GNS 430(A) Pilot’s Guide and Reference
190-00140-00 Rev. P
10-21
SECTION 10
AUX PAGES
CDI Scales and Corresponding Flight Phases:
Oceanic
Enroute
Terminal
Approach
Figure 10-54 CDI Scales
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 nal approach x (FAF). If a lower CDI scale
setting is selected (i.e., 1.0 nm or 0.3 nm) the
higher scale settings are not selected during any
phase of ight. For example, if 1.0 nm is selected,
the GNS 430 uses 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 in Table 10-2 follow the selected CDI scale
and corresponding modes:
CDI Scale/Flight Phase: RAIM Protection:
Auto (oceanic) 4.0 nm
±
5.0 nm or Auto (enroute) 2.0 nm
±
1.0 nm or Auto (terminal) 1.0 nm
±
0.3 nm or Auto (approach) 0.3 nm
Table 10-2 CDI Scales
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 nal approach course (Section
6.3). 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 the pilot with a message when
a user-defined distance to the final destination
(the direct-to waypoint or the last waypoint in a
ight plan) has been reached. Once the aircraft
has reached the set distance (up to 99.9 units), an
‘Arrival at [waypoint]’ message is displayed.
• ‘Units/Mag Var’ - Allows the pilot to congure
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-dened. If ‘Auto’ is
selected, all track, course and heading information
is corrected to the magnetic variation computed
by the GPS receiver. The ‘True’ setting references
all information to true north, and the ‘User’ setting
corrects information to an user-entered value.
