As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN HEAVY MAINTENANCE PERFORMING INSPECTION IT WAS NOTED THAT THE WING CENTER SECTION LOWER FORWARD STIFFENER ON FORWARD CHORD AT BS 740 LBL-45 CORRODED. CORROSION TO BE OUT OF LIMITS, REMOVED STIFFENER, FABRICATED NEW FROM 7075 T6 DIM 15 INCH AND INSTALLED STIFFENER. NO OTHER DEFECTS NOTED. AIRCRAFT WAS RETURNED TO SERVICE.