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Difference between a CTAF and UNICOM

CTAF and UNICOM frequencies are misunderstood by pilots. In this article we will break each one down an explain the differences.

What is a CTAF?

A Common Traffic Advisory Frequency (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. Or when the tower is closed.

When using the CTAF frequency, the pilot can advise other traffic of their position, altitude, and intentions.

CTAF are also used to control Pilot Controlled Lighting (PCL), at airports that are non-towered or after hours when the tower is closed for the night.

What is a UNICOM?

A UNICOM is a radio communication station that may provide airport information at public use airports where there is no tower or FSS. These UNICOM frequencies are usually operated by a Fixed-Base Operation (FBO). FBO’s are privately operated businesses which offers services such as fuel, aircraft parking, maintenance, and more.

On pilot request, UNICOM stations may provide pilots with weather information, wind direction, the recommended runway, or request fuel or other services.

Basically, a CTAF is coordinating with other pilots, and a UNICOM helps you get services and information from the airport.

When a CTAF and UNICOM are the same.

Yes, a CTAF and a UNICOM frequency can be the same. Which means that you will use the same frequency to communicate your intentions with other pilots and contact an FBO or airport staff for services you may need.


Where to find the CTAF frequency

All frequencies can be found in a few different places:

  • Aeronautical Charts

  • Chart Supplement (listed in the Communications section)

  • Digital versions (i.e. ForeFlight, SkyVector, AirNav)


On all digital and paper VFR aeronautical charts the Control Tower, CTAF, or UNICOM frequency will be listed in the airport data.

In the example above, the Control Tower frequency (CT) is 121.0. When the control tower is closed, that frequency (121.0) becomes the CTAF because of the “C” next to the tower frequency of 121.0. The UNICOM is 122.95.

If the “C” is next to the CTAF frequency, then that makes the CTAF and the UNICOM the same.

How to Communicate on a CTAF?

In the Aeronautical Information Manual (AIM) under section 4-1-9, you will find detailed procedures pilots are required to do when approaching an airport with a CTAF.

To make it easy, we’ve listed the main procedures you need to remember:

  • When approaching an airport that has a CTAF, you need to make a radio call 10 miles out or so, and continue to monitor the frequency. This allows you to visualize what is going on in the traffic pattern, and other aircraft approaching or departing the area.

  • When approaching and entering the traffic pattern, pilots are required to make position calls, i.e. entering the downwind, base, final, etc. plus let everyone know your intentions.

Remember to make your radio transmissions clear, use standard phraseology, and to the point. These frequencies are not used to tell a story (don’t use Ah or Um) on your intentions or position, as well as it is not a phone line to talk to your buddies and jam up the radio’s.


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