AIM Text
Frequency use
- The following listing depicts UNICOM and MULTICOM frequency uses as designated by the Federal Communications Commission (FCC). (See TBL 4-1-2.)
TBL 4-1-2
Unicom/Multicom Frequency UsageUse
Frequency
Airports without an operating control tower.
122.700
122.725
122.800
122.975
123.000
123.050
123.075(MULTICOM FREQUENCY) Activities of a temporary, seasonal, emergency nature or search and rescue, as well as, airports with no tower, FSS, or UNICOM.
122.900
(MULTICOM FREQUENCY) Forestry management and fire suppression, fish and game management and protection, and environmental monitoring and protection.
122.925
Airports with a control tower or FSS on airport.
122.950
NOTE-
1. In some areas of the country, frequency interference may be encountered from nearby airports using the same UNICOM frequency. Where there is a problem, UNICOM operators are encouraged to develop a “least interference” frequency assignment plan for airports concerned using the frequencies designated for airports without operating control towers. UNICOM licensees are encouraged to apply for UNICOM 25 kHz spaced channel frequencies. Due to the extremely limited number of frequencies with 50 kHz channel spacing, 25 kHz channel spacing should be implemented. UNICOM licensees may then request FCC to assign frequencies in accordance with the plan, which FCC will review and consider for approval.2. Wind direction and runway information may not be available on UNICOM frequency 122.950.
- The following listing depicts other frequency uses as designated by the Federal Communications Commission (FCC). (See TBL 4-1-3.)
TBL 4-1-3
Other Frequency Usage Designated by FCCUse
Frequency
Air‐to‐air communication
(private fixed wing aircraft).122.750
Helicopter air-to-air communications; air traffic control operations.
123.025
Aviation instruction, Glider, Hot Air Balloon (not to be used for advisory service).
123.300
123.500Assignment to flight test land and aircraft stations (not for air-to-air communication except for those aircraft operating in an oceanic FIR).
123.4001
123.45021This frequency is available only to itinerant stations that have a requirement to be periodically transferred to various locations.
2Mobile station operations on these frequencies are limited to an area within 320 km (200 mi) of an associated flight test land station.
Source: FAA Aeronautical Information Manual · current edition · paragraph 4-1-11.
The short answer
This advisory AIM section lists the UNICOM and MULTICOM frequency assignments designated by the FCC. Airports without an operating control tower use 122.700–123.075; MULTICOM 122.900 serves temporary, seasonal, emergency, and search-and-rescue activity; 122.950 serves airports with a tower or FSS. It also lists air-to-air and other special-use frequencies.
Research Notes
Common Questions
Which UNICOM frequency do I use at a nontowered airport?
For airports without an operating control tower, the FCC-designated UNICOM frequencies are 122.700, 122.725, 122.800, 122.975, 123.000, 123.050, and 123.075. Airports with a control tower or FSS on the airport use 122.950, where the AIM notes wind direction and runway information may not be available.
When is MULTICOM 122.900 used?
MULTICOM frequency 122.900 is designated for activities of a temporary, seasonal, or emergency nature or search and rescue, as well as airports with no tower, FSS, or UNICOM. A separate MULTICOM frequency, 122.925, covers forestry, fire suppression, fish and game, and environmental monitoring and protection.
What frequency is used for air-to-air communication?
Per this AIM table, 122.750 is designated for air-to-air communication between private fixed-wing aircraft, and 123.025 for helicopter air-to-air and air traffic control operations. Glider, balloon, and aviation-instruction use 123.300 and 123.500 (not for advisory service).