Accident Details
A pilot reported that prior to departing on a cross-country flight, a visual inspection of the fuel level showed it was about 1/2 inch below the top of the filler neck on each wing fuel tank. Approximately 4 hours into the flight while established in cruise, the airplane experienced a total loss of engine power. Unable to restore power, the pilot executed a forced landing to a nearby pasture. Shortly after touchdown, the airplane collided with a snow-covered depression, causing it to bounce. It subsequently impacted the terrain in a nose-low attitude, collapsing the nose landing gear. The engine firewall and right wing sustained substantial damage during the forced landing.
Postaccident Examination
A postaccident examination of the airplane revealed that the wing fuel tanks appeared undamaged and were void of any usable fuel.
Pilot Interview
During an interview, the pilot acknowledged that the loss of engine power was likely due to fuel exhaustion. He stated that he had not used the Pilot Operating Handbook procedures to lean the fuel mixture during the accident flight. Having recently replaced a burnt engine cylinder valve, he was operating the engine at a slightly-rich fuel mixture setting to keep the cylinders from overheating. The pilot reported that the airplane departed with about 65 gallons of fuel, which he believed would provide approximately 5 hours of fuel endurance at an average consumption rate of 13 gallons per hour. However, following the accident, he acknowledged that he had not properly accounted for the entire 10 gallons of unusable fuel within the fuel system.