Definition
An aircraft system that automatically broadcasts the aircraft's GPS-derived position, altitude, velocity, identification, and other data once per second to ground stations and to other suitably equipped aircraft. The broadcast is one-way (outbound only) and requires no input from the pilot or interrogation from ATC. ADS-B Out is required to operate in most controlled airspace in the United States.
Plain English
A system on the aircraft that constantly tells ATC and nearby aircraft exactly where you are, how high you are, and how fast you're going -- automatically, without you doing anything.
Context Anchor
You encounter ADS-B Out in NextGen, surveillance, equipment, and airspace requirement discussions, especially when determining whether an aircraft is allowed to operate in certain controlled airspace.
Derivation
The name describes how it works: 'Automatic' (no pilot action needed), 'Dependent' (it depends on the aircraft's own GPS to know its position), 'Surveillance' (used by ATC to track aircraft), 'Broadcast' (sent out to anyone listening). 'Out' means the data is going out from your aircraft -- as opposed to ADS-B In, which receives data coming in.
Why Pilots Care
Required for most operations in Class A, B, C airspace and above 10,000 feet; improves traffic awareness and reduces reliance on radar.
Analogy
It is like the aircraft regularly announcing, “Here I am, this is who I am, and this is where I’m going,” to the traffic system around it.
Intuition Check
“Out” does not mean information displayed to you in the cockpit. Here, “Out” means your aircraft is transmitting information outward to others.
Example Sentence 1
Before entering Class B airspace, the pilot confirmed the ADS-B Out transponder was transmitting correctly.
Example Sentence 2
ADS-B Out allowed the controller to track the aircraft continuously even in areas without radar coverage.