What happened
The aircraft impacted terrain following an uncontrolled descent. During the flight, the airplane was executing a descending right turn on the downwind side of a mountain when the horizontal stabilator and the left wing separated from the airframe.
Prior to takeoff, the pilot had received a full preflight weather briefing, which was subsequently updated with an abbreviated briefing. These briefings contained forecasts for moderate to severe turbulence and icing along the intended route of flight. While en route, the pilot encountered icing conditions and requested a lower altitude. During the flight, the pilot also received pilot reports indicating that icing conditions were being encountered near the destination area.
Findings
A Safety Board weather study determined that atmospheric conditions were conducive to the development of clouds, turbulence, wind shear, icing, and mountain wave activity. Notably, the aircraft was not equipped with anti-icing or deicing equipment to mitigate the encountered icing conditions.