As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - EN ROUTE TO SEA, RUNAWAY RUDDER TRIM FULL RIGHT (FULL SCALE). WAS ABLE TO REVERSE WITH TRIM SWITCH. PULLED THE CIRCUIT BREAKER AT NEUTRAL POSITION. ACCOMPLISHED UNEVENTFUL LANDING. MAINTENANCE REPLACED THE RUDDER TRIM ACTUATOR (PN 399600-1007, SN 176) AND THE RUDDER TRIM CONTROL PANEL. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.