sources will provide information to the single-needle
TCN. Single-needle pointer receives
bearing information from TACAN navigation receiver.
INS. Single-needle pointer receives
bearing information from the inertial navigation system.
ADF. Single-needle pointer receives
bearing information from ADF navigation receiver.
receives bearing information from # 1 VHF navigation
OFF. Removes single-needle pointer
from the EHSI.
ELECTRONIC ATTITUDE DIRECTOR
Description. The EADI (fig. 3-9), combines a
sphere-type attitude display with lateral and vertical
computed steering signals to provide commands
required to intercept and maintain a desired flightpath
The EADI provides the following display information:
Flight director command cue
Flight director mode annunciations
Radio altitude with rising runway display
Decision height setting and annunciations
Marker beacon annunciations
Air data command
Rate of turn
EADI Controls, Indicators, and Functions (fig. 3-9).
Attitude source annunciator. The selected
attitude source will be displayed on the EADI if it is other
than the normal source for that instrument Possible
annunciations are ATT1 (vertical gyro #1), ATI2 (vertical
gyro #2), or AT13 (inertial navigation system). As other
attitude sources are selected, they will be annunciated in
white. When the pilot's and copilot's attitude sources are
the same, the annunciation will be amber.
Lateral mode capture annunciator. Flight
director mode capture is annunciated on the EADI in
green. Possible annunciations are approach (APR),
localizer (LOC), long-range navigation (LNAV), heading
(HDG), and navigation (NAV).
Attitude sphere. The attitude sphere moves
with respect to the symbolic aircraft reference to display
pitch and roll attitude.
Roll attitude pointer. Roll attitude pointer
indicates aircraft roll attitude with respect to the roll
Roll attitude scale. The roll attitude scale
indicates aircraft bank angle in degrees with respect to a
Vertical mode arm annunciator. Flight
director vertical mode arming is annunciated on the
EADI in white. Possible annunciations are altitude select
(ASEL) and glideslope (GS).
(7) Vertical mode capture annunciator. Flight
director vertical mode capture is annunciated on the
EADI in green. Possible annunciations are glideslope
(GS), vertical speed (VS), indicated airspeed (IAS),
altitude (ALT), and go-around (GA).
(8) Pitch attitude scale. The pitch attitude scale
has white reference marks in 5 degree increments.
Horizon line. The horizon line is affixed to
the sphere and remains parallel to the earth's surface.
(10) Glideslope deviation pointer, annunciator,
and scale. The glideslope deviation pointer shows
aircraft deviation from the center of the glideslope
beam. The G annunciator on the glideslope deviation
pointer indicates that the information being presented is
glideslope deviation. Deviation from the center of the
glideslope beam is measured by the glideslope scale.
The distance between two dots is equal to a 0.35 degree
deviation. The glideslope display will not be present on
the EADI unless a valid ILS frequency has been tuned.
(11) Aircraft symbol. The aircraft symbol serves
as a stationary representation of the aircraft. Aircraft
pitch and roll attitudes are displayed by the relationship