Instruction Manual
30
SECTION
1
NAV KEY
RAIM Prediction
Enter the time and date for RAIM prediction.
RAIM available for the entered time, date and
waypoint location.
The RAIM Prediction function allows you to confirm that GPS coverage is
available for your current location or at a specified waypoint any day of the year.
Receiver Autonomous Integrity Monitoring performs checks to ensure that the GNC
300XL will have adequate satellite geometry to work with during your flight. RAIM
availability will be near 100% in Oceanic, En route and Terminal phases of flight.
Because the FAA’s TSO requirements for non-precision approaches specify significantly
better satellite coverage than other flight phases, RAIM may not be available when fly-
ing some approaches. The GNC 300XL will automatically monitor RAIM during
approach operations and warn you if RAIM is not available. RAIM prediction will help
you plan for a pending flight to confirm GPS operation during an approach.
To predict RAIM availability:
1. Press
N
and rotate
O
until NAV Menu 2 is displayed.
2. Press
C
twice and rotate
O
to highlight ‘RAIM Prd?’. Press
E
.
3. Rotate
O
to highlight the field which you would like to change.
4. Use
K
and
O
to enter the waypoint name, or leave it blank to use your current
position. Press
E
to accept.
5. Use
K
and
O
to enter the ETA in hours and minutes (in local or UTC time, whichever you
have selected from the clock display), and the day, month and year. The current date will be
displayed automatically. Press
E
to accept.
6. Rotate
O
to highlight ‘Compute RAIM?’.
7. Press
E
to compute information.
When the computations are complete, the GNC 300XL will display whether or not
RAIM is available for the specified waypoint at the specified date and time, +/- 15 min-
utes of your ETA. Refer to the table on page 103 for specific RAIM protection limits as
they relate to CDI scale figures.
300xl manual 1/25/99 2:35 PM Page 30