What happened
The pilot had requested a Visual Flight Rules (VFR) departure eastbound toward Waterville, with radar flight following provided by air traffic control. The pilot indicated an intention to fly VFR through Stampede Pass. Following takeoff, the aircraft was tracked on a radar heading of east-northeast at an altitude of 2,500 feet mean sea level (MSL). Shortly after departure, the pilot canceled flight following, stating he could maintain VFR conditions and would remain at a low altitude.
The aircraft subsequently impacted rapidly upsloping terrain located one mile north of Interstate 90 at an elevation of 3,950 feet MSL. The accident site was situated on the north side of a valley through which Interstate 90 proceeds generally eastbound. At the 4,000-foot level, the approximate minimum lateral distance across the valley was 12,000 feet.
Weather conditions at the time were severe. The weather recorded at 1555 Pacific Daylight Time (PDT) by the Stampede Pass Weather Observation Facility, located 15 miles from the accident site at an elevation of 3,800 feet, reported a ceiling of indefinite obscuration at the surface and visibility of one-eighth mile in fog.
The investigation
Examination of the wreckage revealed that the flap handle was found pulled up into a position of partial flap extension. This mechanical detail was noted during the post-accident analysis of the aircraft components recovered from the crash site.