Definition
An aircraft system that automatically transmits the aircraft's GPS-derived position, altitude, velocity, identification, and other flight data once per second to ground stations and to other suitably equipped aircraft. ADS-B Out is the broadcasting half of the ADS-B system; it sends information out but does not receive any data back. In the United States, ADS-B Out is required equipment for flight in most controlled airspace where a transponder was previously required.
Plain English
A piece of equipment in the aircraft that constantly tells the outside world where it is, how high it is, how fast it's going, and who it is — using GPS data sent over a radio signal.
Context Anchor
Seen in equipment requirements, avionics discussions, aircraft logbook entries, and airspace rules that require ADS-B Out.
Derivation
The name describes how the system works. Automatic — it transmits without the pilot doing anything. Dependent — it depends on the aircraft's own GPS to know its position (rather than being tracked by an outside radar). Surveillance — its purpose is to allow the aircraft to be watched by air traffic control and other aircraft. Broadcast — the data is sent out openly, not to a specific receiver. Out — refers to the outgoing direction; the aircraft is sending, not receiving.
Why Pilots Care
Required equipment for most controlled airspace in the US, providing better tracking and situational awareness than radar alone.
Grounding Statement
ADS-B Out is the airplane regularly announcing its own position and flight information to the air traffic system.
Intuition Check
Do not read “Out” as meaning the system is turned off or outside the airplane. Here, “Out” means the aircraft is sending information out to others.
Example Sentence 1
Before flying into the Class B airspace, the pilot confirmed the aircraft's ADS-B Out was operating correctly.
Example Sentence 2
ADS-B Out lets controllers track the plane continuously across remote areas.