Garmin GNC 420 - Manual (Page 161)

GNC 420(A) Pilot’s Guide and Reference 9-13
SECTION 9
AUX PAGES
• RAIM Prediction - Predicts if GPS coverage is
available for the current location or at a specified
waypoint at any time and date. Receiver
Autonomous Integrity Monitoring (RAIM)
performs checks to ensure that the GNC 420
will have adequate satellite geometry during
the flight. RAIM availability is near 100% in
Oceanic, Enroute, and Terminal phases of flight.
Because FAA TSO requirements for non-precision
approaches specify significantly better satellite
coverage than other flight phases, RAIM may not
be available when flying some approaches. The
GNC 420 automatically monitors RAIM during
approach operations and warn the pilot if RAIM is
not available. In such cases, use an external LOC
receiver instead for many of the non-precision
and precision approaches stored on the Jeppesen
NavData Card. RAIM prediction helps the pilot
plan for a pending flight to confirm GPS operation
during an approach.
An ‘INTEG’ annunciation at the bottom left corner
of the screen (Figure 9-32) indicates that satellite
coverage is insufficient to pass built-in RAIM tests.
When this occurs, the GPS receiver continues to
provide navigation information, but should not
be used for primary navigation guidance. Use an
alternate navigation source.
Figure 9-32 ‘INTEG’ Annunciation
If a ‘WARN’ annunciation appears at the
bottom left corner, GPS satellite coverage may
be sufficient, but the GNC 420 has detected a
position error which exceeds protection limits.
In this condition, all GPS navigation data on the
GNC 420 is disabled. Use an alternate navigation
source.
• Sunrise/Sunset - Allows the pilot to calculate the
time of sunrise and sunset at any waypoint or the
present position for a specified date.
• Software Versions - Provides software version
information for the operating software within
the GPS receiver, COM transceiver, and main
processor board.
• Database Versions - Displays the current Jeppesen
database type and expiration date, along with the
version and type of built-in land database.
• Terrain Database Versions - Displays the current
version and area of coverage of each terrain and
obstacle database. If a database is found to be
missing and/or deficient, the TERRAIN system
fails the self-test and issues a failure message.
190-00140-20 Rev. K