A UNICOM (universal communications) station is an air-ground communication facility operated by a non-

air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...

private agency to provide advisory service at uncontrolled aerodromes and airports and to provide various non-flight services, such as requesting a

taxi A taxi, also known as a taxicab or simply a cab, is a type of vehicle for hire with a Driving, driver, used by a single passenger or small group of passengers, often for a non-shared ride. A taxicab conveys passengers between locations of thei ...

, even at towered airports. It is also known as an ''aeronautical advisory station'', with these terms being used mostly in the Americas. The equivalent European/ICAO service is known as '' (aerodrome) flight information service'', abbreviated as AFIS or FIS. From an ICAO perspective, UNICOM, historically most commonly provided by flight service stations, is an implementation of FIS.

Description

UNICOM is employed at airports with a low volume of

general aviation General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations except for commercial air transport or aerial work, which is defined as specialized aviation services for other ...

traffic and where no

control tower Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled a ...

is active. UNICOM stations typically use a single communications frequency. Some airfields always offer UNICOM service while others revert to UNICOM procedures only during hours when the control tower is closed. Under this protocol, aircraft may call a non-government ground station to make announcements of their intentions. Pilots who join the frequency later can request field advisories, which may include "weather information, wind direction, the recommended runway" and any previously reported traffic. In some cases, the ground station is not staffed, and attempts to communicate will, of course, receive no acknowledgement. During these times, pilots self-announce their position and/or intentions over the

CTAF Common traffic advisory frequency (CTAF) is the name given to the VHF radio frequency used for air-to-air communication at United States and Australian non-towered airports. Many towered airports close their towers overnight, keeping the airpor ...

frequency, which is often the same as the UNICOM frequency. When a part-time UNICOM station is located on the same airport as a part-time control tower, the same frequency will be used by both ground stations to avoid confusion. Many UNICOM stations are nowadays operated by a

fixed-base operator A fixed-base operator (FBO) is an organization granted the right by an airport to operate at the airport and provide aeronautical services such as fueling, hangaring, tie-down, and parking, aircraft rental, aircraft maintenance, flight instruction ...

(FBO), and it may be possible to request services such as fuel trucks, taxi service from the airport, outgoing phone calls, and others.''FBO at small airport using unassigned unicom frequency for airport information.''
NASA ASRS Report 106369, March 1989. 37000 Feet. August 2007. Retrieved 26 February 2013.

Frequencies

The actual frequency used at any particular airport can be found on the relevant sectional,

terminal area chart In United States and Canada aviation, terminal area charts are aeronautical charts intended for navigation under Visual Flight Rules that depict areas surrounding major airports, primarily those with Class B airspace. Overview Like the VFR sect ...

or in airport directories, such as the

Canada Flight Supplement The Canada Flight Supplement (CFS) () is a joint civil/military publication and is a supplement of the Aeronautical Information Publication (AIP Canada). It is the nation's official airport directory. It contains information on all registered Ca ...

United States

In the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, radio frequencies made available by the

Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...

for use as UNICOM are: Airports with an Air Traffic Control tower or FSS (Alaska only) on the airport. *122.950 MHz Airports without an Air Traffic Control tower or FSS on the airport. *122.700 MHz *122.725 MHz *122.800 MHz *122.975 MHz *123.000 MHz *123.050 MHz *123.075 MHz

Canada

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, the radio frequencies assigned for UNICOM are: *122.700 MHz *122.725 MHz *122.750 MHz *122.775 MHz *122.800 MHz *122.825 MHz *122.950 MHz *123.000 MHz *123.300 MHz *123.350 MHz *123.500 MHz

References

* "Chapter 4:

Air Traffic Control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...

," ''Airman's Information Manual'' (

Washington, DC Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and Federal district of the United States, federal district of the United States. The city is on the Potomac River, across from ...

: Superintendent of Documents, 1999). {{Telecommunications Air traffic control Airbands Aviation communications

Description

Frequencies

United States

Canada

See also

References