Preflight Briefing
Before takeoff, the pilot was advised of a current AIRMET for the area that included precautions for occasional moderate turbulence below 14,000 feet and mountain obscuration. Occasional moderate rime or mixed icing was forecast, as well as rain shower activity.
Flight Progress
After takeoff, the pilot opened a VFR flight plan and was reminded of the precautions and AIRMET for turbulence and icing. The flight continued, and the pilot advised that he would be climbing to 11,500 feet MSL. A few minutes later, he reported that he would deviate from course to "remain VFR on these clouds." No further communication was received from the aircraft.
Witness Observations
Witnesses on the ground heard a loud bang and then saw the aircraft descending below the cloud layer in a spiral with pieces separating. Wreckage was scattered over an area of about half a mile.
Examination Findings
An examination revealed evidence that both outboard sections of the wings separated upward and rearward, while the horizontal stabilator separated downward in flight. The investigation did not verify which mode of flight the aircraft was in when the in-flight breakup occurred.