Garmin G1000 Piper PA32 - Manual (Page 136)

GPS NAVIGATION
190-00692-00 Rev. B 5-2 Garmin G1000 Pilot’s Guide for Piper PA32
5.2 NAVIGATION MAP (MFD)
WARNING: The basemap (land and water data) must not be used for navigation, only for situational
awareness. Any basemap indication should be compared with other navigation sources.
DEAD RECKONING
NOTE: Dead Reckoning Mode will only function in Enroute (ENR) or Oceanic (OCN) phase of flight. In all
other phases, an invalid GPS solution will produce a “NO GPS POSITION” annunciation on the map and the
G1000 will stop navigating in GPS Mode.
While in Enroute or Oceanic phase of flight, if the G1000 detects an invalid GPS solution or is unable to
calculate a GPS position, the system will automatically revert to Dead Reckoning (DR) Mode. In DR Mode, the
G1000 uses its last-known position combined with continuously updated airspeed and heading data (when
available) to calculate and display the aircraft’s current estimated position.
DR Mode is indicated on the G1000 by the appearance of the letters ‘DR’ superimposed in yellow over the
‘own aircraft’ symbol as shown in Figure 5-1. In addition, ‘DR’ will be prominently displayed, also in yellow, on
the HSI slightly above and to the right of the aircraft symbol on the CDI as shown in Figure 5-2. Also, the CDI
deviation bar is removed from the display. Lastly, but at the same time, a ‘GPS NAV LOST’ alert message will
appear on the PFD. Normal navigation using GPS/WAAS source data will resume automatically once a valid
GPS solution is restored.
Figure 5-1 CDI ‘DR’ Indication on PFD
It is important to note that estimated navigation data supplied by the G1000 in DR Mode may become
increasingly unreliable and must not be used as a sole means of navigation. If while in DR Mode airspeed and/
or heading data is also lost or not available, the DR function may not be capable of accurately tracking your
estimated position and, consequently, the system may display a path that is different than the actual movement
of the aircraft. Estimated position information displayed by the G1000 through DR while there is no heading
and/or airspeed data available should not be used for navigation.
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.