What is the primary role of the FMS in flight planning and execution?

• A. It displays passenger information.
• B. To manage route navigation, speeds, vertical profile, and provide guidance and optimization for the flight.
• C. To monitor cabin temperature.
• D. To manage fuel pricing.

Answer: (B)

The FMS’s main job is to handle flight planning and execution by determining and following the optimal route, speeds, and vertical profile, and by providing continuous guidance and optimization throughout the flight. It uses the navigation database and the planned flight plan to compute legs, wind corrections, and constraints, then works with the autopilot and autothrottle to execute LNAV and VNAV modes. It also calculates performance data like fuel burn and arrival timing, updating guidance as conditions change to keep the flight efficient and on track. This focus on route navigation, speed management, vertical profile, and optimization is what sets the FMS apart from systems that handle cabin information, temperature, or pricing.