What was found
AT CRUISE, AIRCRAFT BEGAN YAW SERIES LEFT AND RIGHT WITH AUTHORITY. AFTER SEVERAL SECONDS, YD2 INOP STATUS MESSAGE APPEARED AND AIRCRAFT RETURNED TO NORMAL FLIGHT. AT CRUISE, AUTOPILOT ON, AND YD2 OFF, AIRCRAFT BEGAN YAW SERIES LEFT AND RIGHT AFTER SEVERAL SECONDS AND RETRIMMING OF RUDDER, AIRCRAFT WOULD STABILIZE IN NORMAL FLIGHT. SEVERAL OCCURENCES. REMOVED AND REPLACED NR 1 AND 2 FCC'S IAW CRJ MM 22-12-14. PERFORMED OPERATIONAL CHECKS IAW CRJ MM 22-11-00. S/N OFF: 128VV.