At airports without an operating control tower, a common traffic advisory frequency, or CTAF is used by pilots. The pilots communicate their movements with each other by self announcing intentions and making position and altitude reports. By making these reports, pilots at non-towered airports are more aware of each other and better able to coordinate their actions to provide a smooth flow of traffic.
The CTAF should be monitored anytime you are within 10 nautical miles of the airport.
Self Announcing Over the CTAF
Broadcast your intentions and position in the following order:
1. Who you are calling: any air traffic monitoring the airport's CTAF
2. Who you are: your airplane's registration number
3. Where you are: your location from the airport or prominent landmark
4. What altitude you are at
5. What your intentions are
For example, the pilot of N456AM, a Cessna 150, is departing from runway 36 at the Clinton Memorial Airport. The pilot might make the following radio announcement on the CTAF prior to initiation of the takeoff: "Clinton traffic, Cessna four five six alpha mike, departing runway three six".
Here is an example broadcast from an inbound aircraft: "Clinton traffic, Cherokee niner eight niner bravo papa, one zero miles southeast at three thousand, inbound for landing".
When to Make Announcements
It is recommended that pilots monitor and broadcast their intentions over the CTAF when within 10 miles of the airport. Pilot's usually make CTAF announcements for taxi, takeoff, landing, area arrival or departure, and when clearing the runway. Announcements are also made as a flight progresses through the legs of the traffic pattern.
For example, as the pilot of N989PB might make the following series of announcements during the arrival to Clinton:
"Clinton traffic, Cherokee niner eight niner bravo papa, three miles to the southeast, over the hospital, inbound for landing, will cross midfield for the downwind to runway three six."
"Clinton traffic, Cherokee niner eight niner bravo papa, turning left downwind runway three six."
"Clinton traffic, Cherokee niner eight niner bravo papa, turning left base runway three six."
"Clinton traffic, Cherokee niner eight niner bravo papa, turning final runway three six."
"Clinton traffic, Cherokee niner eight niner bravo papa, clear of runway three six, taxiing to the ramp."
In this example, the pilot reported entering the traffic pattern, progressing through the traffic pattern, and when the landing was complete and the aircraft clear of the runway. These reports allow pilots of radio equipped aircraft in the local area to visualize N989PB's location and progress.