What happened
The pilot performed a preflight engine runup before initiating the flight. During this procedure, he leaned the mixture control and positioned the fuel selector switch to the "both" setting. Shortly after takeoff, at an altitude of approximately 50 feet above ground level, the engine experienced a partial loss of power. The pilot subsequently executed a forced landing.
The investigation
The aircraft involved is a Cessna 140A. An examination of the fuel system configuration revealed that the fuel selector on this specific model has three distinct positions: left tank, right tank, and both off. The source material does not provide details regarding the condition of the engine or fuel tanks post-incident.
Findings
The partial power loss occurred during the initial climb phase. The aircraft's fuel selector configuration allows for selection between individual tanks or a combined supply, though the specific mechanical cause of the power reduction is not detailed in the provided narrative.