What is the function of an aircraft's autothrottle system?

The autothrottle system in an aircraft primarily functions to automatically adjust engine thrust to maintain the selected airspeed. This allows the aircraft to optimize its performance by providing precise control of throttle settings without requiring constant manual adjustments from the pilot. By automatically managing thrust, the system can respond to changing flight conditions such as altitude, weight, and environmental factors, ensuring that the aircraft adheres to the desired airspeed efficiently and safely.

While aspects like fuel efficiency, manual control, and engine performance monitoring might relate to operating an aircraft, they do not encapsulate the primary role of the autothrottle system, which is fundamentally about maintaining a consistent airspeed through automatic thrust adjustments. This capability enhances overall safety and reduces pilot workload, allowing them to focus on other critical aspects of flying.