What happened
The aircraft was operating at an assigned altitude of 10,000 feet when it entered an uncontrolled descent. The plane subsequently crashed in the vicinity of Fairfield, Utah. Emergency responders arrived at the scene at 1125 local time. Upon arrival, they found that 17 occupants were killed and two passengers sustained serious injuries, requiring evacuation.
Investigation indicated that the aircraft experienced a significant change in attitude before losing control. Physical evidence suggested that parts of the wings and the stabilizer detached from the airframe prior to the loss of control.
Findings
The official investigation concluded that the accident resulted from the failure of the left wing tip, or possibly both wing tips, along with the horizontal tail surfaces. This structural failure occurred in flight during a severe pull-up maneuver, which generated unusual and abnormally high air loads on the airframe.
While it was determined that the maneuver likely initiated by the crew, potentially to avoid an obstacle such as a bird or another aircraft, no definitive conclusion could be drawn regarding the specific cause of the pull-up. The evidence did not provide a plausible theory for forces beyond the crew's control causing the maneuver.