Overview
A military aircraft, crewed by three and carrying five civilian spotters, was conducting an air search mission in the Kananaskis region west of Calgary. The mission was launched after two airplanes went missing. Weather conditions were good, and the terrain consisted of hills and valleys with peaks up to 7,000 feet. The search profile called for a 500-foot above ground level (AGL) contour search.
Accident Sequence
Two hours and 20 minutes after takeoff, the aircraft struck terrain at 5,900 feet above sea level (ASL) on the west slope of a 6,200-foot feature. The impact and subsequent post-crash fire destroyed the aircraft. All eight occupants sustained fatal injuries.
Crew and Passengers
Crew members were Captain D. Wayne Plumbtree (pilot), Captain E. M. Kates (co-pilot), and Sergeant Brian G. Burkitt (flight engineer). The passengers were Mr. D. Hall, Mr. J. Schindler, Mr. C. Masur, Mr. C. Grant, and Miss P. McLean.
Probable Cause
The official investigation identified several causal factors: the pilot at the controls experienced a visual illusion during an overhead reconnaissance of the valley; lighting conditions, absence of shadows, and lack of contrast masked a rock outcrop against the surrounding rockface. The pilot did not expect the outcrop due to a previous contour at a higher altitude, leading to slow recognition of the hazard. Additionally, the crew felt pressurised to achieve full search coverage by entering the valley. Supervisory failures at 418 Squadron were also noted: squadron staff did not ensure that current, qualified aircrew were assigned and that the mission was properly authorized. Neither pilot was current per regulations, and the mission was not authorized according to squadron flying orders.