As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CORROSION ON INTERCOSTAL BTW FS=319.00 TO FS=333.00 STGR 20RH AT INTERNAL STRUCTURE OF MAIN AVIONICS COMPARTMENT. INTERCOSTAL BTW FS=319.00 TO FS=333.00 STGR 20RH AT INTERNAL STRUCTURE OF MAIN AVIONICS COMPARTMENT (E/E) WAS REPLACED PER CRJ/900 SRM 51-42-21.