What happened
Approximately one hour after takeoff, the pilot of the aircraft experienced a simultaneous loss of power in both engines. Following the loss of power, the pilot performed an emergency landing in a field and successfully exited the aircraft. The pilot reported that prior to the flight, the aircraft had been topped off with fuel. During the event, the pilot observed that the fuel cap was unsecured and hanging by its chain.
The investigation
An examination of the aircraft revealed that there was no fuel remaining in the fuel system. Investigators found no evidence of fuel splatter on the wing, fuselage, or tail surfaces. Furthermore, the wing skin surrounding the fuel fill port and the chain attachment showed no signs of scratches or dents. The investigation noted that the aircraft was equipped with a non-siphoning fuel fill port. Additionally, the fuel cap chain assembly was a design intended to break free at an airspeed of 20 knots if the cap is left unsecured. No mechanical malfunctions were reported by the pilot, and no defects were observed in the fuel cap chain assembly.