Accident Sequence
After passing an airport and with approximately 30 minutes remaining to his destination, the pilot informed a passenger that fuel was running low and that he intended to turn around to land and refuel. Shortly thereafter, the pilot announced that the airplane was out of fuel and that they needed a road to land on. The engine then quit. The pilot switched to the other fuel tank in an attempt to restart the engine, but the restart was unsuccessful. The airplane subsequently collided with trees and came to rest in a dry riverbed.
Post-Accident Examination
Examination of the engine revealed no evidence of an internal failure. However, a leak was found in the nose seal of the engine-driven fuel pump, which allowed fuel to escape through the unit's overboard vent drain. The leak rate was measured at 3 to 4 gallons per hour at cruise power settings. Disassembly of the fuel pump revealed an area of rust etching on the driveshaft.
Fuel Calculations
The airplane carried a total of 89 usable gallons of fuel. At 65 percent power, the fuel consumption rate was approximately 13.83 gallons per hour. The airplane was airborne for 4.9 hours, which would have used about 67.7 gallons of fuel. A fuel leak of 4 gallons per hour through the fuel pump nose seal would have resulted in a loss of 19.6 gallons over that duration, bringing total fuel usage to 87.3 gallons.