A320
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 139; Flight Crew Total 1267; Flight Crew Type 1267
Distraction
Aircraft Equipment Problem Less Severe
Aircraft Equipment Problem Dissipated; Flight Crew Regained Aircraft Control
Aircraft
While at cruise flight FL330; smooth air; autopilot on; we experienced a momentary un-commanded rudder movement resulting in yaw to the right. Autopilot remained engaged and we got no ECAM; master caution or warning. We discussed this as being highly unusual but felt that we could have hit some wake vortices. The flight resumed normally for approximately 2 hours when we got a second rudder movement shortly before we left cruise altitude. At this point we knew something was not right. At that time we decided to report the condition to maintenance. Both occurrences were brief; lasting no longer than 1 second.During both movements; the autopilot remained engaged and we got no ECAM messages; cautions or warnings. The aircraft remained in full control at all times and maintained normal flight profile. For this reason; ATC was not advised.
A320 Captain reported 2 instances of un-commanded rudder movement while in cruise flight.