The bearing line will always extend to the edge
of the map. When the bearing is invalid or
unavailable, the bearing line is removed from the
display and the primary source abbreviation displayed
in black letters on a solid red box.
n. Bearing Needle and Bearing Source. The
bearing needle and bearing source display and
operation are the same as on the HSI ARC display.
o. Map Format (Full 360 Degree Compass
Map). The map display, Figure 3C-14, provides
position awareness information to the crew. The
operation of the peripheral labels and annunciations is
the same as the ARC display mode. The map (full
360) format is reached by toggling the ARC push
button while in the Map mode. To return to the Map
ARC mode (partial 80 compass) toggle the ARC push
p. Compass Display. The current heading is
graphically indicated within the lubber line. A digital
white current heading readout is provided within the
white lubber line symbol. The point of the lubber line
is located directly above the aircraft symbol along the
outside of the selected range ring. Next to the heading
readout is the heading reference indicator (T = True
reference, Blanked reference = Magnetic reference).
When the heading is invalid, the heading readout
is replaced with the heading annunciator. The heading
annunciator displays HDG in black on a solid red box.
q. Range Ring. The range knob selects range
on the MAP format. The range ring is displayed in
cyan with the aircraft symbol located in the center of
the ring. Two range rings are displayed. An outside
range ring is labeled with the selected range and
passes directly under the lubber line. The range ring
is stationary and provides tick marks in 30 intervals.
The inner range ring is half the selected range. It is a
cyan dashed ring. Available full-scale ranges are 2.5,
5, 10, 20, 40, 80, 160, and 320 nm. A digital readout
of the selected heading is displayed in the upper left-
hand corner of the display. The bearing needle and
bearing source display and operation are the same as
on the 360 HSI.
Figure 3C-14. 360 Degree Map