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APPENDIX C
Troubleshooting Q & A
197
190-00356-00 Rev E
Appendix C
Troubleshooting Q&A
This section is designed to answer some of the
common questions regarding the 400W-series capabili-
ties and operation. If you have a problem operating
the unit, read through this appendix and refer to the
reference section noted. If you don’t find answers to
your particular question here, use the index to find the
appropriate section elsewhere in this manual. If, after
reading through the appropriate reference section, you
still haven’t found the answer to your question, please
see your authorized dealer or contact GARMIN directly
at the address or phone numbers listed on page ii.
GARMIN is dedicated to supporting its products and
customers.
What is RAIM, and how does it affect approach opera-
tions?
RAIM is an acronym for Receiver Autonomous Integ-
rity Monitoring, a GPS receiver function that performs a
consistency check on all tracked satellites. RAIM ensures
that the available satellite geometry will allow the receiver
to calculate a position within a specified protection limit
(4 NM for oceanic, 2 NM for en route, 1 NM for terminal
and 0.3 NM for non-precision approaches).
During oceanic, en route and terminal phases of
ight, RAIMwill beavailable nearly100% ofthe time.
Because of the tighter protection limit on approaches,
there may be times when RAIM is not available. The
400W-series unit automatically monitors RAIM and
will warn you with an alert message (see Section 11)
when it is not available, and the INTEG annunciator
( ) will appear at the bottom left corner of the
screen. If RAIM is not available when crossing the FAF, the
pilot must fly the missed approach procedure. The 400W-
series unit RAIM prediction function will also allow you
to see whether RAIM will be available for a specified date
and time.
NOTE: RAIM prediction is not directly related to
WAAS integrity.
RAIM integrity prediction is performed by the internal
GPS receiver and is performed at all times. WAAS integrity
is reported by the WAAS satellite system and only works
within the WAAS service volume. WAAS approaches re-
quire WAAS integrity. Outside of the WAAS service vol-
ume, such as an Oceanic flight, RAIM prediction will be
used.
Why aren’t there any approaches available for my
flight plan?
Approaches are available for the final destination air-
port in a flight plan or as a direct-to (keep in mind that
someVOR/VORTACidentiersaresimilartoairportiden-
tifiers). If a destination airport does not have a GPS ap-
proach, the 400W-series unit will indicate “NONE” for
the available procedures—as listed on the airport approach
page. For more information on selecting an approach, see
Section 4 - Flight Plans, Select Approach.