(8) Compass Synchronization Annunciator.
The compass synchronization annunciator consists of
a 1 and X symbol display. When the compass system
is in the slaved mode, the display will oscillate
between the 1 and X symbol, indicating the heading
dial is synchronized with a gyro-stabilized magnetic
(9) Course Knob. Positions the course
operation, each dot represents 5° deviation from the
centerline (+ 10°). In ILS operation, each dot
represents 1° deviation from the centerline.
(11) Aircraft Symbol. The fixed miniature
aircraft symbol corresponds to the longitudinal axis of
the aircraft and lubber line markings. The symbol
shows aircraft position and heading with respect to a
radio course and the rotating heading dial.
(12) Heading Knob. Positions the heading
bug to a preselected compass heading.
(13) Glideslope Pointer/Scale. The glide-
slope pointer displays glideslope deviation. The
pointer is in view only when tuned to a localizer
frequency. If the aircraft is below glideslope path, the
pointer is displayed upward on the scale. Each dot on
the scale represents approximately 0.4° displacement.
(14) Course Deviation Bar. The course
deviation bar represents the centerline of the selected
VOR or localizer course. The miniature aircraft symbol
pictorially shows actual aircraft position in relation to
this selected course.
(15) Heading Bug. The notched orange
heading bug is positioned on the rotating heading dial
by the heading knob, and displays preselected
compass heading. The bug rotates with the heading
dial. The difference between the bug and the fore
(upper) lubber line index is the amount of heading
error applied to the flight director computer. In the
heading mode, the ADI will display the proper bank
commands to turn to and maintain this selected
The copilots HSI also has an HDG flag which
indicates loss of heading information, a VERT flag
which covers the glideslope pointer when not receiving
glideslope information, and a NAV flag which indicates
a loss of NAV 2.
3B-15. PILOT'S ATTITUDE DIRECTOR INDICATOR.
a. Description. The pilot's Attitude Director
Indicator (ADI) combines the attitude sphere display
with computed steering information to provide the
commands required to intercept and maintain a
desired flight path. It also contains an eyelid display,
expanded localizer, glideslope, radio altitude display,
rate-of-turn indicator, mode annunciators, go-around
and decision height annunciators, and inclinometer.
Any warning flag in view indicates that portion of
information is unreliable.
b. Controls/Indicators and Functions. Refer
to Figure 3B-8.
(1) Attitude Sphere. Moves with respect to
the symbolic aircraft reference to display actual pitch
and roll attitude. Pitch attitude marks are in 5°
increments on a blue and brown sphere.
(2) Roll Attitude Index. Displays actual roll
attitude through a movable index and fixed scale
reference marks at 0, 10, 20, 30, 45, 60 and 90°.
(3) Go Around (GA) Annunciator. Illuminates
when go-around mode has been selected.
(4) SPD Annunciator. Illuminates when
airspeed is being held by the flight director in the IAS
(5) ALT Annunciator. Illuminates when
altitude is being held by the flight director.
(6) HDG Annunciator. Illuminates when
heading is being held by the flight director in the NAV
ARM or BC ARM mode.
(7) NAV Annunciator. Illuminates when
navigation is being controlled by the flight director, in
the NAV CAP, VOR APR mode.
(8) LOC Annunciator. Illuminates whenever
the flight director is controlling a localizer approach, in
the NAV CAP mode.
(9) APR Annunciator. Illuminates whenever
the flight director is controlling an approach, in the
NAV CAP, VOR APR mode.
(10) GS Annunciator. Illuminates whenever
the flight director is in GS CAP mode, and glideslope
has been captured.
(11) BC Annunciator. Illuminates whenever
the flight director is in BC CAP mode, and has
captured the back course approach heading.