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 AFT CARGO DOOR SILL WEB BETWEEN BS 794 AND BS 799, AT STR 25 RT. MAINTENANCE REMOVED CORRODED AFT CARGO DOOR SILL WEB AT STR 25 RT, FROM BS 794 TO BS 799; FABRICATED A NEW REPLACEMENT WEB PER DWG 65-47957-6; INSTALLED REPAIR PART IAW B737-300 SRM 51-40-02.