What was found
LCQ - MAJOR REPAIR - DURING C-04 CHECK EXFOLIATION CORROSION WAS FOUND ON FASTENER HEADS OF AFT CARGO DOOR THRESHOLD ALONG ENTIRE SURFACE, FORWARD CORNER 100 PERCENT EXFOLIATED MATERIAL LOSS INCLUDING UPPER STRAP, BS 807-847. MAINTENANCE REMOVED AFT CARGO DOOR THRESHOLD WEB, UPPER REINFORCEMENT STRAP, AND LOWER FORWARD AND AFT REINFORCEMENT STRAPS; FABRICATED A NEW REPLACEMENT UPPER REINFORCEMENT STRAP; INSTALLED REPAIR PART, AND REINSTALLED AFT CARGO DOOR THRESHOLD WEB AND LOWER FORWARD AND AFT REINFORCEMENT STRAPS IAW B737-300 SRM 51-40-02, PARA 5.