The Arc HSI is a 140° expanded section of the compass rose. The Arc HSI
contains a Course Pointer, combined To/From Indicator and a sliding deviation
indicator, and a deviation scale. Upon station passage, the To/From Indicator
ips and points to the tail of the aircraft, just like a conventional T
o/From ag.
Depending on the navigation source, the CDI on the Arc HSI can appear in
two different ways, an arrowhead (GPS, VOR, OBS) or a diamond (LOC).
Figure 7-14 – Arc HSI
The Selected Heading is shown to the upper left of the HSI for 3 seconds
after being adjusted The light blue bug on the compass rose corresponds to
the Selected Heading. While the HSI is displayed as an arc, if the Heading
Bug is adjusted off the shown portion of the compass rose, the digital reading
is displayed.
The Selected Course is shown to the upper right of the HSI for 3 seconds
after being adjusted. While the HSI is displayed as an arc, the Selected
Course is displayed whenever the Course Pointer is not within the 140°
currently shown.
Figure 7-15 – Heading and Course Indications
Navigation angles (track, heading, course, bearing) are corrected to the
computed magnetic variation (Mag Var) or referenced to true north (T), set on
the AUX - System Setup Page. When an approach referenced to true north
has been loaded into the ight plan, the system generates a message to
change the navigation angle setting to True at the appropriate time.
Figure 7-16 – Heading and Course Indications (True)
Lateral
Deviation
Scale
Course
Deviation
and To/From