flight included an intermediate stop at Gander and carried 19 passengers along with a crew of three, totaling 22 people on board. Shortly after takeoff, the crew encountered marginal weather conditions characterized by low clouds and limited visibility. During this period, the aircraft followed an incorrect heading, deviating significantly from its intended track.
Unable to acquire visual references due to the dense cloud cover, the crew could not determine their actual position relative to the terrain. The aircraft subsequently impacted the slope of Mt Mullach Buidhe on the Isle of Arran, which stands at 2,366 feet. This location is situated approximately 41 km northwest of the departure point. The impact caused the airframe to disintegrate completely, resulting in 22 fatalities among both military personnel and civilians.
Findings
The official investigation attributed the accident to a navigation error committed by the crew shortly after takeoff. Instead of following the required heading of 012°, the aircraft was flown on a heading of 295°. This mistake caused the plane to deviate approximately 15 km north of its initial track. The combination of poor weather, low visibility, and the absence of ground visual references prevented the crew from recognizing their incorrect position before striking the mountain shrouded in clouds.