FMS/GPS/VFR Navigation Systems
The AXIS™ Pilot's Guide is written to explain the features of building a flight plan using the AXIS flight display. Flight plans using Serial GPS Navigator LRU's refer to the appropriate manuals provided for that system.
If more than one GPS navigators are installed and one of the two GPS navigators is an HSDB navigator, the VFR CDI selection will not be used because the AXIS display’s internal flight plan is shared with the identified GPS navigator.
AXIS Flight Display Systems maintain an internal flight plan at all times. Depending on the system configuration, this flight plan may be used only for VFR navigation, for IFR navigation, or it may be shared with certified IFR navigators. There are three GPS CDI selection groups that may be present in the AXIS Flight Display System (FMS, GPS, or VFR). If more than one GPS is connected to the system each one will be identified with a numerical value (GPS1, GPS2, etc.).
The active CDI source indicates both the navigation source and the available flight plan management functions. If flight plan editing is unavailable on AXIS, the active navigator is maintaining its own flight plan and all changes must be made on that navigator.
The data transfer of flight plans are different depending on the type of navigation LRU installed in the system. When the information is shared between the GPS NAV LRU and the AXIS flight displays (using HSDB connection) "FMS" will be the displayed source of navigation information. This indicates that flight plan modification may be performed from any AXIS display or connected IFR navigator, and will be reflected throughout the system.
When the information is transferred to the AXIS flight display (using Serial connection) "GPS" will be the displayed source of navigation information. This indicates that navigation guidance is being provided by an IFR GPS navigator that maintains its own flight plan. When a flight plan is provided by a serially connected navigator, AXIS displays the navigator's flight plan but cannot modify it ("Read Only"). All flight plan changes must be made on the navigator.
When the navigation source is only from the AXIS Display and the display is not qualified for IFR GPS operation, the system’s mode of operation is VFR. The VFR CDI indicates that the CDI selection is only intended for use in Visual Meteorological Conditions. The VFR CDI will not be available in systems where the internal flight plan is shared with an external flight plan or there is an IFR capable AXIS GDU.
Refer to Failure of the External GPS Navigation Source in the Flight instruments Section for more information.