An electronic flight instrument system (EFIS)is a flight deck instrument display system located at the flight cockpit in thelower deck after the windshield. It is powered electronically and producedigital output.
The electronic display unit system consists of 3different display units, the Primary Flight Display(PFD), NavigationalDisplay(ND) and EICAS / ECAM based on the enginemanufacturer. There is one PFD and ND each for the first officer and captain.However, the EICAS/ECAM are shared between both crews. EFIS installations varygreatly. A light aircraft might be equipped with one display unit, displayedflight and navigation data whereas a wide-body aircraft is likely to have sixor more display units.Purpose of Electronic Flight Instrument System (EFIS)The purpose of anElectronic Flight Instrument System (EFIS) in an aircraft is to display outputflight data in a CRT or LCD screen to monitor the progress of the aircraft’sflight and the correct function of all aircraft’s parts and system. As well asdisplay essential information to aid the flight crew to operate the aircraft ina safe and efficient way.The EFIS units aidthe pilot in controlling of the aircraft and making decision during flight tothe intended destination, by providing the flight information and navigationalinformation of the flight performance.
Operationsand functions of each unit of EFIS1. Air Data Inertial reference unit The inertial reference unit is connected to the aircraft sensors all around the aircraft to produce flight and air data. The sensors include pitot static tube and ring laser gyroscope. The whole system can be split into 2 units, the air data unit and inertial reference unit. In the air data unit, the pitot static tubes are used with air data modules to convert air pressure into electrical signal magnitudes to the Inertial reference unit through data buses. With the calculation of Airspeed, Mach number, temperature and barometric pressure altitude. The Air Data Inertial reference unit then compiles the information and process it to send to the next phase to display the result.
2. Navigational dataNavigational Data is a commonblock of data that gives navigational information to guide the aircraft toreach the intended destination safely and efficiently through available ordecided routes and communication. Normally, updated every 28 days forits contents to be current. The datataken from different sensors and instruments around the aircraft.
Such asweather radars, transponders, and etc. The navigation data consist of theweather data, instrument landing system data, flight path data, trafficcollision alerting system data, and etc, which aids the aircraft to navigatesproperly. 3. EFIS Control Panel EFIS control panel helps togive manual control to the pilot to select the settings and control thedisplays by choosing what information to be displayed in the CRT or LCDdisplays. They provide the pilots with the controls to the displays such asbrightness, range and mode settings in maps and to show preferred data and toenter data.
4. Primary Flight display (PFD)A primary flight displays (PFD) is an instrument dedicated toflight information. It is a representation of “steam gauge”instruments, combined on one compact display,to help simplifying the pilot’s workflow and streamlining cockpit layouts. Theflexibility in the system makes it possible to display at any given moment onlythe information required for the present flight phase. 5.
Navigation display (ND)Thenavigation displays (ND) displays navigational and weather information frommultiple systems. The second display on each pilot’s maininstrument panel can now be used for to replace the conventional HorizontalSituation Indicator (HSI) to a Navigation Display (ND). the aircrew canoverlay different information over a map or chart. The ND overlay information suchas the aircraft’s current route plan, weather information from either on-boardradar or lightning detection sensors or ground-based sensors, restrictedairspace and aircraft traffic. It can be used to view other non-overlay type ofdata such as current route plan and calculated overlay-type data such as theglide radius of the aircraft, the given current location over terrain, winds,and aircraft speed and altitude. ND can also display information about aircraftsystems, such as fuel and electrical systems and changes the colour or shape ofthe data to alert the aircrew of hazardous situations.Pilotshave five modes of presentation 1) Instrument LandingSystem (ILS) ® Displays course andlocalizer deviation. 2) VHF OmnidirectionalRange(VOR) ® Points to theselected VOR course.
3) Navigation(NAV) ® Shows all the necessary information in rosemode. 4) ARC ® Limited to forward 90 degrees sector. 5) PLAN ® Specific to the route visualization. Onlythe programmed route is displayed with all the waypoints in flight plan.
6. EICAS/ ECAMThe EngineIndications and Crew Alerting System displays information about the aircraft’ssystems, such as its fuel, electrical and engines. EICAS displays are designedto mimic traditional round gauges while supplying digital readouts of theparameters. It improves the situational awareness by allowing the aircrew toview complex information in a graphical format and alerts aircrews to hazardoussituations. Proper care must be taken when designing EICAS to ensure that theaircrew are always provided with the most important information. 7. Warning and Caution lightThe Warningalerts are always displayed in red, and also flashes to capture the attentionof the flight crew together with an aural alert.
If the attitude or airspeeddisplay fail, the EFIS loses the system valid signal to the display and scalemarkings will be removed as well as the displaying of the associated warningflags. Cautionary and warning alerts may flash for few seconds before becomingsteady, to draw the flight crews’ attention. Location and Placement References1. En.wikipedia.org. (2018).
Electronic flightinstrument system. online Available at:https://en.wikipedia.org/wiki/Electronic_flight_instrument_system Accessed 15Jan. 2018.2. Skybrary.aero.
(2018). Electronic Flight InstrumentSystem – SKYbrary Aviation Safety. online Available at:https://www.skybrary.aero/index.php/Electronic_Flight_Instrument_SystemAccessed 15 Jan. 2018.