Garmin GFC 600H Pilot's Manual page 46

HFCS
If the CDI is less than half scale, Navigation mode will immediately become the
active mode.
Some navigators that combine both GPS and VHF Nav functions are capable of
automatically switching the CDI source from GPS to VOR/LOC when programmed to
transition from a GPS flight plan to a Localizer approach. The HFCS does not support
automatic transition from a Navigation mode to an Approach mode and the lateral axis
will revert to ATT mode if it senses that the navigation source has changed.
CAUTION:
capability should be configured with automatic switching disabled.
If Navigation mode is active and any of the following occur, the HFCS lateral axis
reverts to ATT Hold mode:
• Different VHF Nav frequency tuned while in VOR or LOC Navigation mode (note
that in some installations Navigation mode may remain engaged if there is still
valid deviation after the frequency changes from VOR to VOR, or from LOC to LOC)
• Navigation source switched (e.g. GPS to VOR/LOC, or VOR to LOC)
• Loss of navigation signal
If NAV is the active mode and the course is changed the FCS will establish an
appropriate track up to 45 degrees to capture the new course.
If VOR or VAPP is the active mode and the course is changed while in the cone of
confusion over the station the FCS will turn to a heading appropriate to capture the
new course and recapture the guidance upon exiting the cone of confusion.
GMC 605H ANNUNCIATIONS
The GMC 605H annunciates the appropriate lateral mode as GPS, VOR, LOC, or BC
depending on the selected navigation source when the NAV key was pressed.
36
Navigators or PFDs with automatic CDI source switching
Garmin GFC 600H Pilot's Guide 190-02081-04 Rev. A