As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C-CHECK INSPECTION, FOUND AFT CABIN FLOOR BEAM CORRODED TOP CHORD BS 1006 LBL 3 - RBL 3 OUT OF LIMITS IAW B 737 SRM 53-10-1. FABRICATED FLOOR BEAM FROM BAC 1505-100617 29.750 INCHES BY 2.25 INCHES IAW B 737 SRM 53-10-9. INSTALLED IAW B 737 SRM 53-10-9. (X)