Air Traffic Control System Command Center

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Air Traffic Management Glossary of Terms
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Acronym Meaning
AAR Airport Acceptance Rate or Airport Arrival Rate. The number of arrivals an airport is capable of accepting each hour.
AC, A/C or ACFT Aircraft
ADZY or ADVZY Advisory
ARPT Airport
AFP An AFP is a traffic management (TM) process administered by the ATCSCC. Aircraft are assigned specific airspace arrival slots utilizing flight schedule monitor (FSM) to manage capacity and demand for a specific area of the National Airspace System (NAS). AFPs support the TM mission and mitigate the effects of en route constraints. Please see the AFP Advisory circular for more details.
ARSR Air Route Surveillance Radar. Air Route Traffic Control Center (ARTCC) radar used primarily to detect and display an aircraft´s position while en route between terminal areas. The ARSR enables controllers to provide radar air traffic control service when aircraft are within the ARSR coverage. In some instances, ARSR may enable an ARTCC to provide terminal radar services similar to but usually more limited than those provided by a radar approach control.
ARTCC Air Route Traffic Control Center. A facility established to provide air traffic control service to aircraft operating on IFR flight plans within controlled airspace and principally during the en route phase of flight. When equipment capabilities and controller workload permit, certain advisory/assistance services may be provided to VFR aircraft. There are 20 ARTCCs in the continental U.S.
ASR Airport Surveillance Radar. Approach control radar used to detect and display an aircraft´s position in the terminal area. ASR provides range and azimuth information but does not provide elevation data. Coverage of the ASR can extend up to 60 miles.
ATC Air Traffic Control. A service operated by appropriate authority to promote the safe, orderly and expeditious flow of air traffic.
ATCSCC Air Traffic Control System Command Center
ATCT Airport Traffic Control Tower. A terminal facility that uses air/ground communications, visual signaling, and other devices to provide ATC services to aircraft operating in the vicinity of an airport or on the movement area. Authorizes aircraft to land or takeoff at the airport controlled by the tower or to transit the Class D airspace area regardless of flight plan or weather conditions (IFR or VFR). A tower may also provide approach control services (radar or nonradar).
CDM Collaborative Decision Making. Cooperative effort between the various components of aviation transportation, both government and industry, to exchange information for better decision making.
CDR Coded Departure Routes. Predefined routes used to route air traffic around areas of severe weather.
CIGS Ceilings. The height above the ground of the base of the lowest layer of clouds when over half of the sky is obscured.
CLSD Closed
EDCT Expect Departure Clearance Time. The time issued to a flight to indicate when it can expect to receive departure clearance. EDCTs are issued as part of Traffic Management Programs, such as a Ground Delay Program (GDP).
EMERG Emergency
EQUIP Equipment
FEA/FCA Flow Evaluation Area (FEA) / Flow Constrained Area (FEA) - FEA/FCAs provide reroutes using the Create Reroute capability and are published through a reroute advisory with an optional flight list attached. Stakeholders can monitor FEA/FCAs through reroute monitor in traffic situation display (TSD), web situation display (WSD) or collaborative constraint situation display (CCSD).
FSM Flight Schedule Monitor. A tool used by Air Traffic Management Specialists to monitor air traffic demand at airports.
FSS Flight Service Station. Air traffic facilities which provide pilot briefing, en route communications and VFR search and rescue services, assist lost aircraft and aircraft in emergency situations, relay ATC clearances, originate Notices to Airmen, broadcast aviation weather and NAS information, receive and process IFR flight plans, and monitor NAVAIDs. In addition, at selected locations, FSSs provide En Route Flight Advisory Service (Flight Watch), take weather observations, issue airport advisories, and advise Customs and Immigration of transborder flights.
GA CDR General Aviation Coded Departure Routes (GA CDR) - The CDR program provides a rapid means to reroute aircraft when the filed route is constrained by either weather or congestion. Historically, abbreviated CDR clearances have only been issued to airline customers who have signed a Memorandum of Agreement (MOA) with the facilities that issue abbreviated CDR clearances. Recently, general aviation customers have requested the use of this reroute capability. This change permits general aviation customers to communicate to Air Traffic Control (ATC) facilities their ability and willingness to accept CDRs and their capability to accept abbreviated clearances associated with CDRs. Please see the GA CDR Advisory circular for more details.
GDP Ground Delay Program. Ground Delay Programs are implemented to control air traffic volume to airports where the projected traffic demand is expected to exceed the airport´s acceptance rate for a lengthy period of time. Lengthy periods of demand exceeding acceptance rate are normally a result of the airport´s acceptance rate being reduced for some reason. The most common reason for a reduction in acceptance rate is adverse weather such as low ceilings and visibility.

How it works:
Flights that are destined to the affected airport are issued Expect Departure Clearance Times (EDCT) at their point of departure. Flights that have been issued EDCTs are not permitted to depart until their Expect Departure Clearance Time. These ECDTs are calculated in such a way as to meter the rate that traffic arrives at the affected airport; ensuring that demand is equal to acceptance rate. The length of delays that result from the implementation of a Ground Delay Program is a factor of two things; how much greater than the acceptance rate the original demand was, and for what length of time the original demand was expected to exceed the acceptance rate.
GPS Global Positioning System
GS Ground Stop. Ground Stops are implemented for a number of reasons. The most common reasons are:
  • To control air traffic volume to airports when the projected traffic demand is expected to exceed the airport´s acceptance rate for a short period of time.
  • To temporarily stop traffic allowing for the implementation of a longer-term solution, such as a Ground Delay Program.
  • The affected airport´s acceptance rate has been reduced to zero.
How it works:
Flights that are destined to the affected airport are held at their departure point for the duration of the Ground Stop.
ICR Integrated collaborative rerouting (ICR) is a process that builds on FEA/FCAs. The ICR process requires that a constraint is identified early. Traffic management may issue a planning (PLN) advisory describing the system constraint and providing route guidance. System stakeholders are allowed an opportunity to consider the area of concern, and provide early intent (EI) messages that communicate their decisions in response to the constraint. EI messages update enhanced traffic management system (ETMS) flight trajectories, monitor alert values and routing intentions. At the expiration of the EI window, traffic management can then analyze the customer responses and decide if the actions taken have resolved the issue, or if recommended routes, required routes, airspace flow programs (AFP) and/or other traffic management initiatives (TMIs) will be necessary to further reduce demand.

ICR allows system stakeholders flexibility in managing their flights based on an identified NAS constraint, reducing the possibility of more restrictive initiatives. Traffic flow management (TFM) tools benefit from enhanced flight information and collaborative responses to system capacity actions.

IFR Instrument Flight Rules. A set of rules governing the conduct of flight under instrument meteorological conditions.
ILS Instrument Landing System. A ground based precision approach system that provides course and vertical guidance to landing aircraft.
LAADR Low Altitude Arrival/Departure Routing.
LAHSO Land and Hold Short Operations. Operations which include simultaneous takeoffs and landings and/or simultaneous landings when a landing aircraft is able and is instructed by the controller to hold short of the intersecting runway/taxiway or designated hold-short point. Pilots are expected to promptly inform the controller if the hold short clearance cannot be accepted.
LO CIGS Low Ceilings. Low clouds.
LOC Localizer. The component of an ILS that provides course guidance to the runway.
MINIT Minutes in Trail. A specified interval between aircraft expressed in time.
MIT Miles in Trail. A specified interval between aircraft expressed in nautical miles.
MULTI-TAXI Many aircraft trying to taxi at once, creating congestion.
N90 New York TRACON
NAS National Airspace System. The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing areas.
NAVAID Navigational Aid. Any visual or electronic device, airborne or on the surface, which provides point-to-point guidance information or position data to aircraft in flight.
NM Nautical Mile. International unit equal to 6076.115 feet (1852 meters).
NOTAM Notice to Airmen. A notice containing information (not known sufficiently in advance to publicize by other means) concerning the establishment, condition, or change in any component (facility, service, or procedure of, or hazard in the National Airspace System) the timely knowledge of which is essential to personnel concerned with flight operations.
NRP North American Route Program. The NRP is a set of rules and procedures which are designed to increase the flexibility of user flight planning within published guidelines.
OTS Out of service
RLSD Released
RRTES Reroutes
RWY Runway
RWY CONFIG Runway Configuration
RY Runway
SPO Strategic Plan of Operation. See SPT.
SPT Strategic Planning Team. The Strategic Planning Team acts as a focal point for the development of collaborative Strategic Plans of Operation. Their goal is to provide advanced planning information for system users and air traffic facilities in order to maximize the utilization of the NAS in an organized and equitable manner.
STMP Special Traffic Management Program. Reservation program implemented to regulate arrivals and/or departures at airports that are in areas hosting special events such as the Masters Golf Tournament and Indianapolis 500.
SVRWX Severe Weather
SWAP Severe Weather Avoidance Plan. An approved plan to minimize the effect of severe weather on traffic flows in impacted terminal and/or ARTCC areas. SWAP is normally implemented to provide the least disruption to the ATC system when flight through portions of airspace is difficult or impossible due to severe weather.
TACAN Tactical Air Navigation Aid. An ultra-high frequency electronic rho-theta air navigation aid which provides suitably equipped aircraft with a continuous indication of bearing and distance to the TACAN station.
TFC Traffic
TRACON Terminal Radar Control Facility. A terminal ATC facility that uses radar and nonradar capabilities to provide approach control services to aircraft arriving, departing, or transiting airspace controlled by the facility.
TSD Traffic Situation Display. A tool used by Traffic Management Specialists to monitor the position of air traffic and to determine the traffic demand on airports and sectors.
TSTMS Thunderstorms
UTC Coordinated Universal Time (abbreviated as UTC, and therefore often spelled out as Universal Time Coordinated and sometimes as Universal Coordinated Time) is the standard time common to every place in the world. Formerly and still widely called Greenwich Mean Time (GMT) and also World Time, UTC nominally reflects the mean solar time along the Earth´s prime meridian.
VAPS Visual Approaches. An approach conducted under Instrument Flight Rules that authorizes the pilot to proceed visually and clear of clouds to the airport. Usually this will be used in conjunction with Visual Separation. When using Visual Separation, a pilot sees the other aircraft involved, and upon instructions from the controller, provides his own separation by maneuvering his aircraft as necessary to avoid it. Visual Separation requires less spacing between aircraft than radar separation allowing more aircraft to land in a given period of time.
VFR Visual Flight Rules. Rules that govern the procedures for conducting flight under visual conditions. The term "VFR" is also used in the United States to indicate weather conditions that are equal to or greater than minimum VFR requirements. In addition, it is used by pilots and controllers to indicate type of flight plan.
VOL Volume. Usually used to indicate that the volume of aircraft exceeds the airport´s capacity.
VOR Very High Frequency Omni Directional Range. A ground-based electronic navigation aid transmitting very high frequency navigation signals, 360 degrees in azimuth, oriented from magnetic north. Used as the basis for navigation in the National Airspace System. The VOR periodically identifies itself by Morse Code and may have an additional voice identification feature. Voice features may be used by ATC or FSS for transmitting instructions/information to pilots.
VORTAC A navigation aid providing VOR azimuth, TACAN azimuth, and TACAN distance measuring equipment (DME) at one site.
VSBY Visibility. The ability, as determined by atmospheric conditions and expressed in units of distance, to see and identify prominent unlighted objects by day and prominent lighted objects by night.
WND Wind
WX Weather
WX DEV Weather Deviation
Z Zulu Time. Another term used to designate Coordinated Universal Time (UTC), the standard time common to every place in the world. Formerly and still widely called Greenwich Mean Time (GMT) and also World Time, UTC nominally reflects the mean solar time along the Earth´s prime meridian.
ZAB Albuquerque Air Route Traffic Control Center (ARTCC)
ZAU Chicago Air Route Traffic Control Center (ARTCC)
ZBW Boston Air Route Traffic Control Center (ARTCC)
ZDC Washington Air Route Traffic Control Center (ARTCC)
ZFW Dallas-Ft Worth Air Route Traffic Control Center (ARTCC)
ZHU Houston Air Route Traffic Control Center (ARTCC)
ZID Indianapolis Air Route Traffic Control Center (ARTCC)
ZJX Jacksonville Air Route Traffic Control Center (ARTCC)
ZKC Kansas City Air Route Traffic Control Center (ARTCC)
ZLA Los Angeles Air Route Traffic Control Center (ARTCC)
ZLC Salt Lake City Air Route Traffic Control Center (ARTCC)
ZMA Miami Air Route Traffic Control Center (ARTCC)
ZME Memphis Air Route Traffic Control Center (ARTCC)
ZMP Minneapolis Air Route Traffic Control Center (ARTCC)
ZNY New York Air Route Traffic Control Center (ARTCC)
ZOA Oakland Air Route Traffic Control Center (ARTCC)
ZOB Cleveland Air Route Traffic Control Center (ARTCC)
ZSE Seattle Air Route Traffic Control Center (ARTCC)
ZTL Atlanta Air Route Traffic Control Center (ARTCC)
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