Definition
A free, ground-based data service that broadcasts non-control aeronautical and weather information to suitably equipped aircraft over the 978 MHz UAT (Universal Access Transceiver) ADS-B link. Products typically include METARs, TAFs, NEXRAD radar imagery, AIRMETs, SIGMETs, PIREPs, winds and temperatures aloft, NOTAMs, special use airspace status, and TFRs. FIS-B is advisory only and is not used for air traffic control separation or clearances.
Plain English
A free service that sends weather and flight information from ground stations up to your cockpit display, so you can see things like radar, weather reports, and notices while you fly.
Context Anchor
Seen in ADS-B In equipment, cockpit displays, avionics manuals, and discussions of in-flight weather information.
Derivation
‘Broadcast’ here keeps its everyday meaning—information sent out widely to anyone listening. ‘Flight Information Service’ describes the content: information that supports the conduct of a flight, as opposed to control instructions.
Why Pilots Care
It supplies changing conditions and airspace details without voice radio calls, supporting better route decisions and safety.
Analogy
It is like a radio station for flight data: the station sends information out, and your receiver picks it up. You do not request individual items the way you would in a two-way conversation.
Intuition Check
Do not read “service” as a person watching your flight or giving instructions. Here, it means an automatic one-way information feed to properly equipped aircraft.
Example Sentence 1
Before departure he checked that his ADS-B In receiver was picking up FIS-B so he would have weather updates en route.
Example Sentence 2
Flight Information Service–Broadcast data showed improving visibility along the planned route.