TM 55-1510-221-10
Figure 3-12. Pilot’s Attitude Director Indicator
(7.) NAV annunciator. Illuminates when
navigation is being controlled by the flight director,
in the NAV CAP, VOR APR mode.
(8.) LOC annunciator. Illuminates when-
ever the flight director is controlling a localizer
approach, in the NAV CAP mode.
(9.) APR annunciator. Illuminates when-
ever the flight director is controlling a approach, in
the NAV CAP, VOR APR mode.
(10.)
GS annunciator. Illuminates whenever
the flight director is in GS CAP mode, and glide
slope has been captured.
(11.) BC annunciator. Illuminates when-
ever the flight director is in BC CAP mode, and has
captured the back course approach heading.
(12.) VRT annunciator. Illuminates when
vertical speed is being held by the flight director, in
the VS mode.
(13.) DH annunciator. Illuminates when
aircraft descends below selected decision height as
set on the radio altimeter indicator.
(14.)
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.
(15.) Speed command display. The pointer
indicates relative airspeed provided by the angle-of-
attack/speed command system.
(16.)
Flight director command cue. Displays
computed commands to capture and maintain a
desired flight path. Always fly the symbolic minia-
ture aircraft to the flight director cue. The cue will
bias from view should a failure occur in either the
pitch or roll channel.
(17.) Radio altitude display. Radio altitude
is digital displayed. The range capability of the dis-
play is from -20 to 2500 feet AGL. The display reso-
lution between 200 and 2500 feet is in 10 foot incre-
ments. The display resolution below 200 feet is 5
feet. The display will be blank at altitudes over 2500
feet AGL. Dashes are displayed whenever invalid
radio altitude is being received.
(18.) DH SET control knob. Sets decision
height from 0 to 990 feet. Decision height displays
in the DH window on lower left corner of ADI. The
brightness of the digital radio altitude and decision
height display is controlled by the dimming knob
3-25
