As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL270 AND -22*C RUDDER TRIM WAS FROZEN AND WOULD NOT MOVE. RUDDER TRIM BECAME FREE AFTER DESCENDING INTO WARMER AIR. LANDING WAS UNEVENTFUL. MAINTENANCE REPLACED THE RUDDER TRIM ACTUATOR. A SUCCESSFUL OPERATIONAL CHECK FLIGHT WAS ACCOMPLISHED. AIRCRAFT WAS RETURNED TO SERVICE.