GPSMAP 496 Owner’s Manual 4TIS > Traffic Information ServiceTIS(Traffic Information Service)TIS provides a graphic representation of traffic advisory informationin the cockpit for non-TCAS equipped aircraft. TIS is a ground-based service providing relative location of all ATCRBS (Air TrafficControl Radar Beacon System) Mode A and Mode C transponder-equipped aircraft within a specified service volume. The TIS groundsensor uses real-time track reports to generate traffic notification.TIS Traffic is available to aircraft equipped with a Mode S DataLink such as the Garmin GTX 330 Transponder. TIS Traffic froma GTX 330 Transponder can then be shown on the GPSMAP 496.Surveillance data includes all transponder-equipped aircraft withinthe coverage volume. Aircraft without an operating transponderare invisible to TIS. TIS shows up to eight traffic targets within7 nautical miles horizontally from 3,000 feet below to 3,500 feetabove the requesting aircraft. Refer to page 159 for information onconnecting your GPSMAP 496 to a GTX 330 Mode S transponder.notE: How TCAS differs from TIS—the main differencebetween TIS and TCAS is the source of surveillance data. TCASuses an airborne interrogator with a half-second update rate,while TIS uses the terminal Mode S ground interrogator and itsData Link to provide about a five-second update rate. The rangeaccuracy of TIS and TCAS is similar.TIS Coverage Volume (not to scale)7.0 nm 3,500 ft3,000 ftWarning: TIS is NOT intended to be used as a collisionavoidance system and does not relieve the pilot responsibilityto “see and avoid” other aircraft. TIS should not be used foravoidance maneuvers. TIS is intended only to assist in visualacquisition of other aircraft in VMC. Avoidance maneuvers arenot recommended, nor authorized, as a direct result of a TISalert.While TIS is a useful aid to visual traffic avoidance, it has somesystem limitations that must be fully understood to ensure properuse. Many of these limitations are inherent in secondary radarsurveillance. In other words, the information provided by TISwill be no better than that provided to ATC.
