Beech A36 N4972M accident near Rock Springs, Wyoming

Probable cause

The total loss of engine power due to fuel starvation because of the incorrectly installed fuel cap. Contributing to the accident was the pilot’s decision to continue the flight using fuel from the left fuel tank after she observed fuel streaming from the left fuel tank cap.

NTSB analysis

The pilot reported that during an uneventful flight, she continued past her original destination to another destination. Shortly thereafter, the pilot observed fuel streaming from the left fuel tank cap and noted that the left fuel tank gauge indicated that the tank was about 3/4 full. The pilot continued the flight toward her new destination while continuing to use fuel from the left fuel tank. As the airplane neared the new destination, the pilot observed that the left fuel tank was about 1/2 full; the engine then lost power.

After the engine lost power, the pilot switched fuel tanks and advanced both the throttle and mixture control levers; however, the engine did not restart, so she performed an off-airport landing to an open field. During a postaccident interview, the pilot stated that the fuel cap was not secured properly after refueling. As a result, fuel was siphoned from that fuel tank during the flight. Further, because the pilot had chosen to continue operating on that fuel tank, the engine lost power due to fuel starvation. A pressure differential likely resulted in the inaccurate fuel gauge indication. Examination of the left fuel tank cap and seal revealed no evidence of any preexisting anomalies that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR12LA309 for the full record.