Multifunctional Display and Electronic Flight Information System
MFD started as a display on a cathode ray tube (CRT) but has advanced to a liquid crystal display (LCD), which is a lighter and clearer technology. All relevant data for pilot use (e. g., air, engine, and navigational data) are displayed simultaneously on the screen. To reduce clutter, the displays are divided into primary and secondary displays. Separate-system displays are accommodated in one or two
(a) Air-Data Systems Display (b) Navigational Display
Figure 15.15. Multifunctional display
EFISs: the primary air-data system display (SD), and the navigational display (ND); each type of system has several pages and each display screen can be changed for specific information. Figure 15.15 shows typical EFIS displays. EFIS/MFD/ND/SD have many pages that can be flipped to as desired, including pages for the engine, cruise, flight-control, fuel, electrical, avionics, oxygen, air-bleed, air-conditioning, cabin-pressurization, hydraulics, undercarriage, doors, and the APU (military aircraft have weapons-management pages).
The primary flight display (PFD) consists of air-data systems, including aircraft speed, altitude, attitude, aircraft reference, and ambient conditions. The secondary system consists of the ND, which provides directional bearings (i. e., GPS and inertial system), flight plan, route information, weather information, airport information, and so forth. For pilot facility, each type has some duplication. In a separate panel, the SD shows the engine data and all other system data, including those required for the ECS. EFISs have removed the clutter of analog dials, one for each type of data. In some designs, the engine display (ED) is shown separately. Forwardlooking weather radar can have the ND or a separate display unit.
Initially, flight decks also had basic analog gauges showing air data as redundancies in case the EFIS failed. Currently, with vastly improved reliability in the EFIS, older analog gauges are gradually being removed.