- aerodrome control tower
means a unit established to provide air traffic control service to aerodrome traffic;
- aerodrome flight information service (AFIS)
means flight information service for aerodrome traffic provided by a designated air traffic services provider;’;
- aerodrome traffic
means all traffic on the manoeuvring area of an aerodrome and all aircraft flying in the vicinity of an aerodrome.
- aerodrome traffic circuit
means the specified path to be flown by aircraft operating in the vicinity of an aerodrome;
- aeronautical fixed station
means a station in the aeronautical fixed service;
- aeronautical ground light
means any light specially provided as an aid to air navigation, other than a light displayed on an aircraft;
- aeronautical information circular (AIC)
means a notice containing information that does not qualify for the origination of a NOTAM or for inclusion in the aeronautical information publication, but which relates to flight safety, air navigation, technical, administrative or legislative matters;
- aeronautical information management (AIM)
means the dynamic, integrated management of aeronautical information through the provision and exchange of quality-assured digital aeronautical data in collaboration with all parties;
- aeronautical information product
means aeronautical data and aeronautical information provided either as digital data sets or as a standardised presentation in paper or electronic media.
- aeronautical information publication (AIP)
means a publication issued by or with the authority of a State and containing aeronautical information of a lasting character essential to air navigation;
- aeronautical information regulation and control
(AIRAC) means a system aimed at advance notification, based on common effective dates, of circumstances that necessitate significant changes in operating practices;
- aeronautical mobile service
means a mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may participate;
- aeronautical station
means a land station in the aeronautical mobile service.
- aeronautical telecommunication station
means a station in a telecommunication service provided for any aeronautical purpose;
- air traffic advisory service
means a service provided within an airspace of defined dimensions, or a designated route (advisory airspace) to ensure separation, in so far as practical, between aircraft which are operating on instrument flight rules (IFR) flight plans;
- air-ground communication
means two-way communication between aircraft and stations or locations on the surface of the earth;
- airborne collision avoidance system (ACAS)
means an aircraft system based on secondary surveillance radar (SSR) transponder signals which operates independently of ground-based equipment to provide advice to the pilot on potential conflicting aircraft that are equipped with SSR transponders’;
- aircraft identification
means a group of letters, figures or a combination thereof which is either identical to, or the coded equivalent of, the aircraft call sign to be used in air-ground communications, and which is used to identify the aircraft in ground-ground air traffic service communications;
- AIRMET
means information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and of the development of those phenomena in time and space, and which was not already included in the forecast issued for low-level flights in the flight information region concerned or sub-area thereof;’;
- alert phase
means a situation wherein apprehension exists as to the safety of an aircraft and its occupants;
- alerting service
means a service provided to notify appropriate organisations regarding aircraft in need of search and rescue aid, and assist such organisations as required;
- approach control unit
means a unit established to provide air traffic control service to controlled flights arriving at, or departing from, one or more aerodromes;
- approach procedure with vertical guidance (APV)
means a performance-based navigation (PBN) instrument approach procedure designed for 3D instrument approach operations Type A.
- area navigation route
means an ATS route established for the use of aircraft capable of employing area navigation;
- assemble
means a process of merging data from multiple sources into a database and establishing a baseline for subsequent processing;
- automatic dependent surveillance – broadcast (ADS-B)
means a means by which aircraft, aerodrome vehicles and other objects can automatically transmit or receive, or transmit and receive data such as identification, position and additional data, as appropriate, in a broadcast mode via a data link;
- automatic dependent surveillance – contract (ADS-C)
means a means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft, via a data link, specifying under what conditions ADS-C reports would be initiated, and what data would be contained in the reports;
- automatic terminal information service (ATIS)
means the automatic provision of current, routine information to arriving and departing aircraft throughout 24 hours a day or a specified portion thereof;
- broadcast
means a transmission of information relating to air navigation that is not addressed to a specific station or stations;
- ceiling
means the height above the ground or water of the base of the lowest layer of cloud below 6000 m (20000 ft) covering more than half of the sky;
- clearance limit
means the point to which an aircraft is granted an ATC clearance;
- cloud base
means the height of the base of the lowest observed or forecast cloud element in the vicinity of an aerodrome or operating site or within a specified area of operations, normally measured above aerodrome elevation or, in the case of offshore operations, above mean sea level;
- completeness
means, in relation to data, the degree of confidence that all data needed to support the intended use is provided;
- conference communications
means communication facilities whereby direct speech conversation may be conducted between three or more locations simultaneously;
- confidence level
means the probability that the true value of a parameter is within a certain interval around the estimate of its value;
- control zone
means a controlled airspace extending upwards from the surface of the Earth to a specified upper limit;
- controlled aerodrome
means an aerodrome at which air traffic control service is provided to aerodrome traffic;
- controlled airspace
means an airspace of defined dimensions within which air traffic control service is provided in accordance with the airspace classification;
- controlled flight
means any flight which is subject to an ATC clearance;
- controller-pilot data link communications (CPDLC)
means a means of communication between air traffic controller and pilot, using data link for ATC communications;
- critical area
means an area of defined dimensions extending around the ground equipment of a precision instrument approach within which the presence of vehicles or aircraft will cause unacceptable disturbance of the guidance signals;
- cruising level
means a level maintained during a significant portion of a flight;
- cyclic redundancy check (CRC)
means a mathematical algorithm applied to the digital expression of data that provides a level of assurance against loss or alteration of data;
- danger area
means an airspace of defined dimensions within which activities dangerous to the flight of aircraft may exist at specified times;
- data accuracy
means a degree of conformance between the estimated or measured value and the true value;
- data collection surface
means a defined surface intended for the purpose of collecting obstacle or terrain data;
- data integrity
means a degree of assurance that aeronautical data and its value has not been lost or altered since the data origination or authorised amendment;
- data item
means a single attribute of a complete data set, which is allocated a value that defines its current status;
- data link communications
means a form of communication intended for the exchange of messages via a data link;
- data link-automatic terminal information service (D-ATIS)
means the provision of ATIS via data link;
- data link-VOLMET (D-VOLMET)
means the provision of current aerodrome routine meteorological reports (METAR) and aerodrome special meteorological reports (SPECI), aerodrome forecasts (TAF), SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET via data link;
- data origination
means the creation of a new data item with its associated value, the modification of the value of an existing data item or the deletion of an existing data item;
- data product specification
means a detailed description of a data set or a collection of data sets together with additional information that will enable it to be created, supplied to and used by another party;
- data set
means an identifiable collection of data;
- datum
means any quantity or set of quantities that may serve as a reference or basis for the calculation of other quantities;
- distress phase
means a situation wherein there is reasonable certainty that an aircraft and its occupants are threatened by grave and imminent danger or require immediate assistance;
- downstream clearance
means a clearance issued to an aircraft by an air traffic control unit that is not the current controlling authority of that aircraft;
- essential local traffic
means any aircraft, vehicle or personnel on or near the manoeuvring area, or traffic in the take-off and climb-out area or the final approach area, which may constitute a hazard to the aircraft concerned;
- essential traffic
means controlled traffic to which the provision of separation by air traffic control service is applicable, but which, in relation to a particular controlled flight is not, or will not be, separated from other controlled traffic by the appropriate separation minimum;
- estimated time of arrival
means:
- feature
means an abstraction of real world phenomena;
- feature attribute
means a characteristic of a feature that has a name, a data type and a value domain associated with it;
- feature type
means a class of real world phenomena with common properties, which forms the basic level of classification in a feature catalogue;
- final approach
means that part of an instrument approach procedure which:
- flight information zone
means an airspace of defined dimension within which aerodrome flight information service and alerting service for aerodrome traffic are provided;
- flight plan
means specified information provided to air traffic services units, relative to an intended flight or portion of a flight of an aircraft;
- flight procedure
means a set of predetermined flight manoeuvres intended to be followed by a pilot, published by electronic, printed or digital means, or both.
- flight procedure design services
means services for the design, documentation, validation, maintenance and periodic review of flight procedures necessary for the safety, regularity and efficiency of air navigation;
- flight procedure designer
means a qualified person who performs design, documentation, validation, continuous maintenance, and periodic review of flight procedures;
- flight visibility
means the visibility forward from the cockpit of an aircraft in flight;
- format
means, in relation to data, a structure of data items, records and files arranged to meet standards, specifications or data quality requirements;
- geoid
means the equipotential surface in the gravity field of the Earth which coincides with the undisturbed mean sea level (MSL) extended continuously through the continents;
- geoid undulation
means the distance of the geoid above (positive) or below (negative) the mathematical reference ellipsoid;
- glide path
means a descent profile determined for vertical guidance during a final approach;
- ground visibility
means the visibility at an aerodrome, as reported by an accredited observer or by automatic systems;
- heading
means the direction in which the longitudinal axis of an aircraft is pointed, usually expressed in degrees from North (true, magnetic, compass or grid);
- heliport
means an aerodrome or a defined area on a structure intended to be used wholly or in part for the arrival, departure and surface movement of helicopters;
- holding fix
means a geographical location that serves as a reference for a holding procedure;
- holding procedure
means a predetermined manoeuvre which keeps an aircraft within a specified airspace while awaiting further clearance;
- identification
means the situation which exists when the position indication of a particular aircraft is seen on a situation display and positively identified;
- instrument approach operations
means an approach and landing using instruments for navigation guidance based on an instrument approach procedure.
- instrument approach procedure (IAP)
means a series of predetermined manoeuvres by reference to flight instruments with specified protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if a landing is not completed, to a position at which holding or en-route obstacle clearance criteria apply.
- instrument meteorological conditions (IMC)
means meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling, less than the minima specified for visual meteorological conditions;
- integrity classification
means, in relation to aeronautical data, a classification based upon the potential risk resulting from the use of corrupted data, defining routine, essential and critical data;
- international NOTAM office (NOF)
means an office designated by a Member State for the exchange of NOTAM internationally;
- low-visibility operations (LVOs)
means approach or take-off operations on a runway with any RVR less than 550 m or taxiing at an aerodrome at which any RVR is less than 550 m;
- manoeuvring area
means that part of an aerodrome to be used for the take-off, landing and taxiing of aircraft, excluding aprons;
- metadata
means data about data;
- meteorological watch office (MWO)
means an office monitoring meteorological conditions affecting flight operations and providing information concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere which may affect the safety of aircraft operations within its specified area of responsibility;’;
- mode Secondary Surveillance Radar (SSR)
means the conventional identifier related to specific functions of the interrogation signals transmitted by an SSR interrogator.
- movement area
means that part of an aerodrome to be used for the take-off, landing and taxiing of aircraft, consisting of the manoeuvring area and the apron;
- navigation aid
means a facility or system external to the aircraft, which generates electro-magnetic signals to be used by aircraft navigation systems for position determination or flight path guidance;
- near-parallel runways
means non-intersecting runways whose extended centre lines have an angle of convergence/divergence of 15 degrees or less;
- non-precision approach (NPA) procedure
means an instrument approach procedure designed for 2D instrument approach operations Type A.
- pilot-in-command
means the pilot designated by the operator, or in the case of General Aviation, the owner, as being in command and charged with the safe conduct of a flight;
- position
means, in a geographical context, a set of coordinates (latitude and longitude) referenced to the mathematical reference ellipsoid, which define the position of a point on the surface of the Earth;
- position indication
means the visual indication, in non-symbolic or symbolic form, or both, on a situation display, of the position of an aircraft, aerodrome vehicle or other object;
- precision approach (PA) procedure
means an instrument approach procedure based on navigation systems (ILS, MLS, GLS and SBAS Cat I) designed for 3D instrument approach operations Type A or B;]
- pressure-altitude
means an atmospheric pressure expressed in terms of altitude which corresponds to that pressure in the Standard Atmosphere;
- primary radar
means a radar system which uses reflected radio signals;
- printed communications
means communications which automatically provide a permanent printed record at each terminal of a circuit of all messages which pass over such circuit;
- prohibited area
means an airspace of defined dimensions, above the land areas or territorial waters of a Member State, within which the flight of aircraft is prohibited;
- radio navigation service
means a service providing guidance information or position data for the efficient and safe operation of aircraft supported by one or more radio navigation aids;
- radiotelephony
means a form of radio communication primarily intended for the exchange of information in the form of speech;
- resolution
means, in relation to data, a number of units or digits to which a measured or calculated value is expressed and used;
- restricted area
means an airspace of defined dimensions, above the land areas or territorial waters of a Member State, within which the flight of aircraft is restricted in accordance with certain specified conditions;
- route stage
means a route or portion of a route flown without an intermediate landing;
- runway-in-use
means the runway or runways that, at a particular time, are considered by the air traffic services unit to be the most suitable for use by the types of aircraft expected to land or take off at the aerodrome.
- secondary radar
means a radar system wherein a radio signal transmitted from the radar station initiates the transmission of a radio signal from another station;
- secondary surveillance radar (SSR)
means a surveillance radar system which uses transmitters and receivers (interrogators) and transponders;
- sensitive area
means an area extending beyond the critical area where the parking or movement of aircraft or vehicles will affect the guidance signal to the extent that it may be rendered as an unacceptable disturbance to aircraft using the signal;
- SIGMET
means information, issued by a meteorological watch office, concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere which may affect the safety of aircraft operations and of the development of those phenomena in time and space;’;
- significant point
means a specified geographical location used in defining an ATS route or the flight path of an aircraft and for other navigation and air traffic services purposes;
- situation display
means an electronic display depicting the position and movement of aircraft and other information as required;
- SNOWTAM
means a special series NOTAM given in a standard format, which provides a surface condition report notifying the presence or cessation of hazardous conditions due to snow, ice, slush, frost or water associated with snow, slush, ice, or frost on the movement area;
- special VFR flight
means a VFR flight cleared by ATC to operate within a control zone in meteorological conditions below VMC;
- standard instrument arrival (STAR)
means a designated IFR arrival route that links a significant point, normally on an ATS route, with a point from which a published instrument approach procedure can be commenced;
- standard instrument departure (SID)
means a designated IFR departure route that links the aerodrome or a specified runway of the aerodrome with a specified significant point, normally on a designated ATS route, at which the en-route phase of a flight commences;
- take-off alternate aerodrome
means an alternate aerodrome at which an aircraft would be able to land should this become necessary shortly after take-off and if it is not possible to use the aerodrome of departure;’;
- taxiing
means movement of an aircraft on the surface of an aerodrome or an operating site under its own power, excluding take-off and landing;
- taxiway
means a defined path on a land aerodrome established for the taxiing of aircraft and intended to provide a link between one part of the aerodrome and another;
- terminal control area (TMA)
means a control area normally established at the confluence of ATS routes in the vicinity of one or more major aerodromes;
- timeliness
means, in relation to data, the degree of confidence that the data is applicable to the period of its intended use;
- traceability
means, in relation to data, the degree to which a system or a data product can provide a record of the changes made to that product and thereby enable an audit trail to be followed from the end-user to the party originating data;
- track
means the projection on the Earth’s surface of the path of an aircraft, the direction of which path at any point is usually expressed in degrees from North (true, magnetic or grid);
- traffic information
means information issued by an air traffic services unit to alert a pilot to other known or observed air traffic which may be in proximity to the position or intended route of flight and to help the pilot avoid a collision;
- transfer of control point
means a defined point located along the flight path of an aircraft, at which the responsibility for providing air traffic control service to the aircraft is transferred from one control unit or control position to the next;
- transferring unit
means air traffic control unit in the process of transferring the responsibility for providing air traffic control service to an aircraft to the next air traffic control unit or air traffic controller along the route of flight;
- transition altitude
means the altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes;
- transition layer
means the airspace between the transition altitude and the transition level;
- transition level
means the lowest flight level available for use above the transition altitude;
- uncertainty phase
means a situation wherein uncertainty exists as to the safety of an aircraft and its occupants;
- unmanned free balloon
means a non-power-driven, unmanned, lighter-than-air aircraft in free flight;
- validation
means, in relation to data, the process of ensuring that data meets the requirements for the specified application or intended use;
- vectoring
means the provision of navigational guidance to aircraft in the form of specific headings, based on the use of an ATS surveillance system;
- verification
means, in relation to data, the evaluation of the output of an aeronautical data process to ensure correctness and consistency with respect to the inputs and applicable data standards, rules and conventions used in that process;
- visual approach
means an approach by an IFR flight when either part or all of an instrument approach procedure is not completed and the approach is executed in visual reference to terrain;
- visual meteorological conditions (VMC)
means meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling, equal to or better than specified minima;
- voice-automatic terminal information service (Voice-ATIS)
means the provision of ATIS by means of continuous and repetitive voice broadcasts;
- VOLMET
means meteorological information for aircraft in flight;
- waypoint
means a specified geographical location used to define an area navigation route or the flight path of an aircraft employing area navigation.
- world area forecast centre (WAFC)
means a meteorological centre preparing and issuing significant weather (SIGWX) forecasts and upper-air forecasts in digital form on a global basis direct to the Member States as part of the aeronautical fixed service (AFS) internet-based services;’;