Definition
A Traffic Information Service-Broadcast (TIS-B) message that tells the pilot whether TIS-B traffic uplink service is currently available to their aircraft from the ADS-B ground network. It indicates when the aircraft has entered or left the coverage area of a TIS-B service volume and whether traffic data being received is complete or not.
Plain English
A heads-up from the ground network letting the pilot know if they are getting the full traffic picture from TIS-B right now, or if traffic service has just started, just stopped, or is unavailable.
Context Anchor
Seen on ADS-B In traffic displays or avionics status pages when checking whether broadcast traffic information is available.
Derivation
TIS-B stands for Traffic Information Service-Broadcast. 'Status' here means the current operating condition of that service. So the term simply names a message that reports whether the traffic service is working for you at the moment.
Why Pilots Care
It tells the pilot whether reliable traffic awareness is available, directly affecting decisions about visual scanning and collision avoidance.
Intuition Check
Do not read “service available” as “all traffic is shown.” It only means the TIS-B data service is being received; it does not guarantee that every nearby aircraft appears on the display.
Example Sentence 1
After takeoff, the display showed a TIS-B service status message confirming traffic uplink had become available.
Example Sentence 2
When the TIS-B service status changed to unavailable, the crew increased their visual lookout.