Garmin GNS 430 Pilot's Manual And Reference page 115

Points to Remember for Localizer-based
Approaches
• The default factory setting allows the CDI output
to automatically switch from the GPS receiver
to the VLOC receiver. If the 'ILS CDI Capture'
setting is changed to 'Manual', the pilot must
determine when to select GPS or VLOC guidance
during the approach. Remember, VLOC is
required for the final course segment from final
approach fix (FAF) to MAP.
• If the CDI output has not automatically switched
from GPS to ILS by 2.0 nm prior to the FAF, the
pilot must manually switch to the VLOC receiver
by pressing the CDI Key. Verify that 'VLOC' is
displayed directly above the CDI Key.
• Automatic switching of CDI output is available
for ILS, localizer, SDF, and LDA approaches.
Automatic CDI switching is not available for
backcourse approaches.
• When flying an approach with the autopilot
coupled, the pilot must monitor system functions
at all times and verify that the autopilot and
external CDI (or HSI) switches to the VLOC
receiver with sufficient time to capture and track
the approach course. Switching to VLOC late
in the approach may not provide the autopilot
enough time to respond and intercept the
approach course prior to the FAF (depending
upon the performance characteristics of the
autopilot and aircraft). In such cases, the pilot
should manually fly the approach or refer to the
documentation provided with the autopilot.
• When an ILS approach is first selected and
'loaded' (or 'activated'), the ILS frequency is
automatically placed in the standby field. In
order to fly the final course segment of the ILS
approach, the pilot must place the ILS frequency
in the active frequency field by pressing the
VLOC Flip-flop Key. If this is not done, a 'Select
appropriate frequency for approach' message
appears within 3.0 nm of the FAF.
• When flying a localizer-based approach (other
than backcourse) with automatic CDI switching
enabled:
• When flying a localizer-based approach with
automatic CDI switching disabled:
GNS 430 Pilot's Guide and Reference
SECTION 6
PROCEDURES
GPS guidance is used while flying outbound
and on the initial portion of the procedure
turn.
VLOC guidance is used on the remainder of
the approach from the time the pilot turns
inbound on the procedure turn.
The localizer frequency must be active to
use VLOC guidance.
The pilot may select VLOC guidance at any
point on the approach prior to reaching the
FAF.
The localizer frequency must be active to
use VLOC guidance.
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