Flight Preparation
Before departure, the pilot reviewed weather conditions and requested a full fuel service. Fuel receipts showed 34.5 gallons were added; the aircraft's total fuel capacity was 50 gallons. During the preflight inspection, the pilot confirmed the fuel tanks were full.
In-Flight Fuel Monitoring
About one hour after takeoff, the fuel gauges indicated less than 10 gallons had been used. Two hours after takeoff, they showed less than 20 gallons used. At three hours, the gauges read 28 gallons consumed. The pilot noted he would have stopped for fuel if less than 17 gallons remained at that point. He continued and estimated 12 gallons remained when 17 miles from the destination. The left tank fuel pressure decreased when the gauge showed 2.5 gallons, prompting a switch to the right tank, which indicated 6 gallons. Approximately nine miles from the destination at 1,000 feet above ground, the airplane encountered brief moderate turbulence. Within one minute, the right fuel tank level dropped to zero, accompanied by a fuel pressure drop. The pilot alternated between tanks attempting to use remaining fuel. When the engine lost power, he selected a field and executed a forced landing about four hours and ten minutes after departure.
Post-Accident Findings
The airplane sustained substantial fuselage damage during the forced landing. No fuel leaks were observed during recovery. The left fuel tank contained approximately one cup of fuel, and the right tank was empty.
Additional Information
A flight-planning chart in the airplane's manual indicated a fuel consumption of 10 gallons per hour with a lean mixture. According to the Federal Aviation Administration's Pilot's Handbook of Aeronautical Knowledge, aircraft certification rules require accuracy in fuel gauges only when they read empty. Any other reading should be verified, and pilots should not depend solely on gauge accuracy.