As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CORROSION FOUND ON STRINGER 21R BETWEEN FS 336 AND FS 379. C-CHECK RO 12/26/2020. REMOVED AND REPLACED STRINGER 21R BETWEEN FS 336 AND FS 379, REF CRJ900 SRM AND DWG. COMPLIED WITH SKYWEST TASK CARD, COMPLETED FORM M-337. SEE CONTINUATION CARD FOR DETAILS. PRESSURE LEAK CHECK GOOD, NO LEAKS NOTED.