Garmin G900X Pilot's Manual - page 325

GPS NAVIGATION

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Garmin G900X Pilot’s Guide

DR Mode is inherently less accurate than the standard GPS/WAAS Mode due to the lack of satellite measurements 

needed to determine a position.  Changes in wind speed and/or wind direction will compound the relative 

inaccuracy of DR Mode.  Because of this degraded accuracy, the crew must maintain position awareness using 

other navigation equipment until GPS-derived position data is restored.

As a result of operating in DR Mode, all GPS-derived data is computed based upon an estimated position and 

is displayed as yellow text on the display to denote degraded navigation source information.  This data includes 

the following:

• Navigation Status Box fields except Active Leg, TAS, and DTK

• GPS Bearing Pointer

• Wind data and pointers in the Wind Data Box on the PFD

• Track Bug

• All Bearing Pointer Distances

• Active Flight Plan distances, bearings, and ETE values

Also, while the G900X is in DR Mode, the autopilot does not couple to GPS, and both TAWS and Terrain 

Proximity is disabled.  Additionally, the accuracy of all nearest information (airports, airspaces, and waypoints) 

is questionable.  Finally, airspace alerts will continue to function, but with degraded accuracy.