As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT ENCOUNTERED UNCOMMANDED YAW. GOC/MX DIRECTED RETURN TO DEPARTURE. REMOVED AND REPLACED STANDBY ACTUATOR IAW AMM 27-20-151-2. CHECKED STANDBY ACTUATOR MOVEMENT, NOTHING OUT OF NORMAL FOUND DURING CHECKS. TESTED SYS IAW AMM 27-00-051-6 AND AMM 22-11-141-5 AND TEST PASSED. PERFORMED VISUAL INSPECTION IN THAT AREA, NO ABNORMAL FINDING. ACFT OK FOR SERVICE.