Appendix F: General Tis-A Information; Tis-A Vs. Tas/Tcas; Tis-A Limitations - Garmin aera 796 Pilot's Manual

APPENDIX F: GENERAL TIS-A INFORMATION

NOTE: Aircraft without an operational transponder are invisible to TIS-A.
WARNING:
avoidance maneuvering. The traffic display does not provide collision avoidance
resolution advisories and does not under any circumstances or conditions relieve the
pilot's responsibility to see and avoid other aircraft.
WARNING:
depict all of the traffic within range of the aircraft. Due to lack of equipment, poor signal
reception, and/or inaccurate information from aircraft or ground stations, traffic may be
present that is not represented on the display.
The Traffic Information Service (TIS-A) provides traffic advisory information to non-
TAS/TCAS-equipped aircraft. TIS-A is a ground-based service providing the relative
locations of all ATCRBS (Air Traffic Control Radar Beacon System) Mode-A and Mode-C
transponder equipped aircraft within a specified service volume. The TIS-A ground
sensor uses real-time track reports to generate traffic notification. The aera 795/796
displays TIS-A traffic information on the Navigation Map. Surveillance data includes all
transponder-equipped aircraft within the coverage volume. The aera 795/796 displays
up to eight traffic targets within a 7.5-nm radius, from 3,000 feet below, to 3,500 feet
above the requesting aircraft.

TIS-A VS. TAS/TCAS

The main difference between the Traffic Information System (TIS-A) and Traffic
Advisory (TAS) or Traffic Collision Avoidance Systems (TCAS) is the source of surveillance
data. TAS/TCAS uses an airborne interrogator with a half-second update rate, while
TIS-A utilizes the terminal Mode-S ground interrogator and accompanying data link to
provide a five-second update rate. TIS-A and TAS/TCAS have similar ranges.

TIS-A LIMITATIONS

TIS-A relies on surveillance of the Mode-S radar system, which is a "secondary
surveillance" radar system similar to that used by ATCRBS. Many limitations are
inherent in secondary radar surveillance. Information provided by TIS-A is neither
190-01194-00 Rev. C
Do not rely solely upon the display of traffic information for collision
Do not rely solely upon the display of traffic information to accurately
Garmin aera 795/796 Pilot's Guide
Appendix F
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