What happened
The pilot was conducting cruise flight at 5,000 feet with the fuel selector set to the left main fuel tank, which contained approximately 12 gallons of fuel. The pilot's plan was to use the remaining fuel in the left tank before switching to the other tank. During the flight, the pilot observed a slight drop in fuel pressure and subsequently switched the fuel selector to the right main tank, which held about 10 gallons.
After turning the electric fuel pump to the 'on' position, the fuel pressure dropped to zero and the engine stopped running. The pilot attempted to restart the engine by selecting the right auxiliary fuel tank, but the engine failed to restart. The pilot performed an emergency landing in a river bed. During the landing, the right wing of the aircraft struck a small bank, resulting in damage to the nose gear, propeller, right main landing gear, and the right wing.
The investigation
An examination of the engine determined that when the electric fuel pump was activated, it successfully delivered fuel to the engine-driven pump. However, manual rotation of the engine did not result in any fuel flow from the engine-driven fuel pump. Subsequent testing of the engine-driven fuel pump on a test bench showed that the component failed to meet the manufacturer's prescribed minimum fuel pressure and was difficult to prime.