In flight, what is the primary function of the Autothrust system?

The primary function of the Autothrust system in the A320 is to set power for thrust. This system automatically adjusts the thrust output of the engines to maintain the desired speed during various phases of flight, such as climb, cruise, and descent. By continuously monitoring the aircraft's performance and intervening when necessary, the Autothrust system helps ensure optimal engine performance and enhances flight safety. This allows pilots to focus more on managing the overall aircraft operation instead of manually adjusting the throttle in response to changing flight conditions.

The other functions mentioned, such as monitoring fuel consumption, engaging the autopilot, and controlling cabin pressure, are achieved through separate systems. While these systems may work together in managing the aircraft's overall flight profile, each has its distinct primary purpose that does not overlap with the Autothrust system's role.