Aeronca 7BCM N68593 accident near Palmer, Alaska

Probable cause

The pilot’s failure to ensure adequate fuel was onboard to complete the flight, which resulted in fuel exhaustion and the subsequent loss of engine power. Contributing to the accident was the improperly calibrated fuel quantity indication system.

NTSB analysis

The pilot reported that the student pilot was flying the leg back to the airplane's home base and that he asked the student pilot how much fuel was remaining, but he did not visually check the fuel quantity before the flight. About 3 miles from the destination airport, the engine lost all power. The pilot assumed control of the airplane and lowered the nose to attain best glide speed. As the airplane's nose lowered, the engine regained power. The student reassumed control of the airplane and initiated a climb. During the climb, the engine lost power again, and the pilot took control of the airplane and started an approach to the airport.

Due to the location and altitude of the airplane, the pilot chose to make an approach to the nearest runway, which resulted in a landing with a tailwind. The airplane was high, so the pilot entered it into a slip to lose altitude. When the pilot exited the slip near the runway, he realized the airplane's airspeed was too high to land on the runway, so he chose to stall the airplane into an area of trees past the departure end of the runway. The airplane sustained substantial damage to the fuselage and wings. No preaccident mechanical anomalies were noted with the airframe or engine that would have precluded normal operation.

Examination of the wreckage revealed that about 1/2 gallon of fuel was in the wing auxiliary tanks and that only a small amount of residual fuel was in the bottom of the center main tank. Postaccident examination revealed that the fuel quantity indicator showed that there was between 1/4 and 1/2 tank of fuel when the center main tank was empty. Given the lack of fuel found in the center main tank, the pilot's statement, and the erroneous fuel gauge reading, it is likely that the pilot used the fuel quantity gauge and the student pilot's statement to determine the available fuel, which resulted in his overestimating the actual quantity of available fuel.

Text from the NTSB. Open the NTSB docket for ANC14LA052 for the full record.