(23) Fast/slow source annunciator. The fast/
slow source annunciator (white) displays A/S.
(24) Lateral mode arm annunciators. Lateral
mode arm function is annunciated on the EADI in white.
Possible annunciations are NAV, APR, LOC, and BC.
EADI Amber Caution and Failure annunciators
Same attitude source. There is no attitude
source annunciated if the pilot and copilot are using their
normal attitude sources. Selecting other attitude
sources causes the new source to be annunciated in
white. If the pilot and copilot have selected the same
attitude source, that attitude source will be annunciated
in amber on both EADI's.
Comparison monitor. The comparison
monitor compares selected pilot and copilot input data in
the symbol generator. If the difference between the data
exceeds predetermined levels, the out-of-tolerance
symbol will be displayed. Table 3-2 shows comparison
monitor symbols and miscompare levels.
When the compared pitch and roll attitude or glideslope
and localizer signals are out of tolerance, a combined
symbol (ATT or ILS) is displayed.
Radio altitude failure. Radio altitude failure
is indicated by amber dashes replacing the numerical
altitude value, and the removal of the rising runway
radio altitude display from the EADI, if present
potentiometer is open, or during self test, amber dashes
will replace numerical values of decision height display.
Autopilot status messages. The following
messages may appear for autopilot status. They will
replace the autopilot engage (AP ENG) annunciator:
AP ENG. Autopilot engaged.
AFCS? Autopilot wraparound signal
TCS ENG. Touch control steering is
Flightdirector failure. In the event of a flight
director failure, an amber FD FAIL warning will be
displayed on the EADI.
Air data command failure. If an air data
flight director mode has been selected, and the air data
computer fails, amber dashes will replace the numerical
values in the air data command display.
Common symbol generator. When in the
reversionary mode and one symbol generator is driving
both the pilot's and copilot' s display tubes, an amber
reversionary warning is given to indicate the information
EADI Red Failure Annunciations (fig 3-11).
Attitude failure. If the attitude display, pitch
scale, or roll pointer fail, they will be removed from the
display, the attitude sphere will become blue, and a red
ATT FAIL will be displayed on the EADI.
Glideslope, expanded Iocalizer, and rate- of-
turn failures. If the glideslope, expanded localizer, or
rate-of-turn system fails, the pointer will be removed and
a red X will be drawn through the scale. The letter G will
remain at the zero deviation position to identify invalid
Internal failure. If an internal failure occurs
within the display system itself, the display will be blank
A failure of the input/output processor will be indicated
by a red X centered on the display with a SG FAIL
annunciated (fig. 3-12).
ELECTRONIC HORIZONTAL SITUATION
Description. The electronic horizontal situation
indicator (fig. 3-13), combines several displays to
provide a maplike display of aircraft position. The
indicator displays aircraft displacement relative to a
VOR or TACAN radial, inertial navigation system
guidance, and localizer and glideslope beam. The EHSI
provides the following full and partial compass display
Full compass displays Heading
Course or azimuth deviation