As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CORROSION ON BACK-UP SILL AT STGR 21L BETWEEN FS 333.00 AND FS 349.00. C-CHECK RO 12/14/2020. REMOVED AND INSTALLED NEW BACK-UP SILL AT STGR 21L BETWEEN FS 333.00 AND FS 349.00, REF CRJ 700 SRM DWG. COMPLIED WITH TASK CARD. PRESSURE CHECK GOOD.