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 airs ...
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 driver, used by a single passenger or small group of passengers, often for a non-shared ride. A taxicab conveys passengers between locations of their choice ...
, even at towered airports.
It is also known as an ''aeronautical advisory station''. The equivalent European/ICAO service is known as ''(aerodrome) flight information service'', abbreviated as AFIS or 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 with the exception of commercial air transport or aerial work, which is defined as specialized aviation services ...
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 airsp ...
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, Canadian and Australian non-towered airports.
Many towered airports close their towers overnight, keeping ...
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 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) (french: link=no, Supplément de vol Canada) 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 ...
.
United States
In the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, radio frequencies made available by the Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
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
In Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
, 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
See also
* CTAF
Common traffic advisory frequency (CTAF) is the name given to the VHF radio frequency used for air-to-air communication at United States, Canadian and Australian non-towered airports.
Many towered airports close their towers overnight, keeping ...
* MULTICOM
In U.S. and Canadian aviation, MULTICOM is a frequency allocation used as a Common Traffic Advisory Frequency (CTAF) by aircraft near airports where no air traffic control is available. Frequency allocations vary from region to region.
Despite th ...
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 airs ...
," ''Airman's Information Manual'' (Washington, DC
)
, image_skyline =
, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan ...
: Superintendent of Documents, 1999).
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Airbands
Aviation communications