What was found
MCN - MAJOR REPAIR - DURING C-04 CHECK FILIFORM CORROSION WAS FOUND ON UPPER SURFACE OF FLOORBEAM Y-1732, FORWARD SIDE OF FR 66. MAINTENANCE REMOVED CORROSION ON UPPER SURFACE OF FLOORBEAM Y-1732, AND DOOR SILL FITTING FORWARD SIDE OF FR 66; MATERIAL LOSS FOUND TO BE OUT OF LIMITS. REMOVED FLOORBEAM Y-1732 AND CUT OUT DAMAGED SECTION OF DOOR SILL FITTING; FABRICATED A NEW REPLACEMENT FLOORBEAM, A FILLER, AND 2 EACH REPAIR ANGLES; INSTALLED REPAIR PARTS IAW A320 SRM 51-42-11 PG 7-41, FIG 2-18, SRM 53-41-14 PG 202-213 FIG 201.