What was found
YAW DAMPER FAILED DURING CLIMB, RESET AND FAILED AGAIN WITH 15 SECONDS. RUDDER TRIM EXCESSIVE TO THE RIGHT DURING ALL PHASES OF FLIGHT. MAINTENANCE PERFORMED OPEATIONAL TEST OF THE RUDDER TRIM SYSTEM IAW Q400 AMM 27-22-00-71-801. OPS CHECKED GOOD. REMOVED AND REPLACED YAW DAMPER ACTUATOR IAW Q400 AMM 22-11-36, PAGES 401-408. PERFORMED OPERATIONAL TEST OF THE YAW DAMPER ACTUATOR IAW Q400 AMM 22-11-36, PAGES 501-503. OPS CHECK GOOD AND RII COMPLIED WITH. AIRCRAFT RETURN TO SERVICE.