As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE REMOVING INTERCOSTAL DD4 AT AFT SIDE FOUND THE CLEAT TO BE CORRODED IN MULTIPLE LOCATIONS. LOCATED DRILLED AND INSTALLED NEW SERVICEABLE INTERCOSTAL DD4 AT AFT SIDE CLEAT IAW CRJ 900 SRM 51-40-11-001-001-A01 AND 51-42-06-001-001-A01 PN: 600-31902-269