Final answer:
The flight mode annunciator (FMA) displays the autopilot, autothrottle, and flight directors' current operating modes, and is essential for providing information about the automation status.
Step-by-step explanation:
The flight mode annunciator (FMA) displays the current operating modes of the aircraft's autopilot, autothrottle, and flight directors. The FMA is part of the aircraft's flight guidance system and is essential for providing the pilot with immediate and crucial information regarding the automation status of the aircraft. For example, the FMA will indicate if the aircraft is in altitude hold, vertical speed, or heading mode. It also shows engagement status of automated systems like auto land, approach mode, or speed commands. The FMA readouts are critical during all phases of flight, especially during takeoff, climb, cruise, descent, approach, and landing to ensure that the selected automation systems are performing as commanded by the flight crew.