What was found
(AIRCRAFT NOT GROUNDED) (DEFECT DISCOVERED DURING AC HEAVY MX) REAR FUSELAGE INTERNAL STRUCTURE, CORROSION FOUND ON ANGLE AT FR71 AND BTW STGR 27R-32R / REAR FUSELAGE INTERNAL STRUCTURE, ANGLE AT FR71 AND BTW STGR 27R-32R REPLACED AS PER SRM 51-72-11-911-001 REV.159.