(a) A pilot may receive an intermittent TIS-B target of themselves, typically when maneuvering (e.g.,
climbing turns) due to the radar not tracking the aircraft as quickly as ADS-B.
(b) The ADS-B-to-radar association process within the ground system may at times have difficulty
correlating an ADS-B report with corresponding radar returns from the same aircraft. When this happens the
pilot may see duplicate traffic symbols (i.e., "TIS-B shadows") on the cockpit display.
(c) Updates of TIS-B traffic reports will occur less often than ADS-B traffic updates. TIS-B position
updates will occur approximately once every 3-13 seconds depending on the type of radar system in use within
the coverage area. In comparison, the update rate for ADS-B is nominally once per second.
(d) The TIS-B system only uplinks data pertaining to transponder-equipped aircraft. Aircraft without
a transponder will not be displayed as TIS-B traffic.
(e) There is no indication provided when any aircraft is operating inside or outside the TIS-B service
volume, therefore it is difficult to know if one is receiving uplinked TIS-B traffic information.
3. Pilots and operators are reminded that the airborne equipment that displays TIS-B targets is for pilot
situational awareness only and is not approved as a collision avoidance tool. Unless there is an imminent
emergency requiring immediate action, any deviation from an air traffic control clearance in response to
perceived converging traffic appearing on a TIS-B display must be approved by the controlling ATC facility
before commencing the maneuver, except as permitted under certain conditions in 14CFR 91.123.
Uncoordinated deviations may place an aircraft in close proximity to other aircraft under ATC control not seen
on the airborne equipment and may result in a pilot deviation or other incident.
e. Reports of TIS-B Malfunctions.
Users of TIS-B can provide valuable assistance in the correction of malfunctions by reporting instances of
undesirable system performance. Since TIS-B performance is monitored by maintenance personnel rather than
ATC, report malfunctions to the nearest Flight Service Station (FSS) facility by radio or telephone, or by sending
an email to the ADS-B help desk at adsb@faa.gov. Reports should include:
1. Condition observed;
2. Date and time of observation;
3. Altitude and location of observation;
4. Type and call sign of the aircraft; and
5. Type and software version of avionics system.
4-5-9. Flight Information Service- Broadcast (FIS-B)
a. Introduction.
FIS-B is a ground broadcast service provided through the ADS-B Services network over the 978 MHz UAT data
link. The FAA FIS-B system provides pilots and flight crews of properly equipped aircraft with a cockpit display
of certain aviation weather and aeronautical information. FIS-B reception is line-of-sight within the service
volume of the ground infrastructure. (See FIG 4-5-9 and FIG 4-5-10.)
b. Weather Products.
FIS-B does not replace a preflight weather briefing from a source listed in paragraph 7-1-2, FAA Weather
Services, or inflight updates from an FSS or ATC. FIS-B information may be used by the pilot for the safe conduct
of flight and aircraft movement; however, the information should not be the only source of weather or
aeronautical information. A pilot should be particularly alert and understand the limitations and quality assurance
issues associated with individual products. This includes graphical representation of next generation weather
radar (NEXRAD) imagery and Notices to Air Missions (NOTAMs)/temporary flight restrictions (TFRs).
REFERENCE-
AIM, Para 7-1-9, Flight Information Services (FIS).
Advisory Circular (AC) 00-63, Use of Cockpit Displays of Digital Weather and Aeronautical Information.

4-5-24

Surveillance Systems