What was found
MCN - MAJOR REPAIR - DURING C-03 CHECK CORROSION WAS FOUND ON LOWER SURFACE OF CABIN FLOOR RT AFT SHEAR PLATE FR 69 TO FR 70, AFT END OF BEAM Y1292. MAINTENANCE REMOVED CORRODED RT AFT SHEAR PLATE FROM FR 69 TO FR 70, BEAM Y1292; FABRICATED A NEW REPLACEMENT SHEAR PLATE; INSTALLED REPAIR PART IAW A320 SRM 51-42-11 FIG 2, 3, & 8.