During flight pilot-in-command uses big amount of flight control equipment. Information from each of them is important for flight control and safety of air traffic.
In the air at a different stages of the flight the pilot-in-command requires various aeronautical information from fundamentally different navigation systems. For example, during landing is the most important information from landing system about deviations from the glide path, and during the en-route flight - guidance by terrestrial navigation beacon and satellite navigation. Modern navigation systems are too difficult to use (pilot must spend a lot of time to use them).
FMS – is a computerized system that helps the pilot to monitor and manage Aircraft's systems for safe flight performance. FMS system performs all technical routine operation with Aircraft's systems used in flight, allowing the pilot to spend more time on the flight control, rather than setting up systems.
In general, the FMS consists of two calculators and of two Multifunction Control and Display Unit – MCDU. A calculator is located in technical bay, and MCDU – "under pilot's hand".
Incoming information FMS takes from (Fig. 143)
- VOR/DME navigation aids;
- ADF;
- radioaltimeter (true height over terrain);
- receiver of sattelite navigation (GPS, GLONASS) (coordinates of Aircraft position) and their functional add-ons (LAAS, WAAS, EGNOS);
- INS;
- TCAS;
- GPWS.
Fig. 143. Collaboration of FMS with other systems
Also incoming information for FMS are
- deviation from the trajectory of the glide path provided by landing system;
- altitude, speed parameters from the the system of air signals;
- the amount of fuel from the respective sensors and the exact time from the the on-board chronometer.
Data from these systems are required to monitor the progress of the flight, perform appropriate calculations and display them in the right format to pilot through primary flight and navigation displays. FMS provides:
- display of aeronautical information necessary for piloting in a particular phase of flight through e-indication;
- changing the radio frequencies of navigation and communication equipment connected through the control unit of communication equipment;
- issuance of deviations from the values of given trajectory for automatic piloting and information systems for engine control.