What was found
FLIGHT CREW REPORTED UNCOMMANDED RUDDER MOVEMENTS ON CLIMB, AT LEAST SIX TIMES, ON BOTH AUTO PILOTS 1 AND 2, IN LEVEL FLIGHT AND TURNS. DECLARED AN EMERGENCY AND RETURNED TO BOS. REMOVED AND REPLACED BOTH LEFT AND RIGHT FLIGHT AUGMENTATION COMPUTERS AND BOTH AILERON/ELEVATOR COMPUTERS. PER VENDOR TEARDOWN REPORT, THE NR 1 FLIGHT AUGMENTATION COMPUTER FAILED PT 10 DURING STRESS TESTING. REPLACED IC10 AND Y1 ON A52 PCB TO CORRECT FAULTS.