As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE AC WAS IN FOR HEAVY CHECK FOUND PASSENGER CABIN CENTER FUSELAGE 3 FLOOR STRUCTURE CORROSION FOUND AT LONGITUDINAL BEAM BTW FR 86-89LBL 12" AREA. AAR MX REPLACED CABIN CENTER FUSELAGE 3 FLOORBEAM PN 170-65669-003 IAW SRM 51-41-01, 51-42-03 PSE:53-23-005. AC REMAINS IN YRQ FOR COMPLETION.