FlyWithX

TAS vs TIS-A vs TIS-B

TAS vs TIS

Traffic Information Service (TIS) and Traffic Advisory System (TAS) are both systems that provide traffic awareness information to pilots.

  • Data source: TIS uses data from a terminal Mode-S ground interrogator, while TAS uses an airborne interrogator.
  • Update rate: TIS provides updates every five seconds, while TAS provides updates every half second.
  • Radar dependency: TIS is dependent on ATC radar, usually around 55 nautical miles (NM) from the radar site; while TAS works independently.
  • Information provided: TIS provides information on other aircraft, but TAS only shows position. TAS does not provide guidance on how to avoid traffic.
  • Range: TIS has a range of up to 48 miles, while TAS has a range of 12 miles.

TIS is considered the most limited traffic awareness system, but it can still help increase situational awareness. TAS is useful for alerting pilots to nearby traffic so they can visually acquire it and decide what to do.

TIS-A vs ## TIS-B

TIS-A and TIS-B are both traffic information services that use radar information to provide pilots with aircraft traffic data:

TIS-A

Traffic Information Service-A provides traffic advisory information to aircraft that aren't equipped with TCAS or TAS. TIS-A uses ground radar uplinks to send information to nearby aircraft. TIS-A is being phased out in favor of ADS-B and is only available in the U.S. at over 100 Terminal Area Secondary Radar Surveillance Areas.

TIS-B

Traffic Information Service-Broadcast is a client-based service that provides surveillance information about aircraft that aren't ADS-B equipped. TIS-B uses ADS-B ground stations to send information to aircraft equipped with ADS-B "In" receivers. TIS-B has a range of up to 48 miles, which is greater than the 12 mile range of TIS-A.

TIS-B converts the position and altitude of radar targets into a format that's compatible with ADS-B. The radar information from TIS-B isn't as accurate as ADS-B targets, so the icon on the cockpit display for non-ADS-B traffic looks like a Pacman with part of its bottom missing.