Flight Details
The airplane departed under visual flight rules (VFR) for a flight over mountainous terrain. Radar tracking followed the aircraft from the departure area to the accident site. While climbing at a normal rate to 15,400 feet, the airplane abruptly disappeared from radar.
Accident Sequence
Radar data showed the aircraft made course changes during the climb above 10,000 feet: from southwest to northwest, back to southwest, then a sharp right turn just prior to the rapid descent. The wreckage was located among pine trees, exhibiting evidence of a steep flight path angle and damage consistent with a stall/spin event.
Investigation Findings
Examination revealed no airframe or flight control anomalies. The powerplant and propeller damage was consistent with engine operation at moderate to high power. The airplane was free of airframe ice at impact. Postaccident calculations indicated the airplane was near the maximum certificated gross weight and aft center of gravity limit.
The pilot did not maintain instrument flying currency and reportedly avoided instrument meteorological conditions (IMC). Evidence indicated the pilot did not use oxygen as required for flight above 12,000 feet. Ground observations and satellite and Doppler radar imagery showed widespread cloudiness over the mountains west of Montrose. Satellite data indicated variable cloud tops higher than the airplane's flight altitude near the accident site.
Probable Cause
The official probable cause is the pilot's failure to maintain sufficient airspeed for undetermined reasons while maneuvering the airplane near the maximum gross weight and aft CG in or near instrument meteorological conditions, resulting in loss of control and entry into a stall/spin. Contributing factors were the pilot's improper in-flight planning and decision-making and failure to use proper stall/spin recovery techniques.