Primary finding
Probable cause
Inflight loss of control when aircraft control was not maintained. Factors to the accident were: flight into known adverse weather and thunderstorm activity.
Investigator assessment
Analysis narrative
Prior to takeoff, the pilot obtained a weather briefing and was informed of mountain obscurement, rain showers, and thunderstorm activity in the area of the flight path. The pilot had filed the route of flight direct from boise, id, to mccall, id, to thompson falls, mt, to kalispell, mt. The accident site was located approximately 45 miles east of the direct line of flight path in mountainous terrain. Radar data identifies the flight as maneuvering on various headings before the flight dropped from radar contact. The wreckage was found confined to a deep crater with the nose of the airplane at the crater's deepest point. It was estimated that the airplane collided with the terrain in an approximate 70 degree nose down attitude. There was no evidence found to indicate a mechanical failure or malfunction.
Source record
Factual narrative
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