As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MIA - FLT 2139 - EN ROUTE MIA-CCS - UNCOMMANDED RUDDER MOVEMENT DURING CLIMB-OUT. ISOLATING A/P SYSTEM DID NOT HELP. NO AIRFRAME VIBRATION NOTICES. RETURNED AND LANDED MIA WITHOUT INCIDENT. REPLACED NR 1 AND NR 2 FLIGHT AUGMENTATION COMPUTERS. DID NOT RESOLVE PROBLEM. REPLACED YAW DAMPER SERVO ACTUATOR AND ACCOMPLISHED YAW DAMPER SERVO ACTUATOR OPERATIONAL CHECK. DID NOT RESOLVE THE PROBLEM. REPLACED YAW DAMPENER. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)