Flight History
The flight departed with full fuel tanks for a planned duration of 4 hours 33 minutes. Three hours and 36 minutes into the flight, approximately 49 nautical miles from the destination airport, the pilot requested to descend to 3,500 feet. According to the performance chart, the descent should have begun at 41.5 nautical miles. About 9 minutes later, the pilot noted that the fuel gauges were indicating low and descended to 1,800 feet. The flight continued for approximately 14 more minutes, after which the engine sputtered. The pilot repositioned the fuel selector and informed the air traffic controller, who vectored the airplane toward a nearby airport. Shortly thereafter, about 4 hours after takeoff, the engine quit completely. Unable to land at the vectored airport, the pilot selected a field, resulting in a hard landing.
Postcrash Examination
Examination of the airplane after the accident revealed fuel exhaustion. The carburetor was tested, and near the power setting used by the pilot during the cruise portion, the fuel flow was found to be 3.0 pounds per hour higher than expected. This was attributed to a failed spring inside the carburetor. The carburetor was 20 years and 4 months old and had never been overhauled since manufacture, although no mandatory requirement for overhaul existed. Additional examination of the carburetor showed evidence of a fuel leak due to one loose carburetor bowl-to-body screw.
Maintenance Background
The airplane had been inspected 5 days and 12 hours earlier in accordance with a 100-Hour inspection. However, the carburetor was not further examined during that inspection.