Definition
A service provided by air traffic control radar facilities in which the controller advises pilots of observed radar targets that may conflict with their flight path. The advisories include the position, direction of movement, and when known, the type and altitude of the other aircraft. The service is provided on a workload-permitting basis and does not relieve the pilot of the responsibility to see and avoid other traffic.
Plain English
A controller watching radar tells you about other aircraft near you so you can look for them. They give you a clock position, distance, direction the other aircraft is moving, and altitude if known. You are still the one responsible for not hitting them.
Context Anchor
Pilots may hear or request this service when talking with air traffic control, especially during flight following, instrument flight, or operations near busy airspace.
Derivation
Radar comes from “radio detection and ranging,” meaning finding objects and their distance by radio waves. Advisory comes from “advise,” meaning to give helpful information. Together, the term means traffic information based on radar, given to help the pilot make safe decisions.
Why Pilots Care
Helps pilots maintain awareness of surrounding traffic and reduce collision risk, especially when visual scanning is limited.
Intuition Check
Do not read “advisory service” as a guarantee that air traffic control will keep you clear of all traffic. Here, it means helpful traffic information based on radar; the pilot still remains responsible for safe flying and lookout.
Example Sentence 1
Cessna 12345, traffic advisory, two o'clock, three miles, eastbound, altitude indicates one thousand five hundred.
Example Sentence 2
Even in Class E airspace, pilots can request radar traffic advisory service when transiting busy areas.