GNC 420(A) Pilot’s Guide and Reference
APPENDIX C
TROUBLESHOOTING
C-2
What happens when I select an approach?
Can I store a flight plan with an approach,
departure, or arrival?
When loading an approach, departure, or arrival into
the active ight plan, a set of approach, departure, or
arrival waypoints is inserted into the ight plan—along
with a header line describing the instrument procedure
(Figure C-2). The original enroute portion of the
ight plan remains active, unless the pilot activates the
instrument procedure; which may be done when the
procedure is loaded or at a later time.
Figure C-2 Active Flight Plan Page
Flight plans can also be stored with an approach,
departure, or arrival. Keep in mind that the active ight
plan is erased when the unit is turned off and overwritten
when another ight plan is activated. When storing
ight plans with an approach, departure, or arrival,
the GNC 420 uses the waypoint information from the
current database to define the waypoints. If the database
is changed or updated, the GNC 420 automatically
updates the information if the procedure has not been
modified. If an approach, departure, or arrival procedure
is no longer available, the ight plan becomes locked
until the procedure is deleted from the ight plan or the
correct database is installed. For information on loading
an approach, departure, or arrival, see Section 6.1. See
Section 5.1 for instructions on saving and copying ight
plans.
Can I file slant Golf (‘/G’) using my GPS?
Yes, the pilot may le the ight plan as ‘/G’ if the GNC
420 is a certied A1 or A2 installation. If ying enroute,
the pilot may le /G with an expired database only after
having verified all route waypoints. Non-precision
approaches may not be own with an expired database.
See an approved Airplane Flight Manual Supplement for
more information.
What does the OBS key do and when do I use
it?
The OBS Key is used to select manual (OBS mode)
or automatic sequencing of waypoints. Activating OBS
mode (as indicated by an OBS annunciation directly above
the OBS Key) holds the current “active to” waypoint
as the navigation reference and prevents the GPS from
sequencing to the next waypoint. When OBS mode is
cancelled, automatic waypoint sequencing is selected, and
the GNC 420 automatically selects the next waypoint in
the ight plan once the aircraft has crossed the present
active-to waypoint.
190-00140-20 Rev. K
