b. Selected Course. Selected course is shown
by a green alphanumeric display located toward the
bottom of the display. In addition to the digital display,
a downward pointing arrow on the heading tape shows
the selected course.
If the selected primary NAV sensor is an on-side
sensor the digital readout and pointer will be displayed
in green. If an on-side LNAV is the selected primary
NAV sensor and it is in the approach mode, the digital
readout and pointer will be green. If the en route
mode is selected, the readout and pointer will be cyan.
If an off-side sensor is selected, the digital readout and
pointer will be yellow.
c. Heading Marker Selected Heading. A
digital display of selected heading is displayed toward
the bottom of the screen to the right of center. The
selected heading is also shown by the orange heading
marker on the heading tape.
As the aircraft heading changes, the
heading marker will follow the heading
tape and may disappear from view.
d. Navigation Source Annunciation. The
primary navigation sensor is displayed on the left side
of the display. A green annunciation indicates an on-
side approach NAV system is being displayed. A
yellow annunciation indicates that a cross-side system
has been selected. Cyan annunciations apply to on-
side non-approach NAV systems. These color codes
apply to the NAV source annunciator CRS pointer,
course deviation bar, CRS, and distance. If both sides
select the same navigation source a yellow box will be
placed around the navigation source annunciator on
both sides of the cockpit. If both sides select their
respective cross-side navigation source, both NAV
source annunciators will be yellow with no yellow box.
e. Lateral Course Deviation Scale. A lateral
course deviation scale, consisting of four white circles
and a center diamond, is located at the bottom of the
display. The course deviation scale provides a
reference for the course deviation bar to indicate the
centerline of the selected navigation or localizer
course in relation to the center diamond. The course
width displayed in the composite mode is identical to
that typically shown on the EHSI.
f. Lateral Course Deviation Bar. The course
deviation bar represents the centerline of the selected
navigation or localizer course. If invalid or failed
primary NAV sensor data is received the course
deviation bar and scale will be removed and a red X
will be annunciated.
g. To / From Indicator. A white TO or FR is
displayed to the left of the center diamond on the
lateral deviation scale when in non-ILS modes.
h. Distance Information. Distance information
is shown in an alphanumeric display, located in the
lower left corner of the display. Distance in nautical
miles from the aircraft to the selected primary NAV
station when in the VOR, TACAN, or ILS mode, or to
the waypoint in LNAV mode is displayed.
i. DME HOLD. When DME HOLD is selected
the, DME distance and annunciator color changes to
white and remains white until the HOLD function is
released. The sensor identifiers (ADF, VOR, or ILS)
retain their original color. The HOLD function is
additionally annunciated by an orange H displayed
immediately to the right of the distance information.
Groundspeed and time to station are not displayed
while DME HOLD is active.
DME HOLD will not function when LNAV is
the selected sensor.
Once DME is placed in HOLD, its distance
continues to be displayed and is not affected when the
primary NAV sensor is changed.
SYSTEM REVERSIONARY MODES.
Three different reversionary modes of operation
are provided for use in the event of a system
component failure: composite, display down, and
composite reversionary mode is generally used to
compensate for a failure of a display unit or the EADI
section of the symbol generator. Pressing the
indicator, placarded CMPST, located on the instrument
panel, selects the composite display on the EADI or
EHSI. The lower half of the CMPST switch illuminates
DISP to indicate that the composite reversionary mode
has been selected. Refer to Paragraph 3A-22 for a
description of the composite mode displays.
b. Display Down Reversionary Mode. The
display (EADI) down reversionary mode is generally
used to compensate for a failure of the EADI display
unit or the EADI section of the symbol generator.
Pressing the respective pilot's or copilots ADI switch
indicator, located on the instrument panel, transfers
the normal EADI display to the MFD. The lower half of
the ADI switch illuminates DOWN to indicate that the
display down reversionary mode has been selected.