a distance of 2 nm inbound to the Final Approach
Fix (FAF) until the Missed Approach Point (MAP)
is reached. A means must be provided to allow the
pilot to predict whether RAIM will be available at
the estimated time of arrival at the destination. Your
Apollo GX55 provides you with a RAIM prediction
page. This page allows you to determine if RAIM
should be available at any location and time. If it
says RAIM will be available, it actually means that
it will be available at your predicted time of arrival
and plus and minus 15 minutes from your arrival
time calculated at 5 minute intervals.
RAIM
prediction
is
required
to
be
done
automatically by the equipment for the estimated
time of arrival at the FAF and the MAP when you
are 3 nm inbound to the FAF.
TSO C129 requires the RAIM alarm limit to be at
least 2.0 nm for en route operations, 1.0 nm for
Terminal operations, and 0.3 nm for Approach
operations.
What are En Route, Terminal, and Approach
Operations?
Approach RAIM, or 0.3 nm alarm limit, is provided
from 2.0 nm inbound to the FAF until you cancel
the Approach Active operation (usually at the
MAP). Approach RAIM is provided only if an
approach is loaded into your active flight plan and it
is enabled. Remember that the Apollo GX55 is not
certified for Approach operation.
Terminal RAIM, or 1.0 nm alarm limit is provided
within 30 nm of your departure and your destination
airport (except when Approach RAIM is provided).
This is automatic and requires no pilot action. For
those of you who are familiar with the traditional
definition of Terminal, which was the ability to
operate on SIDs and STARs that are only 4 nm
wide, the term Terminal has been “redefined” in
Introduction to GPS Navigation
120
