Incident Overview
A pilot reported that the nose fuel tank was full at takeoff. After approximately 15 minutes of flight, the fuel float indicator showed one-third of a tank. Shortly thereafter, the indicator read empty. The pilot performed a precautionary landing in an open field. During the landing roll in tall alfalfa, the airplane nosed over.
Fuel System Inspection
An inspection of the fuel system revealed a wire that was bent approximately four inches above the float. This bent wire created a drag through the cap, resulting in an erroneous fuel quantity indication when the actual fuel quantity was less than indicated. The false reading led the pilot to believe the fuel supply was critically low, prompting the precautionary landing.
Conclusion
The bent wire in the fuel system caused the fuel float indicator to display incorrect readings. The pilot responded to the erroneous indication by landing in a field, where the aircraft nosed over due to the tall vegetation.