As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT GROUNDED FOR HEAVY MAINTENANCE. AFT LOWER CARGO STATION 1351 FLOOR UPPER CHORD IS CORRODED IN SEVERAL SPOTS FROM LEFT BUTT LINE 54 TO RIGHT BUTT LINE 54. REMOVED AND REPLACED AFT LOWER CARGO STATION 1351 UPPER CHORD ON FLOOR IN ACCORDANCE WITH SRM 51-40-02. FABRICATED IN ACCORDANCE WITH DRAWING 146T1213-22.