What was found
THE PILOT REPORTED THE PITCH TRIM ACTUATOR FAILED IN THE STANDBY MODE. AIRCRAFT SYSTEMS WERE CHECKED AND FOUND TO BE OK. REPLACED THE PITCH TRIM ACTUATOR WITH A NEW UNIT. SUBMITTER STATED THIS IS THE 4TH ACTUATOR TO BE INSTALLED SINCE JANUARY, 1997. THE AUTOPILOT SYSTEM OF THE AIRCRAFT OPERATES THROUGH THE STANDBY MOTOR ON THIS ACTUATOR; THUS, AFFECTING THE OPERATION OF THE AIRCRAFT. AIRCRAFT TOTAL TIME: 2,261.1 HOURS.