What happened
A flight involving a twin-engine aircraft began with an incident during a previous flight where the right engine experienced power fluctuations when the auxiliary fuel tank was selected. The pilot noted that the right fuel selector was stiff and difficult to move, though the engine operated normally once returned to the main fuel tank position. Following this, the flight continued for approximately 1.5 hours until the left engine also began experiencing power fluctuations, prompting a precautionary landing at Casey Municipal Airport.
At the time of the landing, the auxiliary tanks remained full, the right main tank was half full, and the left main tank was nearly empty. The pilot attributed the low fuel in the left tank to a gas heater consuming more fuel than documented. After performing ground tests with no anomalies noted and refueling the aircraft, the pilot believed the initial engine issue was caused by momentarily placing the right fuel selector in the off position.
During a subsequent takeoff, the flight proceeded normally until the landing gear retraction phase. At this point, the right engine began experiencing power fluctuations similar to the previous occurrence. The pilot attempted to enter a left traffic pattern and selected fuel cross-feed, but the left engine also began fluctuating. The aircraft entered a downward spiral while on crosswind. The pilot reported that rudder input was difficult due to random yaw moments caused by varying power outputs from both engines. The crew attempted to level the wings using full right aileron and rudder before impact.
The investigation
An FAA inspector conducted an on-scene investigation into the event. The inspection revealed that the fuel selector valves were found in an intermediate or closed position. The investigation determined that the cabling between the fuel gauge switch assemblies and the selector arms was corroded and seized. While the valves functioned as designed when disconnected from the control cable, the cockpit handles moved with significant resistance and failed to reposition the valves.