Flight Details
The pilot had recently purchased a turbocharged twin-engine airplane and completed an acceptance flight. The following day, he departed for home. According to ATC transcripts, about two hours into the flight at 21,000 feet, the pilot exhibited symptoms similar to hypoxia, including inconsistent altitude maintenance and failure to acknowledge all radio calls.
Incident
Approximately three hours and 50 minutes into the flight, while descending, the engines began to surge and subsequently lost power. The pilot landed the airplane in an open field. Examination of the airplane revealed that the fuel tanks were empty except for unusable fuel.
Investigation
Both the pilot and a witness reported that the airplane departed with full fuel tanks. The pilot stated that he had checked the oxygen system on both the acceptance flight and the accident flight, and it was full. A review of the pilot's flight planning indicated that sufficient fuel was available for the planned flight if the engine fuel mixtures were properly leaned. The Aeronautical Information Manual notes that hypoxia can impair judgment, memory, alertness, coordination, and the ability to make calculations.