What happened
The pilot departed Wittman Regional Airport (OSH) in Oshkosh, Wisconsin, bound for Scottsbluff Municipal Airport (BFF) in Nebraska. The flight plan indicated an estimated time en route of four hours and thirty minutes, with the aircraft carrying an estimated 80 gallons of fuel. Fuel consumption was calculated at 15 gallons per hour.
Approximately 37 nautical miles short of Scottsbluff, the pilot observed that the right fuel quantity indicator showed a level lower than expected based on calculations. At this point, the right tank was the only one containing fuel. In response to the discrepancy, the pilot reduced engine power to 55 percent of rated output.
The aircraft continued its flight path and overflew Alliance, Nebraska, where fuel services were available, before proceeding toward Scottsbluff. As the aircraft began its descent into Scottsbluff, the engine failed completely. The pilot attempted to restart the engine while turning toward Alliance for an emergency landing. The aircraft ultimately landed on a rolling sand hill approximately seven miles southwest of Alliance.
The investigation
The investigation focused on the fuel management practices and the mechanical status of the aircraft following the forced landing. Examination of the flight data and pilot statements confirmed that the right fuel tank was depleted before the left tank, leading to fuel exhaustion. No mechanical anomalies were found that would have contributed to the failure other than the lack of fuel.
Findings
The primary factor in this incident was the mismanagement of fuel quantity. The pilot failed to account for the actual fuel remaining in the right tank relative to the calculated consumption, leading to a situation where the engine starved for fuel. The decision to overfly Alliance before attempting to land at Scottsbluff contributed to the depletion of the remaining fuel supply.
Safety message
Pilots should monitor fuel quantities closely and cross-check gauges against calculated consumption rates regularly. If a discrepancy is noted, immediate action should be taken to divert to the nearest suitable airport with fuel services rather than continuing to the planned destination.