What happened
The aircraft collided with mountainous or hilly terrain during a descent under instrument flight conditions. The pilot, who was not instrument rated, had been receiving VFR flight advisories from Air Traffic Control. During communications with approach control, the pilot expressed an intention to proceed to the destination airport in visual conditions and later stated an intention to circle down through a hole in the clouds.
During this period, air traffic control lost radar contact with the aircraft while it was on a southeasterly track at a mode C reported altitude of 3,500 feet. Because the area consisted of hilly terrain where radar signal loss is common at low altitudes, the controller terminated radar service and approved a frequency change, assuming the loss of contact was due to terrain masking. The controller did not receive a response from the pilot following this instruction.
Radar tracking showed the aircraft's altitude decreasing significantly over the following minutes. At 20:09:29, the target was recorded at an altitude of 2,200 feet. By 20:11:03, the target had turned left onto a southwesterly track and descended to 1,300 feet. This was the final recorded position for the flight's assigned secondary beacon code. The elevation of the accident site was approximately 1,000 feet. A local resident reported that heavy fog was present at the time of the accident, with visibility estimated at only 100 feet.