Primary finding
Probable cause
The loss of engine power due to fuel starvation. Contributing to the accident was the failure of the fuel selector valve cotter pin and the inoperative main (center) fuel tank gauge.
Investigator assessment
Analysis narrative
During the first 20 minutes of flight, the fuel selector was set to the main (center) tank. The pilot then switched the selector to the left wing tank, and then to the right tank during the flight. Approximately 20 minutes after switching back to the left tank, the engine lost power. While performing the emergency checklist the fuel selector was found to move freely with little resistance. In a statement written to the National Transportation Safety Board, the pilot stated that he knew the main tank fuel gauge was not working and that if it were operational it would have alerted him to the fuel selector valve control failure. Examination of the airplane revealed that the center fuel tank had a capacity of 10 gallons of fuel and it was not breached. This tank was found empty of fuel. Further inspection of the fuel selector valve and handle revealed that a cotter pin used to secure the handle to the shaft which turns the valve was sheared. This resulted in movement of the fuel selector handle not changing the position of the valve and remaining on the main fuel tank position.
Source record
Factual narrative
On December 29, 2008, about 1300 central standard time, an amateur built Lancair 360 SFB, N360AS, was substantially damaged and the certificated private pilot/owner, the sole occupant, was not injured during a forced landing near Owensboro, Kentucky. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The pilot stated that when he departed the Riverside Airport (RVS), Tulsa, Oklahoma; the main (center), left and right wing fuel tanks were full. For the first 20 minutes of the flight, the pilot had the fuel selector positioned on the main tank. He then selected the left fuel tank which he continued to use until the fuel gauge for that tank indicated that 5 gallons had been used. He then selected the right fuel tank until the fuel gauge indicated that he had used 10 gallons from that tank. He switched back to the left tank and approximately 20 minutes later the engine stopped. While he performed the emergency checklist he noted that the fuel selector moved freely with little resistance. Attempts to restart the engine were unsuccessful, and the pilot made a forced landing to a field. In a statement written to the National Transportation Safety Board, the pilot wrote that he knew the fuel gauge was not working, and if it were operational, it would have alerted him to the fuel selector failure. Examination of the airplane by a Federal Aviation Administration inspector revealed that there was an undetermined amount of fuel in the left and right fuel tanks. Examination of the main fuel tank revealed that it was empty of fuel and not breached. Further inspection of the fuel selector valve and handle revealed that a cotter pin used to secure the handle to the shaft which turns the valve was sheared. This resulted in movement of the fuel selector handle not changing the position of the valve. The fuel selector valve was tested by attempting to flow fuel from the main tank to the engine. A measured amount of fuel was added to the main tank, and the boost pump was turned on. The added fuel in the main tank flowed to the engine freely.