What happened
The incident occurred while the aircraft was flying over the Greenland Ice Cap at an indicated altitude of 4,500 feet. According to charts for the area, this altitude should have provided a clearance of approximately 1,000 feet above the terrain. However, weather conditions combined with snow-covered ground created severe whiteout effects that significantly impaired depth perception.
The crew was not flying on instruments and believed they were at a safe distance from the ice because a horizon was visible. Without realizing how close they were to the surface, the aircraft made contact with the upward slope of a 400-foot rise. The pilot immediately applied full throttle in an attempt to regain airspeed, but the steepness of the slope prevented takeoff. Subsequent attempts to turn the aircraft around for a down-slope departure also failed as the plane sank further into the snow and ice.
Efforts to use dropped block and tackle equipment to assist in recovery were unsuccessful. The crew remained stranded on the ice cap for fifteen days, maintaining constant radio contact with their base. A supply drop was made during this period. On the fourteenth day, a Danish rescue party arrived at the site. On the fifteenth day, the crew abandoned the aircraft after destroying confidential publications, the IFF system, SBAE equipment, and radar units to prevent capture or misuse. They then traveled on foot to the rescue camp and returned to their base, the NORTH STAR, on the sixteenth day.
Findings
The investigation concluded that the fundamental cause of the accident was the near-total lack of depth perception. The unbroken white surface of the ice cap, combined with the absence of prominent coastal landmarks, made it extremely difficult to judge altitude and distance, similar to flying over glassy water in low visibility.
Except for exposure to extreme cold, none of the crew members suffered any lasting ill effects from the incident.