As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE, CORROSION WAS DISCOVERED ON RT AFT CABIN FLOORBEAM Y464 1 INCH FWD OF FRAME 66. REMOVED CORROSION ORIG MAT .140" REMAINING MAT .088" MAT LOSS .052" L 2.5" W 1.3". FOUND TO BE OUT OF LIMITS. REMOVED AND REPLACED FLOORBEAM Y464 AT AFT CABIN FR 64 TO 67 IAW SRM 51-72-11.