Incident Description
Following a landing and after the cargo was unloaded, the aircraft was prepared for departure. The pilot reported that the preflight inspection was normal and satisfactory. When the left engine was started, a loud pop was heard, and the pilot observed flame traces and smoke. He immediately shut down the engine and exited the aircraft to investigate.
Upon inspection, the pilot found that approximately four feet of the outboard, leading-edge section of the left wing had exploded and buckled. Flames and smoke were visible but were promptly extinguished.
Post-Event Findings
The pilot reported that the left fuel strainer cork gasket was faulty. Dry fuel stains were discovered on the bottom of the left wing, the left flap, the left engine nacelle, and the left landing gear.