Flight Details
The flight crew was returning from off-loading their cargo at a remote site on the west side of a mountain range. The return flight provided an option of following a lower mountain pass, or flying over the mountainous terrain.
Weather Conditions
Witnesses related that prior to the flight's departure, the marginal VFR weather conditions began to deteriorate very rapidly, with winds in excess of 50 knots, lowering ceilings, rain, and turbulence. An AIRMET, valid during the time of the accident, forecast high winds, mountain obscuration, and turbulence.
Accident Sequence
A radar track analysis of a target airplane believed to be the accident airplane depicted a track on a direct route of flight over the mountains from the departure airport towards the destination airport. Altitude data was not received from the target airplane's Mode C transponder, and therefore was extrapolated from the less reliable radar plot information. The maximum altitude plotted was approximately 10,800 feet, prior to a descent as the airplane neared the west side of the range. Mountains along the route of flight exceed 10,000 feet msl.
Wreckage and Investigation
The wreckage of the airplane was located near the crest of a 2,900 feet msl ridge. Wreckage debris was scattered on both sides of the ridge, and the airplane was destroyed by the high speed impact. Inspection of the wreckage disclosed no evidence any mechanical anomalies.