As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RUDDER HAS A VIBRATION WITH YAW AND/OR RUDDER ON AND OFF. SEEMS TO LESSEN AS RUDDER TRIM APPROACHED ZERO. INSPECTED RUDDER AND RUDDER TRIM IAW EMB 120 MM 27-21-00 PG 601. NO DEFECTS NOTED. AIRCRAFT IS OK FOR RETURN TO SERVICE. ALL PANELS ARE CLOSED.