Final answer:
When engaged, the autothrottle system (ATS) in an aircraft indicates its status through the flight mode annunciator, visual cues on cockpit displays, and sometimes an audible alert, helping the flight crew know that the power settings are being managed.
Step-by-step explanation:
When the autothrottle system (ATS) is engaged in an aircraft, it provides indications through various methods depending on the type and model of the aircraft. Common indications include an announcement on the flight mode annunciator (FMA) display, a visual cue on the engine-indication and crew-alerting system (EICAS) or primary flight display (PFD), and an engagement or mode confirmation light on the throttle quadrant or cockpit panel. Some aircraft also have an audible tone or voice annunciator system that alerts the flight crew to the engagement of the autothrottle. It is crucial for pilots to be aware of and understand these indicators, as they provide assurance that the ATS is managing the power settings of the engines according to the parameters set by the flight crew or autopilot system.