As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C CHECK THE MAIN DOOR THRESHOLD SILL SUPPORT WAS FOUND TO BE CORRODED AT FRAME 15 TO 18 AND STRINGER 15 LT. MAINTENANCE REMOVED AND REPLACED THE AFFECTED SILL SUPPORT IAW AMM 20-10-01. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.