Airplane Flight Manual Supplement

190-00356-03 Rev. E AFMS, Garmin GNS 4XXW GPS/SBAS System
Page 14 of 21 FAA APPROVED
Section 3. EMERGENCY PROCEDURES
3.1 Emergency Procedures
No change.
3.2 Abnormal Procedures
3.2.1 LOSS OF GPS/SBAS NAVIGATION DATA
When the GPS/SBAS receiver is inoperative or GPS navigation information is
not available or invalid, the GNS will enter one of two modes: Dead Reckoning
mode (DR) or Loss Of Integrity mode (LOI). The mode is indicated on the GNS
by an amber “DR” or “INTEG”.
If the Loss Of Integrity annunciation is displayed, revert to an alternate means of
navigation appropriate to the route and phase of flight.
If the Dead Reckoning annunciation is displayed, the map will continue to be
displayed with an amber ownship icon. Course guidance will be removed on the
CDI. Aircraft position will be based upon the last valid GPS position, then
estimated by Dead Reckoning methods. Changes in true airspeed, altitude,
heading, or winds aloft can affect the estimated position substantially. Dead
Reckoning is only available in Enroute and Oceanic modes. Terminal and
Approach modes do not support Dead Reckoning.
If Alternate Navigation Sources (ILS, LOC, VOR, DME, ADF) Are
Available:
Navigation ......................................................... USE ALTERNATE SOURCES
If No Alternate Navigation Sources Are Available:
DEAD RECKONING (DR) MODE:
Navigation ............................................................................................. USE GNS
NOTE
All information normally derived from GPS will become less
accurate over time.