Air traffic flow management (ATFM) is the regulation of air traffic in order to avoid exceeding airport or
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 airsp ...
capacity in handling traffic (hence the alternative name of ''Air Traffic Flow and Capacity Management'' - ''ATFCM''), and to ensure that available capacity is used efficiently.
Airport capacity
Because only one aircraft can land or depart from a runway at a given time, and because aircraft must be separated by a certain distance or time to avoid collisions, every airport has a finite capacity; it can safely handle only so many aircraft per hour. This capacity depends on many factors, such as the number of
runway
According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concrete ...
s available, layout of taxi tracks, availability of air traffic control, and current or anticipated weather. The weather can cause large variations in capacity; strong winds may limit the number of runways available, and poor visibility may necessitate increases in separation between aircraft.
When an air traffic control unit that will control a flight reaches capacity, arriving aircraft are directed towards
holding patterns where they circle until it is their turn to land. However, aircraft flying in circles is an inefficient and costly way of delaying aircraft, so it is preferable to keep them on the ground at their place of departure, called a
ground delay program
An air traffic control ground delay program or FAA Flow Control is a traffic flow initiative that is instituted by the United States Federal Aviation Administration (FAA) in the National Airspace System.
This program is usually instituted when th ...
.
This way, the delay can be waited out on the ground with engines off, saving considerable amounts of fuel. The careful calculation of en route time for each flight and traffic flow as a whole, which aims to minimize overall delays in the air traffic system, is highly dependent on computers.
Operation in Europe
All
IFR flight plan
Flight plans are documents filed by a pilot or flight dispatcher with the local Air Navigation Service Provider (e.g. the FAA in the United States) prior to departure which indicate the plane's planned route or flight path. Flight plan forma ...
s are tracked by the Central Flow Management Unit (CFMU). Every airport and air traffic control sector has a published maximum capacity. When capacity is exceeded, measures are taken to reduce the traffic. This is termed ''regulation''. The aim is to use capacity effectively, keeping the ''average'' delay as low as possible, while ensuring capacity is not exceeded.
[
]
For example, if two flights are scheduled to arrive at an airport at exactly the same time, and the airport can handle one aircraft every five minutes, the aircraft may be assigned delays to ensure that the second aircraft arrives five minutes after the first. Similarly, the first aircraft will be required to depart on schedule and not allowed to depart late. This way, the second aircraft will not need to enter a holding pattern before landing.
See also
*
Bay of Bengal Cooperative Air Traffic Flow Management System The Bay of Bengal Cooperative Air Traffic Flow Management System (BOBCAT) is the air traffic flow management (ATFM) of Asia. The CFMU (Central Flow Management Unit) was launched in 2007 by the International Civil Aviation Organization (ICAO) and Ae ...
(BOBCAT)
References
{{Reflist
External links
FAA Air Traffic Control System Command Center home page
Air traffic control
Air traffic management