Primary finding
Probable cause
The failure of the pilot to maintain proper glidepath due to loss of visual cues over snow covered terrain in shadow of setting sun. Factors relating to the accident were the reduced light of dusk and the reduction of visual perception of the pilot in civil twilight.
Investigator assessment
Analysis narrative
The pilot executed a normal touch and go in bright daylight at a snow covered airport, followed by the downwind leg directly into the bright setting artic sun. At the time the airplane turned to final approach, the pilot turned away from the sun, sunset occurred and the shadow of civil twilight passed across the threshold of the landing runway. The aircraft descended into the shadow, reducing the visual cues sufficeint for depth perception. The pilot could not account for the undershoot but believed 'it must have been a windshear.' the weather was clear, visibility unlimited, a steady headwind of 8 to 10 knots, and temperature at minus 11 degrees (f).
Source record
Factual narrative
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