What happened
The incident took place at the Wichita Falls, Texas airport. According to the pilot, the right engine stopped functioning after the aircraft had landed. A witness present at the scene observed the pilot attempting to restart the engine multiple times. During the final attempt to start the engine, an explosion occurred in the right wing.
The investigation
Examination of the wreckage revealed that damage was concentrated in the right wing, specifically in the area between the engine nacelle and the main fuel tank. Investigators determined that the explosion originated at the engine area and emanated from within the wing structure. Notably, there was no fire associated with the explosion.
Findings
The pilot indicated that he had taken off using the main fuel tanks but switched to the auxiliary tanks during the flight. Before landing, he had switched back to the main tanks. An FAA inspector at the scene found that the main fuel tanks were overfilled beyond the filler openings. The Pilot Operating Handbook requires substantial operating time on the main tanks prior to switching to auxiliary tanks because overflow from the engines returns to the main tanks only.
Fuel overflow was a critical factor in this event, as the system design necessitates proper tank management to prevent excess fuel from escaping.