AIM

4/20/23

4

−

1

−

3

Services Available to Pilots

airport/traffic information when operating at an airport that does not have an operating tower: by communicating
with an FSS, a UNICOM operator, or by making a self-announce broadcast.

NOTE

−

FSS airport advisories are available only in Alaska.

3.

Many airports are now providing completely automated weather, radio check capability and airport

advisory information on an automated UNICOM system. These systems offer a variety of features, typically
selectable by microphone clicks, on the UNICOM frequency. Availability of the automated UNICOM will be
published in the Chart Supplement U.S. and approach charts.

b. Communicating on a Common Frequency

1.

The key to communicating at an airport without an operating control tower is selection of the correct

common frequency. The acronym CTAF which stands for Common Traffic Advisory Frequency, is synonymous
with this program. A CTAF is a frequency designated for the purpose of carrying out airport advisory practices
while operating to or from an airport without an operating control tower. The CTAF may be a UNICOM,
MULTICOM, FSS, or tower frequency and is identified in appropriate aeronautical publications.

NOTE

−

FSS frequencies are available only in Alaska.