As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CORROSION ON INTERCOSTAL ATTACHED TO STRINGER 20RT IN STA FS 310 TO FS 319 AT MAIN AVIONICS COMPARTMENT (E/E) W1. INTERCOSTAL ATTACHED TO STRINGER 20RT IN STA FS 310 TO FS 319 AT MAIN AVIONICS COMPARTMENT WAS INSTALLED, PER CRJ900 SRM 51-42-21-001-001-A01 PAR 6C.