Accident Summary
An aircraft operating a flight from Homer experienced fuel exhaustion and crashed short of the intended destination airport. The pilot believed he had fully filled the fuel system during the preflight inspection. However, postaccident examination revealed that no fuel was present in the system and no fuel spillage was observed at the crash site.
Investigation Findings
Investigators examined the aircraft's fuel system and discovered a blockage in the fuel vent line from the right fuel tank. The blockage was located 18 inches aft of the right tank, at the lowest point of the vent system. This obstruction prevented approximately 9 gallons of fuel from being pumped into the fuel system, resulting in a reduced fuel capacity that led to fuel exhaustion. The pilot's preflight inspection did not detect this blockage, and no fuel was recovered from the system during the postaccident inspection.
Fuel System Design Considerations
The blockage occurred at a low point in the vent line, where debris accumulation is more likely. Later models of the same aircraft line incorporated a vent system designed without low points, making them less susceptible to such blockages. The absence of fuel spillage at the accident site further indicated that the tanks were nearly empty before impact.