What was found
AIRCRAFT WAS GROUNDED. AIR RETURNED TO DEPARTURE, DUE TO EXCESSIVE RUDDER TRIM. SEEMED OK AT LOW AIRSPEED, GOT PROGRESSIVELY WORSE AT HIGH SPEED, 5 DEGREES LEFT RUDDER TRIM AT C,RZ (5 UNITS TRIM) ABOVE 180 KNOTS. EMERGENCY DECLARED. FLIGHT WAS OVERWEIGHT FOR LANDING. FLIGHT LANDED WITHOUT INCIDENT. AIRCRAFT WAS REMOVED FROM SERVICE. ADJUSTED/RIGGED ALL 3 RUDDER PCA'S IAW STOPS M & N OF AMM 27-21-00-825-055-001.