Figure 3-10. Pilot's Attitude Director Indicator (AD-650B)
computed commands to capture and maintain a desired
flight path. Always fly the symbolic miniature aircraft to
the flight director cue. The cue will bias from view
should a failure occur in either the pitch or roll channel.
Radio altitude display. Radio altitude
is digitally displayed. The range capability of the display
is from -20 to 2500 feet AGL. The display resolution
between 200 and 2500 feet is in 10 foot increments.
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
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 which
is concentric with the DH SET knob. The dimming knob
also dims the distance and course display on the pilot's
HSI, and the altitude alert display.
Expanded localizer. Raw localizer
displacement data from the navigation receiver (HSI
display) is amplified approximately 7 1/2 times to permit
the expanded localizer pointer to be used as a sensitive
reference indicator of the aircraft's position, with respect
to the center of the localizer. It is normally used for
assessment only, since the pointer is very sensitive and
difficult to fly throughout the entire approach. During
final approach, the pointer serves as an indicator of the
Category II window. Full scale deflection of the
expanded localizer pointer is equal to 1/4 degree of
beam signal. The expanded localizer is displayed by
the localizer pointer only when a valid localizer signal is
Inclinometer. Gives the pilot a
conventional display of aircraft slip or skid, and is used
as an aid to coordinated maneuvers.
Rate of turn. Rate of turn is displayed
by the pointer at the bottom of the ADI. The marks at
the extreme left and right sides of the scale represent a
standard rate turn.
Attitude (OTT) test switch. When
depressed, the sphere will show an approximate attitude
change of 20 degree,; of right bank at i 0 degrees pitch-
up. The ATT warning flag will appear.