Garmin GNS 430 Pilot's Manual & Reference page 161

CDI / Alarms— allows you to defi ne the scale for the GNS 430's on-screen course
deviation indicator. The scale values represent full scale defl ection for the CDI to either
side. The default setting is "5.0 nm". At this setting, the CDI scale is set to 5 nm during
the enroute/oceanic phase of fl ight. Within 30 nm of your destination airport the CDI scale
gradually ramps down to 1.0 nm (terminal area). Likewise when leaving your departure
airport the CDI scale is set to 1.0 nm and gradually ramps UP to 5 nm beyond 30 nm (from
the departure airport).
During approach operations the CDI scale gradually ramps down even further, to 0.3 nm.
This transition normally occurs within 2.0 nm of the fi nal approach fi x (FAF). If a lower CDI
scale setting is selected (i.e., 1.0 nm or 0.3 nm) the higher scale settings will not be selected
during ANY phase of fl ight. For example, if 1.0 nm is selected, the GNS 430 will use this for
the enroute and terminal phase and ramp down to 0.3 nm during an approach. Note that the
Receiver Autonomous Integrity Monitoring (RAIM) protection limits listed below follow the
selected CDI scale and corresponding modes:
CDI Scale/Flight Phase:
Auto(oceanic)
+/-5.0 nm or Auto (en route)
+/-1.0 nm or Auto (terminal)
+/-0.3 nm or Auto (approach)
An "auto" ILS CDI selection allows the GNS 430 to automatically switch the external
CDI from the GPS receiver to the VLOC receiver, when established on the fi nal approach
course. (See page 86.) Or, select "manual" to manually switch the external CDI connection,
as needed.
An arrival alarm, provided on the CDI / alarms page, may be set to notify you with a
message when you have reached a user-defi ned distance to the fi nal destination (the direct-to
waypoint or the last waypoint in a fl ight plan). Once you have reached the set distance (up to
99.9 units), an "Arrival at [waypoint]" message will be displayed.
Units / Mag Var— allows you to confi gure the displayed data to standard or metric units
of measure. This setting applies to distance, speed, altitude, fuel, pressure and temperature.
Also provides three magnetic variation (heading) options: True, Auto or User-defi ned. If
"Auto" is selected, all track, course and heading information will be corrected to the magnet-
ic variation computed by the GPS receiver. The "True" setting will reference all information
to true north, and the "User" setting will correct information to an user-entered value.
RAIM Protection:
4.0 nm
2.0 nm
1.0 nm
0.3 nm
AUX PAGES
Setup 1
CDI scales and corresponding Flight Phases:
Oceanic
Enroute
Terminal
Approach
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