Garmin GDL 88 manual Traffic Applications SURF, AIRB, etc

4.2Traffic

The GDL 88 may receive traffic from several sources including external sources (ADS-B,ADS-R, and TIS-B) and onboard sources (TAS/TCAS) and creates a single, fused traffic picture to provide to the flight crew. Using relative altitude, relative bearing, range, directionality, ground track, and other identifying information (ICAO address, flight ID, call sign, tail number), the GDL 88 determines when tracks from multiple sources represent a single traffic target, selects the most accurate position source for the target, and sends the data to the display.

NOTE: The GDL 88 will observe all ADS-B participants within range. However, due to the nature of TIS-B’s service volumes and the incomplete equipage/ adoption of ADS-B Out equipment, NOT ALL TRAFFIC WILL BE OBSERVED by the GDL 88. The flight crew must rely on “see and avoid” procedures to detect and avoid traffic. In addition, when operating on the edges of ATC radar coverage or when using an interfaced active traffic system and TAS/ TCAS targets are intermittent, it is possible that a single target aircraft may be briefly or periodically depicted as two grouped targets in the same location.

4.2.1Traffic Applications – SURF, AIRB, etc

When the GDL 88 is interfaced to a GTN 6XX, GTN 7XX, or other compatible units, a traffic display is available for the flight crew’s situational awareness and to enhance the visual acquisition of surrounding traffic. The GNS 400W/500W units do not support all applications, including SURF.

The exact location of the ownship as shown by the ownship symbol on the moving map varies by the display device. For GTN units, the tip of the ownship icon, or where the dot is, identifies the exact location. For GNS units, the exact location of the ownship is the center of the ownship icon where the wings cross the fuselage.

This display is capable of running in two “modes:” Airborne Situational Awareness (AIRB) and Surface Situation Awareness (SURF).

AIRB is in operation in the en route environment, outside of five NM from and 1,500 feet above the nearest airport.

4-2 GDL 88 ADS-B Transceiver Pilot’s Guide 190-01122-03 Rev. A