Garmin G3X Touch Pilot's Manual page 96

Flight Instruments
FAILURE OF THE EXTERNAL GPS NAVIGATION SOURCE
If the system automatically reverts to using the internal GPS navigation source due
to unavailablity of the external GPS navigation data, 'REV' is display in the lower left
quadrant of the HSI and 'VFR' is displayed in the lower right quadrant. In addition,
a system status message 'Using internal GPS flight plan for navigation' is displayed.
CDI SCALE SELECTION (INTERNAL GPS ONLY)
NOTE: When an external GPS navigator is in use, the CDI scale is determined
by the navigator.
Three factors determine the default distance from the center of the CDI to full left
or right limits:
• CDI scale = 1.25 nm - within 30 nm of any airport in the active route.
• CDI scale = 0.25 nm - on an approach leg or within 2 nm of the FAF or MAP.
• CDI scale = 5.0 nm - if the previous two conditions do not exist.
NOTE: If the CDI scale has been manually adjusted, it will not resume "auto"
scale until the auto scale aligns with the manual scale.
CDI AUTO-SWITCHING
Some external navigators have the ability to automatically switch CDI sources from
GPS to VLOC when flying a ILS, LOC, LDA, or SDF approach. This is indicated on the
HSI by a change in course pointer color from magenta to green. Additionally, the
external navigator may have the ability to automatically switch the LOC course pointer
when the CDI source change occurs. Reference the appropriate external navigator
documentation for more information.
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Garmin G3X Touch Pilot's Guide 190-01754-00 Rev. L