Definition
The designated radio frequency used at airports without an operating control tower, on which pilots broadcast their position and intentions to other traffic in the area. It may be a Common Traffic Advisory Frequency (CTAF), a UNICOM, MULTICOM, or the frequency of a flight service station providing local advisory service.
Plain English
At airports without a tower, this is the radio frequency pilots use to tell each other where they are and what they are doing, so everyone can stay clear of one another.
Context Anchor
Seen in airport information listings and used before arriving at or departing from an airport where an advisory service is provided.
Derivation
From 'advisory' — meaning to give information or counsel rather than instructions. Pilots on this frequency advise each other; no one is directing traffic. This is the key distinction from a tower frequency, where a controller issues clearances.
Why Pilots Care
It supports safe operations by letting pilots coordinate movements and maintain awareness of other traffic without air traffic control instructions.
Intuition Check
Do not read “advisory” as casual advice or an optional chat channel. In this context, it means a specific published radio frequency for receiving airport advisory information.
Example Sentence 1
Ten miles north of the airport, she tuned in the advisory frequency and announced her position and intentions.
Example Sentence 2
Before departing the non-towered field, she checked the sectional for the correct advisory frequency and made a position call.