As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MCN - MAJOR REPAIR - DURING C-18 CHECK CORROSION WAS FOUND ON UPPER AND LOWER SURFACE OF FLOOR SUPPORT BS 951-964, LBL 45. MAINTENANCE REMOVED CORRODED FLOOR SUPPORT FROM BS 951 TO BS 964, LBL 45; FABRICATED A NEW REPLACEMENT FLOOR SUPPORT AND FILLERS; INSTALLED REPAIR PARTS IAW B737-300 SRM 51-40-02, FIG 12, PG 1 & 45.