Incident Overview
A Hughes 369D helicopter, engaged in logging operations for approximately one hour, suffered an engine flameout. The pilot executed a hard landing to a nearby road.
Post-Crash Examination
After the accident, examination of the helicopter found no fuel within the fuel tank. The fuel quantity sending float was entangled in the start pump wiring, which was unsecured. This entanglement prevented the float from registering less than about 120 pounds of fuel, approximately 60 pounds above the activation setting for the low fuel warning light.
Maintenance Background
The helicopter had undergone a 100-hour inspection just before the accident flight. During that inspection, the fuel quantity sending unit was replaced. The maintenance manual contained procedures that included a caution to secure the start pump wiring to prevent entanglement with the float. However, this caution was addressed only in the start pump replacement procedure of the manual and was not included in the fuel quantity sending unit replacement procedures.
Fuel System Implications
The lack of fuel in the tank and the float's entanglement indicate that the fuel level indication was inaccurate, showing a higher fuel quantity than actually present. This likely led to the engine flameout due to fuel exhaustion. The unsecured wiring allowed the float to become stuck, preventing proper low fuel warning.