represents approximately 0. 4 degree displacement.
pointers aligned on the course pointer, are located 180
degrees apart. One always points in the direction of the
station, along the selected VOR or TACAN radial or
toward INS waypoint.
Heading marker. The notched orange
heading marker is positioned on the rotating heading
dial by the heading knob, and displays preselected
compass heading. The marker rotates with the heading
switch (fig. 2-14). Selects desired source of data for
display on copilot's HSI.
NA V 1. Selects data from VOR
NA V 2. Selects data from VOR
TACAN. Selects data from
INS. Selects data from INS.
3-17. PILOT'S ATTITUDE DIRECTOR INDICATOR
Description. The pilot's attitude director
indicator (ADI) (fig. 3-10) 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,
mode annunciators, go-around and decision height
annunciators, and inclinometer. Any warning flag in
view indicates that portion of information is unreliable.
Controls/lndicators and Functions.
Attitude sphere. Moves with respect
to the symbolic aircraft reference to display actual pitch
and roll attitude. Pitch attitude marks are in 5 degree
increments on a blue and brown sphere.
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 degrees.
Illuminates when go-around mode has been selected.
SPD annunciator. Illuminates when
airspeed is being held by the flight director, in the IAS
ALT annunciator. Illuminates when
altitude is being held by the flight director.
HDG annunciator. Illuminates when
heading is being held by the flight director, in the NAV
ARM, BC ARM mode.
NAV annunciator. Illuminates when a
NAV source is controlling the flight director, in the NAV
CAP, VOR APR mode.
whenever the flight director is controlling a localizer
approach, in the NAV CAP mode.
whenever the flight director is controlling an approach,
in the NAV CAP, VOR APR mode.
whenever the flight director is in GS CAP mode, and
glideslope has been captured.
whenever the flight director is in BC CAP mode, and has
captured the back course approach heading.
VRT annunciator. Illuminates when
vertical speed is being held by the flight director, in the
DH annunciator. Illuminates when
aircraft descends below selected decision height as set
on the radio altimeter indicator.
Eyelid display. Surrounds the attitude
sphere and provides positive attitude identification by
means of a blue eyelid which always shows the relative
position of the sky, and a brown eyelid which always
shows the relative position of the ground. The eyelids
maintain the proper ground-sky relationship, regardless
of sphere position.
Speed command display. The pointer
indicates relative airspeed provided by the angle-
ofattack/speed command system.