Commission Implementing Regulation (EU) 2017/373 of 1 March 2017 laying down common requirements for providers of air traffic management/air navigation services and other air traffic management network functions and their oversight, repealing Regulation (EC) No 482/2008, Implementing Regulations (EU) No 1034/2011, (EU) No 1035/2011 and (EU) 2016/1377 and amending Regulation (EU) No 677/2011 (Text with EEA relevance. )

Article 1

Subject matter

This Regulation lays down common requirements for:

• (a) the provision of air traffic management and air navigation services (‘ATM/ANS’) for general air traffic, in particular for the legal or natural persons providing those services and functions;

• (b) the competent authorities and the qualified entities acting on their behalf, which perform certification, oversight and enforcement tasks in respect of the services referred to in point (a);

• (c) the rules and procedures for the design of airspace structures.

Article 2

Definitions

For the purposes of this Regulation, the definitions in Annex I and the following definitions shall apply:

• (1) the definitions in Article 2 of Regulation (EU) 2024/2803 of the European Parliament and of the Council ([^E0001]) and Article 3 of Regulation (EU) 2018/1139 of the European Parliament and of the Council ([^E0002]);

• (2) ‘ATM/ANS provider’ means any legal or natural person providing any of the ATM/ANS as defined in Article 3(5) of Regulation (EU) 2018/1139, either individually or bundled, for general air traffic;

• (3) ‘Network Manager’ means the body entrusted with the tasks necessary for the execution of the functions referred to in Article 6 of Regulation (EC) No 551/2004;

• (4) ‘pan-European service’ means an activity which is designed and established for users within most or all Member States and which may also extend beyond the airspace of the territory to which the Treaty applies;

• (5) ‘data services provider (DAT provider)’ means an organisation, which is:
• (a) type 1 DAT provider that processes aeronautical data for use on aircraft and provides an aeronautical database meeting the DQRs, under controlled conditions, for which no corresponding airborne application/equipment compatibility has been determined;
• (b) type 2 DAT provider that processes aeronautical data and provides an aeronautical database for use on certified aircraft application/equipment meeting the DQRs for which compatibility with that application/equipment has been determined;

• (6) ‘“design of airspace structures”’ means a process that ensures that airspace structures are properly designed, surveyed and validated before they are deployed and used by aircraft

• (7) ‘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’;

• (8) ‘entity originating aeronautical data and aeronautical information’ – means any public or private entity responsible for origination of aeronautical data and aeronautical information used as a source for aeronautical information products and services. These entities do not include ATM/ANS providers referred to in point (2) of Article 2 of this Regulation and aerodromes defined in point (1)(e) of Article 2 of Regulation (EU) 2018/1139;

• (9) ‘Mode S interrogator’ means a system, composed of antenna and electronics, which supports the addressing of individual aircraft through the Mode Select (‘Mode S’);

• (10) ‘eligible Mode S interrogator’ means a Mode S interrogator for which at least one of the following conditions is satisfied:
• (a) the interrogator relies, at least partly, on Mode S all call interrogations and replies for Mode S targets acquisition;
• (b) the interrogator locks out acquired Mode S targets in reply to Mode S all call interrogations, permanently or intermittently, in part or the totality of its coverage; or
• (c) the interrogator uses multisite communications protocols for data link applications;

• (11) ‘Mode S operator’ means a person, organisation or enterprise that operates or offers to operate a Mode S interrogator, including:
• (a) surveillance service providers;
• (b) Mode S interrogator manufacturers;
• (c) aerodrome operators;
• (d) research establishments;
• (e) any other entity entitled to operate a Mode S interrogator;

• (12) ‘harmful interference’ means interference that prevents the performance requirements from being achieved;

• (13) ‘interrogator code allocation plan’ means the most recently approved complete set of interrogator code allocations.

Article 3

Provision of ATM/ANS and design of airspace structures

• (a) entities originating aeronautical data or aeronautical information meet the requirements laid down in:
• (i) point ATM/ANS.OR.A.085 of Annex III, except those in points (c), (d), (f)(1) and (i) thereof;
• (ii) point ATM/ANS.OR.A.090 of Annex III;

• (b) aeronautical data and aeronautical information are originated, processed and transmitted by adequately trained, competent and authorised personnel. When aeronautical data or aeronautical information is intended to be used for the purpose of IFR or special VFR flights, the requirements referred to in letters (a) and (b) of the first subparagraph shall apply to all entities originating such data and information.

6a. Member States shall ensure that the use of a ground-based transmitter operated in their territory does not produce harmful interference on other surveillance systems.

Article 3a

Determination of the need for the provision of air traffic services

• (a) the types of air traffic involved;

• (b) the density of air traffic;

• (c) the meteorological conditions;

• (d) other relevant factors related to the objectives of the air traffic services defined in point ATS.TR.100 of Annex IV.

Article 3b

Coordination between military units and air traffic service providers

Without prejudice to Article 6 of Regulation (EC) No 2150/2005, Member States shall establish special procedures so that:

• (a) air traffic service providers are notified if a military unit observes that an aircraft, which is, or might be, a civil aircraft is approaching, or has entered, any area in which interception might become necessary;

• (b) the air traffic service provider shall in close coordination with the military unit confirm the identity of the aircraft and provide it with the navigational guidance necessary to avoid the need for interception.

Article 3c

Coordination of air operations potentially hazardous to civil aviation

Article 3d

Very-high frequency (VHF) emergency frequency

Article 3e

Allocation of Mode S interrogator codes

• (a) ensure that the third country is informed about the safety requirements related to the allocation and use of interrogator codes;

• (b) take the necessary measures to coordinate the use of interrogator codes with the particular third country.

Article 3f

Use of the single European sky airspace

• (a) which will remain within the 25 kHz channel spacing on the following frequencies:
• (1) the emergency frequency (121,5 MHz);
• (2) the auxiliary frequency for search and rescue operations (123,1 MHz);
• (3) the VHF digital link (VDL) frequencies assigned to be used within the Single European Sky airspace;
• (4) the aircraft communications addressing and reporting system (ACARS) frequencies (131,525 MHz, 131,725 MHz and 131,825 MHz);

• (b) where offset carrier operation within a 25 kHz channel spacing is used.

• (a) secondary surveillance radar Mode-S transponders;

• (b) radios having the 8,33 kHz channel spacing capability.

Article 4

Competent authority for certification, oversight and enforcement

For the purposes of this Regulation, data services providers and the Network Manager shall be considered to be pan-European service providers in respect of which, in accordance with point (c) of Article 22a of Regulation (EC) No 216/2008, the Agency is the competent authority.

• (a) service providers provide services in respect of functional airspace blocks that extend across the airspace falling under the responsibility of more than one Member State, as referred to in Article 2(3) of Regulation (EC) No 550/2004;

• (b) service providers provide cross-border air navigation services as referred to in Article 2(5) of Regulation (EC) No 550/2004.

Article 5

Powers of the competent authority referred to in Article 4

• (a) require the service providers subject to their oversight to provide all necessary information;

• (b) require any representative, manager or other member of the personnel of those service providers to provide oral explanations on any fact, document, object, procedure or other subject matter relevant to the oversight of the service provider;

• (c) enter any premises and land, including operating sites, and means of transport of those service providers;

• (d) examine, copy or make extracts from any document, record or data held by or accessible to those service providers, irrespective of the medium on which the information in question is stored;

• (e) carry out audits, assessments, investigations and inspections of those service providers.

When exercising the powers provided for in paragraphs 1 and 2, the competent authority shall ensure that the members of its staff and, where relevant, any other expert participating in the activities in question are duly authorised.

Article 6

Service providers

Service providers shall be granted a certificate and be entitled to exercise the privileges granted within the scope of that certificate, where, in addition to the requirements referred to in Article 8b(1) of Regulation (EC) No 216/2008, they comply and continue to comply with the following requirements:

• (a) for all service providers, the requirements laid down in Annex III (Part-ATM/ANS.OR), Subparts A and B, and in Annex XIII (Part-PERS);

• (b) for service providers other than providers of air traffic services, in addition to the requirements of point (a), the requirements laid down in Annex III (Part-ATM/ANS.OR), Subpart C;

• (c) for providers of air navigation services, providers of air traffic flow management and the Network Manager, in addition to the requirements of point (a), the requirements laid down in Annex III (Part-ATM/ANS.OR), Subpart D;

• (d) for providers of air traffic services, in addition to the requirements of points (a) and (c), the requirements laid down in Annex IV (Part-ATS) and the requirements laid down in Regulation (EU) No 923/2012;

• (e) for providers of meteorological services, in addition to the requirements of points (a), (b) and (c), the requirements laid down in Annex V (Part-MET);

• (f) for providers of aeronautical information services, in addition to the requirements of points (a), (b) and (c), the requirements laid down in Annex VI (Part-AIS);

• (g) for data services providers, in addition to the requirements of points (a) and (b), the requirements laid down in Annex VII (Part-DAT);

• (h) for providers of communication, navigation or surveillance services, in addition to the requirements of points (a), (b) and (c), the requirements laid down in Annex VIII (Part-CNS);

• (i) for providers of air traffic flow management, in addition to the requirements of points (a), (b) and (c), the requirements laid down in Annex IX (Part-ATFM);

• (j) for providers of airspace management, in addition to the requirements of points (a) and (b), the requirements laid down in Annex X (Part-ASM);

• (k) for providers of flight procedure design services, in addition to the requirements of points (a) and (b), the requirements laid down in Annex XI (Part-FPD);

• (l) for the Network Manager, in addition to the requirements of points (a), (b) and (c), the requirements laid down in Annex XII (Part-NM).

Article 7

Declaration by providers of flight information services

Where Member States allow providers of flight information services to declare their capability and means of discharging the responsibilities associated with the services provided in accordance with Article 8b(3) of Regulation (EC) No 216/2008, those providers shall fulfil, in addition to the requirements referred to in Article 8b(1) of Regulation (EC) No 216/2008, the requirements laid down in point ATM/ANS.OR.A.015 in Annex III to this Regulation.

Article 8

Existing certificates

Article 9

Repeal and amendment

Article 10

Entry into force

This Regulation shall enter into force on the twentieth day following that of its publication in the Official Journal of the European Union.

It shall apply from 2 January 2020.

However:

• (1) Article 9(2) shall apply from the date of entry into force of this Regulation;

• (2) in respect of the Agency, Article 4(1), (2), (5), (6) and (8) and Article 5 shall apply from the date of entry into force of this Regulation;

• (3) in respect of data services providers, Article 6 shall apply in any case from 1 January 2019 and, where such a provider applies for and is granted a certificate in accordance with Article 6, from the date of entry into force of this Regulation.

This Regulation shall be binding in its entirety and directly applicable in all Member States.

ANNEX I

TABLE OF CONTENTS	TABLE OF CONTENTS
ANNEX I	DEFINITIONS OF TERMS USED IN ANNEXES II to XIII (Part-DEFINITIONS)
ANNEX II	REQUIREMENTS FOR COMPETENT AUTHORITIES – OVERSIGHT OF SERVICES AND OTHER ATM NETWORK FUNCTIONS (Part-ATM/ANS.AR)
SUBPART A –	GENERAL REQUIREMENTS (ATM/ANS.AR.A)
SUBPART B –	MANAGEMENT (ATM/ANS.AR.B)
SUBPART C –	OVERSIGHT, CERTIFICATION AND ENFORCEMENT (ATM/ANS.AR.C)
Appendix 1 –	CERTIFICATE FOR SERVICE PROVIDER
ANNEX III	COMMON REQUIREMENTS FOR SERVICE PROVIDERS (Part-ATM/ANS.OR)
SUBPART A –	GENERAL REQUIREMENTS (ATM/ANS.OR.A)
SUBPART B –	MANAGEMENT (ATM/ANS.OR.B)
SUBPART C –	SPECIFIC ORGANISATIONAL REQUIREMENTS FOR SERVICE PROVIDERS OTHER THAN ATS PROVIDERS (ATM/ANS.OR.C)
SUBPART D –	SPECIFIC ORGANISATIONAL REQUIREMENTS FOR ANS AND ATFM PROVIDERS AND THE NETWORK MANAGER (ATM/ANS.OR.D)
Appendix 1 –	AERONAUTICAL DATA CATALOGUE
ANNEX IV –	SPECIFIC REQUIREMENTS FOR PROVIDERS OF AIR TRAFFIC SERVICES (Part-ATS)
SUBPART A –	ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF AIR TRAFFIC SERVICES (ATS.OR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	SAFETY OF SERVICES
SECTION 3 –	SPECIFIC HUMAN FACTORS REQUIREMENTS FOR AIR TRAFFIC CONTROL SERVICE PROVIDERS
SECTION 4 –	REQUIREMENTS FOR COMMUNICATION
SECTION 5 –	REQUIREMENTS FOR INFORMATION
SUBPART B –	TECHNICAL REQUIREMENTS FOR PROVIDERS OF AIR TRAFFIC SERVICES (ATS.TR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	AIR TRAFFIC CONTROL SERVICE
SECTION 3 –	FLIGHT INFORMATION SERVICE
SECTION 4 –	ALERTING SERVICE
Appendix 1	Identification of individual aircraft using the downlinked aircraft identification feature as required by point ATS.OR.446(b)
Appendix 2	Processes to be implemented for automated coordination as required by point ATS.TR.230(c)
ANNEX V	SPECIFIC REQUIREMENTS FOR PROVIDERS OF METEOROLOGICAL SERVICES (Part-MET)
SUBPART A –	ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF METEOROLOGICAL SERVICES (MET.OR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	SPECIFIC REQUIREMENTS
Chapter 1 –	Requirements for aeronautical meteorological stations
Chapter 2 –	Requirements for aerodrome meteorological offices
Chapter 3 –	Requirements for meteorological watch offices
Chapter 4 –	Requirements for volcanic ash advisory centres (VAACs)
Chapter 5 –	Requirements for tropical cyclone advisory centres (TCACs)
Chapter 6 –	Requirements for world area forecast centres (WAFCs)
SUBPART B –	TECHNICAL REQUIREMENTS FOR PROVIDERS OF METEOROLOGICAL SERVICES (MET.TR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	SPECIFIC REQUIREMENTS
Chapter 1 –	Technical requirements for aeronautical meteorological stations
Chapter 2 –	Technical requirements for aerodrome meteorological offices
Chapter 3 –	Technical requirements for meteorological watch offices
Chapter 4 –	Technical requirements for volcanic ash advisory centres (VAACs)
Chapter 5 –	Technical requirements for tropical cyclone advisory centres (TCACs)
Chapter 6 –	Technical requirements for world area forecast centres (WAFCs)
Appendix 1 –	Template for METAR
Appendix 2 –	Fixed areas of coverage of WAFS forecasts in chart form
Appendix 3 –	Template for TAF
Appendix 4 –	Template for wind shear warnings
Appendix 5A –	Template for SIGMET and AIRMET
Appendix 5B –	Template for special air-reports (uplink)
Appendix 6 –	Template for advisory for volcanic ash
Appendix 7 –	Template for advisory for tropical cyclones
Appendix 8 –	Ranges and resolutions for the numerical elements included in a volcanic ash advisory, tropical cyclone advisory, SIGMET, AIRMET, aerodrome warning and wind shear warning
ANNEX VI	SPECIFIC REQUIREMENTS FOR PROVIDERS OF AERONAUTICAL INFORMATION SERVICES (Part-AIS)
SUBPART A –	ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF AERONAUTICAL INFORMATION SERVICES (AIS.OR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	DATA QUALITY MANAGEMENT
SECTION 3 –	AERONAUTICAL INFORMATION PRODUCTS
Chapter 1 –	Aeronautical information in a standardised presentation
Chapter 2 –	Digital data sets
SECTION 4 –	DISTRIBUTION AND PRE-FLIGHT INFORMATION SERVICES
SECTION 5 –	AERONAUTICAL INFORMATION PRODUCTS UPDATES
SECTION 6 –	PERSONNEL REQUIREMENTS
SUBPART B –	TECHNICAL REQUIREMENTS FOR PROVIDERS OF AERONAUTICAL INFORMATION SERVICES (AIS.TR)
SECTION 2 –	DATA QUALITY MANAGEMENT
SECTION 3 –	AERONAUTICAL INFORMATION PRODUCTS
Chapter 1 –	Aeronautical information in a standardised presentation
Chapter 2 –	Digital data sets
SECTION 4 –	DISTRIBUTION AND PRE-FLIGHT INFORMATION SERVICES
SECTION 5 –	AERONAUTICAL INFORMATION PRODUCTS UPDATES
Appendix 1 –	CONTENTS OF THE AERONAUTICAL INFORMATION PUBLICATION (AIP)
Appendix 2 –	NOTAM FORMAT
Appendix 3 –	SNOWTAM FORMAT
Appendix 4 –	ASHTAM FORMAT
ANNEX VII –	SPECIFIC REQUIREMENTS FOR PROVIDERS OF DATA SERVICES (Part-DAT)
SUBPART A –	ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF DATA SERVICES (DAT.OR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	SPECIFIC REQUIREMENTS
SUBPART B –	TECHNICAL REQUIREMENTS FOR PROVIDERS OF DATA SERVICES (DAT.TR)
SECTION 1 –	GENERAL REQUIREMENTS
ANNEX VIII –	SPECIFIC REQUIREMENTS FOR PROVIDERS OF COMMUNICATION, NAVIGATION, OR SURVEILLANCE SERVICES (Part-CNS)
SUBPART A –	ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF COMMUNICATION, NAVIGATION, OR SURVEILLANCE SERVICES (CNS.OR)
SECTION 1 –	GENERAL REQUIREMENTS
SUBPART B –	TECHNICAL REQUIREMENTS FOR PROVIDERS OF COMMUNICATION, NAVIGATION, OR SURVEILLANCE SERVICES (CNS.TR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 —	TECHNICAL REQUIREMENTS FOR PROVIDERS OF SURVEILLANCE SERVICES
ANNEX IX –	SPECIFIC REQUIREMENTS FOR PROVIDERS OF AIR TRAFFIC FLOW MANAGEMENT (Part-ATFM)
	TECHNICAL REQUIREMENTS FOR PROVIDERS OF AIR TRAFFIC FLOW MANAGEMENT (ATFM.TR)
ANNEX X –	SPECIFIC REQUIREMENTS FOR PROVIDERS OF AIRSPACE MANAGEMENT (Part-ASM)
	TECHNICAL REQUIREMENTS FOR PROVIDERS OF AIRSPACE MANAGEMENT (ASM.TR)
SECTION 1 –	GENERAL REQUIREMENTS
ANNEX XI –	SPECIFIC REQUIREMENTS FOR PROVIDERS OF FLIGHT PROCEDURE DESIGN SERVICES (Part-FPD)
SUBPART A –	ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF FLIGHT PROCEDURE DESIGN SERVICES (FPD.OR)
SECTION 1 –	GENERAL REQUIREMENTS
SUBPART B –	TECHNICAL REQUIREMENTS FOR PROVIDERS OF FLIGHT PROCEDURE DESIGN SERVICES (FPD.TR)
SECTION 1 –	GENERAL REQUIREMENTS
Appendix 1 –	REQUIREMENTS FOR AIRSPACE STRUCTURES AND FLIGHT PROCEDURES CONTAINED THEREIN
ANNEX XII –	SPECIFIC REQUIREMENTS FOR THE NETWORK MANAGER (Part-NM)
	TECHNICAL REQUIREMENTS FOR THE NETWORK MANAGER (NM.TR)
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 —	Technical requirements for the execution of air traffic management network functions (network functions)
ANNEX XIII –	REQUIREMENTS FOR SERVICE PROVIDERS CONCERNING PERSONNEL TRAINING AND COMPETENCE ASSESSMENT (Part-PERS)
SUBPART A –	AIR TRAFFIC SAFETY ELECTRONIC PERSONNEL
SECTION 1 –	GENERAL REQUIREMENTS
SECTION 2 –	TRAINING REQUIREMENTS
SECTION 3 –	COMPETENCE ASSESSMENT REQUIREMENTS
SECTION 4 –	INSTRUCTORS AND ASSESSORS REQUIREMENTS
Appendix 1 –	Basic Training – Shared
Appendix 2 –	Basic Training – Streams
Appendix 3 –	Qualification Training – Shared
Appendix 4 –	Qualification Training – Streams

DEFINITIONS OF TERMS USED IN ANNEXES II TO XIII

(Part-DEFINITIONS)

For the purposes of Annexes II to XIII, the following definitions shall apply:

• (1) ‘acceptable means of compliance (AMC)’ means non-binding standards adopted by the Agency to illustrate means to establish compliance with Regulation (EC) No 216/2008 and its implementing rules;

• (2) ‘aerial work’ means an aircraft operation in which an aircraft is used for specialised services such as agriculture, construction, photography, surveying, observation and patrol, search and rescue or aerial advertisement;

• (3) ‘aerodrome climatological summary’ means a concise summary of specified meteorological elements at an aerodrome, based on statistical data;

• (4) ‘aerodrome climatological table’ means a table providing statistical data on the observed occurrence of one or more meteorological elements at an aerodrome;

• (5) ‘aerodrome elevation’ means the elevation of the highest point of the landing area;

• (6) ‘aerodrome flight information service (AFIS)’ means flight information service for aerodrome traffic provided by a designated air traffic services provider;

• (7) ‘aerodrome meteorological office’ means an office responsible for providing meteorological service for an aerodrome;

• (8) ‘aerodrome warning’ means information issued by an aerodrome meteorological office concerning the occurrence or expected occurrence of meteorological conditions which could adversely affect aircraft on the ground, including parked aircraft and the aerodrome facilities and services;

• (9) ‘aeronautical data’ means a representation of aeronautical facts, concepts or instructions in a formalised manner suitable for communication, interpretation or processing;

• (10) ‘aeronautical database’ means a collection of aeronautical data organised and arranged as a structured data set, stored electronically on systems, which is valid for a dedicated period and may be updated;

• (11) ‘aeronautical fixed service (AFS)’ means a telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficient and economical operation of air services;

• (12) ‘aeronautical fixed telecommunication network (AFTN)’ means a worldwide system of aeronautical fixed circuits provided, as part of the AFS, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics;

• (13) ‘aeronautical information’ means information resulting from the assembly, analysis and formatting of aeronautical data;

• (14) ‘aerodrome mapping data’ means data collected for the purpose of compiling aerodrome mapping information;

• (15) ‘aerodrome mapping database (AMDB)’ means a collection of aerodrome mapping data organised and arranged as a structured data set;

• (16) ‘aeronautical meteorological station’ means a station making observations and meteorological reports for use in air navigation;

• (17) ‘air-report’ means a report from an aircraft in flight prepared in conformity with the requirements for position and operational and/or meteorological reporting;

• (18) ‘aircraft’ means any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth's surface;

• (19) ‘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;

• (20) ‘air traffic safety electronics personnel (ATSEP)’ means any authorised personnel who are competent to operate, maintain, release from, and return into operations equipment of the functional system;

• (21) ‘air traffic services unit’ is a generic term meaning variously air traffic control unit, flight information centre, aerodrome flight information service unit or air traffic services reporting office;

• (22) ‘alternate aerodrome’ means an aerodrome to which an aircraft may proceed when it becomes either impossible or inadvisable to proceed to or to land at the aerodrome of intended landing where the necessary services and facilities are available, where aircraft performance requirements can be met and which is operational at the expected time of use;

• (23) ‘alternative means of compliance (AltMOC)’ means those means of compliance that propose an alternative to an existing AMC or those that propose new means to establish compliance with Regulation (EC) No 216/2008 and its Implementing Rules for which no associated AMC have been adopted by the Agency;

• (24) ‘altitude’ means the vertical distance of a level, a point, or an object considered as a point, measured from mean sea level;

• (24a) ‘ancillary activities’ means, for the purposes of point ATM/ANS.OR.B.015 of Annex III, activities that support or enable the provision of ATM/ANS and:
• (a) do not fall under the definition set out in Article 3, point (5), of Regulation (EU) 2018/1139; or
• (b) for which no specific requirements as set out in Annexes III to XIII are applicable under this Regulation;

• (25) ‘area control centre (ACC)’ means a unit established to provide air traffic control service to controlled flights in control areas under its jurisdiction;

• (26) ‘area forecast for low-level flights’ means a forecast of weather phenomena for a flight information region or sub-area thereof, issued to cover the layer below flight level 100 (or below flight level 150 in mountainous areas, or higher, where necessary);

• (27) ‘area navigation (RNAV)’ means a method of navigation which permits aircraft operation on any desired flight path within the coverage of ground- or space-based navigation aids or within the limits of the capability of self-contained aids, or a combination of them;

• (28) ‘argument’ means a claim that is supported via inferences by a body of evidence;

• (29) ‘ASHTAM’ means a special series of NOTAM notifying by means of a specific format of a change in the activity of a volcano, a volcanic eruption and/or volcanic ash cloud that is of significance to aircraft operations;

• (30) ‘ATM network functions’ means the functions performed by the Network Manager in accordance with Regulation (EU) No 677/2011;

• (30a) ‘ATM/ANS equipment’ means ATM/ANS constituents as defined in Article 3(6) of Regulation (EU) 2018/1139, and ATM/ANS systems as defined in Article 3(7) of that Regulation, excluding airborne constituents, which are subject to Commission Regulation (EU) No 748/2012 ([^E0004]);

• (31) ‘audit’ means a systematic, independent and documented process for obtaining evidence and evaluating it objectively to determine the extent to which requirements are complied with;

• (32) ‘authoritative source’ means:
• (a) a State authority: or
• (b) an organisation formally recognised by the State authority to originate and/or publish data which meets the data quality requirements (DQRs) as specified by that State;

• (33) ‘automatic observing system’ means an observing system that measures, derives and reports all required elements without human interaction;

• (34) ‘aviation undertaking’ means an entity, person or organisation, other than the service providers regulated by this Regulation, that is affected by or affects a service delivered by a service provider;

• (34a) ‘boundary’ means a lateral or vertical plane delineating the airspace in which an ATC unit provides air traffic services;

• (35) ‘break’ means a period of time within the duty period when an air traffic controller is not required to perform duties, for recuperation purposes;

• (36) ‘certified aircraft application’ means a software application approved by the Agency as part of aircraft subject to Article 4 of Regulation (EC) No 216/2008;

• (37) ‘cloud of operational significance’ means a cloud with the height of cloud base below 5 000 ft or below the highest minimum sector altitude, whichever is greater, or a cumulonimbus cloud or a towering cumulus cloud at any height;

• (38) ‘commercial air transport’ means any aircraft operation involving the transport of passengers, cargo or mail for remuneration or other valuable consideration;

• (38a) ‘conventional navigation route’ means an ATS route established by reference to ground navigation aids;

• (39) ‘control area’ means a controlled airspace extending upwards from a specified limit above the earth;

• (39a) ‘coordination data’ means data of interest to operational staff in connection with the process of notification, coordination and transfer of flights, and with the process of civil-military coordination;

• (39b) ‘coordination point’ (COP) means a point on or adjacent to the boundary used by the ATC units and referred to in coordination processes;

• (40) ‘critical incident stress’ means the manifestation of unusual and/or extreme emotional, physical and/or behavioural reactions of an individual following an event or incident;

• (40a) ‘data link service’ means a set of related air traffic management transactions, supported by air-ground data link communications, which have a clearly defined operational goal and begin and end on an operational event;

• (41) ‘data quality’ means a degree or level of confidence that the provided data meets the user's data requirements in terms of accuracy, resolution, integrity (or equivalent assurance level), traceability, timeliness, completeness, and format;

• (42) ‘data quality requirements (DQRs)’ means a specification of the characteristics of data (i.e. accuracy, resolution, integrity (or equivalent assurance level), traceability, timeliness, completeness and format) to ensure that the data is compatible with its intended use;

• (43) ‘destination alternate’ means an alternate aerodrome at which an aircraft would be able to land should it become either impossible or inadvisable to land at the aerodrome of intended landing;

• (44) ‘duty’ means any task that an air traffic controller is required to perform by the air traffic control service provider;

• (45) ‘duty period’ means a period which starts when an air traffic controller is required by the air traffic control service provider to report for or be available for or to commence duty and ends when the air traffic controller is free from duty;

• (46) ‘elevation’ means the vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level;

• (46a) ‘eligible interrogator code’ means any code among the II codes and the SI codes, except:
• (a) II code 0;
• (b) the interrogator code(s) reserved for military entities, including intergovernmental organisations and in particular North Atlantic Treaty Organisation management and allocation;

• (47) ‘en-route alternate’ means an alternate aerodrome at which an aircraft would be able to land in the event that a diversion becomes necessary while en-route;

• (47a) ‘estimate data’ means the coordination point, the estimated time of an aircraft and the expected flight level of the aircraft at the coordination point;

• (48) ‘fatigue’ means a physiological state of reduced mental or physical performance capability resulting from sleep loss or extended wakefulness, circadian phase or workload (mental or physical activity, or both) that can impair an individual's alertness and ability to safely perform his/her tasks;

• (49) ‘flight documentation’ means documents, including charts or forms, containing meteorological information for a flight;

• (50) ‘flight information centre (FIC)’ means a unit established to provide flight information service and alerting service;

• (51) ‘flight information region (FIR)’ means an airspace of defined dimensions within which flight information service and alerting service are provided;

• (52) ‘flight level (FL)’ means a surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013,2 hectopascals (hPa), and is separated from other such surfaces by specific pressure intervals;

• (53) ‘flight test’ means a flight for the development phase of a new design (aircraft, propulsion systems, parts and appliances), a flight to demonstrate compliance to certification basis or to type design for aircraft coming from the production line, a flight intended to experiment new design concepts, requiring unconventional manoeuvres or profiles for which it could be possible to exit the already approved envelope of the aircraft or a training flight to perform either of those flights;

• (54) ‘forecast’ means a statement of expected meteorological conditions for a specified time or period, and for a specified area or portion of airspace;

• (55) ‘forecast for take-off’ means a forecast for a specified period of time, prepared by an aerodrome meteorological office, which contains information on expected conditions over the runways complex in regard to surface wind direction and speed and any variations thereof, temperature, pressure (QNH) and any other element as agreed locally;

• (56) ‘functional system’ means a combination of procedures, human resources and equipment, including hardware and software, organised to perform a function within the context of ATM/ANS and other ATM network functions;

• (57) ‘general aviation’ means any civil aircraft operation other than aerial work or commercial air transport;

• (58) ‘grid point data in digital form’ means computer-processed meteorological data for a set of regularly spaced points on a chart, for transmission from a meteorological computer to another computer in a code form suitable for automated use;

• (59) ‘guidance material’ means non-binding material developed by the Agency that helps to illustrate the meaning of a requirement or specification and is used to support the interpretation of Regulation (EC) No 216/2008, its implementing rules and AMC;

• (60) ‘gridded global forecasts’ means forecasts of expected values of meteorological elements on a global grid with a defined vertical and horizontal resolution;

• (61) ‘hazard’ means any condition, event, or circumstance which could induce a harmful effect;

• (62) ‘height’ means the vertical distance of a level, a point or an object considered as a point, measured from a specified datum;

• (62a) ‘implementation sequence’ means the time-bounded sequence of implementation of interrogator code allocations with which Mode S operators need to comply to avoid temporary interrogator code conflicts;

• (63) ‘level’ is a generic term relating to the vertical position of an aircraft in flight and meaning variously height, altitude or flight level;

• (64) ‘local routine report’ means a meteorological report issued at fixed time intervals, intended only for dissemination at the aerodrome of origin where the observations were made;

• (65) ‘local special report’ means a meteorological report issued in accordance with the criteria established for special observations, intended only for dissemination at the aerodrome of origin where the observations were made;

• (66) ‘meteorological bulletin’ means a text comprising meteorological information preceded by an appropriate heading;

• (67) ‘meteorological information’ means meteorological report, analysis, forecast, and any other statement relating to existing or expected meteorological conditions;

• (68) ‘meteorological observation’ means the measurement and/or evaluation of one or more meteorological elements;

• (69) ‘meteorological report’ means a statement of observed meteorological conditions related to a specified time and location;

• (70) ‘meteorological satellite’ means an artificial Earth satellite making meteorological observations and transmitting these observations to Earth;

• (71) ‘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;

• (72) ‘minimum sector altitude (MSA)’ means the lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000  ft) above all objects located in an area contained within a sector of a circle of 46 km (25 NM) radius centred on a significant point, the aerodrome reference point (ARP) or the heliport reference point (HRP);

• (73) ‘NOTAM’ means a notice distributed by means of telecommunication containing information concerning the establishment, condition, or change in any aeronautical facility, service, procedure, or hazard, the timely knowledge of which is essential to personnel concerned with flight operations;

• (73a) ‘notified unit’ means the ATC unit that has received the notification information;

• (74) ‘obstacle’ means all fixed (whether temporary or permanent) and mobile objects, or parts thereof, that:
• (a) are located on an area intended for the surface movement of aircraft; or
• (b) extend above a defined surface intended to protect aircraft in flight; or
• (c) stand outside those defined surfaces and have been assessed as being a hazard to air navigation;

• (75) ‘OPMET’ means operational meteorological information for use in preparatory or in-flight planning of flight operations;

• (76) ‘OPMET databank’ means a databank established to store and make available internationally operational meteorological information for aeronautical use;

• (77) ‘pre-eruption volcanic activity’ means an unusual and/or increasing volcanic activity which could presage a volcanic eruption;

• (78) ‘prevailing visibility’ means the greatest visibility value, observed in accordance with the definition of ‘visibility’, which is reached within at least half the horizon circle or within at least half of the surface of the aerodrome. These areas could comprise contiguous or non-contiguous sectors;

• (79) ‘problematic use of psychoactive substances’ means the use of one or more psychoactive substances by an individual, in a way that:
• (a) constitutes a direct hazard to the user or endangers the lives, health, or welfare of others; and/or
• (b) causes or worsens an occupational, social, mental or physical problem or disorder;

• (80) ‘prognostic chart’ means a forecast of (a) specified meteorological element(s) for a specified time or period and a specified surface or portion of airspace, depicted graphically on a chart;

• (81) ‘psychoactive substances’ means alcohol, opioids, cannabinoids, sedatives and hypnotics, cocaine, other psychostimulants, hallucinogens, and volatile solvents, whereas caffeine and tobacco are excluded;

• (81a) ‘receiving unit’ means the air traffic control unit that receives data;

• (82) ‘rescue coordination centre (RCC)’ means a unit responsible for promoting efficient organisation of search and rescue services, and for coordinating the conduct of search and rescue operations within a search and rescue region;

• (83) ‘rest period’ means a continuous and defined period of time, subsequent to and/or prior to duty, during which an air traffic controller is free of all duties;

• (84) ‘rostering system’ means the structure of duty and rest periods of air traffic controllers in accordance with legal and operational requirements;

• (85) ‘risk’ means the combination of the overall probability or frequency of occurrence of a harmful effect induced by a hazard and the severity of that effect;

• (86) ‘runway’ means a defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft;

• (87) ‘runway visual range (RVR)’ means the range over which the pilot of an aircraft on the centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its centre line;

• (88) ‘safety directive’ means a document issued or adopted by a competent authority which:
• (1) mandates actions to be performed on a functional system or sets restrictions to its operational use to restore safety when evidence shows that aviation safety may otherwise be compromised; or
• (2) mandates actions to be performed on ATM/ANS equipment subject to the statement of compliance issued in accordance with Article 6 to Commission Delegated Regulation (EU) 2023/1768 ([^E0005]) to address an unsafe or insecure condition, or both, that has been identified and restore the performance and interoperability of that ATM/ANS equipment when evidence shows that the safety, security, performance or interoperability of that particular equipment may otherwise be compromised;

• (89) ‘safety management system (SMS)’ means a systematic approach to managing safety, including the necessary organisational structures, accountabilities, policies, and procedures;

• (90) ‘search and rescue services unit’ is a generic term covering, as the case may be, rescue coordination centre, rescue sub-centre or alerting post;

• (92) ‘semi-automatic observing system’ means an observing system that allows the augmentation of measured elements and requires a human in the loop for issuing the appropriate reports;

• (93) ‘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;

• (95) ‘special air-report’ means a meteorological report by an aircraft issued in accordance with the criteria based on observations made during the flight;

• (96) ‘stress’ means the outcomes experienced by an individual when faced with a potential cause (‘stressor’) of human performance modification. The experience of the stressor may impact the individual's performance negatively (distress), neutrally or positively (eustress), based on the individual's perception of his/her ability to manage the stressor;

• (97) ‘system and equipment rating training’ means training designed to impart specific system/equipment knowledge and skills leading towards operational competence;

• (98) ‘tailored data’ means aeronautical data which is provided by the aircraft operator or DAT provider on the aircraft operator's behalf and produced for this aircraft operator for its intended operational use;

• (99) ‘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;

• (100) ‘terminal aerodrome forecast (TAF)’ means a concise statement of the expected meteorological conditions at an aerodrome for a specified period;

• (101) ‘terrain’ means the surface of the Earth containing naturally occurring features such as mountains, hills, ridges, valleys, bodies of water, permanent ice and snow, and excluding obstacles;

• (102) ‘threshold’ means the beginning of that portion of the runway usable for landing;

• (103) ‘touchdown zone’ means the portion of a runway, beyond the threshold, where it is intended that landing aeroplanes first contact the runway;

• (104) ‘tropical cyclone’ is a generic term for a non-frontal synoptic-scale cyclone originating over tropical or subtropical waters with organised convection and definite cyclonic surface wind circulation;

• (105) ‘tropical cyclone advisory centre (TCAC)’ means a meteorological centre providing advisory information to meteorological watch offices, world area forecast centres and international OPMET databanks regarding the position, forecast direction and speed of movement, central pressure and maximum surface wind of tropical cyclones;

• (106) ‘visibility’ means visibility for aeronautical purposes, which is the greater of:
• (a) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognised when observed against a bright background;
• (b) the greatest distance at which lights in the vicinity of 1 000 candelas can be seen and identified against an unlit background;

• (107) ‘volcanic ash advisory centre (VAAC)’ means a meteorological centre that provides advisory information to meteorological watch offices, area control centres, flight information centres, world area forecast centres and international OPMET databanks regarding the lateral and vertical extent and forecast movement of volcanic ash in the atmosphere;

• (107a) ‘working position’ means the furniture and technical equipment at which a member of the air traffic services staff undertakes task associated with their job;

• (107b) ‘warning’ means a message displayed at a working position when the automated coordination process has failed;

• (108) ‘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;

• (109) ‘world area forecast system (WAFS)’ means a worldwide system by which world area forecast centres provide aeronautical meteorological en-route forecasts in uniform standardised formats;

• (110) ‘aerodrome control tower’ means a unit established to provide air traffic control service to aerodrome traffic;

• (111) ‘aerodrome traffic’ means all traffic on the manoeuvring area of an aerodrome and all aircraft flying in the vicinity of an aerodrome. An aircraft operating in the vicinity of an aerodrome includes but is not limited to aircraft entering or leaving an aerodrome traffic circuit;

• (112) ‘aerodrome traffic circuit’ means the specified path to be flown by aircraft operating in the vicinity of an aerodrome;

• (113) ‘aeronautical fixed station’ means a station in the aeronautical fixed service;

• (114) ‘aeronautical ground light’ means any light specially provided as an aid to air navigation, other than a light displayed on an aircraft;

• (115) ‘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;

• (116) ‘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;

• (117) ‘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 products include:
• — aeronautical information publication, including amendments and supplements;
• — AIC;
• — aeronautical charts;
• — NOTAM;
• — digital data sets;

• (118) ‘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;

• (119) ‘AIP amendment’ means a permanent change to the information contained in the AIP;

• (120) ‘AIP supplement’ means a temporary change to the information contained in the AIP, which is provided by means of special pages;

• (121) ‘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;

• (122) ‘aeronautical mobile service’ means a mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may participate; emergency position-indicating radio beacon stations may also participate in this service on designated distress and emergency frequencies;

• (123) ‘aeronautical station’ means a land station in the aeronautical mobile service. In certain instances, an aeronautical station may be located, for example, on board a ship or on a platform at sea;

• (124) ‘aeronautical telecommunication station’ means a station in a telecommunication service provided for any aeronautical purpose;

• (125) ‘AFIS aerodrome’ means an aerodrome where AFIS is provided within the airspace associated with such aerodrome;

• (126) ‘AFIS unit’ means a unit established to provide AFIS and alerting service;

• (127) ‘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;

• (128) ‘air-ground communication’ means two-way communication between aircraft and stations or locations on the surface of the earth;

• (129) ‘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;

• (130) ‘air traffic control clearance’ or ‘ATC clearance’ means authorisation for an aircraft to proceed under conditions specified by an air traffic control unit;

• (131) ‘air traffic control instruction’ or ‘ATC instruction’ means directives issued by ATC for the purpose of requiring a pilot to take a specific action;

• (132) ‘air traffic control (ATC) unit’ or ‘ATC unit’ is a generic term meaning variously, area control centre, approach control unit or aerodrome control tower;

• (133) ‘ALERFA’ is the code word used to designate an alert phase;

• (134) ‘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;

• (135) ‘alert phase’ means a situation wherein apprehension exists as to the safety of an aircraft and its occupants;

• (136) ‘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;

• (137) ‘area navigation route’ means an ATS route established for the use of aircraft capable of employing area navigation;

• (138) ‘assemble’ means a process of merging data from multiple sources into a database and establishing a baseline for subsequent processing;

• (139) ‘ATS route’ means a specified route designed for channelling the flow of traffic as necessary for the provision of ATS;

• (140) ‘ATS surveillance service’ means a service provided directly by means of an ATS surveillance system;

• (141) ‘ATS surveillance system’ means a generic term meaning variously, ADS-B, PSR, SSR or any comparable ground-based system that enables the identification of aircraft;

• (142) ‘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;

• (143) ‘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;

• (144) ‘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;

• (145) ‘data link-automatic terminal information service (D-ATIS)’ means the provision of ATIS via data link;

• (146) ‘voice-automatic terminal information service (Voice-ATIS)’ means the provision of ATIS by means of continuous and repetitive voice broadcasts;

• (147) ‘broadcast’ means a transmission of information relating to air navigation that is not addressed to a specific station or stations;

• (148) ‘ceiling’ means the height above the ground or water of the base of the lowest layer of cloud below 6 000 m (20 000 ft) covering more than half of the sky;

• (149) ‘clearance limit’ means the point to which an aircraft is granted an ATC clearance;

• (150) ‘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;

• (151) ‘completeness’ means, in relation to data, the degree of confidence that all data needed to support the intended use is provided;

• (152) ‘confidence level’ means the probability that the true value of a parameter is within a certain interval around the estimate of its value;

• (153) ‘conference communications’ means communication facilities whereby direct speech conversation may be conducted between three or more locations simultaneously;

• (154) ‘control zone’ means a controlled airspace extending upwards from the surface of the Earth to a specified upper limit;

• (155) ‘controlled aerodrome’ means an aerodrome at which air traffic control service is provided to aerodrome traffic;

• (156) ‘controlled airspace’ means an airspace of defined dimensions within which air traffic control service is provided in accordance with the airspace classification;

• (157) ‘controlled flight’ means any flight which is subject to an ATC clearance;

• (158) ‘controller-pilot data link communications (CPDLC)’ means a means of communication between air traffic controller and pilot, using data link for ATC communications;

• (159) ‘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;

• (160) ‘cruising level’ means a level maintained during a significant portion of a flight;

• (161) ‘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;

• (162) ‘danger area’ means an airspace of defined dimensions within which activities dangerous to the flight of aircraft may exist at specified times;

• (163) ‘data accuracy’ means a degree of conformance between the estimated or measured value and the true value;

• (164) ‘data collection surface’ means a defined surface intended for the purpose of collecting obstacle or terrain data;

• (165) ‘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;

• (166) ‘data item’ means a single attribute of a complete data set, which is allocated a value that defines its current status;

• (167) ‘data link communications’ means a form of communication intended for the exchange of messages via a data link;

• (168) ‘data link-VOLMET (D-VOLMET)’ means the provision of aerodrome routine meteorological report (METAR), aerodrome special meteorological report (SPECI), TAF, SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET via data link;

• (169) ‘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;

• (170) ‘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;

• (171) ‘data set’ means an identifiable collection of data;

• (172) ‘datum’ means any quantity or set of quantities that may serve as a reference or basis for the calculation of other quantities;

• (173) ‘DETRESFA’ is the code word used to designate a distress phase;