The term 'Aircraft System' is a broad term that encompasses the various components of an aircraft, such as the autopilot. The autopilot is a system that allows the aircraft to fly autonomously without the need for manual control from the pilot. It is responsible for controlling the aircraft's altitude, speed, and direction, as well as other functions such as navigation and communication. The autopilot can be programmed to follow a predetermined flight path or it can be manually overridden by the pilot.