Aircraft Accident/Incident Report

Lee Vining, California 93541
Monday, February 19, 1996 13:15 PST

There was no evidence of a preflight weather briefing. Weather forecasts noted cloud bases and tops of 6,000 (less than 1,000 agl) and 25,000 feet, respectively. AIRMETS predicted mountain obscuration, moderate mixed icing conditions, and moderate to severe turbulence from the 7,000-foot freezing level to 26,000 feet. Winds aloft were out of the west at 65 to 70 knots over the mountains. About 1 hour into the flight the pilot air-filed an IFR flight plan and requested 13,000 feet. He was subsequently given 16,000 feet. 10 minutes later the pilot made the first of many subsequent requests for a clearance to a lower altitude. The controller responded that 16,000 feet was the lowest MVA for the next 60 miles or more. 2 hours and 22 minutes from departure the pilot declared an emergency due to an engine failure. The controllers provided vectors to the closest airport, which was behind the aircraft at 9 miles. The aircraft collided with a mountain at the 10,900-foot level. The pilot had only recently moved to the west coast and had limited experience flying over the Sierra Nevada Mountains. No oxygen tubes were found plugged into the cabin side wall regulator panel, and the main supply tank in the aircraft empennage was in the off position. The fuel selector was found selected to the left main tank. Hydraulic fuel cell bladder rupture and deformation to the surrounding containment structures was noted to the right main and fuselage auxiliary tanks. No such evidence was found to the left main tank bladder or surrounding structures. No evidence of preimpact malfunction or failure was found during examination of the engine. Review of the flight timing elements reveals that the pilot operated at msl altitudes above 12,000 feet in excess of 1 hour 50 minutes, with about 1 hour of that time spent between 15,000 and 16,000 feet. Section 8-1-2 of the AIM states in part that due to hypoxia pilot performance and judgment can seriously deteriorate within 15 minutes at 15,000 feet.

Fuel starvation due to the pilot's failure to adequate monitor the aircraft's fuel system and select a tank containing fuel in a timely manner. The pilot's failure to monitor the fuel system was due to the effects of hypoxia. Factors in the accident were the pilot's failure to obtain a preflight weather briefing, his inadequate preflight planning/in-flight decisions, and his lack of familiarity with the mountains.