ATC Glossary/Terms
Procedural Preference
1) Automation preferred to non-automation 2) Radar separation preferred to nonradar separation 3) Nonradar separation in preference to radar separation when an operational advantage is gained.
Airway
A Class E airspace area established in the form of a corridor, the centerline of which is defined by radio navigational aids.
Flight Check (FLC)
A call sign prefix used by FAA aircraft engaged in flight inspection?certification of navigational aids and flight procedures. The word "recorded" may be added as a suffix; e.g., "Flight Check 320 recorded" to indicate that an automated flight inspection is in progress in terminal areas.
Voice Switching and Control System (VSCS)
A computer controlled sitching system that provides air traffic controllers with all voice circuits (air to ground and ground to ground) necessary for all air traffic control.
Runway (RWY, RY)
A defined rectangular area on a land airport prepared for the landing and takeoff run of aircraft along it's length. Runways are normally numbered in relation the their magnetic direction rounded off to the nearest 10 degrees.
Radar
A device which, by measuring the time interval between transmission and reception of radio pulses and correlating the angular orientation of the radiated antenna beam or beams in azimuth and/or elevation, provides information on range, azimuth, and/or elevation or objects in the path of the transmitted pulses.
Nonradar Route
A flight path or route over which the pilot is performing his/her own navigation. Pilot may be receiving radar separation, radar monitoring, or other ATC services while on a nonradar route.
Air Traffic Service Routes (ATS Routes)
A generic term that includes "VOR Federal airways," "colored Federal airways," "jet routes," and "RNAV routes." The term "ATS Route" does not replace these more familiar route names, but serves only as an overall title when listing the types of routes that comprise the United States route structure.
Fix
A geographical position determined by visual reference to the surface, by reference to one or more radio NAVAIDs, by celestial plotting, or by another navigational device.
Very High Frequency Omni Directional Range Navigational Aid (VOR)
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 NAS. It 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.
Flight Level (FL)
A level of constant atmospheric pressure related to a reference datum of 29.92 inches of mercury. Each is stated in three digits that represent hundreds of feet. For example, flight level (FL) 250 represents a barometric altimeter indication of 25,000 feet; FL255, an indication of 25,500 feet.
Visual Separation
A means employed by ATC to separate aircraft in terminal areas.
Very High Frequency Omni Directional Range/Tactical Air Navigation Navigational Aid (VORTAC)
A navigational aid providing VOR azimuth, TACAN azimuth, and TACAN DME at one site.
Air Traffic Control Specialists (ATCS)
A person authorized to provide air traffic control services.
Instrument Landing System (ILS)
A precision instrument approach system which normally consists of the following electronic components and visual aids: a. Localizer. b. Glideslope. c. Outer Marker. d. Middle Marker. e. Approach Lights.
Hold Procedure
A predetermined maneuver which keeps aircraft within a specified airspace while awaiting further clearance from air traffic control. Also used during ground operations to keep aircraft within a specified area or at a specified point while awaiting further clearance from air traffic control.
Instrument Departure Procedure (DP)
A preplanned instrument flight rule (IFR) air traffic control departure procedure printed for pilot use in graphic and/or textual form. DP's provide transition from the terminal to the appropriate en route structure.
Jet Route
A route designed to serve aircraft operations from 18,000 feet MSL up to and including flight level 450. The routes are referred to as "J" routes with numbering to identify the designated route; e.g., J105.
Air Traffic Control (ATC)
A service operated by appropriate authority to promote the safe, orderly and expeditious flow of air traffic.
Global Positioning System (GPS)
A space-based radio positioning, navigation, and timetransfer system. The system provides highly accurate position and velocity information, and precise time, on a continuous global basis, to an unlimited number of properly equipped users. The system is unaffected by weather, and provides a worldwide common grid reference system.
Restricted Area
A type of Special Use Airspace designated under FAR Part 73, within which the flight of aircraft, while not wholly prohibited, is subject to restriction. Most restricted areas are designated joint use and IFR/VFR operations in the area may be authorized by the controlling ATC facility when it is not being utilized by the using agency. Restricted areas are depicted on en route charts. Where joint use is authorized, the name of the controlling ATC facility is also listed.
Controlled Firing Area (CFA)
A type of Special Use Airspace wherein activities are conducted under conditions so controlled as to eliminate hazards to nonparticipating aircraft and to ensure the safety of persons and property on the ground.
Warning Area
A type of Special Use Airspace which may contain hazards to nonparticipating aircraftin international airspace.
Alert Area
A type of Special Use Airspace which may contain high volume of pilot training activities or an unusual type of aerial activity, neither of which is hazardous to aircraft. Alert Areas are depicted on aeronautical charts for the information of non-participating pilots. All activities within an Alert Area are conducted in accordance with the Federal Aviation Regulations, and pilots of participating aircraft as well as pilots transiting the area are equally responsible for collision avoidance.
Squawk
Activate specific codes on the aircraft transdponder.
Air Traffic (AT)
Aircraft operating in the air or on the an airport surface, exclusive of loading ramps and parking areas.
Special Use Area (SUA)
Airspace of defined dimensions identified by an area on the surface of the earth wherein activities must be confined because of their nature and/or wherein limitations may be imposed upon aircraft operations that are not part of those activities.
Mean Sea Level Altitude (MSL)
Altitude expressed in feet measured from mean sea level.
Above Ground Altitude (AGL)
Altitude expresses in feet measured above ground level.
Nonradar Approach Control
An ATC facility providing approach control service without the use of radar.
Non-Directional Beacon (NDB)
An L/MF or UHF radio beacon transmitting nondirectional signals whereby the pilot of an aircraft equipped with direction finding equipment can determine his bearing to or from the radio beacon and "home" on or track to or from the station.
Non-directional Beacon (NDB)
An L/MF or UHF radio beacon transmitting nondirectional signals whereby the pilot of an aircraft equipped with direction finding equipment can determine his bearing to or from the radio beacon and "home" on or track to or from the station.
Radar Point Out
An action taken by a controller to transfer the radar identification of an aircraft to another controller if the aircraft will or may enter the airspace or protected airspace of another controller and radio communications will not be transferred.
Handoff
An action taken to transfer the radar identification of an aircraft from one controller to another if the aircraft will enter the receiving controller's airspace and radio communications with the aircraft will be transferred.
Traffic Alert and Collision Avoidance System (TCAS)
An airborne collision avoidance system based on radar beacon signals which operates independent of ground-based equipment.
Nonradar Arrival
An aircraft arriving at an airport without radar service or at an airport served by a radar facility and radar contact has not been established or has been terminated due to a lack of radar service to the airport.
VFR Aircraft
An aircraft conducting flight in accordance with visual flight rules.
Military Operations Area (MOA)
An airspace assignment of defined vertical and lateral dimensions established outside Class A airspace to separate/segregate certain military activities from IFR traffic and to identify for VFR traffic where these activities are conducted.
Air Traffic Clearance
An authorization by air traffic control for the purpose of preventing a collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace. The pilot-in-command of an aircraft may not deviate from the provisions of a Visual Flight Rules (VFR) or Instrument Flight Rules (IFR) air traffic clearance except in an emergency or unless an amended clearance had been obtained.
Video Map
An electronically displayed map on the radar display that may depict data such as airports, heliports, runway centerline extensions, hospital emergency landing areas, NAVAIDs and fixes, reporting points, airway/route centerlines, boundaries, handoff points, special use tracks, obstructions, prominent geographic features, map alignment indicators, range accuracy marks, minimum vectoring altitudes.
Tactical Air Navigation (TACAN)
An ultra-high frequency electronic rho-theta air navigation aid which provides suitably equipped aircraft a continuos indication of bearing and distance to its station.
Navigational Aid (NAVAID)
Any visual or electronic device airborne or on the surface which provides point-to-point guidance information or position data to aircraft in flight.
Airport Surveillance (ASR)
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.
Stabilizer
Are located in the tail section of the aircraft. The vertical one is in the upright position, while the horizontal one is in a horizontal position. These are manipulated by the pilot in order to control the aircraft.
AFSS Preflight
Brief and translate to pilots weather, NOTAMS, and flow control restrictions in use on routee of flight.
AFSS Broadcast
Complies and disseminates weathher and flight information via recorded broadcasts (TWEB, TIBS, or HIWAS)
AFSS Flight Data/NOTAM Coordinator
Compliles data, initiates SARs.
Prohibited Area
Designated airspace within which the flight of aircraft is prohibited.
Distance Measuring Equipment (DME)
Equipment (airborne and ground) used to measure, in nautical miles, the slant range and distance of an aircraft from the DME navigational aid.
Operational Priority
First come, first served basis except: 1) Aircraft in distress 2) Air ambulance flight 3) Search and Rescue (SAR) 4) Presidential 5) Flight Check 6) Special military/civilian operations 7) Diverted flights
Duty Priority
First priority is given to separating aircraft and issuing safety alerts. Second priority is to provide support to national security and homeland defense.
AFSS Inflight
Fix NAVAIDS, issue aiport advisories, relay clearances from ATC, solicit and issue pilot reports (PIREPs), etc.
Nonradar
Generally means without the use of radar, such as nonradar approach, nonradar approach control, nonradar arrival, nonradar route, and nonradar separation.
Data Block (Alphanumeric Display)
Letters and numerals used to show identification, altitude, beacon code, and other information concerning a target on a radar display.
Flow Control
Measures designed to adjust the flow of traffic into a given airspace, along a given route, or bound for a given aerodrome (airport) so as to ensure the most effective utilization of the airspace.
Tower Flight Data
Perform clerical duties, process and forward flight plan info, compiles data, and observe weather info.
Wake Turbulence
Phenomena resulting frrom the passage of an aircraft through the atmosphere. The term includes vortices, thrust stream turbulence, jet blast, jet wash, propeller wash, and rotor wash both on the ground and in the air.
AFSS En Route Flight Advisory Service (EFAS)
Provides pilots with most up-to-date and accurate weather information available tailored to a specific flight plan, also called "Flight Watch."
Precision Approach Radar (PAR)
Radar equipment in some ATC facilities operated by the FAA and/or the military services at joint-use civil/military locations and separate military installations to detect and display azimuth, elevation, and range of aircraft on the final approach course to a runway. This equipment may be used to monitor certain nonradar approaches, but is primarily used to conduct a precision instrument approach wherein the controller issues guidance instructions to the pilot based on the aircraft's glidepath (elevation), and the distance (range) from the touchdown point on the runway as displayed on the radar scope.
Instrument Flight Rules (IFR)
Rules governing the procedures for conducting instrument flight . Also a term used by pilots and controllers to indicate type of flight plan.
Visual Flight Rules (VFR)
Rules that govern the procedures for conducting flight under visual conditions. The term "VFR" is also used in the United States too. In addition, it is used by pilots and controllers to indicate type of flight plan.
Vertical Separation
Separation established by assignment of different altitudes or flight levels.
Radar Vectors
Specific headings, issued to the pilot by a controller, to provide navigational guidance, based on the use of radar.
Flight Plan (FP)
Specified information relating to the intended flight of an aircraft that is filed orally or in writing with an FSS or an ATC facility.
Non-movement Area
Taxiways and apron (ramp) areas not under the control of air traffic.
General Aviation (GA)
That portion of civil aviation which encompasses all facets of aviation except air carriers holding a certificate of public convenience and necessity from the Civil Aeronautics Board and large aircraft commercial operators.
Visibility (VIS)
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. Visibility is reported as statute miles, hundreds of feet or meters.
Transponder
The airborne radar beacon receiver/transmitter portion of the Air Traffic Control Radar Beacon System (ATCRBS) which automatically receives radio signals from interrogators on the ground, and selectively replies with a specific reply pulse or pulse group only to those interrogations being received on the mode to which it is set to respond.
True Airspeed (TAS)
The airspeed of an aircraft relative to undisturbed air. Used primarily in flight planning and en route portion of flight. When used in pilot/controller communications, it is referred to as "true airspeed" and NOT shortened to "airspeed."
Altimeter Setting (ALSTG)
The barometric pressure reading used to adjust a pressure altimeter for variations in existing atmospheric pressure or to the standard altimeter setting (29.92).
National Airspace System (NAS)
The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing area; aeronautical charts, information and services; rules, regulations and procedures, technical information, and manpower and material. Included are system components shared jointly with the military.
Tower Clearance Delivery
The first person a pilot talks to, process/forward flight plan, issue departure clearance and ensure accuracy of pilot readback, operate communications equipment.
Initial Approach Fix (IAF)
The fixes depicted on instrument approach procedure charts that identify the beginning of the initial approach segment(s).
Altitude
The height of a level, point of object measured in feet Above Ground Level (AGL) or from Mean Sea Level (MSL).
Airport/Field Elevation
The highest point of an airport's usable runways measured in feet from mean sea level.
Target
The indication shown on a radar display from a primary radar return or a radar beacon reply.
Mayday
The international radiotelephony distress signal. When repeated three times, it indicates imminent and grave danger and that immediate assistance is requested.
Lateral Separation
The lateral spacing of aircraft at the same altitude by requiring operation on different routes or in different geographical locations.
Longitudinal Separation
The longitudinal spacing of aircraft at the same altitude by a minimum distance expressed in units of time or miles.
IFR/VRF Aircraft
The pilot using Instrument Flight Rules (IFR) relies on instruments for navigation during poor weather conditions and is provided ATC separation. The Visual Flight Rules (VFR) pilot relies on his/her own vision for separation and may or may not use instruments for navigation.
Mach Number
The ratio of true airspeed to the speed of sound; e.g., MACH .82, MACH 1.6.
Movement Area
The runways, taxiways, and other areas of an airport/heliport which are utilized for taxiing/hover taxiing, air taxiing, takeoff, and landing of aircraft, exclusive of loading ramps and parking areas. At those airports/heliports with a tower, specific approval for entry onto the movement area must be obtained from ATC.
Positive Control
The separation of all air traffic within designated airspace by air traffic control.
Nonradar Separation
The spacing of aircraft in accordance with established minima without the use of radar, e.g., vertical, lateral, or longitudinal separation.
Airspeed
The speed of an aircraft relative to its surrounding air mass. The unqualified term "airspeed" means either INDICATED AIRSPEED (IAS) or TRUE AIRSPEED (TAS).
Indicated Airspeed (IAS)
The speed shown on the aircraft airspeed indicator. This is the speed used in pilot/controller communication under the general term "airspeed."
Safety Alert
This is issued by ATC to aircraft under their control if ATC is aware if the aircraft is at an altitude which, in the controllers judgement, places the aircraft in unsafe proximity to terrain, obstructions, or other aircraft.
Coordinated Universal Time (UTC)
Time is given in Coordinated Universal Time, the local standard time at the Prime Meridian an Greenwich, England. Local Standard Time is based on each 15 degrees of longitude.
Primary purpose of the ATC system
To prevent a collision between aircraft operating in the system and to organize and expedite the flow of traffic in a manner which is 1) safe, 2) orderly, and 3) expeditious.
Nonradar Approach
Used to describe instrument approaches for which course guidance on final approach may or may not be provided by ATC.
IFR Conditions
Weather conditions below the minimum for flight under visual flight rules. Generally, IFR weather conditions exist when the ceiling is below 1,000 feet AGL or the visibility is below 3 statute miles.
VFR Conditions
Weather conditions that are equal to or greater than minimum VFR requirements. Generally, VFR weather conditions exist when the ceiling is at or above 1,000 feet AGL and the visibility is at least 3 statute miles.
