As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A HEAVY MAINTENANCE VISIT, THE FLOOR BEAM (LEFT HAND SIDE, BEHIND THE CAPTAIN`S SEAT) AT FS 280 WAS FOUND TO BE CORRODED. THE CORROSION WAS CLASSIFIED AS LEVEL 2 AND MEASURED 10" LENGTH X 1" WIDTH AND .018" DEPTH. THIS BEAM ITSELF IS .040" THE CORROSION WAS NEARLY HALF WAY THROUGH. THE BEAM WAS REPLACED AND ASSOCIATED COMPONENTS WERE REINSTALLED IN ACCORDANCE WITH REO 670-53-11-579.