Dead Reckoning - Garmin GNS 400W Pilot's Manual & Reference

Dead Reckoning

Dead reckoning is the process of continuing navi-
gation using your last known position and speed after
a loss of GPS navigation while on an active flight plan.
CAUTION: Navigation using dead reckoning is
therefore only an estimate and should not be
used as the sole means of navigation. Use other
means of navigation, if possible.
Dead reckoning becomes active after a loss of GPS
position while you are navigating using an active flight
plan. A pop-up message will appear and you must
clear the message before continuing operation.
The ownship icon color is changed to yellow. The To/
From flag is removed from the CDI. The Dead Reckon-
ing annunciator (DR) appears on the left side of the
map display when GPS position is unavailable and the
unit is in Dead Reckoning mode. All external outputs
dependent on GPS position are flagged.
Terrain will be noted as not available and new terrain
advisory pop-ops will not occur. Traffic and Storm-
scope information will not be shown on the Map page,
but will continue to be available on their own dedi-
cated pages. XM weather will still be available on the
Map page.
Dead Reckoning mode will continue until GPS posi-
tion is restored, when GPS navigation is restored Dead
Reckoning mode is exited. The DR annunciations
will be removed and GPS information will be used to
compute navigation related information for the current
flight phase.
Dead Reckoning is only allowed in En Route and
Oceanic flight modes. If the unit is in a Terminal or
Approach flight mode when Dead Reckoning takes
place, "No GPS Position" will be displayed on the map
pages and all navigation data will be dashed. If you are
operating in Dead Reckoning mode and a transition to
Terminal or Approach flight modes would occur from
the projected Dead Reckoning position, Dead Reckon-
ing mode will be discontinued. "No GPS Position" will
be displayed on the map pages and all navigation data
will be dashed.
190-00356-00 Rev G
2 - NAV PAGES
Dead Reckoning
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