Definition
A radio frequency designated for use at airports without an operating control tower, on which pilots transmit and receive position and intention reports to coordinate with other traffic in the area. The CTAF for a given airport may be a UNICOM, MULTICOM, FSS, or tower frequency, and is published on aeronautical charts and in the Chart Supplement.
Plain English
It is the shared radio channel pilots use at uncontrolled airports to tell each other where they are and what they intend to do, so everyone can fit together safely without a tower directing them.
Context Anchor
Seen on airport information pages, charts, and flight planning sources for non-towered airports or airports whose tower is closed.
Derivation
Common means shared by all. Traffic Advisory means information about other aircraft. Frequency is the radio channel. The name says exactly what it is: the shared frequency for swapping traffic information.
Why Pilots Care
Keeps traffic separated and prevents runway conflicts when no controller is providing separation services.
Intuition Check
“Advisory” does not mean the frequency is unimportant or just casual talk. It means pilots use it to advise each other of their position and intentions when no controller is providing direct instructions.
Example Sentence 1
Ten miles north of the airport, she switched to the CTAF and announced her position and intention to enter a left downwind for runway 27.
Example Sentence 2
Before taxiing, the pilot checked the sectional chart for the designated CTAF and listened for other traffic.