What was found
MCN - MAJOR REPAIR - DURING C-17 CHECK, GALVANIC CORROSION WAS FOUND ON UPPER AND LOWER SURFACE OF RT AFT LAVATORY SUB-FLOOR PAN BETWEEN BS 1017 AND BS 1025, RBL 1 AND RBL 35, WL 208. MAINTENANCE REMOVED CORRODED RT AFT LAVATORY SUB-FLOOR WEB AND STRAP; FABRICATED A NEW REPLACEMENT WEB AND STRAP; INSTALLED REPAIR PARTS IAW B737-300 SRM 51-40-02.