Garmin G1000H Bell 407GX Cockpit Reference Guide - Page 97

Flight Instruments EICAS Nav/Com/ XPDR/Audio AFCS GPS Nav Flight Planning Abnormal Operation DEAD RECKONING While in Enroute or Oceanic phase of flight, if the G1000H detects an invalid GPS solution or is unable to calculate a GPS position, the system automatically reverts to Dead Reckoning (DR) Mode. In DR Mode, the G1000H 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. NOTE: Dead Reckoning Mode only functions in Enroute (ENR) or Oceanic (OCN) phase of flight. In all other phases, an invalid GPS solution produces a "NO GPS POSITION" annunciation on the map and the G1000H stops navigating in GPS Mode. DR Mode is indicated on the G1000H by the appearance of the letters 'DR' superimposed in yellow over the 'own aircraft' symbol as shown in the following figure. In addition, 'DR' is prominently displayed, also in yellow, on the HSI slightly above and to the right of the aircraft symbol on the CDI as shown in the following figure. Also, the CDI deviation bar is removed from the display. Lastly, but at the same time, a 'GPS NAV LOST' alert message appears on the PFD. Normal navigation using GPS/SBAS source data resumes automatically once a valid GPS solution is restored. It is important to note that estimated navigation data supplied by the G1000H 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 estimating your 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 G1000H 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/SBAS Mode due to the lack of satellite measurements needed to determine a position. Changes in wind speed and/or wind direction compounds 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. Procedures Hazard Avoidance Additional Features Abnormal Operation Annun/ Alerts Appendix Index 190-01254-00 Rev. A Garmin G1000H™ Cockpit Reference Guide for the Bell 407GX 81