As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY CHECK MAINTENANCE, THERE WAS EVIIDENCE OF CORROSION UNDER DOOR SILL PLATE CENTER SECTION OTBD BETWEEN THRESHOLD AND R2 DOOR SILL. REMOVED CORROSION AND FOUND TO BE OUT OF LIMITS IAW SRM 53-41-14. REMOVED AND REPLACED THE DOOR SILL IAW SRM 51-72-11.