Chapter 10. Flight management system

10.3. The main functions of FMS

Using a global database of aeronautical information and information from the on-board equipment, FMS has three main functions:

  • navigation;
  • estimation of the optimal flight parameters;
  • flight control.

Navigation functionality of FMS

Before the flight, the pilot selects required flight plan with the appropriate database compiled by airline or creates a new one. The internal memory of FMS has global database of:

  • airports;
  • air routes;
  • radio beacons;
  • Standard Instrument Departure (SID) and Standard Instrument Arrival Route (STAR);
  • FPLs complied by airline, etc.

During the flight FMS displays the required aeronautical information from these databases to pilot on the navigation display. In addition, during the flight in accordance with laid trajectory of the flight plan FMS changes the setting of radio navigation equipment.

FMS estimates the exact position of the PC, using information from satellite navigation systems, inertial and beacon systems.

FMS's calculator uses the world's information database to calculate optimal trajectories and flight mode. Assessment results are compared to the actual position of the Aircraft with the planned trajectory and displayed on the map via Navigation Display (ND).

Evaluation of optimal flight parameters

In FMS specialized database stored mathematical model of Aircraft that takes into account engine actions, and the required options for flight simulation.

Before the flight, the pilot enters into FMS information:

  • Aircraft load and weight;
  • cruise FL;
  • Cost Index.

FMS system uses this information to calculate:

  • optimal, most economical airspeed;
  • optimal cruise FL;
  • maximum allowable flight parameters.

This data is displayed on the MCDU. Based on the measured data FMS predicts passage of navigation points and displays the time of arrival at the destination aerodrome. Control. FMS system connected with a digital flight control system and autopilot. Estimated coordinates of Aircraft are compared with the planned trajectory to identify unplanned deviations. The values of these deviations are transmitted to the automatic piloting system to correct the trajectory. Under optimal speed and estimated time of arrival FMS gives information on power plant control system for maintaining the optimal trajectory movement and time. In addition, FMS controls all radio navigation beacon receivers of different systems and air radio communication control unit using communication equipment.

AVIONICS training course materials represented only in demonstrative mode. If it useful, all grammar mistakes will be corrected and more documents will be added. Let me know if you interest in avionics.
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Avionics training in details by
Ostroumov IvanOSTROUMOV Ivan, PhD
Associate Professor, www.ostroumov.sciary.com