The interaction of FMS with the pilot is provided by MCDU. This unit is used for programming the FMS functions and display of business information.
Typical MCDU is shown on Fig.144. MCDU interface consists of a screen and keyboard. Liquid Crystal Display (LCD) is used to display information.Obsolete models of MCDU were built on the basis of monochrome cathode-ray tube. The usage of LCD for manufactoring made possible to reduce the size of the reflective part and point out some information by different colours for a better visual perception.
Keys on the MCDU allow to select the correct modes and enter the required navigational information. Examples of displaying of navigation information on MCDU during the flight from the tnavigation point BENB to SIE shown on Fig. 145.