TM 55-1510-222-10
Figure 3-9. Copilot's Horizontal Situation Indicator (RD-550R)
dial to provide a continuous readout of course error to
the computer.
(7)
Course deviation bar. The course
deviation bar represents the centerline of the selected
VOR, TACAN, INS or localizer course. The miniature
aircraft symbol pictorially shows actual aircraft position
in relation to this selected course.
(8)
NAV flag. Indicates that information
derived from the selected navigational source (VOR,
TACAN or INS) is invalid and should not be used.
(9)
Compass
synchronization
annunciator. The compass synchronization annunciator
consists of a dot and X symbol display. When the
compass system is in the slaved mode, the display will
oscillate between the dot and X symbol, indicating the
heading dial is synchronized with a gyro stabilized
magnetic heading.
(10)
Course knob. Positions the course
indicator.
(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 (azimuth) dial.
(12)
Reciprocal heading index. Fixed
heading mark.
(13)
Course deviation dots. In VOR,
TACAN, or INS operation, each dot represents a 5
degree deviation from the centerline ( 10 degrees). In
ILS operation, each dot represents 1 degree deviation
from the centerline. In INS operation, each dot
represents a 3.75 nautical miles deviation from
centerline.
(14)
Heading knob. Positions the heading
marker to a preselected compass heading.
(15)
VERT
flag.
Indicates
that
the
information displayed by the glideslope pointer is invalid
and should not be use.
(16)
Glideslope
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.
3-22
