Non-towered airport
Encyclopedia
A non-towered airport, sometimes referred to as an uncontrolled airport, is an airport
with no operating tower, or air traffic control
unit. The vast majority of the world's airports are non-towered, and even airports with control tower
s may operate as untowered during off-hours, typically during the night.
At untowered airports, instead of taking instructions from a tower controller, aircraft follow standard procedures. The exact procedures vary from country to country, but they often involve standard arrival and departure patterns, and they may also include radio calls over a common frequency, such as a Common Traffic Advisory Frequency
in the United States
, Canada
, and Australia
.
For special events such as fly-in
s, temporary towers may operate for only several days each year at fields that are otherwise untowered. Temporary towers may operate out of an existing airport building, a RV
, or even simply a lawnchair (with a portable transmitter and binoculars).
Non-towered airports may lie inside or underneath controlled airspace
. In that case, some or all aircraft arriving and departing will require clearances from a remote air traffic control unit, such as terminal or centre control, even though there is no control tower managing landings and takeoffs. Pilots may be able to obtain those clearances by radio, by phone, or through a company dispatcher or local Flight Service Station
; in some cases, departing aircraft (IFR
or VFR
) will take off and level out below the floor of controlled airspace, then radio for a clearance before climbing further. Some countries establish low-altitude VFR corridors for non-towered airports in large urban areas, so that VFR arrivals and departures can avoid controlled airspace altogether.
to assist aircraft arriving, departing, or maneuvering on the ground. These radio operators have no authority to give aircraft clearances or instructions, but they can issue advisories to let them know about weather conditions, runway conditions, traffic, and other concerns.
Dangers can be created by failure to use radios to report positions and intentions when operating within the airspace, which can cause mid-air collisions between aircraft unaware of each other. Some pilots also fail to use the correct runway at non-towered airports. Under almost every circumstance, airplanes should land into the wind, or as much so as possible, but with no air traffic control regulating runway use, pilots may opt to land on the most convenient runway instead.
Some countries, such as Canada and Norway
, use mandatory frequency airport
s (MF) or mandatory traffic advisory airports (MTAF), which operate like towered airports in some ways: the radio operators (typically a Flight Service Station
) still issue only advisories, but aircraft are required to make radio contact with the ground station before operating in the airport's Control Zone
.
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
with no operating tower, or air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
unit. The vast majority of the world's airports are non-towered, and even airports with control tower
Control tower
A control tower, or more specifically an Air Traffic Control Tower , is the name of the airport building from which the air traffic control unit controls the movement of aircraft on and around the airport. Control towers are also used to control the traffic for other forms of transportation such...
s may operate as untowered during off-hours, typically during the night.
At untowered airports, instead of taking instructions from a tower controller, aircraft follow standard procedures. The exact procedures vary from country to country, but they often involve standard arrival and departure patterns, and they may also include radio calls over a common frequency, such as a Common Traffic Advisory Frequency
Common Traffic Advisory Frequency
Common Traffic Advisory Frequency , is the name given to the VHF radio frequency used for air-to-air communication at U.S., Canadian and Australian non-towered airports....
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Criteria
When the traffic volume at an airport gets too high for safe and efficient operations, or when the mix of aircraft types and speeds becomes too large, an airport may be considered for a tower. However, it is also necessary to find the money to construct a building and pay the controllers' salaries, and in some cases aviation regulations or local opposition may prevent establishment of the unit.For special events such as fly-in
Fly-in
A fly-in is a pre-arranged gathering of aircraft, pilots and passengers for recreational and social purposes.Fly-ins may be formally or informally organised, members of the public may or may not be invited, the gathering may be at an airport or in a farmer's field.Fly-ins can be aimed at specific...
s, temporary towers may operate for only several days each year at fields that are otherwise untowered. Temporary towers may operate out of an existing airport building, a RV
Recreational vehicle
Recreational vehicle or RV is, in North America, the usual term for a Motor vehicle or trailer equipped with living space and amenities found in a home.-Features:...
, or even simply a lawnchair (with a portable transmitter and binoculars).
Procedures
Airspace
Airspace means the portion of the atmosphere controlled by a country above its territory, including its territorial waters or, more generally, any specific three-dimensional portion of the atmosphere....
. In that case, some or all aircraft arriving and departing will require clearances from a remote air traffic control unit, such as terminal or centre control, even though there is no control tower managing landings and takeoffs. Pilots may be able to obtain those clearances by radio, by phone, or through a company dispatcher or local Flight Service Station
Flight service station
A Flight Service Station is an air traffic facility that provides information and services to aircraft pilots before, during, and after flights, but unlike air traffic control , is not responsible for giving instructions or clearances or providing separation...
; in some cases, departing aircraft (IFR
Instrument flight rules
Instrument flight rules are one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other are visual flight rules ....
or VFR
Visual flight rules
Visual flight rules are a set of regulations which allow a pilot to operate an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better than basic VFR weather minimums, as specified in the rules of the...
) will take off and level out below the floor of controlled airspace, then radio for a clearance before climbing further. Some countries establish low-altitude VFR corridors for non-towered airports in large urban areas, so that VFR arrivals and departures can avoid controlled airspace altogether.
Variations
Even though they do not have control towers, many non-towered airports have radio operations such as UNICOMUNICOM
Universal Communications or as known by its abbreviation, UNICOM, is an air-ground communication facility operated by a private agency to provide advisory service at uncontrolled aerodromes and airports.-Description:...
to assist aircraft arriving, departing, or maneuvering on the ground. These radio operators have no authority to give aircraft clearances or instructions, but they can issue advisories to let them know about weather conditions, runway conditions, traffic, and other concerns.
Danger
A non-towered airport can often be a challenging environment in which to operate an aircraft. Unlike towered airports, non-towered airports do not have any sort of air traffic control associated with operations in the immediate vicinity of the airport, and there are very few legally mandated procedures associated with flight operations. Thus, despite the seemingly casual nature of non-towered airport operations, problems can arise when pilots are left to determine for themselves what is the best course of action when approaching, leaving, or operating within the airport environment.Dangers can be created by failure to use radios to report positions and intentions when operating within the airspace, which can cause mid-air collisions between aircraft unaware of each other. Some pilots also fail to use the correct runway at non-towered airports. Under almost every circumstance, airplanes should land into the wind, or as much so as possible, but with no air traffic control regulating runway use, pilots may opt to land on the most convenient runway instead.
Some countries, such as Canada and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, use mandatory frequency airport
Mandatory frequency airport
An airport with a mandatory frequency , mandatory traffic advisory frequency or air/ground radio is an airport which does not have a control tower but still requires arriving and departing aircraft to communicate with other aircraft or a radio operator on a published frequency.Mandatory frequency...
s (MF) or mandatory traffic advisory airports (MTAF), which operate like towered airports in some ways: the radio operators (typically a Flight Service Station
Flight service station
A Flight Service Station is an air traffic facility that provides information and services to aircraft pilots before, during, and after flights, but unlike air traffic control , is not responsible for giving instructions or clearances or providing separation...
) still issue only advisories, but aircraft are required to make radio contact with the ground station before operating in the airport's Control Zone
Control zone
A control zone is an aviation term that describes a volume of controlled airspace, normally around an airport, which extends from the surface to a specified upper limit, established to protect air traffic operating to and from that airport...
.