An electronic flight instrument system (EFIS) is a flight deck instrument display system
located at the flight cockpit in the lower deck after the windshield. It is powered
electronically and produce digital output.

The electronic display unit system consists of 3 different display units, the Primary
Flight Display(PFD), Navigational Display(ND) and EICAS / ECAM based on the
engine manufacturer. There is one PFD and ND each for the first officer and captain.
However, the EICAS/ECAM are shared between both crews.

EFIS installations vary greatly. A light aircraft might be equipped with one display unit,
displayed flight and navigation data whereas a wide-body aircraft is likely to have six
or more display units.

Purpose of Electronic Flight Instrument System (EFIS)

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The purpose of an Electronic Flight Instrument System (EFIS) in an aircraft is to
display output flight data in a CRT or LCD screen to monitor the progress of the
aircraft’s flight and the correct function of all aircraft’s parts and system. As well as
display essential information to aid the flight crew to operate the aircraft in a safe and
efficient way.

The EFIS units aid the pilot in controlling of the aircraft and making decision during
flight to the intended destination, by providing the flight information and navigational
information of the flight performance.

Operations and functions of each unit of EFIS

1. AirDataInertialreferenceunit

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. Navigationaldata

Navigational Data is a common block of data that gives navigational information to
guide the aircraft to reach the intended destination safely and efficiently through
available or decided routes and communication. Normally, updated every 28 days
for its contents to be current. The data taken from different sensors and instruments
around the aircraft. Such as weather radars, transponders, and etc. The navigation
data consist of the weather data, instrument landing system data, flight path data,
traffic collision alerting system data, and etc, which aids the aircraft to navigates

3. EFISControlPanel

EFIS control panel helps to give manual control to the pilot to select the settings
and control the displays by choosing what information to be displayed in the CRT
or LCD displays. They provide the pilots with the controls to the displays such as
brightness, range and mode settings in maps and to show preferred data and to
enter data.

4. PrimaryFlightdisplay(PFD)

A primary flight displays (PFD) is an instrument dedicated to flight 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. The
flexibility in the system makes it possible to display at any given moment only the
information required for the present flight phase.

5. Navigationdisplay(ND)

The navigation displays (ND) displays navigational and weather information from
multiple systems. The second display on each pilot’s main instrument panel can
now be used for to replace the conventional Horizontal Situation Indicator (HSI) to
a Navigation Display (ND). the aircrew can overlay different information over a map
or chart. The ND overlay information such as the aircraft’s current route plan,
weather information from either on-board radar or lightning detection sensors or
ground-based sensors, restricted airspace and aircraft traffic. It can be used to
view other non-overlay type of data such as current route plan and calculated
overlay-type data such as the glide radius of the aircraft, the given current location
over terrain, winds, and aircraft speed and altitude. ND can also display information
about aircraft systems, such as fuel and electrical systems and changes the colour
or shape of the data to alert the aircrew of hazardous situations.

Pilots have five modes of presentation

1)  Instrument Landing System (ILS) ? Displays course and localizer deviation.

2)  VHF Omnidirectional Range(VOR) ? Points to the selected VOR course.

3)  Navigation(NAV) ? Shows all the necessary information in rose mode.

4)  ARC ? Limited to forward 90 degrees sector.

5)  PLAN ? Specific to the route visualization. Only the programmed route is
displayed with all the waypoints in flight plan.


The Engine Indications and Crew Alerting System displays information about the
aircraft’s systems, such as its fuel, electrical and engines. EICAS displays are
designed to mimic traditional round gauges while supplying digital readouts of the
parameters. It improves the situational awareness by allowing the aircrew to view
complex information in a graphical format and alerts aircrews to hazardous
situations. Proper care must be taken when designing EICAS to ensure that the
aircrew are always provided with the most important information.

7. WarningandCautionlight

The Warning alerts are always displayed in red, and also flashes to capture the
attention of the flight crew together with an aural alert. If the attitude or airspeed
display fail, the EFIS loses the system valid signal to the display and scale
markings will be removed as well as the displaying of the associated warning flags.
Cautionary and warning alerts may flash for few seconds before becoming steady,
to draw the flight crews’ attention.

Location and Placement

Control Panel
Warning and Caution Light
EFIS display units

References Accessed 15
Jan. 2018.
Safety. online Available at:
Accessed 15 Jan. 2018. 


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