What is the primary role of a flight management system (FMS)?

The primary role of a flight management system (FMS) is to assist pilots with navigation and flight planning. The FMS integrates various aircraft systems and provides crucial information to the flight crew for optimizing flight paths and fuel efficiency. It automates some flight planning tasks, enabling pilots to enter a route and receive guidance on waypoints, altitude changes, and speed management throughout the flight. This system improves situational awareness and reduces the workload on pilots, allowing them to focus on safe and efficient operation of the aircraft.

In contrast, other options such as managing cabin pressurization or monitoring air conditioning systems pertain to different aircraft systems specifically designed for passenger comfort and cabin safety, rather than the navigation and operational aspects facilitated by the FMS. Additionally, controlling retail operations in-flight is related to service and sales conducted during a flight, which is not within the scope of the FMS's functions.