BASIC
OPERATION
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Heading data from the directional gyro and fluxgate compass is
always applied directly to the SN3500’s compass card display, while
other types of sensor data can be displayed in several different
ways. You can control these displays by configuring the course
pointer, the bearing pointers, the map data and the weather data.
Selecting the Primary NAV Source
The SN3500’s course pointer and CDI can be driven from VOR or
GPS data.
In some installations, the [NAV] button on the SN3500 is used to
select the primary NAV source. In others, an external switch
performs this function and the [NAV] button has no effect. Refer to
the Aircraft Flight Manual Supplement for the details of the
installation. If external switching is used, this section does not
apply.
Pressing the [NAV] button will cycle through the available choices,
which are specific to your aircraft and were configured during
installation. Selecting a primary navigation source also connects it
to the autopilot, if configured.
The current NAV source selection will be annunciated next to the
NAV button as shown below.
Figure 3-3 NAV source annunciations
Depending on the configuration of the aircraft, the available choices
are NAV1, NAV2, GPS1, GPS2, FMS1 and FMS2. If the selected
NAV source is a VOR receiver tuned to a localized frequency, the
annunciation will be either LOC1 or LOC2. If a valid glide slope
signal is detected then the annunciation will be either ILS1 or ILS2.
Numeric data from the primary NAV source, such as distance,
bearing and groundspeed will be displayed in the upper display area
if available.
BASIC
OPERATION
82005-PG-D
SANDEL SN3500 EHSI PILOT’S GUIDE
PAGE
3-4
In some installations, the ILS Lockout function may be enabled on
the SN3500. This function forces the selection of the NAV receiver
when an ILS frequency is selected. Refer to the Aircraft Flight
Manual Supplement to see if the ILS Lockout function has been
enabled in the aircraft being operated.
While NAV1 is tuned to an ILS frequency and the ILS Lockout is in
effect, pressing the [NAV] button will not change sources. Instead,
the following message is displayed: “NAV TUNED TO ILS”. To
defeat the override and restore the function of the [NAV] button,
simply select a non-ILS frequency in the NAV1 receiver.
Selecting and Displaying Bearing Pointers 1 & 2
To display the bearings pointers, press [BRG] to cycle through
available selections. In addition to no bearing pointer display, there
are three selections:
•
Push [BRG] once:
Bearing pointer 1 only
•
Push [BRG] twice:
Bearing pointer 2 only
•
Push [BRG] third time: Bearing pointers 1 and 2
Details about the bearing pointers are in Chapter 5 of this Pilot’s
Guide.
Displaying the Map Data
Map data consists of flight plan waypoints from the LNAV receiver
(GPS/FMS), as well as nearby airports, navaids, intersections and
airspace from the SN3500’s internal database. The different
categories of map information can be enabled or disabled
individually.
To display the map data, press [MAP] to cycle through the available
map memory locations. The currently displayed map memory
setting is displayed next to the MAP button. In addition to the no
map data display, there are three default map memory settings.
These setting are shown below with the displayed map status bar
icons:
Map Memory 1:
[no icon]
GPS/FMS flight plan
Map Memory 2:
Airports, Airspace, and GPS/FMS flight plan
Map Memory 3:
VORs and GPS/FMS flight plan
