Garmin GPS 500 Pilot's Manual & Reference

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Garmin GPS 500 Pilot's Manual & Reference Manual pdf 170 page image

Appendix D162What is RAIM, and how does it affect approach operations?RAIM is an acronym for Receiver Autonomous Integrity Monitoring, a GPS receiver function that performs a consistency check on all trackedsatellites. RAIM ensures that the available satellite geometry allows the receiver to calculate a position within a specified protection limit (2.0 nauticalmiles for oceanic and en route, 1.0 nm for terminal and 0.3 nm for non-precision approaches).During oceanic, en-route and terminal phases of flight, RAIM is available nearly 100% of the time. Because of the tighter protection limit onapproaches, there may be times when RAIM is not available. The GPS 500 automatically monitors RAIM and warns you with an alert message (seeSection 10) when it is not available, and the INTEG annunciator ( ) appears at the bottom left corner of the screen. If RAIM is not availablewhen crossing the FAF, the pilot must fly the missed approach procedure. The GPS 500 RAIM prediction function (see page 123) also allows you tosee whether RAIM will be available for a specified date and time.If RAIM is not predicted to be available for the final approach course, the approach does not become active—as indicated by an “Approach isnot active” message, a “RAIM not available from FAF to MAP” message and the INTEG annunciator.Appendix D: Troubleshooting Q & AThis Appendix is designed to answer some of the common questions regarding the capabilities andoperation of the GPS 500. If you have a problem operating the unit, read through this appendix andrefer to the reference section noted. If you don’t find answers to your particular question here, use theindex to find the appropriate section elsewhere in this manual. If, after reading through the appropriatereference section, you still haven’t found the answer to your question, please see your authorized dealeror contact Garmin directly at the address or phone numbers listed on page i. Garmin is dedicated tosupporting its products and customers.Troubleshooting Q & A