Accident Sequence
A private pilot reported that shortly after takeoff, the engine of his single-engine airplane developed an abnormal fluctuation while climbing through 1,300 feet mean sea level. As a precaution, he elected to return to the departure airport. However, while turning toward the airport, the engine lost power, and he prepared for a forced landing to an open field. Prior to touch down, he noticed freshly dug ditches on both sides of the field and repositioned to an adjacent field to the right of his initial landing spot. The pilot added that the engine began to surge when the airplane was about 300 feet above the ground, which extended his glide. The airplane touched down on soft ground, the tires sank in, and the airplane nosed over.
Post-Accident Examination
Examination of the airplane revealed that the fuel bladders in both wings were not breached and there was no evidence of fuel stains around the vented fuel caps. Approximately 1 gallon of light blue fuel was drained from the right tank, and less than 1 gallon of light blue fuel was drained from the left tank. The fuel was free of water and debris. The engine-mounted fuel strainer bowl was empty, and the fuel screen was clean.
The pilot reported that he performed a preflight inspection of the airplane but did not visually inspect the fuel tanks. Instead, he relied on a fuel flow meter installed in the cockpit, which indicated a total of 43.6 gallons. The pilot stated that the gauge was usually accurate and that he was unaware of what happened to the fuel he thought was onboard.