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GPSMAP 396 Owner’s Manual
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TIS provides a graphic representation of traffic advisory information
in the cockpit for non-TCAS equipped aircraft. TIS is a ground-
based service providing relative location of all ATCRBS (Air Traffic
Control Radar Beacon System) Mode A and Mode C transponder-
equipped aircraft within a specified service volume. The TIS ground
sensor uses real-time track reports to generate traffic notification.
TIS Traffic is available to aircraft equipped with a Mode S Data
Link such as the Garmin GTX 330 Transponder. TIS Traffic from
a GTX 330 Transponder can then be shown on the GPSMAP 396.
Surveillance data includes all transponder-equipped aircraft within
the coverage volume. Aircraft without an operating transponder
are invisible to TIS. TIS shows up to eight traffic targets within
7 nautical miles horizontally from 3,000 feet below to 3,500 feet
above the requesting aircraft. Refer to
for information on
connecting your GPSMAP 396 to a GTX 330 Mode S transponder.
notE:
How TCAS differs from TIS—the main difference
between TIS and TCAS is the source of surveillance data. TCAS
uses an airborne interrogator with a half-second update rate,
while TIS uses the terminal Mode S ground interrogator and its
Data Link to provide about a five-second update rate. The range
accuracy of TIS and TCAS is similar.
TIS Coverage Volume (not to scale)
7.0 nm
3,500 ft
3,000 ft
Warning:
TIS is NOT intended to be used as a collision
avoidance system and does not relieve the pilot responsibility
to “see and avoid” other aircraft. TIS should not be used for
avoidance maneuvers. TIS is intended only to assist in visual
acquisition of other aircraft in VMC. Avoidance maneuvers are
not recommended, nor authorized, as a direct result of a TIS
alert.
While TIS is a useful aid to visual traffic avoidance, it has some
system limitations that must be fully understood to ensure proper
use. Many of these limitations are inherent in secondary radar
surveillance. In other words, the information provided by TIS
will be no better than that provided to ATC.
