Air Traffic Services Process Brief -- Changing Unicom Frequencies

Air Traffic Services Process Brief

Changing Unicom Frequencies

The Issue

A common complaint heard at many non-towered airports is the frequency congestion on Unicom or CTAF frequency during a typical VFR weekend day. Many airports within transmission range of each other have been assigned the same frequency. A combination of factors can lead to a severe safety problem. There are frequencies available that significantly reduce the problem. This process brief explains the process.

The Importance to our Members

Most of the flying done by AOPA members includes operations at non-towered airports. Standard procedures include both see-and-avoid and broadcast transmissions on the Unicom frequency for traffic avoidance. Using both of these methods is desirable for maximum safety of traffic separation. Having a useable frequency available will provide maximum safety at non-towered airports.

Background on UNICOM/CTAF

Originally, 122.8 MHz was the standard Unicom frequency for all airports. As flying activity and the number of airports increased, 122.7 MHz and 123.0 MHz were added to accommodate the increased traffic. Although three Unicom frequencies were unable to handle the general aviation Unicom traffic, additional frequencies were unavailable. Unfortunately, the aeronautical frequency spectrum was fully committed due to the increased air traffic demand. To open up more frequency channels, the existing aeronautical frequency spectrum of 118 MHz to 136 MHz, consisting of 360 channels with a 50 kHz bandwidth, was reduced to 25 kHz bandwidth, thus creating 720 channels. AOPA successfully lobbied for additional frequencies when this change took place. Four more Unicom frequencies became available: 122.725 MHz, 122.975 MHz, 123.050 MHz, and 123.075 MHz.

AOPA Position

AOPA encourages licensed Unicom operators to consider changing a frequently overloaded Unicom frequency to a frequency unique to the area, thus avoiding congestion and improving safety. A minimum of 60 statute miles is desirable, although not always possible, between airports with the same frequency.

How to change Unicom frequencies

Using tools such as a sectional or terminal area chart and the FAA Airport/Facility Directory review the frequencies used in the immediate vicinity of the airport considering the Unicom frequency change. Select the best frequency from the 7 mentioned above.

Once complete, the operator of the Unicom can change the frequency by submitting an application for modification on FCC forms 601 and 159 along with the $95 application fee. The current time for approval is typically 30 to 60 days from filing.

The fee and filing information is contained within form 1070M. All of the forms and instructions are available at (Either scroll down that page to find the forms that are listed above, or type the form numbers into the search window and click "GO.")

After the FCC has approved a frequency change, the station operator should notify the FAA's National Aeronautical Charting Office (NACO) at 1-800-638-8972 to update the charts and Airport/Facility Directory. Once a date has been determined for the new chart (IFR and VFR) publication, the Unicom operator should then contact the nearest Flight Service Station (FSS) to issue a Notam pertaining to the frequency change. The Unicom operator should make every effort to ensure that pilots receive the information about the frequency change well in advance.

Additional Notes:

  • Radio stations licensed to a government agency need only file form 601. Government agencies are exempt from the fee requirements
  • Forms are also available from the FCC by contacting their forms contractor at 800/418-3676 or, Fax-On-Demand at 202/418-0177