As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE OUT OF SERVICE IN HEAVY CHECK, MAINTENANCE FOUND AFT CABIN FLOOR CREASE BEAM CORRODED AT FR89 RBL 36. MAINTENANCE REMOVED AND REPLACED AFT CABIN FLOOR CREASE BEAM IAW SRM 51-40-08 PAGES 1-4. THIS AIRCRAFT REMAINS OUT OF SERVICE FOR DURATION OF THE HEAVY CHECK COMPLETION.