Departure and Forecast Conditions
The pilot departed under an instrument flight plan. Forecast conditions for the route included mountain obscuration, clouds, precipitation, and possible icing.
Climbing Difficulty and Course Reversal
The pilot had been cleared to 12,000 feet but reported trouble climbing above 11,000 feet. He soon informed air traffic control that he was reversing course and returning to the departure airport.
Descent Reported
When the controller stated he could not clear the pilot below 11,000 feet, the pilot responded that the aircraft was continuing to descend. The last clearly audible transmission from the pilot indicated he was at 8,800 feet. Another pilot in the area reported hearing what he believed was a transmission stating the aircraft had descended to 6,200 feet.
Terrain Impact
The aircraft subsequently impacted mountainous terrain. At the time, other aircraft in the area were reporting airframe icing conditions.