Flight Details
A commercial pilot was conducting a cross-country flight to a family residence in a turbine-powered, single-engine airplane. The pilot was familiar with the route, which traversed a mountain pass and remote terrain. Before departure, the pilot texted a family member at the residence and was aware that the weather was windy but the mountain tops were clear.
Weather and Preflight Planning
There was no record of the pilot obtaining a preflight weather briefing from an official, access-controlled source. The pilot indicated to a friend before departure that he had not accessed weather cameras. Weather forecast products available to the pilot showed possible turbulence at low altitudes and icing at altitudes above 12,000 ft along the route. Weather cameras along the planned route and near the destination would have indicated deteriorating visibility in snow showers and mountain obscuration starting about 1.5 hours before departure.
Radar and Communications
The airplane departed and climbed from 4,600 ft to 14,700 ft before turning west over the mountains. Text messages the pilot sent during the initial climb revealed that the mountain pass he planned to fly through was obscured, and he intended to climb over the mountains and descend through holes in the clouds. Radar data indicated the airplane operated above 12,500 ft mean sea level for about 30 minutes and above 14,000 ft for an additional 14 minutes before entering a gradual descent during the last approximate 20 minutes of flight.
Weather Conditions and Icing
Review of weather information indicated that cloud layers over the accident area increased during the 30 minutes before the accident. It is likely that the airplane was operating in icing conditions, although it was not certified for flight in such conditions, which may have resulted in structural or induction icing and an uncontrolled loss of altitude.
Wreckage and Investigation
The airplane wreckage came to rest on the steep face of a snow-covered mountain in a slight nose-down, level attitude. The empennage was intact, the right wing was completely separated, and the forward fuselage and cockpit were partially separated and displaced from the airframe with significant crush damage, indicative of impact with terrain during forward flight. There was no indication that the airplane was equipped with supplemental oxygen; pilots are required to use oxygen when operating at altitudes above 12,500 ft for more than 30 minutes and anytime at altitudes above 14,000 ft. It could not be determined if, or to what extent, the pilot may have experienced symptoms of hypoxia that would have affected his decision-making. The wreckage was not recovered or examined due to hazardous terrain and environmental conditions, and the reason for the impact with terrain could not be determined.