Garmin GTN 625 Pilot's Manual page 107

6.11 ilS Approaches (GTn 650 Only)
Precision ILS approaches can be performed with the built-in VLOC (VOR/
localizer/glideslope) receivers. The GPS receiver can be used for guidance prior
to reaching the final approach fix, but once there, the proper frequency must
be selected on the VLOC window (right side of screen) and the CDI output set
to "VLOC".
190-01004-03 Rev. B
The GTN 6XX can be set to automatically
switch the external CDI output from GPS to
VLOC as you intercept the final approach
course (if used with a KAP140/KFC225
autopilot, you will need to manually enable
outputs). See instructions in the "Enabling
Autopilot Outputs for the King KAP140/
KFC225" section. When the ILS approach is
activated (and the correct ILS frequency is
active in the VLOC window), the GTN 6XX
automatically switches within 1.2 NM left or
right of the final approach course. This
switch can take place anywhere from 2.0 to
15.0 NM from the FAF.
The illustration shows multiple locations
along the approach path and the CDI
selection that you can expect: GPS or VLOC.
Within the area of the shaded box, the
automatic switch from GPS to VLOC should
occur.
Garmin GTN 625/635/650 Pilot's Guide
Foreword
Getting
Started
Xpdr Ctrl
Com/Nav
FPL
Direct-To
Proc
Wpt Info
Map
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Nearest
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Appendix
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6-13