The mode used normally is the MAP display, which, in conjunction with the flight plan data
programmed into a flight management computer, displays information against a moving map
background with all elements to a common scale.
The symbol representing the aircraft is at the lower part of the display, and an arc of the
compass scale, or rose, covering 45 degrees on either side of the instantaneous track, is at the
upper part of the display.
Heading information is supplied by the appropriate inertial reference system and the compass
rose is automatically referenced to magnetic north (via a crew-operated MAG/TRUE selector
switch) when between latitudes 73°N and 65°S, and to true north when above these latitudes.
When the selector switch is set at TRUE the compass rose is referenced to true north regardless
of latitude.
The aircraft active route as derived from the FMC is shown as a magenta coloured line joining
the waypoints. The active waypoint (the one the aircraft is currently navigating towards) is
shown as a magenta coloured star. The other waypoints making up the active route are called
inactive waypoints and are shown as a white star. Both are identified by name

With an ILS frequency selected, the EHSI displays a full compass rose with the ILS source in the
lower left and the frequency in the lower right.
Course selection (localizer) is displayed by the magenta course needle, the tip pointing to the
selected course (150). Localizer deviation is shown by the traditional deviation bar moving
across a two dot left and two dot right scale. This scale is exponential.
Glide slope deviation is shown by a magenta coloured triangle moving up and down the
traditional scale on the right hand side.
DME distance is displayed in the top left corner.
Current heading is shown in the window and by the lubber line at the top of the compass rose
(130), the current selection is Magnetic Heading as shown either side of the window.
Current track is shown by the white triangle on the inside edge of the compass rose.
Selected heading is shown by the magenta heading “bug” on the outer scale of the compass
rose.
Wind speed and direction are shown in the lower left corner orientated to the display selection
(Heading or Track, Magnetic or True).
Weather radar displays are not available.

With a VOR frequency selected, the EHSI displays about 90° of compass rose with the VOR
source in the lower left and the frequency in the lower right.
The white triangle at the bottom of the display is the aircraft symbol.
Selected course (track) is displayed by the magenta course needle, the tip pointing to the
selected course (150). The course selectors are usually on either side of the autoflight main
control panel (one for the Captain and one for the First Officer). Course deviation is shown by
the traditional deviation bar moving across a two dot left and two dot right scale.
A TO /FROM annunciation is shown.
DME distance is displayed in the top left corner.
Current heading is shown in the window and by the lubber line at the top of the compass rose
(130), the current selection is Magnetic Heading as shown either side of the track window.
Current track is shown by the white line from the tip of the aircraft symbol to the compass arc.
Selected heading is shown by the magenta heading “bug” on the outer scale of the compass
rose. Wind speed and direction are shown in the lower left corner orientated to the display
selection (Heading or Track, Magnetic or True).
Weather radar displays are available; when selected “on”, range arcs are also visible. Weather
radar shows three colours: green, yellow and red, green being the least turbulence, red being
the worst. If turbulence mode is available, it is shown as magenta, the area of greatest activity
in the cloud. The range of the display can be selected on the control panel, half scale range is
displayed (10 NM) so this display is selected to 20 NM. The outer arc of the compass rose is the
furthest range from the aircraft.

In ‘PLAN’ mode a static map background is used with active route data orientated to true
north. Any changes to the route may be selected at the keyboard of the flight management
computer, and the display shown on the EHSI, so they can be checked before they are entered
into the FMC.
The top portion of the EHSI remains the same as in the map mode.
This mode allows the pilot to review the planned route by using the FMC / CDU LEGS page.
Weather radar display data is inhibited.
No wind speed or direction information is shown
Students should be aware that the arc of compass shown is “real time”. The planning section
below this is north orientated. The heading from TOBIX to LOGAN is approximately 020°, NOT
155°.

if the aircraft is on the glide slope, it would look like

this

if the aircraft is intercepting, the glide slope from below. It would look like this

if the aircraft has intercepted the localiser, it would look like this

if you want to travel from zappo to bantu you need to select true track of 180 deg

if you want to travel from bantu to zappo you need to select true track of 360 deg

you current heading is 130 deg magnetic .

EADI  stands for Electronic Attitude Director Indicator

ALSO CALLED PFD(PRIMARY FLIGHT DISPLAY)

EADI ON A BOEING LOOKS LIKE THIS

Below 1000 ft the display automatically changes to a white circular scale calibrated in increments
of 100 ft,

and the selected decision height is then displayed as a magenta-coloured marker on
the outer scale. The radio altitude also appears within the scale as a digital read-out. As the
aircraft descends, segments of the altitude scale are simultaneously erased so that the scale
continuously diminishes in length in an anticlockwise direction.

AS WE KNOW THAT Below 1000 ft the display automatically changes to a white circular scale calibrated in increments
of 100 ft, HERE WE CAN SEE THAT THE SECOND BAR ON THE SCALE IS HIGHLIGHTED WE CAN ASSSUME ITS 200 FEET

The mode used normally is the MAP display, which, in conjunction with the flight plan data
programmed into a flight management computer, displays information against a moving map
background with all elements to a common scale.
The symbol representing the aircraft is at the lower part of the display, and an arc of the
compass scale, or rose, covering 45 degrees on either side of the instantaneous track, is at the
upper part of the display.
Heading information is supplied by the appropriate inertial reference system and the compass
rose is automatically referenced to magnetic north (via a crew-operated MAG/TRUE selector
switch) when between latitudes 73°N and 65°S, and to true north when above these latitudes.
When the selector switch is set at TRUE the compass rose is referenced to true north regardless
of latitude.
The aircraft active route as derived from the FMC is shown as a magenta coloured line joining
the waypoints. The active waypoint (the one the aircraft is currently navigating towards) is
shown as a magenta coloured star. The other waypoints making up the active route are called
inactive waypoints and are shown as a white star. Both are identified by name.

Distance to next waypoint and time at next waypoint are shown at the top of the display
Weather radar (WXR) return data and range arcs are displayed when the WXR switch is on.
Turbulence mode (+T) may be available as previously described.
Indications of other data such as wind speed and direction, lateral and vertical deviations from
the selected flight path are also displayed

With an ILS frequency selected, the EHSI displays a full compass rose with the ILS source in the
lower left and the frequency in the lower right.
Course selection (localizer) is displayed by the magenta course needle, the tip pointing to the
selected course (150). Localizer deviation is shown by the traditional deviation bar moving
across a two dot left and two dot right scale. This scale is exponential.
Glide slope deviation is shown by a magenta coloured triangle moving up and down the
traditional scale on the right hand side.
DME distance is displayed in the top left corner.
Current heading is shown in the window and by the lubber line at the top of the compass rose
(130), the current selection is Magnetic Heading as shown either side of the window.
Current track is shown by the white triangle on the inside edge of the compass rose.
Selected heading is shown by the magenta heading “bug” on the outer scale of the compass
rose.
Wind speed and direction are shown in the lower left corner orientated to the display selection
(Heading or Track, Magnetic or True).
Weather radar displays are not available.

With a VOR frequency selected, the EHSI displays about 90° of compass rose with the VOR
source in the lower left and the frequency in the lower right.
The white triangle at the bottom of the display is the aircraft symbol.
Selected course (track) is displayed by the magenta course needle, the tip pointing to the
selected course (150). The course selectors are usually on either side of the autoflight main
control panel (one for the Captain and one for the First Officer). Course deviation is shown by
the traditional deviation bar moving across a two dot left and two dot right scale.
A TO /FROM annunciation is shown.
DME distance is displayed in the top left corner.
Current heading is shown in the window and by the lubber line at the top of the compass rose
(130), the current selection is Magnetic Heading as shown either side of the track window.
Current track is shown by the white line from the tip of the aircraft symbol to the compass arc.
Selected heading is shown by the magenta heading “bug” on the outer scale of the compass
rose. Wind speed and direction are shown in the lower left corner orientated to the display
selection (Heading or Track, Magnetic or True).
Weather radar displays are available; when selected “on”, range arcs are also visible. Weather
radar shows three colours: green, yellow and red, green being the least turbulence, red being
the worst. If turbulence mode is available, it is shown as magenta, the area of greatest activity
in the cloud. The range of the display can be selected on the control panel, half scale range is
displayed (10 NM) so this display is selected to 20 NM. The outer arc of the compass rose is the
furthest range from the aircraft.

In ‘PLAN’ mode a static map background is used with active route data orientated to true
north. Any changes to the route may be selected at the keyboard of the flight management
computer, and the display shown on the EHSI, so they can be checked before they are entered
into the FMC.
The top portion of the EHSI remains the same as in the map mode.
This mode allows the pilot to review the planned route by using the FMC / CDU LEGS page.
Weather radar display data is inhibited.
No wind speed or direction information is shown
Students should be aware that the arc of compass shown is “real time”. The planning section
below this is north orientated. The heading from TOBIX to LOGAN is approximately 020°, NOT
155°.

THIS IS ON BOTH THE CAPTAIN AND THE FO SIDES

Decision height (DH) is selected on the ADI control panel and shown on both the ADI and on
the control panel.

Below 1000 ft the display automatically changes to a white circular scale calibrated in increments
of 100 ft, and the selected decision height is then displayed as a magenta-coloured marker on
the outer scale. The radio altitude also appears within the scale as a digital read-out. As the
aircraft descends, segments of the altitude scale are simultaneously erased so that the scale
continuously diminishes in length in an anticlockwise direction

Both the first officer and captain has one navigation display each.

they can see the weather on the nd each wit there own display

THERE ARE TWO EADI ONE EACH ON THE CAPTAINS SIDE AND THE FO SIDE.

Heading information is supplied by the appropriate inertial reference system and the compass
rose is automatically referenced to magnetic north (via a crew-operated MAG/TRUE selector
switch) when between latitudes 73°N and 65°S, and to true north when above these latitudes.
When the selector switch is set at TRUE the compass rose is referenced to true north regardless
of latitude.

the IRS establishes true north. Magnetic indications are obtained by the application of variation, which,
in the case of the Boeing 737-400 is stored in each IRS memory. The range covered for variation is from 73° North to 60° South latitude.

The ‘EHSI’ Display Presentation
The EHSI presents a selectable, dynamic colour display of flight progress and a plan view
orientation. Four principal display modes may be selected on the EFIS control panel;-
• VOR
• ILS
• MAP
• PLAN
Of these VOR and ILS can be displayed as full or expanded compass displays.

EFIS

As in the case of a multi-crew conventional flight director system, a complete EFIS installation
is made up of left (Captain), and right (First Officer), systems.

Each system in turn is comprised of:
• Electronic Attitude Director Indicator (EADI) or Primary Flight Display (PFD)
• Electronic Horizontal Situation Indicator (EHSI) or Navigation Display (ND)
• Control Panel
• Symbol Generator (SG)
• Remote Light Sensor Unit

A third (centre) symbol generator is also incorporated so that its drive signals may be switched
to either the left or right display units in the event of failure of their corresponding symbol
generators.
The signal switching is accomplished within the left and right symbol generators, using
electromechanical relays powered from an aircraft’s DC power supply, via pilot-controlled
switches