As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C4 CHECK DISCOVERED CORROSION ALONG LOWER SILL COVER SHEET, UPPER SURFACE, FROM FS 52A TO FS 56 IN THE AFT CARGO COMPARTMENT. MAINTENANCE MECHANICALLY REMOVED CORROSION AND FOUND TO BE OUT OF LIMITS IAW AIRBUS 320 SRM 53-41-49. REMOVED COVER SHEET AND INSTALLED NEW COVER SHEET FROM FS 52A TO FS 56 IN THE AFT CARGO COMPARTMENT IAW AIRBUS 320 SRM 51-42-11.