AUNICOM (universal communications) station is an air-ground communication facility operated by a non-air traffic control private agency to provide advisory service at uncontrolled aerodromes and airports and to provide various non-flight services, such as requesting a taxi, even at towered airports.[1] It is also known as an aeronautical advisory station, with these terms being used mostly in the Americas.[2] 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.[3]
UNICOM is employed at airports with a low volume of general aviation traffic and where no control tower is active.[4] 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.[5]
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 frequency, which is often the same as the UNICOM frequency.[6] 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 (FBO), and it may be possible to request services such as fuel trucks, taxi service from the airport, outgoing phone calls, and others.[7]
^Fuera de peligro aeropuerto Mercedita. Omar Alfonso. La Perla del Sur. Ponce, Puerto Rico. 23 February 2013. Retrieved 26 February 2013 (Printed edition publication data: Recortes en la FAA: Fuera de peligro el Aeropuerto Mercedita. Year 31. Issue 1526. Page 14. 27 February 2013.).
