Airplane Flight Manual Supplement

AFMS, Garmin GNS 4XXW GPS/SBAS System 190-00356-03 Rev. E
FAA APPROVED Page 15 of 21
LOSS OF INTEGRITY (LOI) MODE:
Navigation ..................... FLY TOWARDS KNOWN VISUAL CONDITIONS
NOTE
All information derived from GPS will be removed.
NOTE
The airplane symbol is removed from all maps. The map will
remain centered at the last known position. “No GPS
Position” will be annunciated in the center of the map.
3.2.2 GPS APPROACH DOWNGRADE
During a GPS LPV, LNAV/VNAV, LP +V, or LNAV+V approach, if GPS
accuracy requirements cannot be met by the GPS receiver prior to the Final
Approach Fix, the GNS will downgrade the approach. The downgrade will
remove vertical deviation indication from the VDI and change the approach
annunciation accordingly from LPV, L/VNAV, LP +V, or LNAV+V to LNAV.
The approach may be continued using the LNAV only minimums. After the
Final Approach Fix has been passed, the approach will be aborted using the
indications described below.
During a GPS approach in which GPS accuracy requirements cannot be met by
the GPS receiver for any GPS approach type, the GNS will flag all CDI
guidance and display a system message “ABORT APPROACH - Loss of
Navigation”. Immediately upon viewing the message, the unit will revert to
Terminal navigation mode alarm limits. If the position integrity is within these
limits lateral guidance will be restored and the GPS may be used to execute the
missed approach, otherwise alternate means of navigation must be utilized.
3.2.3 LOSS OF COM RADIO TUNING FUNCTIONS
If alternate COM is available:
Communications ........................................................ USE ALTERNATE COM
If no alternate COM is available:
COM RMT XFR key (if installed)....... PRESS AND HOLD FOR 2 SECONDS
NOTE
This procedure will tune the active COM radio the emergency
frequency 121.5, regardless of what frequency is displayed on
the GNS. Certain failures of the tuning system will
automatically tune 121.5 without flight crew action.