What happened
During the cruise phase of flight, the pilot performed a fuel tank switch from the left main tank to the right auxiliary tank. According to the pilot, after completing the switch, the fuel gauges indicated a full reading and the selector moved into the detent position. The aircraft had departed with 30 gallons of fuel contained in the left main tank.
Approximately 2 hours and 7 minutes into the flight, the engine lost power. In an attempt to restore power, the pilot switched the fuel selector to the right main tank and activated the electrical fuel pump. These efforts were unsuccessful. The pilot subsequently performed an emergency landing on a gravel road. The aircraft sustained substantial damage during the event; there were no injuries reported.
The investigation
An examination of the fuel selector assembly was conducted to determine the cause of the engine power loss. Investigators discovered that the cam had separated from the shaft along the line of the braze joint. Additionally, the O-ring was found to have separated, showing evidence of a brittle break oriented on helical planes.