As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DOUBLER FAILURE DUE TO IMPROPER MANUFACTURE PROCESS. DOUBLER BROKE AT MACHINE RADIUS AND CORNER OF FUEL ACCESS PANEL LOCATED IN LOWER INBOARD WING SKIN AREA. WING SKIN DEVELOPED CRACKS LOCALIZED TO CORNER OF ACCESS PANEL. REMOVED PAINT AND DYE PEN. INSPECTED ALL CORNERS OF PANELS. INSTALLED EXTERNAL DOUBLERS OVER SKIN CRACKED. (SW)