What happened
The pilot-in-command was operating at 4,000 feet MSL over Lake Pontchartrain when the flight crew heard a loud bang. Initially, the pilots believed the aircraft had experienced a bird strike. The crew subsequently performed an uneventful landing at New Orleans.
The investigation
A post-flight examination of the left wing revealed that the fuel vent was blocked with duct tape, which resulted in the collapse of the wet wing fuel tank. This failure caused structural damage to the fuel tank stringers and the wing ribs.
Prior to the flight, the fuel tanks had undergone repairs and a pressure test. Following this procedure, the mechanic responsible for the repairs removed the tape from the right wing's fuel vent. However, both the mechanic and the flight crew failed to identify that duct tape remained over the left wing's fuel vent. The crew noted that no streamers or markers were used to indicate that the vent was covered.