Specifications

SECTION III
INSTRUMENTATION AND AVIONICS
MODEL 560
ELECTRONIC HORIZONTAL SITUATION INDICATOR (EHSI)
The displays in the EHSI portion of the PFD are discussed below in three categories: FULL TIME
which are always present, PART TIME which are sometimes present, and the arc mode.
FULL TIME DISPLAYS
Certain displays are always present on the EHSI or are always present when certain navigation
equipment is in operation. The airplane symbol is always present and provides a quick visual cue of
airplane position relative to a selected course or heading.
The other full time displays are discussed serially below. The angular presentations are all similar to
those seen on a mechanical HSI.
TO/FROM Annunciator - Indicator points along selected course depicting whether the course will
generally take the airplane to or from the selected station or waypoint.
Indicator does not appear during localizer operation.
Distance Display - Indicates nautical miles to selected station or waypoint. Distance display
is in 0-399.9 NM for selection of short range navigation equipment and
0-3999 NM format for long range equipment. DME HOLD is indicated by
an amber H next to the readout.
Navigation Source NAV source annunciations are displayed in the upper right corner of the
Annunciators - EHSI presentation. Long range sources are in magenta and short range
sources are in green or yellow. A yellow indication means an “offside”
selection or that both sources are the same. The label identification will
always be white. A yellow annunciation of FMS indicates that both pilots
are selected to the FMS.
Heading Source Annunciation - Heading source is annunciated at the top left center of the EHSI
presentation. A green annunciation indicates a normal selection and
yellow indicates an “off-side” selection or that both selections are the
same.
Heading SYNC Annunciator - The heading SYNC annunciation is located to the left of the heading
source annunciation in the upper left side of the EHSI presentation. The
bar in the indicator represents commands to the compass to slew in the
indicated direction. Plus indicates an increase in heading and zero
indicates a reduction in heading. Slow oscillation indicates normal
operation.
Heading Dial and Digital
Heading Readout -
Heading information is presented on standard type compass dial format
and digital heading readout is shown above the heading dial when in the
ARC mode.
Heading Select Bug and
Heading Select Readout -
The
heading bug is positioned around a compass dial with HDG knob on
the remote instrument controller. The bug then retains its position in
relation to the dial. A digital heading select readout is provided at the
lower left of the display (cyan digits, white HDG label). The heading bug
provides a heading error signal to the flight director.
Course Deviation Indicator - Navigation or localizer course. Course deviation and airplane position
relationships are depicted as on a mechanical HSI instrument. The
course deviation indicator also operates in conjunction with the long
range NAV system. Refer to Part Time Displays, below, for Desired
Track information. The CDI is positioned by the course knob on the
remote instrument controller. The course knob is not functional when
FMS mode is selected. The CDI is magenta when FMS course
information is presented, green when on-side NAV information is being
presented, and yellow when off-side NAV information is being presented.
I 3-56 Configuration AA 56OMB-01