What happened
The aircraft departed Cheyenne at 11:21 and proceeded northwest. At 11:46, the pilot contacted Cheyenne Approach Control reporting being in clouds and requesting a vector to Cheyenne. After a brief conversation, the pilot contacted Denver ARTCC with the same message but stated he would accept vectors to any location outside the weather. As soon as the controller provided a heading, the pilot radioed that he was in trouble, after which no further transmissions were received. Radar contact was lost at 11:51.
A witness reported hearing a high-pitched whine followed by a loud bang. The aircraft crashed in rolling terrain, missing approximately 6 feet of its left wing. This portion of the wing was found about 339 feet east of the main wreckage. Examination revealed evidence that the outboard portion of the wing separated in an upward and aft direction, indicative of positive loading in flight.
The investigation
A toxicology report on the deceased pilot initially reported an ethyl alcohol content of 0.38% in a liver tissue fluid sample. This was later corrected to .038%. The pilot had received a weather briefing by telephone but did not file a flight plan.
Findings
The pilot was 1 fatal. The aircraft type was a Cessna 172M with registration N98SW. Contributing factors included the pilot's decision to continue flying into instrument meteorological conditions without an instrument rating or adequate preparation, and the subsequent loss of control. The official probable cause is restated below.