Final answer:
The Flight Management System (FMS) provides tuning, mode, and test control for radio communication and navigation. A specific number of presets are offered for each radio band or Nav receiver to improve efficiency and reduce manual input by the flight crew during operations.
Step-by-step explanation:
The Flight Management System (FMS) is a specialized computer system that automates a wide variety of in-flight tasks, thereby reducing the workload on the flight crew to the point that modern civilian aircraft no longer carry navigators or flight engineers. Primarily, it is used for flight planning, navigation, performance computations, and aircraft guidance. The FMS provides tuning, mode, and test control for radio communication and navigation. For enhanced usability and efficiency, a set number of presets are provided for each radio band or Nav receiver. These presets allow flight crew to quickly select specific frequencies or navigation aids without manually entering them each time, which is a crucial feature in situations that require rapid changes or during high-workload phases of flight.
Storage of presets is typically managed through the FMS interface, where the crew can save frequently used or important frequencies and navigation fix data. For instance, preset channels might contain frequencies for ATC communication, VOR tracking, ILS approaches, and so on. The exact number of presets available can vary between different FMS models and aircraft types, but generally, there is a sufficient number to cover the needs of routine operations and to accommodate any specific requirements of a particular flight.