What happened
The pilot reported that while flying in cruise conditions at an altitude of 1200 feet mean sea level (MSL), the engine power unexpectedly dropped to idle. In response to the situation, the pilot attempted standard fuel system troubleshooting procedures. This included switching to a different fuel tank, turning on the fuel boost pump, and setting the mixture control to the rich position. Despite these efforts, the engine did not regain power, leading to a crash.
The investigation
A post-crash examination of the aircraft was conducted to determine the cause of the failure. The inspection revealed that the fuel boost pump did not operate during the incident. To verify the condition of the component, the pump was removed and subjected to a bench test. The bench test results indicated that the pump operated correctly when tested outside of the aircraft.
Findings
The investigation focused on the mechanical integrity of the fuel system components. The primary finding was the discrepancy between the in-flight performance and the bench test results. While the fuel exhaustion was not the direct cause due to the pump's failure, the inability of the boost pump to function during flight was the critical factor. The bench test confirmed that the pump itself was mechanically sound at the time of inspection, suggesting a potential electrical or installation issue during the flight.