6 INSTALLATION CONFIGURATIONS
6.1Possible Installation Configurations
6.1.1GDL 88 with ADS-B Out Transmission Enabled
The GDL 88 can provide for both the ADS-B Out and ADS-B In functionality. In this case, the GDL 88 transmits ADS-B messages on 978 MHz and receives ADS-B, ADS-R, TIS-B, and FIS-B services on the 1090 and 978 MHz links using its dual link receive capabilities. This installation is limited by FAR 91.227 to use below FL180.
6.1.2GDL 88 with ADS-B Out Transmission Disabled
With ADS-B Out transmission disabled, the GDL 88 can provide for only ADS-B In functionality. In this case, the GDL 88 receives ADS-B,ADS-R,TIS-B, and FIS-B services on the 1090 and 978 MHz links using its dual link receive capabilities. In order for the ADS-B Out mandate to be met, another LRU, Such as a Garmin GTX 330ES transponder, must be installed that complies with the ADS-B Out mandate on either the 978 MHz or 1090 MHz link. For aircraft operated above FL180, a 1090 MHz ADS-B Out compliant LRU will be required.
6.1.3GDL 88 Only – No Display
In a minimal installation, the GDL 88 provides the required ADS-B Out functionality with a standalone set of annunciators and control switches installed in the cockpit. When a GDL 88 is installed without interface to an external display, some ADS-B In functionality is still retained. A traffic annunciation light is installed in the cockpit for CSA alerts and aural alerts are provided for these threat aircraft, to include directionality from the ownship and range.
190-01122-03 Rev. A | GDL 88 ADS-B Transceiver Pilot’s Guide | 6-1 |