What happened
During a cruise climb, a turboprop aircraft departed from controlled flight while executing a turn directed by air traffic control. Radar data indicated the aircraft was traveling northeast and reached a peak altitude of 13,800 feet MSL before entering an increasingly tight, right-hand descending turn. The descent rate was calculated at 7,000 feet per minute. An eyewitness observed the aircraft in a nose-low descent, noting an unusually loud engine sound prior to the impact. The aircraft disappeared behind a ridgeline, followed by a loud noise and a large cloud of black smoke.
Prior to the flight, the instrument-rated pilot received a weather briefing that highlighted building thunderstorm activity near the departure point and along the intended route. The pilot expressed an intention to depart immediately to avoid the approaching weather. Reports from the departure airport suggested the passenger had concerns regarding the weather conditions, but the pilot maintained that the flight needed to proceed to stay ahead of the storm.
Findings
At the time of the accident, the aircraft was operating under IFR conditions at altitude, while the accident site was under MVFR conditions. A reconstruction of the wreckage confirmed that all primary structural components, flight control surfaces, and engine components were present at the scene. While the extensive damage prevented the establishment of flight control continuity, an inspection of recovered components showed no evidence of pre-impact malfunction. The standby attitude indicator showed rotational damage consistent with the aircraft being in motion at impact. However, both solid-state AHRS units were destroyed, leaving no digital flight data available from those systems.