Garmin GNC 355 Pilot's Manual page 186

Navigation
If GPS integrity exceeds the horizontal and/or vertical alarm limits:
•
Approach downgrades to non-precision
•
"LNAV" appears in the annunciator bar to inform of the change if there are
LNAV minimums for the approach
•
Advisory message: "GPS approach downgraded. Use LNAV minima."
•
Glideslope indication disappears
•
Pilot continues approach using LNAV non-precision minimums, if applicable
If GPS integrity does not meet the non-precision horizontal alarm limits:
•
Advisory message: "Abort Approach. GPS approach is no longer available."
•
Pilot acknowledges message
•
Unit reverts to terminal limits of 1 nm to support navigation to the missed
approach
After the aircraft passes final approach fix:
•
Approach aborts due to a loss of WAAS integrity
•
Pilot captures the glideslope (method is same as for ILS glideslope)
When crossing the final approach fix:
•
Waypoint sequences to the missed approach point
(e.g., RW31, the runway threshold)
•
Pilot flies toward missed approach point, keeping the needle on the external
CDI (or HSI) at center, and observing published altitude minimums
•
Final course segment becomes the active flight plan leg
Approaching missed approach point:
•
Advisory message: "Arriving at Waypoint."
Crossing missed approach point:
•
Sequencing suspends
•
Pop-up message: "Missed Approach Waypoint Reached"
•
Pilot decides whether to remain suspended or activate the missed approach
•
Tapping Remain Suspended allows you to continue with sequencing
suspended
•
Tapping Activate GPS Missed Approach allows you to continue with
guidance to the missed approach hold point
Prepare aircraft for missed approach operation:
•
Pilot taps UNSUSP (sequences missed approach), then follows the unit
provided guidance to the missed approach hold point and holds
3-84 Pilot's Guide 190-02488-01 Rev. B