What was found
MCN - MAJOR REPAIR - DURING C-04 CHECK FILIFORM CORROSION WAS FOUND ON UPPER SURFACE OF FLOORBEAM Y-1292, FORWARD AND AFT SIDE OF FR 67. MAINTENANCE REMOVED CORROSION AND FOUND MATERIAL LOSS TO BE OUT OF LIMITS. REMOVED FLOORBEAM Y-1292, FORWARD AND AFT SIDE OF FR 67; FABRICATED A NEW REPLACEMENT FLOORBEAM; INSTALLED REPAIR PART IAW A320 SRM 51-42-11, PG 39-41 FIG 18, SRM 51-72-11 PG 1-2.