190-00726-00 Rev. J Garmin G900X Pilot’s Guide 77FLIGHT INSTRUMENTSSYSTEMOVERVIEW FLIGHTINSTRUMENTS EIS AUDIO PANEL& CNS FLIGHTMANAGEMENT HAZARDAVOIDANCE AFCS ADDITIONALFEATURES APPENDICES INDEXCOURSE DEVIATION INDICATOR (CDI)NOTE: If a heading change of greater than 105˚ with respect to the course is made, the CDI on the Arc HSIswitches to the opposite side of the deviation scale and displays reverse sensing.The Course Deviation Indicator (CDI) moves left or right from the course pointer along a lateral deviationscale to display aircraft position relative to the course. If the course deviation data is not valid, the CDI is notdisplayed.Figure 2-24 Course Deviation IndicatorCrosstrackErrorScaleCDINavigationSource360º HSIFlightPhaseNavigationSourceArc HSICDICDI ScaleFlightPhaseCrosstrackErrorThe CDI can display two sources of navigation: GPS or NAV (VOR, localizer). Color indicates the currentnavigation source: magenta (for GPS) or green (for VOR and LOC). The full scale limits for the CDI are definedby a GPS-derived distance when coupled to GPS. When coupled to a VOR or localizer (LOC), the CDI has thesame angular limits as a mechanical CDI. If the CDI exceeds the maximum deviation on the scale (two dots)while coupled to GPS, the crosstrack error (XTK) is displayed below the white aircraft symbol.Figure 2-25 Navigation SourcesNavigationSourceSelected onBoth PFDs
