What was found
CREW REPORTS TWO UNCOMMANDED YAW EVENTS EN ROUTE. LT AND RT YAW DAMPENER MODULES WERE CHECKED FOR RECORDED FLT FAULTS AND NONE WERE FOUND. MCDP CHECKS 1, 9, 40, AND 69, RELATING TO THE AUTOPILOT DIRECTIONAL SERVOS, WERE PERFORMED AND ALL CHECKED OK. CENTER FCC WAS REPLACED AS A PRECAUTION. AUTOPILOT DOES NOT INTERFACE WITH RUDDER SERVOS DURING CRUISE. FLIGHT RECORDER DATA DID NOT INDICATE ANY ENGINE ANOMALIES TO ACCOUNT FOR THE EVENT. THERE IS NO CLEAR EXPLANATION FOR THE UNCOMMANDED YAW.