As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ACFT WAS IN FOR HEAVY MAINTENANCE VISIT. MAINTENANCE FOUND CORROSION ON FWD WET AREA FWD OF LT SILL FROM FR 12 TO FR 16 AS MARKED. REMOVED CORROSION ON FWD WET AREA BY REMOVING AND INSTALLING NEW LT SILL FROM FR12 TO FR16. ACFT REMAINS OUT OF SERVICE FOR HEAVY CHECK COMPLETION.