WPR11FA256 · Bellanca 17-31ATC

On the morning of the visual flight rules flight, the non-instrument-rated pilot obtained a verbal weather briefing and stated that he planned to depart early afternoon, with an expected flight duration of about 3 hours. The pilot was advised of the possibility of turbulence and clouds along his route, which was primarily over mountainous terrain, with cloud tops forecast to be 25,000 feet and above. There were no records of any subsequent telephonic or computer weather briefings, and the pilot did not file a flight plan.

Although the pilot did not communicate with air traffic control (ATC), ground-based ATC radar captured the majority of the flight. When the airplane was reported overdue by relatives of one of the passengers, the radar data were used to search for and locate the airplane, which had impacted terrain in a remote wilderness area about 110 miles from the departure airport. Evaluation of the radar data indicated that the total flight duration was about 1 hour and that the airplane was above 12,500 feet for about 28 minutes and above 14,000 feet for about 8 minutes. The last 2 minutes of radar data depicted a course reversal, followed by an erratic course and an irregular, rapid descent. Meteorological data indicated that broken or overcast cloud base altitudes ranged from about 7,000 to 10,000 feet, with tops near 28,000 feet and that icing conditions could be expected in the clouds above about 10,000 feet. Terrain elevations within 30 miles of the impact site ranged from about 4,000 to 7,000 feet.

Wreckage patterns and ground scars indicated a near-vertical impact trajectory. A supplemental oxygen tank was present in the wreckage, but the tank inspection expired 8 years before the accident, and no hoses or masks were present. Postaccident examination of the airplane and engine did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation.

The radar ground track was consistent with the pilot trying to find a route clear of the clouds. The pilot's lack of an instrument rating, combined with the erratic ground track, rapid descent, and steep impact angle, indicated that the pilot lost control of the airplane after it entered clouds. Available evidence supported the likelihood of spatial disorientation, as well as the possibility of hypoxia.

Verbatim NTSB analysis and probable cause from the NTSB dataset