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 EXFOLIATION CORROSION WAS FOUND ON FLOOR SUPPORT STIFFENER AT RBL 11, BETWEEN BS 315 AND BS 326. MAINTENANCE REMOVED CORRODED FLOOR SUPPORT STIFFENER AT RBL 11, FROM BS 315 TO BS 326; FABRICATED A NEW REPLACEMENT STIFFENER PER DWG 65-45834; INSTALLED REPAIR PART IAW B737-300 SRM 51-40-02 FIG 12.