1-15190-00601-02 Rev. J Garmin G500/G600 Pilot’s GuideCoverTOCForewordSec 1SystemSec 2PFDSec 3MFDSec 4HazardAvoidanceSec 5AdditionalFeaturesSec 6Annun.& AlertsSec 7SymbolsSec 8Glossary Appendix A Index1.3 International Geomagnetic Reference FieldThe IGRF (International Geomagnetic Reference Field) model is containedin the AHRS and is only updated once every five years. The IGRF model ispart of the Navigation Database. At system power-up, the IGRF models in theAHRS and in the Navigation Database are compared, and if the IGRF modelin the AHRS is out of date, the user is prompted to update the IGRF model inthe AHRS. After the G500H splash screen is acknowledged on the MFD, thefollowing update message appears.For GRS 77/79:GRS MV DB UPDATE AVAILABLE:UPDATE AS FOLLOWS?yyyy to yyyy###-#####-## to ###-#####-##GSU AHRS MV DB UPDATE AVAILABLE:UPDATE AS FOLLOWS?yyyy to yyyy###-#####-## to ###-#####-##To initiate the update process, follow the on-screen instructions.1. When the Update message appears, press the ENT key with “OK” highlighted.To update at another time, turn the Large knob to highlight “Cancel” and thenpress ENT.Figure 1-17 GRS MV DB Update2. After the update is complete, press the ENT key to continue normal operation.For GSU 75:
