When will the autothrottle system automatically disengage?

The autothrottle system is designed to manage engine power automatically for optimal performance in flight. When Airspeed Mode is activated while Flight Level Change (FLC) mode is also active, the two modes can conflict with each other. In this scenario, the activation of Airspeed Mode takes precedence, leading the autothrottle system to disengage automatically to allow for the pilot's control of thrust based on the selected airspeed. This ensures that the aircraft can respond appropriately to the new mode without interference from the conflicting commands of FLC.

Understanding this interaction is crucial for pilots, as it emphasizes the importance of managing flight mode changes effectively. In practice, this automatic disengagement helps to maintain safe and efficient operation, as it prevents potential misunderstandings between autothrust settings and pilot inputs during critical phases of flight.