Flight Details
The flight was a Part 135 cargo operation conducted under an IFR flight plan. The pilot initially requested the ILS-DME approach to runway 10, but two minutes later changed the request to the VOR-B approach to runway 28. Air Traffic Control cleared the flight for the approach to the non-towered airport. The pilot contacted the airport's Unicom and requested that ramp personnel stand by with fuel and oxygen.
Approach and Descent
The airplane was found 5.8 nautical miles from the approach end of runway 28, at an elevation of 7,900 feet. The approach minimums for the VOR-B approach were 7,900 feet, which the pilot could descend to at a distance of 8.7 nautical miles from the runway. The VOR station was located 285 degrees at a distance of 13.6 nautical miles from the accident site. The ILS-DME transmitter was located 285 degrees at 5.6 nautical miles from the accident site.
Aircraft Equipment
The airplane was equipped with a single DME display head that had a Nav 1/Nav 2 selector switch.
Probable Cause
According to the official investigation, the probable cause was the pilot not following instrument procedures and subsequently descending to minimums prematurely. Factors in the accident were the mountainous terrain and the falling snow.