What happened
While operating a flight to carry canceled checks, the pilot elected to use the remaining fuel from the inboard tanks after leveling off. During the flight, the left engine began running roughly. The pilot attempted to switch the left side fuel selector to the outboard main tank with the boost pump on, but there was no change in engine performance. When the pilot moved the left fuel selector back to the inboard tank, normal engine operation returned momentarily. An identical sequence of events then occurred on the right side.
Following the dual power loss, the pilot attempted to return to the departure airport but was unable to do so. The aircraft eventually landed in a field, striking trees before coming to a stop. There were no injuries reported.
The investigation
An examination of the aircraft revealed that the inboard tanks were empty, while the outboard tanks remained full of fuel. Investigators could not determine the exact position of the fuel selectors at the moment the engines lost power. No preimpact mechanical failure or malfunction was found in any aircraft parts.
Investigators discovered that the fuel selector panel was located on the floor between the pilot and co-pilot seats. Due to recent re-upholstering of the seats, the pilot was unable to see the panel unless the seat cushions were pulled apart.