Pre-Flight Weather Briefings
The pilot obtained two weather briefings before departure. These briefings included a current AIRMET and SIGMET advisory. The SIGMET forecast occasional severe turbulence below 15,000 feet and potential for low-level wind shear due to a strong low-level westerly airflow. The AIRMET advised that mountain obscurement and moderate turbulence were possible throughout the area below 15,000 feet. Additionally, a pilot report from a Boeing 737 that had encountered moderate turbulence in the vicinity of the accident site was relayed to the pilot.
Flight and Incident
The pilot filed an IFR flight plan and departed along a route over mountainous terrain at an assigned altitude of 8,000 feet. During the flight, the aircraft encountered a strong downdraft. The pilot reported that despite applying full power and maintaining best angle of climb airspeed, he could not counter the downdraft. According to the pilot, the vertical speed indicator at times showed a descent rate of 1,500 feet per minute. The flight entered clouds at 6,000 feet and shortly thereafter collided with trees and mountainous terrain at about the 5,500-foot level.
Conclusion
The accident investigation source provided no stated cause, and no further details were given.