Garmin GNC 420, Pilot'S Manual & Reference

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GNC 420(A) Pilot’s Guide and Reference
APPENDIX C
TROUBLESHOOTING
C-6
Why does my CDI not respond like a VOR when
OBS mode is active?
Unlike a VOR, the CDI scale used on GPS equipment
is based on the cross-track distance to the desired course,
not an angular relationship to the destination (Figure
C-8). Therefore, the CDI deflection on the GPS is
constant regardless of the distance to the destination, and
does not become less sensitive when further away from
the destination. For more information on the
CDI scale,
see Section 9.4.
Figure C-8 CDI Comparison
5 nm 5 nm 5 nm 5 nm
2
nm
2
nm
GPS VOR
What is the correct missed approach
procedure? How do I select the missed
approach holding point?
To comply with TSO specifications, the GNC 420
does not automatically sequence past the MAP. The
active-to waypoint sequences to the first waypoint in the
missed approach procedure when the
OBS Key is pressed
after crossing the MAP. All published missed approach
procedures must be followed, as indicated on the approach
plate.
To execute the missed approach procedure prior to the
MAP (not recommended), select the Active Flight Plan
Page, highlight the MAHP, press the
Direct-to Key, and
then press the ENT Key twice.
How do I re-select the same approach
or activate a new approach after a missed
approach?
After flying all missed approach procedures, the pilot
may reactivate the same approach for another attempt from
the Procedures Page. Once given clearance for another
attempt, activate the approach from the Procedures Page by
highlighting ‘Activate Approach?’ and pressing the ENT Key.
The GNC 420 provides navigation along the desired course
to the waypoint and rejoins the approach in sequence from
that point on. See Section 5.2, Active Flight Plan Options
for information on activating a specific flight plan leg.
Activating a new approach for the same
airport:
1) Press the
PROC
Key.
2) Turn the large
right
knob to highlight ‘Select
Approach?’.
3) Press the
ENT
Key.
4) Turn the large
right
knob to highlight the new
desired approach.
5) Press the ENT Key to select the approach, then
select the desired transition.
6) Highlight ‘Activate?’ at the bottom right corner
of the screen and press the ENT Key to activate
the new approach.
Activating a new approach to a different
airport:
1) Press the
Direct-to
Key.
2) Select the desired airport using the small and
large
right
knobs.
3) Press the
ENT
Key to accept the selected
airport, then follow the steps in the preceding
paragraph to select an approach for the new
airport. See Section 6.1 for more information
on selecting and activating approaches.
190-00140-20 Rev. K