What happened
On the morning of the accident, the Boeing KB-29P, registration 44-83950, departed from RAF Lakenheath in Suffolk at 09:17 local time. The mission was intended to consist of a radar navigation flight followed by four hours of air-to-air refueling exercises with a Boeing B-50.
By 11:03 local time, the aircraft had entered the Scottish Flight Information Region and was communicating with controllers at Prestwick. At that time, the pilot reported an altitude of approximately 14,500 feet under visual flight conditions. However, shortly thereafter, witnesses on the ground near Carsphairn observed the aircraft descending through cloud cover at an altitude between 1,500 and 2,000 feet while traveling on a north-northwest course. These observers noted that the engine sounds were atypical compared to the aircraft's usual flight profile.
Following this observation, the aircraft transitioned to a southeast heading. The aircraft subsequently entered a stall and subsequent spin. The crew was unable to recover the aircraft before it struck the ground in a deep gully located at the edge of a field. An explosion involving the aircraft's fuel tanks, which held roughly 8,000 US gallons, caused the total destruction of the airframe and significant debris dispersal.
Findings
The accident resulted in 11 fatalities among the crew members on board. The sequence of events indicates that the aircraft entered a spin from which it could not recover following a stall.