Accident Overview
An airplane on an instrument approach collided with terrain under conditions of controlled flight into terrain, as determined by the official investigation. The air traffic controller had cleared the flight for the approach, and the pilot acknowledged the clearance.
Flight Path and Impact
Radar data showed the airplane turning toward the final approach course, then continuing the turn 180 degrees before disappearing from radar at an altitude of 11,200 feet. The wreckage was subsequently located at an elevation of 10,725 feet. Examination of the terrain and ground scars indicated that the airplane struck the ground in a nose-down, right-turn attitude.
Aircraft Damage and Examination
Impact forces and a post-impact fire resulted in substantial damage to the airplane. However, examination of the airframe, engines, and de-icing systems revealed no mechanical anomalies that could have contributed to the accident.
Weather Conditions
Weather at the time of the accident was characterized by overcast skies, reduced visibility, and snow showers in the area. An icing probability chart indicated a probability of moderate rime and mixed icing. Both AIRMETs and SIGMETs had been issued, advising of moderate icing between the freezing level and flight level 220, as well as occasional severe rime and mixed icing below 16,000 feet. During his weather briefing, the pilot stated that he was aware of the adverse weather conditions.