As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REFERENCE NON ROUTINE C044797. DURING C4 S1 C-CHECK INSPECTION NOTED PANEL 222FF HAS SEVERE CORROSION ON BOTTOM SIDE. MAINTENANCE REMOVED AND REPLACED FLOOR PANEL IN ACCORDANCE WITH THE REQUIREMENTS OF WORK CARD CP753-12. UPON COMPLETION OF THE REPAIR IT WAS INSPECTED AND FOUND ACCEPTABLE. (A)