What was found
THREE UNCOMMANDED RUDDER MOVEMENTS ON APPROACH. MECHANICS PERFORMED CAT3 CHECKS PER AMM 22-11-00 PG 501, AMM 22-31-00 AND RUDDER ACTUATOR CONFIDENCE CHECK ON MAT, ALL OPS CHECKS NORMAL. ENGINEERING REVIEWED MAINTENANCE RECORDS AND DOWN LINKED CMC FAULT DATA FOR FLIGHT 958. THERE WERE NO REPORTS OF FAULTED FLIGHT CONTROLS, HYDRAULICS OR INSTRUMENT SYSTEMS THAT COULD CAUSE THIS PROBLEM. THERE ARE NO PRIOR REPORTS IN MAINTENANCE HISTORY FOR RUDDER MOVEMENTS. ENGINEERING SUSPECTS THIS REPORT MAY HAVE BEEN DUE TO AN ATMOSPHERIC ANOMALY. AIRPLANE WILL BE MONITORED FOR ANY SYSTEM MALFUNCTIONS.