What happened
The aircraft had completed 1.7 hours of operation prior to the accident flight and was 2.5 hours into its mission when the engine lost power. During the flight, the pilot observed that the low fuel warning light for the left tank had illuminated. Because the pilot had previously experienced uneven fuel flow between the tanks, he did not consider the warning unusual and elected to continue the flight.
Approximately fifteen minutes after the warning light appeared, the engine lost power, forcing the pilot to perform a forced landing.
The investigation
The investigation focused on the aircraft's fuel management system. While the pilot had accumulated 2,400 hours of flight time in this specific aircraft type, he noted that he had never operated an aircraft with this particular fuel management configuration. Furthermore, the pilot admitted to not reading the flight manual.
Investigators identified a handle in the cockpit labeled "Overflow Fuel Valve - Pull." According to the aircraft manual, this valve is designed to prevent engine failure by equalizing fuel levels between the left and right tanks. The pilot stated that he believed the handle was a dump valve and, as a result, made no attempt to use it to correct the imbalance.
Additionally, other operators of this aircraft type reported experiencing issues with fuel vents during the import and assembly process.