What happened
The aircraft was engaged in a visual flight rules (VFR) pleasure flight at night when it crashed into an open field. Upon impact, the landing gear was found in the down and locked position. Examination of the propeller indicated that it was windmilling at the moment of touchdown; however, there were no signs suggesting the engine was developing power at that time.
The investigation
A detailed examination of the aircraft's engine was conducted to determine the cause of the power loss. The inspection revealed a specific mechanical failure within the fuel system. A malfunction occurred in the fuel diaphragm assembly, identified by part number 2529471, located within the regulator. This failure allowed fuel to flow incorrectly into the impact tubes.
Findings
The primary factor leading to the accident was fuel exhaustion caused by the internal regulator failure. The malfunction of the fuel diaphragm assembly prevented proper fuel delivery, resulting in a loss of engine power during flight. The aircraft type involved was a Cessna 172. No injuries were reported among the occupants.
Safety message
Regular inspection and maintenance of fuel system components, particularly diaphragms and regulators, are critical to preventing unexpected fuel flow issues that can lead to in-flight power loss.