A four-dimensional (x, y, z, and time) trajectory of an aircraft from gate-to-gate, at the level of fidelity required for attaining the agreed ATM system performance levels.
Aborted - interrupted approach
The phase of flight where the pilot aborts the approach during an ils or other precision approach involving an abnormally early turn on approach before reaching minimum decision altitude or decision height.
The phase of flight in which any attempt is made to terminate a take-off between the application of take-off power, through rotation and up to 50 feet [or 15 metres] above the elevation of the runway end.
Accelerate-stop distance available
The length of the take-off run available plus the length of stopway, if provided.
Acceptance check flight
A flight in association with aircraft acceptance or hand back.
Air traffic control unit next to take control of an aircraft.
An occurrence associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time as it comes to rest at the end of the flight and the primary propulsion system is shut down, in which: a) a person is fatally or seriously injured as a result of: - being in the aircraft, or - direct contact with any part of the aircraft, including parts which have become detached from the aircraft, or - direct exposure to jet blast, except when the injuries are from natural causes, self-inflicted or inflicted by other persons, or when the injuries are to stowaways hiding outside the areas normally available to the passengers and crew; or b) the aircraft sustains damage or structural failure which: - adversely affects the structural strength, performance or flight characteristics of the aircraft, and - would normally require major repair or replacement of the affected component, except for engine failure or damage, when the damage is limited to a single engine, (including its cowlings or accessories), to propellers, wing tips, antennas, probes, vanes, tires, brakes, wheels, fairings, panels, landing gear doors, windscreens, the aircraft skin (such as small dents or puncture holes), or for minor damages to main rotor blades, tail rotor blades, landing gear, and those resulting from hail or bird strike (including holes in the radome); or c) the aircraft is missing or is completely inaccessible.
Accredited medical conclusion
The conclusion reached by one or more medical experts acceptable to the Licensing Authority for the purposes of the case concerned, in consultation with flight operations or other experts as necessary.
A person designated by a State, on the basis of his or her qualifications, for the purpose of participating in an investigation conducted by another State. Where the State has established an accident investigation authority, the designated accredited representative would normally be from that authority.
A degree of conformance between the estimated or measured value and the true value.
Notification that a given communication has been correctly received and understood.
Manoeuvres intentionally performed by an aircraft involving an abrupt change in its attitude, an abnormal attitude, or an abnormal variation in speed.
Acts of unlawful interference
These are acts or attempted acts such as to jeopardize the safety of civil aviation, including but not limited to: - unlawful seizure of aircraft, - destruction of an aircraft in service, - hostage-taking on board aircraft or on aerodromes, - forcible intrusion on board an aircraft, at an airport or on the premises of an aeronautical facility, - introduction on board an aircraft or at an airport of a weapon or hazardous device or material intended for criminal purposes, - use of an aircraft in service for the purpose of causing death, serious bodily injury, or serious damage to property or the environment, - communication of false information such as to jeopardize the safety of an aircraft in flight or on the ground, of passengers, crew, ground personnel or the general public, at an airport or on the premises of a civil aviation facility.
Adequate alternate aerodrome
An adequate alternate aerodrome is one at which the landing performance requirements can be met and which is expected to be available, if required, and which has the necessary facilities and services, such as air traffic control, lighting, communications, meteorological services, navigation aids, rescue and fire-fighting services and one suitable instrument approach procedure.
The permission granted to a person to enter a State by the public authorities of that State in accordance with its national laws.
An ADS reporting plan which establishes the conditions of ADS data reporting (i.e. data required by the air traffic services unit and frequency of ADS reports which have to be agreed to prior to the provision of the ADS services). Note. - The terms of the agreement will be exchanged between the ground system and the aircraft by means of a contract, or a series of contracts.
A service using aircraft information provided by means of automatic dependent surveillance.
A reporting plan which establishes the conditions of ADS-C data reporting (i.e. data required by the air traffic services unit and frequency of ADS-C reports which have to be agreed to prior to using ADS-C in the provision of air traffic services).
Advance Passenger Information System
An electronic communications system whereby required data elements are collected and transmitted to border control agencies prior to flight departure or arrival and made available on the primary line at the airport of entry.
A person appointed by a State, on the basis of his or her qualifications, for the purpose of assisting its accredited representative in an investigation.
An airspace of defined dimensions, or designated route, within which air traffic advisory service is available.
A designated area within a flight information region where air traffic advisory service is available.
A designated route along which air traffic advisory service is available.
Aerial advertising flight
A flight to carry out aerial advertising (e.g. banner towing).
Aerial observation flight
A flight to carry out aerial observations (e.g. crowds etc).
Aerial patrol flight
A flight to carry out aerial patrols (e.g. pipeline controls).
Aerial survey flight
A flight to carry out aerial surveys.
An aircraft operation in which an aircraft is used for specialized services such as agriculture, construction, photography, surveying, observation and patrol, search and rescue, aerial advertisement, etc.
An event involving any phase of flight in which manoeuvring into an abrupt change in attitude, abnormal attitude or abnormal acceleration occurs, (usually associated with air shows and military flight).
A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft.
Aeronautical beacon used to indicate the location of an aerodrome from the air.
A certificate issued by the appropriate authority under applicable regulations for the operation of an aerodrome.
Aerodrome climatological summary
Concise summary of specified meteorological elements at an aerodrome, based on statistical data.
Aerodrome climatological table
Table providing statistical data on the observed occurrence of one or more meteorological elements at an aerodrome.
Aerodrome control radio station
A station providing radiocommunication between an aerodrome control tower and aircraft or mobile aeronautical stations.
aerodrome control service
an ATC service for aerodrome traffic
Aerodrome control service
Air traffic control service for aerodrome traffic.
Aerodrome control tower
A unit established to provide air traffic control service to aerodrome traffic.
The elevation of the highest point of the landing area.
Aerodrome identification sign
A sign placed on an aerodrome to aid in identifying the aerodrome from the air.
Aerodrome mapping data
Data collected for the purpose of compiling aerodrome mapping information.
Aerodrome mapping database
A collection of aerodrome mapping data organized and arranged as a structured data set.
Aerodrome meteorological office
An office, located at an aerodrome, designated to provide meteorological service for international air navigation.
Aerodrome operating minima
The limits of usability of an aerodrome for: a) take-off, expressed in terms of runway visual range and/or visibility and, if necessary, cloud conditions; b) landing in precision approach and landing operations, expressed in terms of visibility and/or runway visual range and decision altitude/height (DA/H) as appropriate to the category of the operation; c) landing in approach and landing operations with vertical guidance, expressed in terms of visibility and/or runway visual range and decision altitude/height (DA/H); and d) landing in non-precision approach and landing operations, expressed in terms of visibility and/or runway visual range, minimum descent altitude/height (MDA/H) and, if necessary, cloud conditions.
Aerodrome reference point
The designated geographical location of an aerodrome.
Aerodrome surface movement area
That part of an aerodrome that is to be used for the take-off, landing, and taxiing of aircraft. This includes runways, taxiways, and apron areas.
Aerodrome taxi circuit
The specified path of aircraft on the manoeuvring area during specific wind conditions.
aerodrome taxi time
the pre-determined time value from off-block to take-off, expressed in minutes and valid during normal airport operations
All traffic on the manoeuvring area of an aerodrome and all aircraft flying in the vicinity of an aerodrome.
Aerodrome traffic circuit
The specified path to be flown by aircraft operating in the vicinity of an aerodrome.
Aerodrome traffic density
a) Light. Where the number of movements in the mean busy hour is not greater than 15 per runway or typically less than 20 total aerodrome movements. b) Medium. Where the number of movements in the mean busy hour is of the order of 16 to 25 per runway or typically between 20 to 35 total aerodrome movements. c) Heavy. Where the number of movements in the mean busy hour is of the order of 26 or more per runway or typically more than 35 total aerodrome movements.
Aerodrome traffic zone
An airspace of defined dimensions established around an aerodrome for the protection of aerodrome traffic.
Aeronautical administrative communications
Communications necessary for the exchange of aeronautical administrative messages.
An aeronautical ground light visible at all azimuths, either continuously or intermittently, to designate a particular point on the surface of the earth.
Aeronautical broadcasting service
A broadcasting service intended for the transmission of information relating to air navigation.
A representation of a portion of the Earth, its culture and relief, specifically designated to meet the requirements of air navigation.
A representation of aeronautical facts, concepts or instructions in a formalized manner suitable for communication, interpretation or processing.
Aeronautical data preparation agency
An agency, public or private, other than an originator and/or publisher of government source documents, who compiles official government document information into charts or electronic formats for computer-based systems.
Any data that is stored electronically in a system that supports airborne or ground based aeronautical applications. An aeronautical database may be updated at regular intervals.
Aeronautical fixed circuit
A circuit forming part of the aeronautical fixed service (AFS).
Aeronautical fixed service
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.
Aeronautical fixed station
A station in the aeronautical fixed service.
Aeronautical fixed telecommunication network
A worldwide system of aeronautical fixed circuits provided, as part of the aeronautical fixed service, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 3;
Aeronautical fixed telecommunication network circuit
A circuit forming part of the aeronautical fixed telecommunication network (AFTN).
Aeronautical ground light
Any light specially provided as an aid to air navigation, other than a light displayed on an aircraft.
Information resulting from the assembly, analysis and formatting of aeronautical data.
Aeronautical Information Circular
A notice containing information that does not qualify for the origination of a NOTAM or for inclusion in the AIP, but which relates to flight safety, air navigation, technical, administrative or legislative matters.
Aeronautical Information Publication
A publication issued by or with the authority of a State and containing aeronautical information of a lasting character essential to air navigation.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 15; ICAO Annex 2;
Aeronautical information regulation and control
A system aimed at advance notification based on common effective dates, of circumstances that necessitate significant changes in operating practices.
aeronautical information service
a service established within the defined area of coverage responsible for the provision of aeronautical information and data necessary for the safety, regularity, and efficiency of air navigation
Aeronautical information service
A service established within the defined area of coverage responsible for the provision of aeronautical information/data necessary for the safety, regularity and efficiency of air navigation.
Aeronautical meteorological station
A station designated to make observations and meteorological reports for use in international air navigation.
An aeronautical mobile service reserved for communications relating to safety and regularity of flight, primarily along national or international civil air routes.
Aeronautical mobile service (RR S1.32)
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.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 3;
Aeronautical mobile-satellite (R)* service (RR S1.36)
An aeronautical mobile-satellite service reserved for communications relating to safety and regularity of flights, primarily along national or international civil air routes.
Aeronautical mobile-satellite service (RR S1.35)
A mobilesatellite service in which mobile earth stations are located on board aircraft; survival craft stations and emergency position-indicating radiobeacon stations may also participate in this service.
Aeronautical operational control
Communication required for the exercise of authority over the initiation, continuation, diversion or termination of flight for safety, regularity and efficiency reasons.
Aeronautical radio navigation service
A radio navigation service intended for the benefit and for the safe operation of aircraft.
A land station in the aeronautical mobile service. In certain instances, an aeronautical station may be located, for example, on board ship or on a platform at sea.
Aeronautical telecommunication agency
An agency responsible for operating a station or stations in the aeronautical telecommunication service.
Aeronautical telecommunication log
A record of the activities of an aeronautical telecommunication station.
Aeronautical telecommunication network
A global internetwork architecture that allows ground, air-ground and avionic data subnetworks to exchange digital data for the safety of air navigation and for the regular, efficient and economic operation of air traffic services.
Aeronautical telecommunication service
A telecommunication service provided for any aeronautical purpose.
Aeronautical telecommunication station
A station in the aeronautical telecommunication service.
A power-driven heavier-than-air aircraft, deriving its lift in flight chiefly from aerodynamic reactions on surfaces which remain fixed under given conditions of flight.
Aeroplane reference field length
The minimum field length required for take-off at maximum certificated take-off mass, sea level, standard atmospheric conditions, still air and zero runway slope, as shown in the appropriate aeroplane flight manual prescribed by the certificating authority or equivalent data from the aeroplane manufacturer. Field length means balanced field length for aeroplanes, if applicable, or take-off distance in other cases.
An aeroplane system includes all elements of equipment necessary for the control and performance of a particular major function. It includes both the equipment specifically provided for the function in question and other basic related aeroplane equipment such as that required to supply power for the equipment operation. As used herein [see Attachment E of Annex 6, Volume I] the power-unit is not considered to be an aeroplane system.
An alpha character group used to designate an airfiled flight plan.
A mode of engine operation wherein a combustion system fed (in whole or part) by vitiated air is used.
AFTN communication centre
An AFTN station whose primary function is the relay or retransmission of AFTN traffic from (or to) a number of other AFTN stations connected to it.
AFTN destination station
An AFTN station to which messages and/or digital data are addressed for processing for delivery to the addressee.
AFTN origin station
An AFTN station where messages and/or digital data are accepted for transmission over the AFTN.
A station forming part of the aeronautical fixed telecommunication network (AFTN) and operating as such under the authority or control of a State.
Agreed 4D trajectory
The current 4D trajectory that is agreed between the airspace user and the ASP after collaboration, or imposition of pre-collaborated rules.
Agreed reporting point
A point specified in the route description of a flight plan and agreed between the operator and the air traffic services unit to serve as a reporting point for the flight concerned.
A flight to service agricultural needs (e.g. crop spraying etc.). This includes flights to and from the spray area.
Aid to air navigation
Any visual or electronic system which provides information to be used by the pilot or aircraft navigation systems for position determination or flight path guidance.
Source: ICAO Doc 9294;
Synonyms: navaid, air navigation installation, navigation aid, air navigation aid
Permanent changes to the information contained in the AIP.
Temporary changes to the information contained in the AIP which are published by means of special pages.
an air transport undertaking holding a valid operating licence or equivalent at the latest on 31 January for the following summer season or on 31 August for the following winter season. For the purpose of Articles 4, 8, 8a and 10, the definition of air carrier shall also include business aviation operators, when they operate according to a schedule; for the purposes of Articles 7 and 14; the definition of air carrier shall also include all civil aircraft operators
Air defence identification zone
Special designated airspace of defined dimensions within which aircraft are required to comply with special identification and/or reporting procedures additional to those related to the provision of air traffic services (ATS).
air navigation service providers
any public or private entity providing air navigation services for general air traffic
air navigation services
air traffic services; communication, navigation and surveillance services; meteorological services for air navigation; and aeronautical information services
Air operator certificate
A certificate authorizing an operator to carry out specified commercial air transport operations.
Air route facilities
Facilities provided to permit safe operation of aircraft along an air route, including visual and radio navigation aids for approach and landing at aerodromes, and communication services, meteorological services and air traffic services and facilities.
a flight or a series of flights carrying passengers, cargo or mail for remuneration or hire
iI its broadest sense, includes any service performed by aircraft for public transportation, whether on a scheduled or non-scheduled basis.
For regulatory purposes, however, the term always has a specific meaning (defined in Article 96(a) of the Convention on International Civil Aviation and used in most bilateral air transport agreements between States) and refers to any scheduled air service performed by aircraft for the public transport of passengers, mail or cargo.
Air taxi service
A type of on-demand air service usually performed by small capacity aircraft on short notice in a very similar way to an automobile taxi service; or in some cases, a service operated on a scheduled basis with stops made only at points where passengers and cargo are to be picked up or discharged.
Air taxi/hover taxi
Air-taxiing. movement of a helicopter/vtol above the surface of an aerodrome, normally in ground effect and at a ground speed normally less than 37 km/h (20 kt). icao annex 2.
All aircraft in flight or operating on the manoeuvring area of an aerodrome.
Air traffic advisory service
A service provided within advisory airspace to ensure separation, in so far as practical, between aircraft which are operating on IFR flight plans.
air traffic control (ATC) service
a service provided for the purpose of:(a) preventing collisions:- between aircraft, and - in the manoeuvring area between aircraft and obstructions; and(b) expediting and maintaining an orderly flow of air traffic;
air traffic control clearance
the authorisation for an aircraft to proceed under conditions specified by an air traffic control unit
Air traffic control clearance
Authorization for an aircraft to proceed under conditions specified by an air traffic control unit.
Air traffic control instruction
Directives issued by air traffic control for the purpose of requiring a pilot to take a specific action.
Air traffic control service
A service provided for the purpose of: a) preventing collisions: 1) between aircraft, and 2) on the manoeuvring area between aircraft and obstructions, and b) expediting and maintaining an orderly flow of air traffic.
Air traffic control unit
A generic term meaning variously, area control centre, approach control unit or aerodrome control tower.
air traffic flow management
a function established with the objective of contributing to a safe, orderly and expeditious flow of air traffic by ensuring that ATC capacity is utilised to the maximum extent possible, and that the traffic volume is compatible with the capacities declared by the appropriate air traffic service providers
Air traffic flow management
A service established with the objective of contributing to a safe, orderly and expeditious flow of air traffic by ensuring that ATC capacity is utilized to the maximum extent possible and that the traffic volume is compatible with the capacities declared by the appropriate ATS authority.
air traffic flow management (ATFM) departure slot
a calculated take-off time attributed by the central unit for ATFM with a time tolerance managed by the local ATS unit
air traffic flow management (ATFM) measure
the actions taken to perform air traffic flow management and capacity management
air traffic management
the aggregation of the airborne and ground-based functions (air traffic services, airspace management and air traffic flow management) required to ensure the safe and efficient movement of aircraft during all phases of operations
Air traffic management
The dynamic, integrated management of air traffic and airspace including air traffic services, airspace management and air traffic flow management - safely, economically and efficiently - through the provision of facilities and seamless services in collaboration with all parties and involving airborne and ground-based functions.
Air traffic management system
A system that provides ATM through the collaborative integration of humans, information, technology, facilities and services, supported by air and ground- and/or space-based communications, navigation and surveillance.
Air traffic service
A generic term meaning variously, flight information service, alerting service, air traffic advisory service, air traffic control service (area control service, approach control service or aerodrome control service).
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 2; ICAO Annex 4;
air traffic service (ATS) unit sector configuration
the four dimensional description of an ATS unit airspace sector, or group of sectors, which may be operated on a permanent or temporary basis
air traffic service route
a specified part of the airspace structure designed for channelling the flow of traffic as necessary for the provision of air traffic services
air traffic services
the various flight information services, alerting services, air traffic advisory services and ATC services (area, approach and aerodrome control services)
air traffic services (ATS) reporting office
an ATS unit established for the purpose of receiving reports concerning ATS and flight plans submitted before the first delivery of an air traffic control clearance
Air traffic services airspaces
Airspaces of defined dimensions, alphabetically designated, within which specific types of flights may operate and for which air traffic services and rules of operation are specified.
Air traffic services reporting office
A unit established for the purpose of receiving reports concerning air traffic services and flight plans submitted before departure.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 2;
Synonyms: ATS reporting office
Air traffic services unit
A generic term meaning variously, air traffic control unit, flight information centre or air traffic services reporting office.
Air transit route
A defined route for the air transiting of helicopters.
Air-filed flight plan
A flight plan provided to an air traffic services unit by an aircraft during its flight.
Two-way communication between aircraft and stations or locations on the surface of the earth.
Air-ground control radio station
An aeronautical telecommunication station having primary responsibility for handling communications pertaining to the operation and control of aircraft in a given area.
A report from an aircraft in flight prepared in conformity with requirements for position, and operational and/or meteorological reporting.
Movement of a helicopter/VTOL above the surface of an aerodrome, normally in ground effect and at a ground speed normally less than 37 km/h (20 kt).
One-way communication from aircraft to stations or locations on the surface of the earth.
An acronym (aeronautical information regulation and control) signifying a system aimed at advance notification based on common effective dates, of circumstances that necessitate significant changes in operating practices.
Airborne collision avoidance system
An aircraft system based on secondary surveillance radar (SSR) transponder signals which operates independently of groundbased equipment to provide advice to the pilot on potential conflicting aircraft that are equipped with SSR transponders.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 2;
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.
Aircraft - category
Classification of aircraft according to specified basic characteristics, e.g. aeroplane, helicopter, glider, free balloon.
Aircraft - type of
All aircraft of the same basic design including all modifications thereto except those modifications which result in a change in handling or flight characteristics.
A unique combination of twenty-four bits available for assignment to an aircraft for the purpose of air-ground communications, navigation and surveillance.
A term designating any electronic device - including its electrical part - for use in an aircraft, including radio, automatic flight control and instrument systems.
Aircraft call sign
A group of alphanumeric characters used to identify an aircraft in air-ground communication.
Aircraft certificated for single-pilot operation
A type of aircraft which the State of Registry has determined, during the certification process, can be operated safely with a minimum crew of one pilot.
Aircraft classification number
A number expressing the relative effect of an aircraft on a pavement for a specified standard subgrade category.
Aircraft earth station
A mobile earth station in the aeronautical mobile-satellite service located on board an aircraft (see also "GES").
Articles, including first-aid and survival equipment and commissary supplies, but not spare parts or stores, for use on board an aircraft during flight.
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 services communications.
Information on planned future aircraft behaviour, which can be obtained from the aircraft systems (avionics). It is associated with the commanded trajectory and will enhance airborne functions. The aircraft intent data correspond either to aircraft trajectory data that directly relate to the future aircraft trajectory as programmed inside the avionics, or the aircraft control parameters as managed by the automatic flight control system. These aircraft control parameters could either be entered by the flight crew or automatically derived by the flight management system.
The evaluation of one or more meteorological elements made from an aircraft in flight.
Aircraft operating agency
The person, organization or enterprise engaged in, or offering to engage in, an aircraft operation.
Aircraft operating manual
A manual, acceptable to the State of the Operator, containing normal, abnormal and emergency procedures, checklists, limitations, performance information, details of the aircraft systems and other material relevant to the operation of the aircraft.
A person, organization or enterprise engaged in or offering to engage in an aircraft operation.
Aircraft operators' documents
Air waybills/consignment notes, passenger tickets and boarding passes, bank and agent settlement plan documents, excess baggage tickets, miscellaneous charges orders (M.C.O.), damage and irregularity reports, baggage and cargo labels, timetables, and weight and balance documents, for use by aircraft operators.
A situation in which, in the opinion of a pilot or air traffic services personnel, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved may have been compromised. An aircraft proximity is classified as follows:
Risk of collision. The risk classification of an aircraft proximity in which serious risk of collision has existed.
Safety not assured. The risk classification of an aircraft proximity in which the safety of the aircraft may have been compromised.
No risk of collision. The risk classification of an aircraft proximity in which no risk of collision has existed.
Risk not determined. The risk classification of an aircraft proximity in which insufficient information was available to determine the risk involved, or inconclusive or conflicting evidence precluded such determination.
Aircraft required to be operated with a co-pilot
A type of aircraft that is required to be operated with a co-pilot, as specified in the flight manual or by the air operator certificate.
Aircraft security check
An inspection of the interior of an aircraft to which passengers may have had access and an inspection of the hold for the purposes of discovering suspicious objects, weapons, explosives or other dangerous devices, articles and substances.
Aircraft security search
A thorough inspection of the interior and exterior of the aircraft for the purpose of discovering suspicious objects, weapons, explosives or other dangerous devices, articles or substances.
A designated area on an apron intended to be used for parking an aircraft.
Aircraft stand taxilane
Aircraft stand taxilane. A portion of an apron designated as a taxiway and intended to provide access to aircraft stands only.
A mobile station in the aeronautical mobile service, other than a survival craft station, located on board an aircraft.
The aircraft trajectory is the trajectory that the aircraft intends to fly (and has flown).
Aircraft type designator
A group of alphanumeric characters used to identify, in an abbreviated form, a type of aircraft.
As provided in Article 96 of the Convention, any air transport enterprise offering or operating a scheduled international air service.
Airline and operators' documents
Air waybills/consignment notes, passenger tickets and boarding passes, bank and agent settlement plan documents, excess baggage tickets, miscellaneous charges orders (M.C.O.), damage and irregularity reports, baggage and cargo labels, timetables, and weight and balance documents, for use by airlines and operators.
The consistent use of good judgement and well-developed knowledge, skills and attitudes to accomplish flight objectives.
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 which was not already included in the forecast issued for low-level flights in the flight information region concerned or sub-area thereof.
Airport � Collaborative Decision Making
a process in which decisions related to Air Traffic Flow and Capacity Management (hereinafter: �ATFCM�) at airports are made based on interaction between operational stakeholders and other actors involved in ATFCM and which aims at reducing delays, improving the predictability of events and optimising the utilisation of resources
The number of passengers and amount of cargo which an airport can accommodate in a given period of time; it is a combination of runway capacity and terminal capacity.
Airport Operations Plan
a single, common and collaboratively agreed rolling plan available to all airport stakeholders whose purpose is to provide common situational awareness and to form the basis upon which stakeholder decisions relating to process optimisation can be made
the �managing body of an airport� as defined in point (j) of Article 2 of Regulation (EEC) No 95/93
airport slot coordinator
the function established at coordinated airports in application of Regulation (EEC) No 95/93
two or more airports grouped together and serving the same city or conurbation, as indicated in Annex II to Regulation (EEC) No 2408/92
The code word used in an air traffic incident report to designate aircraft proximity.
A power-driven lighter-than-air aircraft.
Flights carried out in conjunctions with airshows / air races.
The movement area of an airport, adjacent terrain and buildings or portions thereof, access to which is controlled.
an airspace of defined dimensions, in space and time, within which air navigation services are provided
a process to contribute to the achievement of network related performance targets and to cater for airspace users needs as well as to ensure or increase the established safety level and increase the airspace capacity and environmental performance through the development and implementation of advanced navigational capabilities and techniques, improved route networks and associated sectorisation, optimised airspace structures and capacity enhancing ATM procedures
a planning function with the primary objective of maximising the utilisation of available airspace by dynamic time-sharing and, at times, the segregation of airspace among various categories of airspace users on the basis of short-term needs
The process by which airspace options are selected and applied to meet the needs of the ATM community.
a defined volume of airspace temporarily reserved for exclusive or specific use by categories of users
A defined volume of airspace normally under the jurisdiction of one aviation authority and temporarily reserved, by common agreement, for exclusive use by another aviation authority.
a defined volume of airspace within which, variously, activities dangerous to the flight of aircraft may be conducted at specified times (a �danger area�); or such airspace situated above the land areas or territorial waters of a State, within which the flight of aircraft is restricted in accordance with certain specified conditions (a �restricted area�); or such airspace situated above the land areas or territorial waters of a State, within which the flight of aircraft is prohibited (a �prohibited area�)
a specific volume of airspace designed to ensure the safe and optimal operation of aircraft
Airspace user trajectory constraint
Airspace user's trajectory constraint on the acceptable solutions.
operators of aircraft operated as general air traffic
airspace users' representative
any legal person or entity representing the interests of one or several categories of users of air navigation services
the way that airspace is operationally used
Airspace volume concept
A concept of controlled airspace organization which allows an aircraft operator complete freedom to manoeuvre within a designated airspace.
The temperature indicated by a thermometer exposed to the air in a place sheltered from direct solar radiation.
A control area or portion thereof established in the form of a corridor.
The status of an aircraft, engine, propeller or part when it conforms to its approved design and is in a condition for safe operation.
Aeronautical information provided in the form of the elements of the Integrated Aeronautical Information Package (except NOTAM and PIB), including aeronautical charts, or in the form of suitable electronic media.
The code word used to designate an alert phase.
A situation wherein apprehension exists as to the safety of an aircraft and its occupants.
Any facility intended to serve as an intermediary between a person reporting an emergency and a rescue coordination centre or rescue subcentre.
a service provided to notify relevant organisations regarding aircraft in need of search and rescue aid, and to assist such organisations as required
A service provided to notify appropriate organizations regarding aircraft in need of search and rescue aid, and assist such organizations as required.
An equation relating illuminance (E) produced by a point source of light of intensity (I) on a plane normal to the line of sight, at distance (x) from the source, in an atmosphere having a transmissivity (T).
Distribution of frequencies, SSR codes, etc. to a State, unit or service. Distribution of 24-bit aircraft addresses to a State or common mark registering authority.
A fix tolerance along the nominal track resulting from the airborne and ground equipment tolerances.
A collective term for letters and figures (digits).
A presentation of letters and figures either on a radar display or on a separate screen or panel.
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. Alternate aerodromes include the following:
Take-off alternate. An alternate aerodrome at which an aircraft can land should this become necessary shortly after take-off and it is not possible to use the aerodrome of departure.
En-route alternate. An aerodrome at which an aircraft would be able to land after experiencing an abnormal or emergency condition while en-route.
ETOPS en-route alternate. A suitable and appropriate alternate aerodrome at which an aeroplane would be able to land after experiencing an engine shutdown or other abnormal or emergency condition while en-route in an ETOPS operation.
Destination alternate. An alternate aerodrome to which an aircraft may proceed should it become either impossible or inadvisable to land at the aerodrome of intended landing.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 2; ICAO Annex 3; ICAO Annex 6;
An airport to which an aircraft may proceed when it becomes either impossible or inadvisable, for technical reasons, to proceed to or to land at the airport of intended landing.
A heliport to which a helicopter may proceed when it becomes either impossible or inadvisable to proceed to or to land at the heliport of intended landing. Alternate heliports include the following: Take-off alternate. An alternate heliport at which a helicopter can land should this become necessary shortly after take-off and it is not possible to use the heliport of departure. En-route alternate. A heliport at which a helicopter would be able to land after experiencing an abnormal or emergency condition while en-route. Destination alternate. An alternate heliport to which a helicopter may proceed should it become either impossible or inadvisable to land at the heliport of intended landing.
Alternative means of communication
A means of communication provided with equal status, and in addition to the primary means.
Altitude setting (also known as QNH) is defined as barometric pressure adjusted to sea level. It is a pressure setting used by pilots, air traffic control (ATC), and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to read altitude above mean sea level within a certain defined region.
Altimetry system error
The difference between the altitude indicated by the altimeter display, assuming a correct altimeter barometric setting, and the pressure altitude corresponding to the undisturbed ambient pressure.
The vertical distance of a level, a point or an object considered as a point, measured from mean sea level (MSL).
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 2; ICAO Annex 3; ICAO Annex 4;
The ampere is that constant electric current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in a vacuum, would produce between these conductors a force equal to 2 x 10-7 newton per metre of length.
Angles of coverage
"a) Angle of coverage A is formed by two intersecting vertical planes making angles of 70 degrees to the right and 70 degrees to the left respectively, looking aft along the longitudinal axis to a vertical plane passing through the longitudinal axis. b) Angle of coverage F is formed by two intersecting vertical planes making angles of 110 degrees to the right and 110 degrees to the left respectively, looking forward along the longitudinal axis to a vertical plane passing through the longitudinal axis.c) Angle of coverage L is formed by two intersecting vertical planes, one parallel to the longitudinal axis of the aeroplane, and the other 110 degrees to the left of the first, when looking forward along the longitudinal axis.d) Angle of coverage R is formed by two intersecting vertical planes, one parallel to the longitudinal axis of the aeroplane, and the other 110 degrees to the right of the first, when looking forward along the longitudinal axis."
Anticipated operating conditions
Those conditions which are known from experience or which can be reasonably envisaged to occur during the operational life of the aircraft taking into account the operations for which the aircraft is made eligible, the conditions so considered being relative to the meteorological state of the atmosphere, to the configuration of terrain, to the functioning of the aircraft, to the efficiency of personnel and to all the factors affecting safety in flight. Anticipated operating conditions do not include: a) those extremes which can be effectively avoided by means of operating procedures; and b) those extremes which occur so infrequently that to require the Standards to be met in such extremes would give a higher level of airworthiness than experience has shown to be necessary and practical.
Manipulation and processing of data in support of user requirements (ISO 19104).
Conceptual schema for data required by one or more applications.
The phase of flight from the outer marker to the to the point of transition from nose-low to nose-high attitude immediately prior to the flare above the runway [ifr]; or [vfr] from 1500 feet (450 metres) above the runway end elevation or from the point of vfr pattern entry to the flare above the runway.
Approach - holding
The phase of flight in which a pre-determined ad-hoc manoeuvre during the approach keeps the aircraft within a specified airspace awaiting further instructions.
Approach and landing operations using instrument approach procedures
Instrument approach and landing operations are classified as follows: Non-precision approach and landing operations. An instrument approach and landing which utilizes lateral guidance but does not utilize vertical guidance. Approach and landing operations with vertical guidance. An instrument approach and landing which utilizes lateral and vertical guidance but does not meet the requirements established for precision approach and landing operations. Precision approach and landing operations. An instrument approach and landing using precision lateral and vertical guidance with minima as determined by the category of operation.
Approach and landing operations with vertical guidance
An instrument approach and landing which utilizes lateral and vertical guidance but does not meet the requirements established for precision approach and landing operations.
Approach and landing phase - helicopters
That part of the flight from 300 m (1 000 ft) above the elevation of the FATO, if the flight is planned to exceed this height, or from the commencement of the descent in the other cases, to landing or to the balked landing point.
approach control service
an ATC service for arriving or departing controlled flights
Approach control service
Air traffic control service for arriving or departing controlled flights.
Approach control unit
A unit established to provide air traffic control service to controlled flights arriving at, or departing from, one or more aerodromes.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 2; ICAO Annex 3;
Synonyms: Approach control office; ATC Unit
A specified airspace around a nominal approach path within which an aircraft approaching to land is considered to be making a normal approach.
The operating phase defined by the time during which the engine is operated in the approach operating mode.
Approach procedure with vertical guidance
An instrument approach procedure which utilizes lateral and vertical guidance but does not meet the requirements established for precision approach and landing operations.
The order in which two or more aircraft are cleared to approach to land at the aerodrome.
Appropriate airworthiness requirements
The comprehensive and detailed airworthiness codes established, adopted or accepted by a Contracting State for the class of aircraft, engine or propeller under consideration (see 3.2.2 of Part II of this Annex).
Appropriate ATS authority
The relevant authority designated by the State responsible for providing air traffic services in the airspace concerned.
a) Regarding flight over the high seas: The relevant authority of the State of Registry. b) Regarding flight other than over the high seas: The relevant authority of the State having sovereignty over the territory being overflown.
An authorization granted by an appropriate national authority for: a) the transport of dangerous goods forbidden on passenger and/or cargo aircraft where the Technical Instructions state that such goods may be carried with an approval; or b) other purposes as provided for in the Technical Instructions.
Accepted by a Contracting State as suitable for a particular purpose.
Approved maintenance organization
An organization approved by a Contracting State, in accordance with the requirements of Annex 6, Part I, Chapter 8 - Aeroplane Maintenance, to perform maintenance of aircraft or parts thereof and operating under supervision approved by that State.
Training conducted under special curricula and supervision approved by a Contracting State.
Approved training organization
An organization approved by and operating under the supervision of a Contracting State in accordance with the requirements of Annex 1 to perform approved training.
A defined area, on a land aerodrome, intended to accommodate aircraft for purposes of loading or unloading passengers, mail or cargo, fuelling, parking or maintenance.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 14; ICAO Annex 2; ICAO Annex 4;
Synonyms: tarmac; ramp
Apron management service
A service provided to regulate the activities and the movement of aircraft and vehicles on an apron.
Apron taxiway. A portion of a taxiway system located on an apron and intended to provide a through taxi route across the apron.
Area control centre
A unit established to provide air traffic control service to controlled flights in control areas under its jurisdiction.
area control service
an ATC service for controlled flights in a block of airspace
Area control service
Air traffic control service for controlled flights in control areas.
Area minimum altitude
The minimum altitude to be used under instrument meteorological conditions (IMC), that provides a minimum obstacle clearance within a specified area, normally formed by parallels and meridians.
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 these.
Area navigation route
An ATS route established for the use of aircraft capable of employing area navigation.
Arresting gear location
Location of the arresting gear cable across the runway.
Routes identified in an instrument approach procedure by which aircraft may proceed from the en-route phase of flight to an initial approach fix.
A special series NOTAM notifying by means of a specific format change in activity of a volcano, a volcanic eruption and/or volcanic ash cloud that is of significance to aircraft operations.
A process of merging data from multiple sources into a database and establishing a baseline for subsequent processing.
Distribution of frequencies to stations. Distribution of SSR codes or 24-bit aircraft addresses to aircraft.
Associated aircraft systems
Those aircraft systems drawing electrical/pneumatic power from an auxiliary power unit during ground operations.
An ordered cycle of information or data flow, computation, co-ordination, decision making, control and monitoring, which constitutes the complete function of an air traffic control unit.
a defined volume of airspace for which an associated controller(s) has ATC responsibility at any given time
The symbol used to designate automatic terminal information service.
The aggregate of organizations, agencies or entities that may participate, collaborate and cooperate in the planning, development, use, regulation, operation and maintenance of the ATM system.
ATM Master Plan
the plan endorsed by Council Decision 2009/320/EC (1), in accordance with Article 1(2) of Council Regulation (EC) No 219/2007 of 27 February 2007 on the establishment of a Joint Undertaking to develop the new generation European air traffic management system (SESAR) (1)
ATM operational concept
The ATM operational concept is a high-level description of the ATM services necessary to accommodate traffic at a given time horizon; a description of the anticipated level of performance required from, and the interaction between, the ATM services, as well as the objects they affect; and a description of the information to be provided to agents in the ATM system and how that information is to be used for operational purposes. The operational concept is neither a description of the air navigation infrastructure nor a technical system description nor a detailed description of how a particular functionality or technology could be used.
ATM trajectory constraint
Trajectory constraint imposed by the ATM system.
ATS direct speech circuit
An aeronautical fixed service (AFS) telephone circuit, for direct exchange of information between air traffic services (ATS) units.
A specified route designed for channelling the flow of traffic as necessary for the provision of air traffic services.
ATS surveillance service
A term used to indicate a service provided directly by means of an ATS surveillance system.
ATS surveillance system
A generic term meaning variously, ADS-B, PSR, SSR or any comparable ground-based system that enables the identification of aircraft.
A person who represents an aircraft operator and who is authorized by or on behalf of such operator to act on formalities connected with the entry and clearance of the operator's aircraft, crew, passengers, cargo, mail, baggage or stores and includes, where national law permits, a third party authorized to handle cargo on the aircraft.
Automatic dependent surveillance
A surveillance technique in which aircraft automatically provide, via a data link, data derived from on-board navigation and position-fixing systems, including aircraft identification, four-dimensional position and additional data as appropriate.
Automatic dependent surveillance - broadcast
A means by which aircraft, aerodrome vehicles and other objects can automatically transmit and/or receive data such as identification, position and additional data, as appropriate, in a broadcast mode via a data link.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 15; ICAO Annex 2;
Automatic dependent surveillance - contract
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.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 15; ICAO Annex 2;
Automatic dependent surveillance-broadcast IN
A function that receives surveillance data from ADS-B OUT data sources.
Automatic dependent surveillance-broadcast OUT
A function on an aircraft or vehicle that periodically broadcasts its state vector (position and velocity) and other information derived from on-board systems in a format suitable for ADS-B IN capable receivers.
Automatic deployable ELT
An ELT which is rigidly attached to an aircraft and which is automatically deployed and activated by impact, and, in some cases, also by hydrostatic sensors. Manual deployment is also provided.
Automatic fixed ELT
An automatically activated ELT which is permanently attached to an aircraft.
Automatic portable ELT
An automatically activated ELT which is rigidly attached to an aircraft but readily removable from the aircraft.
Automatic relay installation
A teletypewriter installation where automatic equipment is used to transfer messages from incoming to outgoing circuits.
Automatic telecommunication log
A record of the activities of an aeronautical telecommunication station recorded by electrical or mechanical means.
Automatic terminal information service
The automatic provision of current, routine information to arriving and departing aircraft throughout 24 hours or a specified portion thereof: Data link-automatic terminal information service (D-ATIS). The provision of ATIS via data link. Voice-automatic terminal information service (Voice-ATIS). The provision of ATIS by means of continuous and repetitive voice broadcasts.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 15;
Autorotation:a rotorcraft flight condition in which the lifting rotor is driven entirely by action of the air when the rotorcraft is in motion. During powered flight, the rotor drag is overcome with engine power. When the engine fails, or is deliberately disengaged from the rotor system, some other force must be used to sustain rotor RPM so controlled flight can be continued to the ground. This force is generated by adjusting the collective pitch to allow a controlled descent. Airflow during helicopter descent provides the energy to overcome blade drag and turn the rotor. When the helicopter is descending in this manner, it is said to be in a state of autorotation.
Autorotative landing - helicopter
The phase of flight where the helicopter lands with no engine power being delivered to the aircraft's rotors, e.g. where the helicopter is manoeuvring in an emergency situation following an engine failure, with the intent to touch down.
A self-contained power-unit on an aircraft providing electrical/pneumatic power to aircraft systems during ground operations.
The ability of a system to perform its required function at the initiation of the intended operation. It is quantified as the proportion of the time the system is available to the time the system is planned to be available.
aviation frequency band
an entry in the ITU Radio Regulations Table of Frequency Allocations of a given frequency band in which frequency assignments are made for the purpose of general air traffic
A check of a person's identity and previous experience, including where legally permissible, any criminal history, as part of the assessment of an individual's suitability to implement a security control and/or for unescorted access to a security restricted area.
Personal property of passengers or crew carried on an aircraft by agreement with the operator.
A landing manoeuvre that is unexpectedly discontinued at any point below the obstacle clearance altitude/height (OCA/H).
A non-power-driven lighter-than-air aircraft.
Surface of the Earth including bodies of water and permanent ice and snow, and excluding vegetation and man-made objects.
Three or more aeronautical ground lights closely spaced in a transverse line so that from a distance they appear as a short bar of light.
A turn executed by the aircraft during the initial approach between the end of the outbound track and the beginning of the intermediate or final approach track. The tracks are not reciprocal.
Basic instrument flight trainer
[Apparatus] which is equipped with appropriate instruments, and which simulates the flight deck environment of an aircraft in flight in instrument flight conditions.
The activity of a radionuclide having one spontaneous nuclear transition per second.
Reduced cost to the user (to the ATM community as a whole) in the form of a saving in time and/or fuel; increased revenue; and/or an improvement to safety.
Bit error rate
The number of bit errors in a sample divided by the total number of bits in the sample, generally averaged over many such samples.
A transmission from one station to another station in circumstances where two-way communication cannot be established but where it is believed that the called station is able to receive the transmission.
The radial velocity of a moving target such that the target is not seen on primary radars fitted with certain forms of fixed echo suppression.
From the statistical point of view, blunders or mistakes are observations that cannot be considered as belonging to the same sample from the distribution in question. They should not be used with other observations. They should be located and eliminated.
The enforcement, by a State, of its laws and/or regulations concerning the movement of goods and/or persons across its borders.
Oral commentary on existing and/or expected meteorological conditions.
A radar display capable of being used under relatively high ambient light levels.
A transmission of information relating to air navigation that is not addressed to a specific station or stations.
bundle of services
two or more air navigation services
that sector of general aviation which concerns the operation or use of aircraft by companies for the carriage of passengers or goods as an aid to the conduct of their business, where the aircraft are flown for purposes generally considered not for public hire and are piloted by individuals having, at a minimum, a valid commercial pilot license with an instrument rating
Flight to carry company personnel. Includes corporate operations.
The ratio of the air mass flow through the bypass ducts of a gas turbine engine to the air mass flow through the combustion chambers calculated at maximum thrust when the engine is stationary in an international standard atmosphere at sea level.
Cabin crew member
A crew member who performs, in the interest of safety of passengers, duties assigned by the operator or the pilot-in-command of the aircraft, but who shall not act as a flight crew member.
Discrete temporal reference system that provides the basis for defining temporal position to a resolution of one day (ISO 19108).
The luminous intensity, in the perpendicular direction, of a surface of 1/600 000 square metre of black body at the temperature of freezing platinum under a pressure of 101 325 newtons per square metre.
Bare Earth supplemented by vegetation height.
The ability of a system to provide a service or perform a function that, either on its own or with other services or functions, can deliver a definable level of performance. This level of performance is measurable within a framework of performance indicators and safety requirements.
Capacitor discharge light
A lamp in which high-intensity flashes of extremely short duration are produced by the discharge of electricity at high voltage through a gas enclosed in a tube.
The maximum number of aircraft that can be accommodated in a given time period by the system or one of its components (throughput).
Any property carried on an aircraft other than mail, stores and accompanied or mishandled baggage.
Cargo air service
An air service provided for the public transport of freight and mail.
Any aircraft, other than a passenger aircraft, which is carrying goods or property.
The ratio of the carrier power received directly, i.e. without reflection, to the multipath power, i.e. carrier power received via reflection.
Carrier-to-noise density ratio
The ratio of the total carrier power to the average noise power in a 1 Hz bandwidth, usually expressed in dBHz.
With respect to helicopters, means a multi-engine helicopter designed with engine and system isolation features specified in Part IVB and capable of operations using take-off and landing data scheduled under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight or safe rejected take-off.
With respect to helicopters, means a single-engine or multi-engine helicopter which does not meet Category A standards. Category B helicopters have no guaranteed capability to continue safe flight in the event of an engine failure, and a forced landing is assumed.
Category I (CAT I) operation
A precision instrument approach and landing with a decision height not lower than 60 m (200 ft) and with either a visibility not less than 800 m or a runway visual range not less than 550 m.
Category II (CAT II) operation
A precision instrument approach and landing with a decision height lower than 60 m (200 ft), but not lower than 30 m (100 ft), and a runway visual range not less than 350 m.
Category IIIA (CAT IIIA) operation
A precision instrument approach and landing with: a) a decision height lower than 30 m (100 ft) or no decision height; and b) a runway visual range not less than 200 m.
Category IIIB (CAT IIIB) operation
A precision instrument approach and landing with: a) a decision height lower than 15 m (50 ft) or no decision height; and b) a runway visual range less than 200 m but not less than 50 m.
Category IIIC (CAT IIIC) operation
A precision instrument approach and landing with no decision height and no runway visual range limitations.
Actions, omissions, events, conditions, or a combination thereof, which led to the accident or incident. The identification of causes does not imply the assignment of fault or the determination of administrative, civil or criminal liability.
The height above the ground or water of the base of the lowest layer of cloud below 6 000 metres (20 000 feet) covering more than half the sky.
The Celsius temperature is equal to the difference t�C = T - T0 between two thermodynamic temperatures T and T0 where T0 equals 273.15 kelvin.
a document issued by a national supervisory authority in any form complying with national law, which confirms that an air navigation service provider meets the requirements for providing a specific service
A formal evaluation and confirmation by or on behalf of the appropriate authority for aviation security that a person possesses the necessary competencies to perform assigned functions to an acceptable level as defined by the appropriate authority.
An aerodrome whose operator has been granted an aerodrome certificate.
Certify as airworthy (to)
To certify that an aircraft or parts thereof comply with current airworthiness requirements after maintenance has been performed on the aircraft or parts thereof.
Change of cruise level
The phase of flight during which the aircraft climbs, or descends, from one cruising flight level or altitude to the next cruising flight level or altitude.
The point at which an aircraft navigating on an ATS route segment defined by reference to very high frequency omnidirectional radio ranges is expected to transfer its primary navigational reference from the facility behind the aircraft to the next facility ahead of the aircraft.
The rate at which bits are transmitted over the RF channel. These bits include those bits used for framing and error correction, as well as the information bits. For burst transmission, the channel rate refers to the instantaneous burst rate over the period of the burst.
Channel rate accuracy
This is relative accuracy of the clock to which the transmitted channel bits are synchronized. For example, at a channel rate of 1.2 kbits/s, maximum error of one part in 106 implies the maximum allowed error in the clock is �1.2 � 10-3 Hz.
A flight carried out to verify the qualifications/ability of a license holder.
An extension of an instrument approach procedure which provides for visual circling of the aerodrome prior to landing.
A configuration of the communications network which gives the appearance to the application of a dedicated transmission path.
Circuit Pattern - Crosswind (VFR)
A flight path of the VFR traffic pattern, which is perpendicular to the landing runway, crosses the departure end of the runway, and connects with the downwind leg.
Circuit pattern - downwind
The phase of vfr flight from 1500 feet above runway end elevation (450 metres) or the point of vfr pattern entry; commences at about 45 degrees from the threshold, continues parallel to the runway in the direction opposite to landing and terminates upon initiating the turn to base final.
Circuit pattern - final
The phase of flight between the start of the turn from base leg to a flight path along the extended runway centre line, to the runway.
Circuit pattern-base leg
The phase of vfr flight from the start of the turn at end of downwind leg, then at 90 degrees to the landing runway until reaching the extended centre line off the approach end of the runway.
Circular error probability
CEP refers to the radius of a circle within which a stated percentage of measurements for a given point will fall. For example, if the horizontal accuracy of a surveyed point is stated as 1 m with 90% CEP, then 90% of measurements of this point will fall within a circle of radius 1 m. The true position is then estimated to lie at the centre of this circle.
Civil aviation inspector
A civil aviation inspector is an individual, designated by a Contracting State, who is charged with the inspection of the safety, security or related aspects of air transport operations as directed by the appropriate authority.
the interaction between civil and military authorities and components of air traffic management necessary to ensure safe, efficient and harmonious use of the airspace
Class A airspace
IFR flights only are permitted, all flights are provided with air traffic control service and are separated from each other.
Class B airspace
IFR and VFR flights are permitted, all flights are provided with air traffic control service and are separated from each other.
Class C airspace
IFR and VFR flights are permitted, all flights are provided with air traffic control service and IFR flights are separated from other IFR flights and from VFR flights. VFR flights are separated from IFR flights and receive traffic information in respect of other VFR flights.
Class D airspace
IFR and VFR flights are permitted and all flights are provided with air traffic control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights, VFR flights receive traffic information in respect of all other flights.
Class E airspace
IFR and VFR flights are permitted, IFR flights are provided with air traffic control service and are separated from other IFR flights. All flights receive traffic information as far as is practical. Class E shall not be used for control zones.
Class F airspace
IFR and VFR flights are permitted, all participating IFR flights receive an air traffic advisory service and all flights receive flight information service if requested. Note.- Where air traffic advisory service is implemented, this is considered normally as a temporary measure only until such time as it can be replaced by air traffic control.
Class G airspace
IFR and VFR flights are permitted and receive flight information service if requested.
The formulation and transmission of a clearance by an air traffic control unit as well as the acknowledgement and acceptance of such clearance by the pilot.
The point to which an aircraft is granted an air traffic control clearance.
Clearance of goods
The accomplishment of the customs formalities necessary to allow goods to enter home use, to be exported or to be placed under another customs procedure.
Clearance void time
A time specified by an air traffic control unit at which a clearance ceases to be valid unless the aircraft concerned has already taken action to comply therewith.
A defined rectangular area on the ground or water under the control of the appropriate authority, selected or prepared as a suitable area over which an aeroplane may make a portion of its initial climb to a specified height.
Climb into traffic pattern
The phase of flight from 50 feet [15 metres] above runway end elevation to the first prescribed power reduction on reaching the vfr pattern. applies to pilot training in which the aircraft's climb phase is not intended to reach altitude.
The operating phase defined by the time during which the engine is operated in the climb operating mode.
Climb to cruising level or altitude
The phase of flight in which the climb from the completion of the initial climb to cruising level or altitude occurs.
Closed path CDO procedures
Procedures coded with track to fix (TF) legs and fly-by waypoints. STARs that terminate with a link to an instrument approach procedure should terminate at a fly-by waypoint. STARs that terminate with vector-based legs may be coded with fix to manual termination (FM) or heading to manual termination (VM) path terminators.
Cloud of operational significance
A cloud with the height of cloud base below 1 500 m (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.
For a given cloud or cloud layer, height of the lowest level in the atmosphere at which the air contains a perceptible quantity of cloud particles.
Co-ordinated Universal Time
International term for time at the prime meridian.
The process of obtaining agreement on clearances, transfer of control, advice or information to be issued to aircraft, by means of information exchanged between air traffic services units or between controller positions within such units.
A licensed pilot serving in any piloting capacity other than as pilot-in-command but excluding a pilot who is on board the aircraft for the sole purpose of receiving flight instruction.
Coast guard flight
A flight carried out by the Coast Guard or similar agency.
The number assigned to a particular multiple pulse reply signal transmitted by a transponder in Mode A or Mode C.
Collision avoidance logic
The sub-system or part of ACAS that analyses data relating to an intruder and own aircraft, decides whether or not advisories are appropriate and, if so, generates the advisories. It includes the following functions: range and altitude tracking, threat detection and RA generation. It excludes surveillance.
An air service that carries both passengers and cargo on board the same aircraft.
Commencement of journey
The point at which the person began his journey, without taking into account any airport at which he stopped in direct transit, either on a through-flight or a connecting flight, if he did not leave the direct transit area of the airport in question.
Commercial air transport operation
An aircraft operation involving the transport of passengers, cargo or mail for remuneration or hire.
Source: ICAO Annex 1; ICAO Annex 17; ICAO Annex 6;
Synonyms: commercial air transport flight
An airport used by the general public that includes facilities for processing passengers, handling cargo and servicing commercial aircraft.
Commercial transport aircraft
Transport aircraft that are used for remuneration or hire.
Items, either disposable or intended for multiple use, that are used by the aircraft operator for provision of services during flights, in particular for catering, and for the comfort of passengers.
A mark assigned by the International Civil Aviation Organization to the common mark registering authority registering aircraft of an international operating agency on other than a national basis.
Common mark registering authority
The authority maintaining the non-national register or, where appropriate, the part thereof, in which aircraft of an international operating agency are registered.
A point on the surface of the earth common to the tracks of two aircraft, used as a basis for the application of separation (e.g. significant point, waypoint, navigation aid, fix).
An aeronautical fixed station which relays or retransmits telecommunication traffic from (or to) a number of other aeronautical fixed stations directly connected to it.
aeronautical fixed and mobile services to enable ground-to-ground, air-to-ground and air-to-air communications for ATC purposes
Community air carrier
an air carrier with a valid operating licence issued by a Member State in accordance with Council Regulation (EEC) No 2407/92 of 23 July 1992 on licensing of air carriers (1)
Snow which has been compressed into a solid mass that resists further compression and will hold together or break up into lumps if picked up; specific gravity: 0.5 and over.
A combination of skills, knowledge and attitudes required to perform a task to the prescribed standard.
An action that constitutes a task that has a triggering event and a terminating event that clearly defines its limits, and an observable outcome.
A discrete function consisting of a number of competency elements.
The primary quality parameter describing the degree of conformance of a subset of data compared to its nominal ground with respect to the presence of objects, associations instances, and property instances.
A device which performs sequences of arithmetical and logical steps upon data without human intervention.Note.- When the word computer is used in this document it may denote a computer complex, which includes one or more computers and peripheral equipment.
concept of operation
the criteria for the operational use of the EATMN or of part thereof
an ATS route that is only available for flight planning and use under specified conditions
Communication facilities whereby direct speech conversation may be conducted between three or more locations simultaneously.
Meta-quality element describing the correctness of quality information.
The probability that the true value of a parameter is within a certain interval around the estimate of its value. The interval is usually referred to as the accuracy of the estimate.
Configuration (as applied to the aeroplane)
A particular combination of the positions of the moveable elements, such as wing flaps and landing gear, etc., that affect the aerodynamic characteristics of the aeroplane.
Configuration deviation list
A list established by the organization responsible for the type design with the approval of the State of Design which identifies any external parts of an aircraft type which may be missing at the commencement of a flight, and which contains, where necessary, any information on associated operating limitations and performance correction.
Any situation involving an aircraft and a hazard in which the applicable separation minima may be compromised.
The discovery of a conflict as a result of a conflict search.
The extent to which hazards along the aircraft's future trajectory are considered for separation provision.
The determination of alternative flight paths which would be free from conflicts and the selection,of one of these flight paths for use.
Computation and comparison of the predicted flight paths of two or more aircraft for the purpose of determining conflicts.
In relation to a city, town or settlement, any area which is substantially used for residential, commercial or recreational purposes.
Congested hostile environment
A hostile environment within a congested area.
One or more packages of dangerous goods accepted by an operator from one shipper at one time and at one address, receipted for in one lot and moving to one consignee at one destination address.
tangible objects such as hardware and intangible objects such as software upon which the interoperability of the EATMN depends
Any limitation on the implementation of an "operational improvement".
Part of a movement area under construction.
Construction/sling load flight
A flight to assist in construction work or carrying sling loads (other than logging flights).
Discussion with a meteorologist or another qualified person of existing and/or expected meteorological conditions relating to flight operations; a discussion includes answers to questions.
A specified position, time or level at which an aircraft is required to establish radiocommunication with an air traffic control unit.
The set of processes by which an aircraft, engine, propeller or part complies with the applicable airworthiness requirements and remains in a condition for safe operation throughout its operating life.
The probability of a system performing its required function without unscheduled interruptions during the intended period of operations.
Continuous descent operation
An operation, enabled by airspace design, procedure design and ATC facilitation, in which an arriving aircraft descends continuously, to the greatest possible extent, by employing minimum engine thrust, ideally in a low drag configuration, prior to the final approach fix /final approach point.
Note 1.- An optimum CDO starts from the top of descent and uses descent profiles that reduce segments of level flight, noise, fuel burn, emissions and controller/pilot communications, while increasing predictability to pilots and controllers and flight stability.
Note 2.- A CDO initiated from the highest possible level in the en-route or arrival phases of flight will achieve the maximum reduction in fuel burn, noise and emissions.
A line on a map or chart connecting points of equal elevation.
The minimum value of the luminance contrast that the human eye can detect, i.e. the value which allows an object to be distinguished from its background (dimensionless).
A controlled airspace extending upwards from a specified limit above the earth.
A person who assists in the provision of air traffic services but who is not authorized to make decisions regarding clearances, advice or information to be issued to aircraft.
A subdivision of a designated control area within which responsibility is assigned to one controller or to a small group of controllers.
A controlled airspace extending upwards from the surface of the earth to a specified upper limit.
An aerodrome at which air traffic control service is provided to aerodrome traffic.
An airspace of defined dimensions within which air traffic control service is provided in accordance with the airspace classification.
Controlled airspace (instrument restricted)
Controlled airspace within which only IFR flights are permitted.
Controlled airspace (instrument/visual)
Controlled airspace within which only IFR and controlled VFR flights are permitted.
Controlled airspace (visual exempted)
Controlled airspace within which both IFR and VFR flights are permitted, but VFR flights are not subject to control.
Any flight which is subject to an air traffic control clearance.
Controlled VFR flight
A controlled flight conducted in accordance with the visual flight rules.
A person authorized to provide air traffic control services.
Controller-pilot data link communications
A means of communication between controller and pilot, using data link for ATC communications.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 15; ICAO Annex 2;
Training required when a pilot is posted to a different aircraft type or model
cooperative decision making
a process in which decisions are made based on a constant interaction and consultation with Member States, operational stakeholders and other actors as appropriate
Delegation of the role of "separator". The delegation can be for a particular type of hazard or from nominated hazards. If the delegation is accepted, then the accepting party is responsible for compliance with the delegation, using appropriate separation modes.
Coordinate reference system
Coordinate system that is related to the real world by a datum.
Set of mathematical rules for specifying how coordinates are to be assigned to points.
any airport where, in order to land or take-off, it is necessary for an air carrier or any other aircraft operator to have been allocated a slot by a coordinator, with the exception of State flights, emergency landings and humanitarian flights
Any airport where, in order to land or take-off, it is necessary for an aircraft operator to have been allocated a slot by an appropriate authority.
the expression in operational terms of all the capacity available for slot allocation at an airport during each coordination period, reflecting all technical, operational and environmental factors that affect the performance of the airport infrastructure and its different sub-systems
A point on or adjacent to the boundary used by the ATC units and referred to in coordination processes
The non-commercial operation or use of aircraft by a company for the carriage of passengers or goods as an aid to the conduct of company business, flown by a professional pilot employed to fly the aircraft. (Note that corporate aviation is a subset of general aviation.)
Corporate aviation operation
The non-commercial operation or use of aircraft by a company for the carriage of passengers or goods as an aid to the conduct of company business, flown by a professional pilot(s) employed to fly the aircraft.
Data meeting stated quality requirements.
A change to previously correct data introduced during processing, storage, or transmission, which causes the data to no longer be correct.
The quantity of electricity transported in 1 second by a current of 1 ampere.
A feature that acts as a function to return one or more feature attribute values for any direct position within its spatiotemporal domain.
Configuration of the spatiotemporal domain of a coverage described in terms of coordinates.
Recognition of alternative means or prior qualifications.
A person assigned by an operator to duty on an aircraft during a flight duty period.
an unusual situation or crisis involving a major loss of EATMN capacity, or a major imbalance between EATMN capacity and demand, or a major failure in the information flow in one or several parts of the EATMN
The power-unit(s) failure of which gives the most adverse effect on the aircraft characteristics relative to the case under consideration.
Note.- On some aircraft there may be more than one equally critical power-unit. In this case, the expression 'the critical power-unit' means one of those critical power-units.
An international shorthaul air service operating across the borders of two contiguous States.
any situation where air navigation services are provided in one Member State by a service provider certified in another Member State.
A flight between a point of departure and a point of arrival following a pre-planned route using standard navigation procedures.
Private flying operations for a cross-country flight.
A fix tolerance measured perpendicularly to the nominal track resulting from the airborne and ground equipment tolerances and the flight technical tolerance (FTT).
The phase of flight from the top of climb to cruise altitude, or flight level, to the start of the descent toward the destination aerodrome or landing site.
An aeroplane cruising technique resulting in a net increase in altitude as the aeroplane mass decreases.
Cruise relief pilot
A flight crew member who is assigned to perform pilot tasks during cruise flight, to allow the pilot-in-command or a co-pilot to obtain planned rest.
A level maintained during a significant portion of a flight.
Manmade morphological formations that include transportation systems (roads and trails; railroads and pipelines; runways; transmission lines), and other manmade structures, (buildings, houses, schools, churches, hospitals).
All man-made features constructed on the surface of the Earth, such as cities, railways and canals.
Current data authority
The designated ground system through which a CPDLC dialogue between a pilot and a controller currently responsible for the flight is permitted to take place.
Current flight plan
The flight plan, including changes, if any, brought about by subsequent clearances.
Cyclic redundancy check
A mathematical algorithm applied to the digital expression of data that provides a level of assurance against loss or alteration of data.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 14; ICAO Annex 15; ICAO Annex 4;
The amount (positive or negative) by which the altitude (Z) of a point on an isobaric surface differs from the altitude (Zp) of the same isobaric surface in the ICAO Standard Atmosphere (i.e. D-value = Z - Zp).
An airspace of defined dimensions within which activities dangerous to the flight of aircraft may exist at specified times.
Articles or substances which are capable of posing a risk to health, safety, property or the environment and which are shown in the list of dangerous goods in the Technical Instructions or which are classified according to those Instructions.
Dangerous goods accident
An occurrence associated with and related to the transport of dangerous goods by air which results in fatal or serious injury to a person or major property or environmental damage.
Dangerous goods incident
An occurrence, other than a dangerous goods accident, associated with and related to the transport of dangerous goods by air, not necessarily occurring on board an aircraft, which results in injury to a person, property or environmental damage, fire, breakage, spillage, leakage of fluid or radiation or other evidence that the integrity of the packaging has not been maintained. Any occurrence relating to the transport of dangerous goods which seriously jeopardizes the aircraft or its occupants is also deemed to constitute a dangerous goods incident.
An agreed set of rules governing the manner or sequence in which a set of data may be combined into a meaningful communication.
A term used to describe any component of an AMDB. For example: a feature, an attribute, an object, an entity, or a value.
The part of an organisation, which takes data from one or more sources to produce a terrain or obstacle database that satisfies a particular specification.
Data link communications
A form of communication intended for the exchange of messages via a data link.
Data link flight information services
The provision of FIS via data link.
Data link initiation capability
A data link application that provides the ability to exchange addresses, names and version numbers necessary to initiate data link applications.
Data link-automatic terminal information service
The provision of ATIS via data link.
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.
The part of an organisation which performs measurements by a particular means and which then groups those measurements to represent an area of terrain or a set of obstacles.
A systematic sequence of operations performed on data.
Data set or data set series that conforms to a data product specification (ISO 19131).
Data product specification
Detailed description of a data set or data set series together with additional information that will enable it to be created, supplied to and used by another party (ISO 19131).
A degree or level of confidence that the data provided meet the requirements of the data user in terms of accuracy, resolution and integrity.
Identifiable collection of data (ISO 19101).
Data set series
Collection of data sets sharing the same product specification (ISO 19115).
Specification of the legal value domain and legal operations allowed on values in this domain.
One or more files of data so structured that appropriate applications may draw from the files and update them.
Note.- This primarily refers to data stored electronically and accessed by computer rather than in files of physical records.
Date of manufacture
The date of issue of the document attesting that the individual aircraft or engine as appropriate conforms to the requirements of the type or the date of an analogous document.
Any quantity or set of quantities that may serve as a reference or basis for the calculation of other quantities (ISO 19104).
Datum crossing point
The DCP is a point on the glide path directly above the LTP or FTP at a height specified by the RDH.
A facility where frost, ice or snow is removed (de-icing) from the aeroplane to provide clean surfaces, and/or where clean surfaces of the aeroplane receive protection (anti-icing) against the formation of frost or ice and accumulation of snow or slush for a limited period of time.
An area comprising an inner area for the parking of an aeroplane to receive de-icing/anti-icing treatment and an outer area for the manoeuvring of two or more mobile de-icing/anti-icing equipment.
Dead reckoning navigation
The estimating or determining of position by advancing an earlier known position by the application of direction, time and speed data.
A crew member positioned by the operator in flight or by surface transport.
Decision altitude or decision height
A specified altitude or height in the precision approach or approach with vertical guidance at which a missed approach must be initiated if the required visual reference to continue the approach has not been established.
Source: ICAO Annex 6;
Synonyms: decision altitude/height; DA/H
Any person who makes a goods declaration or in whose name such a declaration is made.
A measure of the ability of the ATC system or any of its subsystems or operating positions to provide service to aircraft during normal activities. It is expressed as the number of aircraft entering a specified portion of airspace in a given period of time, taking due account of weather, ATC unit configuration, staff and equipment available, and any other factors that may affect the workload of the controller responsible for the airspace.
a) Take-off run available (TORA). The length of runway declared available and suitable for the ground run of an aeroplane taking off. b) Take-off distance available (TODA). The length of the take-off run available plus the length of the clearway, if provided. c) Accelerate-stop distance available (ASDA). The length of the take-off run available plus the length of the stopway, if provided. d) Landing distance available (LDA). The length of runway which is declared available and suitable for the ground run of an aeroplane landing.
Declared distances - heliports
a) Take-off distance available (TODAH). The length of the FATO plus the length of helicopter clearway (if provided) declared available and suitable for helicopters to complete the take-off. b) Rejected take-off distance available (RTODAH). The length of the FATO declared available and suitable for helicopters operated in performance class 1 to complete a rejected take-off. c) Landing distance available (LDAH). The length of the FATO plus any additional area declared available and suitable for helicopters to complete the landing manoeuvre from a defined height.
A temperature selected in such a way that when used for performance purposes, over a series of operations, the average level of safety is not less than would be obtained by using official forecast temperatures.
Decoder (or ground decoder, or ground decoding equipment)
The device used to decipher replies received from transponders.
The aeronautical data process is not adequate to ensure that data quality requirements are satisfied.
Defined point after take-off
The point, within the take-off and initial climb phase, before which the helicopter's ability to continue the flight safely, with one engine inoperative, is not assured and a forced landing may be required.
Defined point before landing
The point, within the approach and landing phase, after which the helicopter's ability to continue the flight safely, with one engine inoperative, is not assured and a forced landing may be required.
The special name for the unit kelvin for use in stating values of Celsius temperature.
The difference between actual block time and ideal block time.
The number of aircraft requesting to use the ATM system in a given time period.
A flight carried out to demonstrate the aircraft capabilities.
Aerodrome or point in space from which departure takes place.
Dependent parallel approaches
Simultaneous approaches to parallel or near-parallel instrument runways where radar separation minima between aircraft on adjacent extended runway centre lines are prescribed.
deployment target date
the date by which the deployment of the ATM functionality in question is to be completed and fully used operationally.
A written order, issued by the competent authorities of a State and served upon a deportee, directing him to leave that State.
A person who had legally been admitted to a State by its authorities or who had entered a State illegally, and who at some later time is formally ordered by the competent authorities to leave that State.
An aircraft gas turbine engine of the same generic family as an originally type-certificated engine and having features which retain the basic core engine and combustor design of the original model and for which other factors, as judged by the certificating authority, have not changed.
Derived version of a helicopter
A helicopter which, from the point of view of airworthiness, is similar to the noise certificated prototype but incorporates changes in type design which may affect its noise characteristics adversely.
Derived version of an aeroplane
An aeroplane which, from the point of view of airworthiness, is similar to the noise certificated prototype but incorporates changes in type design which may affect its noise characteristics adversely.
A fix established in a precision approach at the FAP to eliminate certain obstacles before the FAP, which would otherwise have to be considered for obstacle clearance purposes.
Design landing mass
The maximum mass of the aircraft at which, for structural design purposes, it is assumed that it will be planned to land.
Design take-off mass
The maximum mass at which the aircraft, for structural design purposes, is assumed to be planned to be at the start of the take-off run.
Design taxiing mass
The maximum mass of the aircraft at which structural provision is made for load liable to occur during use of the aircraft on the ground prior to the start of take-off.
Desired 4D trajectory
The current 4D trajectory that is requested and generated by the airspace user with knowledge of the ATM system's operational constraints and resource contention.
An alternate aerodrome to which an aircraft may proceed should it become either impossible or inadvisable to land at the aerodrome of intended landing.
The code word used to designate a distress phase.
The temperature to which a given air parcel must be cooled at constant pressure and constant water vapor content in order for saturation to occur.
Digital Elevation Model
The representation of terrain surface by continuous elevation values at all intersections of a defined grid, referenced to common datum.
Source: ICAO Annex 1; ICAO Annex 15; ICAO Annex 4;
Synonyms: digital terrain model; DTM
Digital ortho-rectified imagery
Digital aerial photography or satellite imagery that has been matched, or registered, to a surveyed ground control coordinate system and to spatially corresponding elevation data. Directions, angles, and distances are all to scale. A digital ortho-rectified image, therefore, is one whose coordinates have been adjusted to match its corresponding ground location, including adjustment for the effects of terrain undulations.
Digital surface model
Digital model of the topographic surface, including vegetation and man-made structures.
direct air service
a service between two airports including stopovers with the same aircraft and same flight number
Direct transit area
A special area established in an international airport, approved by the public authorities concerned and under their direct supervision or control, where passengers can stay during transit or transfer without applying for entry to the State.
Direct transit arrangements
Special arrangements approved by the public authorities concerned by which traffic which is pausing briefly in its passage through the Contracting State may remain under their direct control.
A four-digit SSR code with the last two digits not being "00".
Discrete source damage
Structural damage of the aeroplane that is likely to result from: impact with a bird, uncontained fan blade failure, uncontained engine failure, uncontained high-energy rotating machinery failure or similar causes.
The leaving of an aircraft after a landing, except by crew or passengers continuing on the next stage of the same through-flight.
The procedure whereby health measures are taken to control or kill infectious agents on a human or animal body, in or on affected parts of aircraft, baggage, cargo, goods or containers, as required, by direct exposure to chemical or physical agents.
The procedure whereby health measures are taken to control or kill insects present in aircraft, baggage, cargo, containers, goods and mail.
A threshold not located at the extremity of a runway.
Source: ICAO Annex 1; ICAO Annex 14; ICAO Annex 4;
Synonyms: displaced runway threshold
A visual presentation of data in a manner which permits interpretation by a controller.
A passenger who fails to respect the rules of conduct at an airport or on board an aircraft or to follow the instructions of the airport staff or crew members and thereby disturbs the good order and discipline at an airport or on board the aircraft.
DR is the horizontal distance that the helicopter has travelled from the end of the take-off distance available.
A situation wherein there is reasonable certainty that an aircraft and its occupants are threatened by grave and imminent danger or require immediate assistance.
The process of duplication of formatted aeronautical data into a database and the shipping and loading of the database into the target system for application. Distribution is usually achieved by transferring the data from one medium to another, with each transfer being verified.
The process of disseminating documents containing formatted aeronautical data in various media, including the shipping and loading of a database into the target system for application.
The forced landing of an aircraft on water.
The act of proceeding to an aerodrome other than one at which a landing was intended.
The line of sight distance (slant range) from the source of a DME signal to the receiving antenna.
Domestic air service
An air service operated wholly within the territory of a State.
An airport used for domestic air services only.
The frequency shift observed at a receiver due to any relative motion between transmitter and receiver.
Double channel simplex
Simplex using two frequency channels, one in each direction.
A clearance issued to an aircraft by an air traffic control unit that is not the current controlling authority of that aircraft.
Downstream data authority
A designated ground system, different from the current data authority, through which the pilot can contact an appropriate ATC unit for the purposes of receiving a downstream clearance.
Digital overlaying of one spatial data set onto another, where both data sets have been georectified (digitally matched) to the same coordinate system and map projection. Particularly useful in 3D visualizations of spatial data. Example: draping a satellite image over terrain data and creating a fly-through visualization in motion.
Snow, which can be blown if loose or, if compacted by hand, will fall apart upon release; specific gravity: up to but not including 0.35.
A flight during which a person is receiving flight instruction from a properly authorized pilot on board the aircraft.
Dual instruction time
Flight time during which a person is receiving flight instruction from a properly authorized pilot on board the aircraft.
A method in which telecommunication between two stations can take place in both directions simultaneously.
Any task that flight or cabin crew members are required by the operator to perform, including, for example, flight duty, administrative work, training, positioning and standby when it is likely to induce fatigue.
A period which starts when a flight or cabin crew member is required by an operator to report for or to commence a duty and ends when that person is free from all duties.
Dynamic load-bearing surface
A surface capable of supporting the loads generated by a helicopter conducting an emergency touchdown on it.
Effective acceptance bandwidth
The range of frequencies with respect to the assigned frequency for which reception is assured when all receiver tolerances have been taken into account.
Effective adjacent channel rejection
The rejection that is obtained at the appropriate adjacent channel frequency when all relevant receiver tolerances have been taken into account.
The effective intensity of a flashing light is equal to the intensity of a fixed light of the same colour which will produce the same visual range under identical conditions of observation.
The ratio of the cost of ideal flight to the cost of procedurally constrained flight.
Electronic aeronautical chart display
An electronic device by which flight crews are enabled to execute, in a convenient and timely manner, route planning, route monitoring and navigation by displaying required information.
A heliport located on a raised structure on land.
The vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 3; ICAO Annex 4;
Synonyms: gravity-related height
The height related to the reference ellipsoid, measured along the ellipsoidal outer normal through the point in question.
Source: ICAO Annex 1; ICAO Annex 14; ICAO Annex 15; ICAO Annex 4;
Synonyms: geodetic height
The boarding of an aircraft for the purpose of commencing a flight, except by such crew or passengers as have embarked on a previous stage of the same through-flight.
The phase of flight in which an intentionally rapid or premature descent, from a previously normal manoeuvre, is made in response to an in-flight emergency. the descent is controlled by the crew.
Emergency descent during approach
The phase of flight in which an intentionally rapid or premature descent is made in response to an in-flight emergency during approach. the descent is controlled by the crew.
Emergency descent during take-off
The phase of flight in which an intentional descent is made, in response to an emergency, which occurs after rotation but before the first prescribed power reduction, on reaching 1500 feet (450 metres) or the vfr pattern, whichever comes first.
Emergency descent en-route
The phase of flight in which an intentionally rapid, or premature, descent is made en-route, in response to an in-flight emergency.the descent is controlled by the crew.
Emergency landing or off-runway landing
The phase of flight where an intentional landing is made at a point other than a runway or normal landing site, in response to an in-flight emergency.
Emergency locator transmitter
A generic term describing equipment which broadcast distinctive signals on designated frequencies and, depending on application, may be automatically activated by impact or be manually activated. An ELT may be any of the following: Automatic fixed ELT (ELT(AF)). An automatically activated ELT which is permanently attached to an aircraft. Automatic portable ELT (ELT(AP)). An automatically activated ELT which is rigidly attached to an aircraft but readily removable from the aircraft. Automatic deployable ELT (ELT(AD)). An ELT which is rigidly attached to an aircraft and which is automatically deployed and activated by impact, and, in some cases, also by hydrostatic sensors. Manual deployment is also provided. Survival ELT (ELT(S)). An ELT which is removable from an aircraft, stowed so as to facilitate its ready use in an emergency, and manually activated by survivors.
A generic term meaning, as the case may be, uncertainty phase, alert phase or distress phase.
Emergency service provider
Provider of emergency services, such as search and rescue organizations.
An MRTD (passport, visa or card) that has a contactless integrated circuit embedded in it and the capability of being used for biometric identification of the MRTD holder in accordance with the standards specified in the relevant Part of Doc 9303 - Machine Readable Travel Documents.
En-route - holding
The phase of flight, in which a pre-determined ad-hoc manoeuvre occurs, which keeps the aircraft within a specified airspace en-route awaiting further instructions.
An aerodrome at which an aircraft would be able to land after experiencing an abnormal or emergency condition while en-route.
A clearance covering the flight path of an aircraft after take-off to the point at which an approach to land is expected to commence.
Note.- In some circumstances it may be necessary to subdivide this clearance, e.g. into sections divided by control area boundaries or into the departure, climb, or descent phases of flight.
That part of the flight from the end of the take-off and initial climb phase to the commencement of the approach and landing phase.
Initiatives, such as (new) technologies, systems, operational procedures, and operational or socio-economic developments, which facilitate the implementation of operational improvements or of other enablers.
Pertaining or relating to an entire communication path, typically from (1) the interface between the information source and the communication system at the transmitting end to (2) the interface between the communication system and the information user or processor or application at the receiving end.
An ultimate source and/or consumer of information.
Energy per symbol to noise density ratio
The ratio of the average energy transmitted per channel symbol to the average noise power in a 1 Hz bandwidth, usually expressed in dB. For A-BPSK and A-QPSK, one channel symbol refers to one channel bit.
A unit used or intended to be used for aircraft propulsion. It consists of at least those components and equipment necessary for functioning and control, but excludes the propeller/rotors (if applicable).
The phase of flight after start-up, during which power is applied to engines, for a pre-flight engine performance test.
Engine(s) not operating
The phase of flight after the first person boards the aircraft with the intention of flight until the first engine is started. subsequently, from engine shut down upon reaching the destination after flight until the last person has exited the aircraft.
The phase of flight following engine start-up, or after post-flight arrival at the destination.
Enhanced vision system
A system to display electronic real-time images of the external scene achieved through the use of image sensors.
The phase of flight from the completion of initial climb at the departure aerodrome to the completion of controlled descent to the outer marker [ifr] or [vfr] to completion of the controlled descent to the vfr pattern or 1,500 feet [450 metres] above runway end elevation, whichever comes first.
Common data used by multiple users but stored at a single location.
The first reporting point, determined by reference to a navigation aid, over which an aircraft passes or is expected to pass upon entering a flight information region or a control area.
The first aircraft ready to use the ATM resources will receive priority, except where significant overall safety or system operational efficiency would accrue or national interests dictate that priority be provided on a different basis. Equity is ensured for all airspace users that have access to a given airspace or service by the global ATM system.
Equivalent isotropically radiated power
The product of the power supplied to the antenna and the antenna gain in a given direction relative to an isotropic antenna (absolute or isotropic gain).
An action or inaction by an operational person that leads to deviations from organizational or the operational person's intentions or expectations.
The process of detecting and responding to errors with countermeasures that reduce or eliminate the consequences of errors and mitigate the probability of further errors or undesired states.
A volcano that is currently erupting, or has recently erupted, that is the source of volcanic ash or other significant meteorological phenomena described in operational weather reports.
Essential radio navigation service
A radio navigation service whose disruption has a significant impact on operations in the affected airspace or aerodrome.
Estimated elapsed time
The estimated time required to proceed from one significant point to another.
Estimated off-block time
The estimated time at which the aircraft will commence movement associated with departure.
Estimated time of arrival
For IFR flights, the time at which it is estimated that the aircraft will arrive over that designated point, defined by reference to navigation aids, from which it is intended that an instrument approach procedure will be commenced, or, if no navigation aid is associated with the aerodrome, the time at which the aircraft will arrive over the aerodrome. For VFR flights, the time at which it is estimated that the aircraft will arrive over the aerodrome.
ETOPS en-route alternate
A suitable and appropriate alternate aerodrome at which an aeroplane would be able to land after experiencing an engine shut-down or other abnormal or emergency condition while en-route in an ETOPS operation.
the European Organisation for the Safety of Air Navigation set up by the International Convention of 13 December 1960 relating to Cooperation for the Safety of Air Navigation (3)
European air traffic management network
the collection of systems listed in Annex I to Regulation (EC) No 552/2004 of the European Parliament and of the Council of 10 March 2004 on the interoperability of the European air traffic management network (the interoperability Regulation) (2) enabling air navigation services in the Community to be provided, including the interfaces at boundaries with third countries
European Route Network Improvement Plan
the plan developed by the Network Manager in coordination with the operational stakeholders that includes the result of its operational activities with respect to route network design on short and medium terms in accordance with the guiding principles of the Network Strategy Plan
A combination of a task or a sub-task and the conditions under which the task or sub-task is to be performed.
A provision in this Annex which excludes a specific item of dangerous goods from the requirements normally applicable to that item.
Executed 4D trajectory
The actual 4D trajectory of the aircraft from the start-up to the present position.
An authorization, other than an approval, granted by an appropriate national authority providing relief from the provisions of the Technical Instructions.
The last reporting point, determined by reference to a navigation aid, over which an aircraft passes or is expected to pass before leaving a flight information region or a control area.
Used in relation to various aspects of performance (e.g. rate or gradient of climb), this term means the standard performance for the type, in the relevant conditions (e.g. mass, altitude and temperature).
Expected approach time
The time at which ATC expects that an arriving aircraft, following a delay, will leave the holding fix to complete its approach for a landing.
Extended flight over water
A flight operated over water at a distance of more than 93 km (50 NM), or 30 minutes at normal cruising speed, whichever is the lesser, away from land suitable for making an emergency landing.
Extended range operation
Any flight by an aeroplane with two turbine engines where the flight time at the one engine inoperative cruise speed (in ISA and still air conditions), from a point on the route to an adequate alternate aerodrome, is greater than the threshold time approved by the State of the Operator.
Source: ICAO Annex 3;
Synonyms: extended twin-engine operation; ETOPS; extended range operation by twin-engined aeroplane
Any instrument, mechanism, part, apparatus, appurtenance, or accessory that is attached to or extends from the helicopter exterior but is not used nor is intended to be used for operating or controlling a helicopter in flight and is not part of an airframe or engine.
The proportion of luminous flux lost by a collimated beam, emitted by an incandescent source at a colour temperature of 2 700 K, while travelling the length of a unit distance in the atmosphere (per metre, m-1).
Factor of safety
A design factor used to provide for the possibility of loads greater than those assumed, and for uncertainties in design and fabrication.
Fan marker beacon
A type of radio beacon, the emissions of which radiate in a vertical fan-shaped pattern.
The capacitance of a capacitor between the plates of which there appears a difference of potential of 1 volt when it is charged by a quantity of electricity equal to 1 coulomb.
A physiological state of reduced mental or physical performance capability resulting from sleep loss or extended wakefulness and/or physical activity that can impair a crew member's alertness and ability to safely operate an aircraft or perform safety related duties.
Abstraction of real world phenomena (ISO 19101).
Characteristic of a feature (ISO 19101).
Catalog containing definitions and descriptions of the feature types, feature attributes, and feature relationships occurring in one or more sets of geographic data, together with any feature operations that may be applied.
Operation that every instance of a feature type may perform (ISO 19110).
Relationship that links instances of one feature type with instances of the same or a different feature type (ISO 19101).
Class of real world phenomena with common properties (ISO 19110).
A non-revenue flight flown for a positioning or other purpose (such as to enable the aircraft to undergo maintenance).
Fictitious threshold point
The FTP is a point over which the final approach segment path passes at a relative height specified by the reference datum height. It is defined by the WGS-84 latitude, longitude and ellipsoid height. The FTP replaces the LTP when the final approach course is not aligned with the runway extended centreline or when the threshold is displaced from the actual runway threshold. For non-aligned approaches the FTP lies on the intersection of the perpendicular from the FAS to the runway threshold. The FTP elevation is the same as the actual runway threshold elevation.
Filed flight plan
The flight plan as filed with an ATS unit by the pilot or a designated representative, without any subsequent changes.
Note.- When the word "message" is used as a suffix to this term, it denotes the content and format of the filed flight plan data as transmitted.
That part of an instrument approach procedure which commences at the specified final approach fix or point, or where such a fix or point is not specified, a) at the end of the last procedure turn, base turn or inbound turn of a racetrack procedure, if specified; or b) at the point of interception of the last track specified in the approach procedure; and ends at a point in the vicinity of an aerodrome from which: 1) a landing can be made; or 2) a missed approach procedure is initiated.
Final approach and take-off area
A defined area over which the final phase of the approach manoeuvre to hover or landing is completed and from which the take-off manoeuvre is commenced. Where the FATO is to be used by helicopters operating in performance Class 1, the defined area includes the rejected take-off area available.
Source: ICAO Annex 1; ICAO Annex 14; ICAO Annex 4; ICAO Annex 6; ICAO Annex 8;
Final approach fix or point
That fix or point of an instrument approach procedure where the final approach segment commences.
Final approach segment
That segment of an instrument approach procedure in which alignment and descent for landing are accomplished.
Final approach track
The flight track in the final approach segment that is normally aligned with the runway centreline. For offset final approach segments, the final approach track is aligned with the orientation of the FTP and the FPAP.
Fire fighting flight
A flight to carry out fire fighting activities (e.g. spotting, water bombing etc.). This includes flights to and from the fire area.
The capability to withstand the application of heat by a flame for a period of 5 minutes.
The capability to withstand the application of heat by a flame for a period of 15 minutes.
A material capable of withstanding heat as well as or better than steel when the dimensions in both cases are appropriate for the specific purpose.
An aircraft operation in which an aircraft is used to carry persons by air for their first flight.
A light having constant luminous intensity when observed from a fixed point.
Fixed message sign
A sign presenting only one message.
flexible use of airspace
an airspace management concept applied in the European Civil Aviation Conference area on the basis of the �Airspace management handbook for the application of the concept of the flexible use of airspace� issued by Eurocontrol
Flight crew member
A licensed crew member charged with duties essential to the operation of an aircraft during a flight duty period.
Data regarding the actual or intended movement of aircraft, normally presented in coded or abbreviated form.
Flight data analysis
A process of analysing recorded flight data in order to improve the safety of flight operations.
Term encompassing the flight crew and/or aircraft systems.
Written or printed documents, including charts or forms, containing meteorological information for a flight.
Flight duty period
A period which commences when a flight or cabin crew member is required to report for duty that includes a flight or a series of flights and which finishes when the aeroplane finally comes to rest and the engines are shut down at the end of the last flight on which he/she is a crew member.
Information useful for the safe and efficient conduct of flight, including information on air traffic, meteorological conditions, aerodrome conditions or air route facilities.
Flight information centre
A unit established to provide flight information service and alerting service.
flight information region
an airspace of defined dimensions within which flight information services and alerting services are provided
Flight information region
An airspace of defined dimensions within which flight information service and alerting service are provided.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 2; ICAO Annex 3; ICAO Annex 4;
flight information service
a service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights
Flight information service
A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights.
The future aircraft trajectory expressed as a 4-D profile until destination (taking account of aircraft performance, weather, terrain, and ATM service constraints), calculated and "owned" by the aircraft flight management system, and agreed by the pilot.
a surface of constant atmospheric pressure which is related to the specific pressure datum of 1 013,2 hectopascals and is separated from other such surfaces by specific pressure intervals
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.
Source: ICAO Annex 1; ICAO Annex 10; ICAO Annex 11; ICAO Annex 2; ICAO Annex 3; ICAO Annex 4;
A manual, associated with the certificate of airworthiness, containing limitations within which the aircraft is to be considered airworthy, and instructions and information necessary to the flight crew members for the safe operation of the aircraft.
Flight operations officer/flight dispatcher
A person designated by the operator to engage in the control and supervision of flight operations, whether licensed or not, suitably qualified in accordance with Annex 1, who supports, briefs and/or assists the pilot-in-command in the safe conduct of the flight.
Flight path alignment point
The FPAP is a point in the same lateral plane as the LTP or FTP that is used to define the alignment of the final approach segment. For approaches aligned with the runway centreline, the FPAP is located at or beyond the opposite threshold of the runway. The delta length offset from the opposite threshold of the runway defines its location.
Flight path monitoring
The use of ATS surveillance systems for the purpose of providing aircraft with information and advice relative to significant deviations from nominal flight path, including deviations from the terms of their air traffic control clearances.
Specified information provided to air traffic services units, relative to an intended flight or portion of a flight of an aircraft.
Flight plan data
Data selected from the flight plan for purposes of processing, display or transfer.
flight plan suspension
the process initiated by an entity performing ATFM to ensure that a change is made to the flight plan by the operator before the execution of the flight
Flight procedures trainer
[Apparatus] which provides a realistic flight deck environment, and which simulates instrument responses, simple control functions of mechanical, electrical, electronic, etc. aircraft systems, and the performance and flight characteristics of aircraft of a particular class.
Flight progress board
A board designed and used for the tabular display of flight data.
Flight progress display
A display of data from which the actual and intended progress of flights may be readily determined.
Flight progress strip
Strip used for the display of flight data on a flight progress board.
Any type of recorder installed in the aircraft for the purpose of complementing accident/incident investigation.
Flight safety documents system
A set of interrelated documentation established by the operator, compiling and organizing information necessary for flight and ground operations, and comprising, as a minimum, the operations manual and the operator's maintenance control manual.
A flight or one of a series of flights which commences at a parking place of the aircraft and terminates at a parking place of the aircraft. It is composed of :- flight preparation,- flight time,- post-flight period after the flight sector or series of flight sectors.
Flight simulation training device
Any one of the following three types of apparatus in which flight conditions are simulated on the ground: A flight simulator, which provides an accurate representation of the flight deck of a particular aircraft type to the extent that the mechanical, electrical, electronic, etc. aircraft systems control functions, the normal environment of flight crew members, and the performance and flight characteristics of that type of aircraft are realistically simulated; A flight procedures trainer, which provides a realistic flight deck environment, and which simulates instrument responses, simple control functions of mechanical, electrical, electronic, etc. aircraft systems, and the performance and flight characteristics of aircraft of a particular class; A basic instrument flight trainer, which is equipped with appropriate instruments, and which simulates the flight deck environment of an aircraft in flight in instrument flight conditions.
See Flight simulation training device.
An indication of whether a given aircraft requires special handling by air traffic services units or not.
Flight time - aeroplanes
The total time from the moment an aeroplane first moves for the purpose of taking off until the moment it finally comes to rest at the end of the flight.
Flight time - helicopters
The total time from the moment a helicopter's rotor blades start turning until the moment the helicopter finally comes to rest at the end of the flight, and the rotor blades are stopped.
Flight Training/Instructional flight
Flights for the specific purpose of flight training and check by an institution other than an airline.
The visibility forward from the cockpit of an aircraft in flight.
Measures designed to adjust the flow of traffic into a given airspace, along a given route, or bound for a given aerodrome, so as to ensure the most effective utilization of the airspace.
A waypoint which requires turn anticipation to allow tangential interception of the next segment of a route or procedure.
Display or �exhibition� flying (for the benefit of persons on the ground) carried out by a commercial operator.
A waypoint at which a turn is initiated in order to join the next segment of a route or procedure.
The length equal to 0.304 8 metre exactly.
A statement of expected meteorological conditions for a specified time or period, and for a specified area or portion of airspace.
The process of translating, arranging, packing, and compressing a selected set of data for distribution to a specific target system.
Forward error correction
The process of adding redundant information to the transmitted signal in a manner which allows correction, at the receiver, of errors incurred in the transmission.
An object of low mass designed to break, distort or yield on impact so as to present the minimum hazard to aircraft.
Free Route Airspace
a specific airspace within which users can freely plan their routes between an entry point and an exit point without reference to the ATS route network
A part of the territory of a Contracting State where any goods introduced are generally regarded, insofar as import duties and taxes are concerned, as being outside the customs territory.
Designated part of a surface movement area where a specific frequency is required by air traffic control or ground control.
authorisation given by a Member State to use a radio frequency or radio frequency channel under specified conditions
A continuous portion of the frequency spectrum appropriate for a transmission utilizing a specified class of emission.
Fully automatic relay installation
A teletypewriter installation where interpretation of the relaying responsibility in respect of an incoming message and the resultant settingup of the connections required to effect the appropriate retransmissions is carried out automatically, as well as all other normal operations of relay, thus obviating the need for operator intervention, except for supervisory purposes.
functional airspace block
an airspace block based on operational requirements and established regardless of State boundaries, where the provision of air navigation services and related functions are performance-driven and optimised with a view to introducing, in each functional airspace block, enhanced cooperation among air navigation service providers or, where appropriate, an integrated provider
Gain-to-noise temperature ratio
The ratio, usually expressed in dB/K, of the antenna gain to the noise at the receiver output of the antenna subsystem. The noise is expressed as the temperature that a 1 ohm resistor must be raised to produce the same noise power density.
GAMET area forecast
An area forecast in abbreviated plain language for low-level flights for a flight information region or sub-area thereof, prepared by the meteorological office designated by the meteorological authority concerned and exchanged with meteorological offices in adjacent flight information regions, as agreed between the meteorological authorities concerned.
The degradation of code information due to the simultaneous presence in a decoder of overlapping reply pulse trains.
Gate to gate
A concept where the air traffic operations of ATM community members are such that the successive planning and operational phases of their processes are managed and can be achieved in a seamless and coherent way.
Considers the operation of an aircraft not just from take-off to touchdown (the airborne segment) but from the first movement with intention of flight to completion of movement after flight; that is from the gate (or stand or parking position) to gate (or stand or parking position).
An international airport that is the first point of arrival or last point of departure in a State for international air services.
GBAS azimuth reference point
The GARP is defined to be beyond the FPAP along the procedure centreline by a fixed offset of 305 m (1 000 ft). It is used to establish the lateral deviation display limits.
general air traffic
all movements of civil aircraft, as well as all movements of State aircraft (including military, customs and police aircraft) when these movements are carried out in conformity with the procedures of the ICAO
General aviation operation
An aircraft operation other than a commercial air transport operation or an aerial work operation.
The shortest distance between any two points on a mathematically defined ellipsoidal surface.
A minimum set of parameters required to define location and orientation of the local reference system with respect to the global reference system/frame.
The shortest distance between any two points on a mathematically defined ellipsoidal surface.
The values of latitude, longitude, and height that define the position of a point on the surface of the Earth with respect to a reference datum.
Data with implicit or explicit reference to a location relative to the Earth.
The equipotential surface in the gravity field of the Earth which coincides with the undisturbed mean sea level (MSL) extended continuously through the continents.
The distance of the geoid above (positive) or below (negative) the mathematical reference ellipsoid.
(Also known as geometric altitude) Vertical distance (Z) of a level, a point or an object considered as a point, measured from mean sea level.
A descent profile determined for vertical guidance during a final approach.
A non-power-driven heavier-than-air aircraft, deriving its lift in flight chiefly from aerodynamic reactions on surfaces which remain fixed under given conditions of flight.
Glider flight time
The total time occupied in flight, whether being towed or not, from the moment the glider first moves for the purpose of taking off until the moment it comes to rest at the end of the flight.
Global navigation satellite system
A worldwide position and time determination system that includes one or more satellite constellations, aircraft receivers and system integrity monitoring, augmented as necessary to support the required navigation performance for the intended operation.
Globally unique flight identifier
A single reference for FF-ICE information pertinent to a flight that is unique globally.
Government excluding state flights
Any government operation not covered under State flights (e.g. ambulance service operated by the Ministry of Health)
The energy imparted by ionizing radiation to a mass of matter corresponding to 1 joule per kilogram.
Calendar in general use; first introduced in 1582 to define a year that more closely approximates the tropical year than the Julian calendar (ISO 19108).
Grid point data in digital form
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.
Ground earth station
An earth station in the fixed satellite service, or, in some cases, in the aeronautical mobile-satellite service, located at a specified fixed point on land to provide a feeder link for the aeronautical mobilesatellite service.
A condition of improved performance (lift) due to the interference of the surface with the airflow pattern of the rotor system when a helicopter or other VTOL aircraft is operating near the ground.
Articles of a specialized nature for use in the maintenance, repair and servicing of an aircraft on the ground, including testing equipment and cargo- and passenger-handling equipment.
Services necessary for an aircraft's arrival at, and departure from, an airport, other than air traffic services.
The speed of an aircraft relative to the surface of the earth.
The visibility at an aerodrome as reported by an accredited observer or by automatic systems.
One-way communication from stations or locations on the surface of the earth to aircraft.
group of air carriers
two or more air carriers which together perform joint operations, franchise operations or codesharing for the purpose of operating a specific air service
Maximum speed of a gust during a given period.
A heavier-than-air aircraft supported in flight by the reactions of the air on one or more rotors which rotate freely on substantially vertical axes.
An aeronautical beacon used to designate a danger to air navigation.
The objects or elements that an aircraft can be separated from. These are: other aircraft, terrain, weather, wake turbulence, incompatible airspace activity and, when the aircraft is on the ground, surface vehicles and other obstructions on the apron and manoeuvring area. For any hazard (i.e. any condition, event or circumstance that could induce an accident), a risk can be identified as the combination of the overall probability or frequency of occurrence of a harmful effect induced by the hazard, and the severity of that effect. The terms accident and incident are defined in Annex 13 - Aircraft Accident and Incident Investigation.
A display system that presents flight information into the pilot's forward external field of view.
The direction in which the longitudinal axis of an aircraft is pointed, usually expressed in degrees from North (true, magnetic, compass or grid).
Any aircraft deriving its lift in flight chiefly from aerodynamic forces.
The vertical distance of a level, a point or an object considered as a point, measured from a specified datum.
A heavier-than-air aircraft supported in flight chiefly by the reactions of the air on one or more power-driven rotors on substantially vertical axes.
Helicopter air taxiway
A defined path on the surface established for the air taxiing of helicopters.
A defined area on the ground or water, selected and/or prepared as a suitable area over which a helicopter operated in performance class 1 may accelerate and achieve a specific height.
Helicopter Emergency Medical Service flight
A flight by a helicopter operating under a HEMS approval, the purpose of which is to facilitate emergency medical assistance, where immediate and rapid transportation is essential, by carrying: (i) Medical personnel; or (ii) Medical supplies (equipment,blood, organs, drugs); or (iii) Ill or injured persons and other persons directly involved.
Source: Appendix 1 to JAR-OPS 3.005(d)
Helicopter ground taxiway
A ground taxiway intended for the ground movement of wheeled undercarriage helicopters.
An aircraft stand which provides for parking a helicopter and where ground taxi operations are completed or where the helicopter touches down and lifts off for air taxi operations.
A heliport located on an offshore structure such as an exploration or production platform used for the exploitation of oil or gas.
A small designated area, usually with a prepared surface, on a heliport, aerodrome, landing/take-off area, apron area, or movement area used for take-off, landing, or parking of helicopters.
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.
Heliport operating minima
The limits of usability of a heliport for: a) take-off, expressed in terms of runway visual range and/or visibility and, if necessary, cloud conditions; b) landing in precision approach and landing operations, expressed in terms of visibility and/or runway visual range and decision altitude/height (DA/H) as appropriate to the category of the operation; c) landing in approach and landing operations with vertical guidance, expressed in terms of visibility and/or runway visual range and decision altitude/height (DA/H); and d) landing in non-precision approach and landing operations, expressed in terms of visibility and/or runway visual range, minimum descent altitude/height (MDA/H) and, if necessary, cloud conditions.
The inductance of a closed circuit in which an electromotive force of 1 volt is produced when the electric current in the circuit varies uniformly at a rate of 1 ampere per second.
The frequency of a periodic phenomenon of which the period is 1 second.
A defined area where aircraft can be held, or bypassed, to facilitate efficient surface movement of aircraft.
A geographical location that serves as a reference for a holding procedure.
A specified location, identified by visual or other means, in the vicinity of which the position of an aircraft in flight is maintained in accordance with air traffic control clearances.
A predetermined manoeuvre which keeps an aircraft within a specified airspace while awaiting further clearance.
The estimated time the anti-icing fluid (treatment) will prevent the formation of ice and frost and the accumulation of snow on the protected (treated) surfaces of an aeroplane.
The procedure of using the direction-finding equipment of one radio station with the emission of another radio station, where at least one of the stations is mobile, and whereby the mobile station proceeds continuously towards the other station.
Homogeneous ATM area
An airspace with a common air traffic management interest, based on similar characteristics of traffic density, complexity, air navigation system infrastructure requirements or other specified considerations wherein a common detailed plan will foster the implementation of interoperable CNS/ATM systems.
The plane containing the longitudinal axis and perpendicular to the plane of symmetry of the aeroplane.
An environment in which: a) a safe forced landing cannot be accomplished because the surface and surrounding environment are inadequate; or b) the helicopter occupants cannot be adequately protected from the elements; or c) search and rescue response/capability is not provided consistent with anticipated exposure; or d) there is an unacceptable risk of endangering persons or property on the ground.
A location on an aerodrome movement area with a history or potential risk of collision or runway incursion, and where heightened attention by pilots/drivers is necessary.
Hovering in ground effect
Hovering in ground effect. Hover: The helicopter maintains a constant position at a selected point. Ground effect is a condition of improved performance encountered when operating near (within 1/2 rotor diameter) of the ground
Hovering out of ground effect
Hovering out of ground effect. The helicopter maintains a constant position at a selected point. Ground effect is a condition of improved performance encountered when operating near (within 1/2 rotor diameter) of the ground
Human Factors principles
Principles which apply to aeronautical design, certification, training, operations and maintenance and which seek safe interface between the human and other system components by proper consideration to human performance.
Human capabilities and limitations which have an impact on the safety and efficiency of aeronautical operations.
A succession of shades or colour gradations used to depict ranges of elevation.
the International Civil Aviation Organisation, as established by the 1944 Chicago Convention on International Civil Aviation
ICAO Public Key Directory
The central database serving as the repository of Document Signer Certificates (CDS) (containing Document Signer Public Keys), CSCA Master List (MLCSCA), Country Signing CA Link Certificates (lCCSCA) and Certificate Revocation Lists issued by Participants, together with a system for their distribution worldwide, maintained by ICAO on behalf of Participants in order to facilitate the validation of data in eMRTDs.
The situation which exists when the position indication of a particular aircraft is seen on a situation display and positively identified.
An aeronautical beacon emitting a coded signal by means of which a particular point of reference can be identified.
The symbol used to designate the instrument flight rules.
A flight conducted in accordance with the instrument flight rules.
Any illegal operation (aircraft stolen, unauthorized flight, illegal flight)
The luminous flux per unit area (lux, lx).
The product of photography or advanced imaging sensors. Can be produced via either aerial or satellite fly-overs.
The symbol used to designate instrument meteorological conditions.
Measures adopted by States to control the entry into, transit through and departure from their territories of persons travelling by air.
impact on the network
in the context of the radio frequency function set out in Annex II a situation when a radio frequency assignment will degrade, obstruct or interrupt the functioning of one or more radio frequency assignments of the network, or will counter the optimal use of aviation frequency bands within the scope of this Regulation
Import duties and taxes
Customs duties and all other duties, taxes or charges, which are collected on or in connection with the importation of goods. Not included are any charges which are limited in amount to the approximate cost of services rendered or collected by the customs on behalf of another national authority.
Improperly documented person
A person who travels, or attempts to travel: (a) with an expired travel document or an invalid visa; (b) with a counterfeit, forged or altered travel document or visa; (c) with someone else's travel document or visa; (d) without a travel document; or (e) without a visa, if required.
In-flight security officer
A person who is authorized by the government of the State of the Operator and the government of the State of Registration to be deployed on an aircraft with the purpose of protecting that aircraft and its occupants against acts of unlawful interference. This excludes persons employed to provide exclusive personal protection for one or more specific people travelling on the aircraft, such as personal bodyguards.
A person who is or will be refused admission to a State by its authorities.
The code word used to designate an uncertainty phase.
An occurrence, other than an accident, associated with the operation of an aircraft which affects or could affect the safety of operation.
Describing dangerous goods which, if mixed, would be liable to cause a dangerous evolution of heat or gas or produce a corrosive substance.
Independent parallel approaches
Simultaneous approaches to parallel or near-parallel instrument runways where radar separation minima between aircraft on adjacent extended runway centre lines are not prescribed.
Independent parallel departures
Simultaneous departures from parallel or near-parallel instrument runways.
The uncorrected reading on the airspeed indicator.
Industry codes of practice
Guidance material developed by an industry body, for a particular sector of the aviation industry to comply with the requirements of the International Civil Aviation Organization's Standards and Recommended Practices, other aviation safety requirements and the best practices deemed appropriate.
(for human health purposes) Defined as geographical areas where human and/or animal vector-borne diseases are actively transmitted, as reported by local or national public health authorities or by the World Health Organization. Note.- A list of infected areas notified by health administrations is published in the World Health Organization's Weekly Epidemiological Record.
Information for a collaborative environment
Information necessary to enable the collaborative environment envisioned in the Global ATM Operational Concept. It contains, but is not limited to, information domains such as flight and flow information, aeronautical information and surveillance information.
Initial Approach (IFR): From the Initil Approach Fix (IAF) to the Final Approach Fix (FAF).
Initial approach fix
A fix that marks the beginning of the initial segment and the end of the arrival segment, if applicable. In RNAV applications this fix is normally defined by a fly-by waypoint.
Initial approach segment
That segment of an instrument approach procedure between the initial approach fix and the intermediate approach fix or, where applicable, the final approach fix or point.
The phase of flight from 50 feet [15 metres] above runway end elevation to the first prescribed power reduction, or until reaching 1500 feet (450 metres).
A system of geostationary satellites for world-wide mobile communications services, and which support the Global Maritime Distress and Safety System and other emergency communications systems.
Instrument approach procedure
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 approach procedures are classified as follows:
Non-precision approach (NPA) procedure. An instrument approach procedure which utilizes lateral guidance but does not utilize vertical guidance.
Approach procedure with vertical guidance (APV). An instrument approach procedure which utilizes lateral and vertical guidance but does not meet the requirements established for precision approach and landing operations.
Precision approach (PA) procedure. An instrument approach procedure using precision lateral and vertical guidance with minima as determined by the category of operation.
instrument flight rules
instrument flight rules as defined in Annex 2 of the 1944 Chicago Convention on International Civil Aviation (hereinafter Chicago Convention)
Instrument flight rules
A set of rules governing the conduct of flight under instrument meteorological conditions.
Instrument flight time
Time during which a pilot is piloting an aircraft solely by reference to instruments and without external reference points.
Instrument ground time
Time during which a pilot is practising, on the ground, simulated instrument flight in a flight simulation training device approved by the Licensing Authority.
Instrument meteorological conditions
Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling*, less than the minima specified for visual meteorological conditions.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 2; ICAO Annex 6;
One of the following types of runways intended for the operation of aircraft using instrument approach procedures: a) Non-precision approach runway. An instrument runway served by visual aids and a non-visual aid providing at least directional guidance adequate for a straight-in approach. b) Precision approach runway, category I. An instrument runway served by ILS and/or MLS and visual aids intended for operations with a decision height not lower than 60 m (200 ft) and either a visibility not less than 800 m or a runway visual range not less than 550 m. c) Precision approach runway, category II. An instrument runway served by ILS and/or MLS and visual aids intended for operations with a decision height lower than 60 m (200 ft) but not lower than 30 m (100 ft) and a runway visual range not less than 300 m. d) Precision approach runway, category III. An instrument runway served by ILS and/or MLS to and along the surface of the runway and: A - intended for operations with a decision height lower than 30 m (100 ft), or no decision height and a runway visual range not less than 175 m. B - intended for operations with a decision height lower than 15 m (50 ft), or no decision height and a runway visual range less than 175 m but not less than 50 m. C - intended for operations with no decision height and no runway visual range limitations.
Instrument flight time or instrument ground time.
Integrated Aeronautical Information Package
A package which consists of the following elements: - AIP, including amendment service; - Supplements to the AIP; - NOTAM and PIB; - AIC; and - checklists and lists of valid NOTAM.
Integrated survival suit
A survival suit which meets the combined requirements of the survival suit and life jacket.
Integrity (aeronautical data)
A degree of assurance that an aeronautical data and its value has not been lost nor altered since the data origination or authorized amendment.
The phase of flight between the middle approach fix and the final approach fix; or between the end of a reversal procedure or dead-reckoning track procedure and the final approach fix.
Intermediate approach segment
That segment of an instrument approach procedure between either the intermediate approach fix and the final approach fix or point, or between the end of a reversal, racetrack or dead reckoning track procedure and the final approach fix or point, as appropriate.
A fix that marks the end of an initial segment and the beginning of the intermediate segment. In RNAV applications this fix is normally defined by a fly-by waypoint.
Intermediate holding position
A designated position intended for traffic control at which taxiing aircraft and vehicles shall stop and hold until further cleared to proceed, when so instructed by the aerodrome control tower.
International air service
An air service that passes through the airspace over the territory of more than one State.
Any airport designated by the Contracting State in whose territory it is situated as an airport of entry and departure for international air traffic, where the formalities incident to customs, immigration, public health, animal and plant quarantine and similar procedures are carried out.
International airways volcano watch
International arrangements for monitoring and providing warnings to aircraft of volcanic ash in the atmosphere.
International NOTAM office
An office designated by a State for the exchange of NOTAM internationally.
International operating agency
An agency of the kind contemplated in Article 77 of the Convention.
International telecommunication service
A telecommunication service between offices or stations of different States, or between mobile stations which are not in the same State, or are subject to different States.
A protocol that transfers data packets between intermediate systems and end systems interconnected by subnetworks and that is supported by the routing protocols and addressing plan.
Source: ICAO Doc 9713;
Synonyms: internetwork protocol; Internet protocol
a set of functional, technical and operational properties required of the systems and constituents of the EATMN and of the procedures for its operation, in order to enable its safe, seamless and efficient operation. Interoperability is achieved by making the systems and constituents compliant with the essential requirements
Interpilot air-to-air communication
Two-way communication on the designated air-to-air channel to enable aircraft engaged in flights over remote and oceanic areas out of range of VHF ground stations to exchange necessary operational information and to facilitate the resolution of operational problems.
A process conducted for the purpose of accident prevention which includes the gathering and analysis of information, the drawing of conclusions, including the determination of causes and/or contributing factors and, when appropriate, the making of safety recommendations.
A person charged, on the basis of his or her qualifications, with the responsibility for the organization, conduct and control of an investigation.
A line on a map or chart on which all points have the same magnetic variation for a specified epoch.
A line on a map or chart which joins points of equal angular difference between the North of the navigation grid and Magnetic North.
The point at which an aircraft enters or is expected to enter a control area from uncontrolled airspace.
Joint rescue coordination centre
A rescue coordination centre responsible for both aeronautical and maritime search and rescue operations.
The work done when the point of application of a force of 1 newton is displaced a distance of 1 metre in the direction of the force.
An atmosphere of trust in which people are encouraged (even rewarded) for providing essential safety-related information, but in which they are also clear about where the line must be drawn between acceptable and unacceptable behaviour.
A unit of thermodynamic temperature which is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
The unit of mass equal to the mass of the international prototype of the kilogram.
The speed equal to 1 nautical mile per hour.
A consignor who originates cargo or mail for its own account and whose procedures meet common security rules and standards sufficient to allow the carriage of cargo or mail on any aircraft.
A relationship between the apparent luminance contrast (Cx) of an object, seen against the horizon sky by a distant observer, and its inherent luminance contrast (C0), i.e. the luminance contrast that the object would have against the horizon when seen from very short range.
The placing of cargo, mail, baggage or stores on board an aircraft to be carried on a flight.
Land and hold short operations location
Marking used for land and hold short operations (LAHSO).
The phase of flight from the point of transition from nose-low to nose-up attitude, immediately before landing (flare), through touchdown and until aircraft exits landing runway or comes to a stop, whichever occurs first.
Landing aborted after touch-down
The phase of flight in which an attempt is made to get airborne after touchdown (successful or not). this does not include the take-off portion of a touch-and-go.
That part of a movement area intended for the landing or take-off of aircraft.
Landing decision point
The point used in determining landing performance from which, an engine failure occurring at this point, the landing may be safely continued or a balked landing initiated.
Landing direction indicator
A device to indicate visually the direction currently designated for landing and for take-off.
Landing distance available
The length of runway which is declared available and suitable for the ground run of an aeroplane landing.
Landing distance available (helicopter)
The length of the final approach and take-off area plus any additional area declared available and suitable for helicopters to complete the landing manoeuvre from a defined height.
Landing distance required (helicopter)
The horizontal distance required to land and come to a full stop from a point 10.7 m (35 ft) above the landing surface.
The phase of flight from touchdown until the aircraft exits the landing runway or comes to a stop, whichever occurs first.
That part of the surface of an aerodrome which the aerodrome authority has declared available for the normal ground or water run of aircraft landing in a particular direction.
Landing threshold point
The LTP is a point over which the glide path passes at a relative height specified by the reference datum height. It is defined by the WGS-84 latitude, longitude and ellipsoid height. The LTP is normally located at the intersection of the runway centreline and threshold.
That portion of the aerodrome that is not considered airside. It consists primarily of passenger and cargo terminals, including appurtenances that may extend onto the airside, and those other facilities not located within the area defined by the term airside.
An aeroplane of a maximum certificated take-off mass of over 5 700 kg.
Laser-beam critical flight zone
Airspace in the proximity of an aerodrome but beyond the LFFZ where the irradiance is restricted to a level unlikely to cause glare effects.
Laser-beam free flight zone
Airspace in the immediate proximity of the aerodrome where the irradiance is restricted to a level unlikely to cause any visual disruption.
Laser-beam sensitive flight zone
Airspace outside, and not necessarily contiguous with, the LFFZ and LCFZ where the irradiance is restricted to a level unlikely to cause flash-blindness or after-image effects.
Separation between aircraft expressed in terms of distance or angular displacement between tracks.
The point at which an aircraft leaves or is expected to leave a control area for uncontrolled airspace.
A generic term relating to the vertical position of an aircraft in flight and meaning variously, height, altitude or flight level.
The phase of flight from the point of transition from nose-low to nose-up attitude, just before landing, until touchdown.
The Authority designated by a Contracting State as responsible for the licensing of personnel.
Any aircraft supported chiefly by its buoyancy in the air.
Lighting system reliability
The probability that the complete installation operates within the specified tolerances and that the system is operationally usable.
In the context of the medical provisions in Chapter 6, likely means with a probability of occurring that is unacceptable to the medical assessor.
The maximum loads assumed to occur in the anticipated operating conditions.
A connected sequence of points.
Linear Error Probability
A linear magnitude within which a stated percentage of measurements for a given point will fall. For example, if the vertical accuracy of a surveyed point is stated as 1 m with 90% LEP, then 90% of measurements of the height of this point will fall along a vertical line of length 1 m. The true position is then estimated to lie at the center of this vertical line.
A direct connection between an operational improvement and an enabler, between operational improvements, between enablers or between lines of action. In "road-mapping", a link defines a prerequisite for, or an enabler of, an operational improvement, another enabler or a line of action.
A unit of volume restricted to the measurement of liquids and gases which is equal to 1 cubic decimetre.
The ratio of a specified load to the weight of the aircraft, the former being expressed in terms of aerodynamic forces, inertia forces, or ground reactions.
local air traffic flow management (ATFM) unit
a flow management entity operating on behalf of one or more other flow management entities as the interface between the central unit for ATFM and an ATS unit or a group of such units
Private flying operations for a local area flying.
Local runway safety teams
A team comprised of representatives from aerodrome operations, air traffic services providers, airlines or aircraft operators, pilot and air traffic controllers associations and any other group with a direct involvement in runway operations that advise the appropriate management on the potential runway incursion issues and recommend mitigation strategies.
A four-letter code group formulated in accordance with rules prescribed by ICAO and assigned to the location of an aeronautical fixed station.
A flight to carry out logging activities
A specified code used for data link logon to an ATS unit.
Longitudinal axis of the aeroplane
A selected axis parallel to the direction of flight at a normal cruising speed, and passing through the centre of gravity of the aeroplane.
Separation between aircraft expressed in units of time or distance along track.
The phase of flight made at a height below the normal minima, e.g. in preparation for, or during, observation work, demonstration, photography work or aerial application.
The luminous flux emitted in a solid angle of 1 steradian by a point source having a uniform intensity of 1 candela.
Luminance (photometric brightness)
The luminous intensity of any surface in a given direction per unit of projected area (candela per square metre, cd/m2).
The ratio of the difference between the luminance of an object and its background to the luminance of the background (dimensionless).
The quantity derived from radiant flux by evaluating the radiation according to its action upon the International Commission on Illumination (CIE) standard photometric observer (lumen, lm).
The luminous flux per unit solid angle (candela, cd).
The illuminance produced by a luminous flux of 1 lumen uniformly distributed over a surface of 1 square metre.
The angular difference between True North and Magnetic North.
Dispatches of correspondence and other items tendered by and intended for delivery to postal services in accordance with the rules of the Universal Postal Union (UPU).
The performance of tasks required to ensure the continuing airworthiness of an aircraft, including any one or combination of overhaul, inspection, replacement, defect rectification, and the embodiment of a modification or repair.
Maintenance organization's procedures manual
A document endorsed by the head of the maintenance organization which details the maintenance organization's structure and management responsibilities, scope of work, description of facilities, maintenance procedures and quality assurance or inspection systems.
A document which describes the specific scheduled maintenance tasks and their frequency of completion and related procedures, such as a reliability programme, necessary for the safe operation of those aircraft to which it applies.
A document which contains a certification confirming that the maintenance work to which it relates has been completed in a satisfactory manner, either in accordance with the approved data and the procedures described in the maintenance organization's procedures manual or under an equivalent system.
Major traffic flow
A concentration of significant volumes of air traffic on the same or proximate flight trajectories.
An aeroplane on the surface of the water is 'making way' when it is under way and has a velocity relative to the water.
managing body of an airport
the body which, in conjunction with other activities or otherwise, has the task under national laws or regulations of administering and managing the airport facilities and coordinating and controlling the activities of the various operators present at the airport or within the airport system concerned
An event involving a phase of flight in which planned low-level flight, or attitude, or planned abnormal attitude, or abnormal acceleration occurs.
That part of an aerodrome to be used for the take-off, landing and taxiing of aircraft, excluding aprons.
An object displayed above ground level in order to indicate an obstacle or delineate a boundary.
A symbol or group of symbols displayed on the surface of the movement area in order to convey aeronautical information.
Master minimum equipment list
A list established for a particular aircraft type by the organization responsible for the type design with the approval of the State of Design containing items, one or more of which is permitted to be unserviceable at the commencement of a flight. The MMEL may be associated with special operating conditions, limitations or procedures.
Maximum diameter (size) of hailstone (observed).
Maximum certificated take-off mass.
Mean power (of a radio transmitter)
The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently long compared with the lowest frequency encountered in the modulation taken under normal operating conditions.
Mean sea level
The average location of the interface between the ocean and the atmosphere, over a period of time sufficiently long so that all random and periodic variations of short duration average to zero.
The atmospheric pressure at mean sea level, either directly measured or, most commonly, empirically determined from the observed station pressure.
The evidence issued by a Contracting State that the licence holder meets specific requirements of medical fitness.
A physician, appointed by the Licensing Authority, qualified and experienced in the practice of aviation medicine and competent in evaluating and assessing medical conditions of flight safety significance.
A physician with training in aviation medicine and practical knowledge and experience of the aviation environment, who is designated by the Licensing Authority to conduct medical examinations of fitness of applicants for licences or ratings for which medical requirements are prescribed.
A communication sent from one location to another and comprising an integral number of fields.
The smallest assembly of characters, in a message, which has an independent meaning. Note. - A message element is analogous to a word in plain language.
An assigned area of a message containing specified elements of data.
The disposition and structure of the message fields which constitute a message.
Data about data (ISO 19115).
The authority providing or arranging for the provision of meteorological service for international air navigation on behalf of a Contracting State.
A text comprising meteorological information preceded by an appropriate heading.
Meteorological report, analysis, forecast, and any other statement relating to existing or expected meteorological conditions.
An office designated to provide meteorological service for international air navigation.
Meteorological operational channel
A channel of the aeronautical fixed service (AFS), for the exchange of aeronautical meteorological information.
Meteorological operational telecommunication network
An integrated system of meteorological operational channels, as part of the aeronautical fixed service (AFS), for the exchange of aeronautical meteorological information between the aeronautical fixed stations within the network.
Meteorological optical range
The length of the path in the atmosphere required to reduce the luminous flux in a collimated beam from an incandescent lamp, at a colour temperature of 2 700 K, to 0.05 of its original value, the luminous flux being evaluated by means of the photometric luminosity function of the International Commission on Illumination (CIE) (metre (m) or kilometre (km)).
A statement of observed meteorological conditions related to a specified time and location.
An artificial Earth satellite making meteorological observations and transmitting these observations to Earth.
those facilities and services that provide aircraft with meteorological forecasts, briefs and observations as well as any other meteorological information and data provided by States for aeronautical use
The distance travelled by light in a vacuum during 1/299 792 458 of a second.
Operations of the armed forces other than those for remuneration which should be covered under public transport operations.
Minimum descent altitude or minimum descent height
A specified altitude or height in a non-precision approach or circling approach below which descent must not be made without the required visual reference.
Source: ICAO Annex 6;
Synonyms: MDA/H; minimum descent altitude/height
Minimum en-route altitude
The altitude for an en-route segment that provides adequate reception of relevant navigation facilities and ATS communications, complies with the airspace structure and provides the required obstacle clearance.
Minimum equipment list
A list which provides for the operation of aircraft, subject to specified conditions, with particular equipment inoperative, prepared by an operator in conformity with, or more restrictive than, the MMEL established for the aircraft type.
The term used to describe a situation in which an aircraft's fuel supply has reached a state where little or no delay can be accepted.
Minimum obstacle clearance altitude
The minimum altitude for a defined segment of flight that provides the required obstacle clearance.
Minimum sector altitude
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 radio aid to navigation.
Minimum stabilization distance
The minimum distance to complete a turn manoeuvre and after which a new manoeuvre can be initiated. The minimum stabilization distance is used to compute the minimum distance between waypoints.
Baggage involuntarily, or inadvertently, separated from passengers or crew.
Missed approach holding fix
A fix used in RNAV applications that marks the end of the missed approach segment and the centre point for the missed approach holding.
Missed approach or go-around
The phase of flight where the aircraft aborts the approach during an ils or other precision approach involving an abnormally early turn on approach before reaching minimum decision altitude or decision height, or where the aircraft breaks off any approach to execute a missed approach or vfr go-around procedure when the approach cannot be continued.
Missed approach point
That point in an instrument approach procedure at or before which the prescribed missed approach procedure must be initiated in order to ensure that the minimum obstacle clearance is not infringed.
Missed approach procedure
The procedure to be followed if the approach cannot be continued.
Mixed navigation environment
An environment where different navigation specifications may be applied within the same airspace (e.g. RNP 10 routes and RNP 4 routes in the same airspace) or where operations using conventional navigation are allowed in the same airspace with RNAV or RNP applications.
Mobile surface station
A station in the aeronautical telecommunication service, other than an aircraft station, intended to be used while in motion or during halts at unspecified points.
The conventional identifier related to specific functions of the interrogation signals transmitted by an SSR interrogator. There are four modes specified in Annex 10: A, C, S and intermode.
Mode S subnetwork
A means of performing an interchange of digital data through the use of secondary surveillance radar (SSR) Mode S interrogators and transponders in accordance with defined protocols.
Abstraction of some aspects of reality.
The amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12.
An area of changing terrain profile where the changes of terrain elevation exceed 900 m (3 000 ft) within a distance of 18.5 km (10.0 NM).
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(s).
One or more polygons located inside another polygon that excludes the area of the inner polygons (e.g. doughnut, figure eight).
multiple flight plan
more than one flight plan for the same intended flight between two airports
multiple route options
the availability to the airspace user of more than one routing option on the ATS route network
Measures to control the illicit movement of narcotics and psychotropic substances by air.
The length equal to 1 852 metres exactly.
Navigation aid infrastructure
Navaid infrastructure refers to space-based and or ground-based navigation aids available to meet the requirements in the navigation specification.
The application of a navigation specification and the supporting navaid infrastructure, to routes, procedures, and/or defined airspace volume, in accordance with the intended airspace concept. Note.- The navigation application is one element, along with communication, surveillance and ATM procedures which meet the strategic objectives in a defined airspace concept.
The detailed capability of the navigation system (such as the execution of leg transitions, parallel offset capabilities, holding patterns, navigation databases) required to meet the airspace concept. Note.- Navigational functional requirements are one of the drivers for the selection of a particular navigation specification. Navigation functionalities (functional requirements) for each navigation specification can be found in the Performance-based Navigation (PBN) Manual (Doc 9613), Volume II, Parts B and C.
those facilities and services that provide aircraft with positioning and timing information
A set of aircraft and flight crew requirements needed to support performance-based navigation operations within a defined airspace. There are two kinds of navigation specifications: Required navigation performance (RNP) specification. A navigation specification based on area navigation that includes the requirement for performance monitoring and alerting, designated by the prefix RNP, e.g. RNP 4, RNP APCH. Area navigation (RNAV) specification. A navigation specification based on area navigation that does not include the requirement for performance monitoring and alerting, designated by the prefix RNAV, e.g. RNAV 5, RNAV 1.
Non-intersecting runways whose extended centre lines have an angle of convergence/divergence of 15 degrees or less.
Negotiating 4D trajectory
A 4D trajectory proposed by airspace user or ASP as a potential agreed 4D trajectory.
The net gradient of climb throughout these requirements [Annex 6/I] is the expected gradient of climb diminished by the manoeuvre performance (i.e. that gradient of climb necessary to provide power to manoeuvre) and by the margin (i.e. that gradient of climb necessary to provide for those variations in performance which are not expected to be taken explicit account of operationally).
a state of inability to provide air navigation service at required level resulting in a major loss of network capacity, or a major imbalance between network capacity and demand, or a major failure in the information flow in one or several parts of the network following an unusual and unforeseen situation
the body established under Article 6 of Regulation (EC) No 551/2004 to perform the duties provided for in that Article and this Regulation
Network Operations Plan
the plan, including its supporting tools, developed by the Network Manager in coordination with the operational stakeholders to organise its operational activities in the short and medium term in accordance with the guiding principles of the Network Strategic Plan. For the European route network design- specific part of the Network Operations Plan, it includes the European Route Network Improvement Plan
Network Operations Plan
the plan developed by the Network Manager in coordination with the operational stakeholders to organise its operational activities in the short and medium term in accordance with the guiding principles of the Network Strategic Plan. For the European route network design (ERND)-specific part of the Network Operations Plan, it includes the European Route Network Improvement Plan
An aeronautical station forming part of a radiotelephony network.
Network Strategy Plan
the plan developed by the Network Manager, consistent with the European ATM Master Plan, in coordination with Member States and the operational stakeholders defining the guiding principles for the network operation and its long term perspective
"(i) an air carrier requesting, as part of a series of slots, a slot at an airport on any day, where, if the carrier's request were accepted, it would in total hold fewer than five slots at that airport on that day, or(ii) an air carrier requesting a series of slots for a non-stop scheduled passenger service between two Community airports where at most two other air carriers operate the same non-stop scheduled service between these airports or airport systems on that day, where, if the air carrier's request were accepted, the air carrier would nonetheless hold fewer than five slots at that airport on that day for that non-stop service, or(iii) an air carrier requesting a series of slots at an airport for a non-stop scheduled passenger service between that airport and a regional airport where no other air carrier operates a direct scheduled passenger service between these airports or airport systems on that day, where, if the air carrier's request were accepted, the air carrier would nonetheless hold fewer than five slots at that airport on that day for that non-stop service.An air carrier holding more than 5 % of the total slots available on the day in question at a particular airport, or more than 4 % of the total slots available on the day in question in an airport system of which that airport forms part, shall not be considered as a new entrant at that airport;"
The force which when applied to a body having a mass of 1 kilogram gives it an acceleration of 1 metre per second squared.
Next data authority
The ground system so designated by the current data authority through which an onward transfer of communications and control can take place.
The hours between the end of evening civil twilight and the beginning of morning civil twilight or such other period between sunset and sunrise, as may be prescribed by the appropriate authority.
No risk of collision
The risk classification of an aircraft proximity in which no risk of collision has existed.
No transgression zone
In the context of independent parallel approaches, a corridor of airspace of defined dimensions located centrally between the two extended runway centre lines, where a penetration by an aircraft requires a controller intervention to manoeuvre any threatened aircraft on the adjacent approach.
Non-congested hostile environment
A hostile environment outside a congested area.
An environment in which: a) a safe forced landing can be accomplished because the surface and surrounding environment are adequate; b) the helicopter occupants can be adequately protected from the elements; c) search and rescue response/capability is provided consistent with anticipated exposure; and d) the assessed risk of endangering persons or property on the ground is acceptable.
A runway intended for the operation of aircraft using visual approach procedures.
Radiotelephony communications conducted by a station of the aeronautical mobile service, other than those conducted as part of a radiotelephony network.
Non-precision approach and landing operations
An instrument approach and landing which utilizes lateral guidance but does not utilize vertical guidance.
Non-precision approach procedure
An instrument approach procedure which utilizes lateral guidance but does not utilize vertical guidance.
Source: ICAO; ICAO Annex 2; ICAO Annex 4;
Synonyms: NPA procedure
Non-precision approach runway
An instrument runway served by visual aids and a non-visual aid providing at least directional guidance adequate for a straight-in approach.
The separation used when aircraft position information is derived from sources other than radar.
Non-scheduled international flight
Any international flight performed other than as a scheduled international air service.
Any air service that is performed other than as a scheduled air service, including but not limited to charter operations.
The phase of flight in which a controlled descent is made from cruise to the initial approach fix, final approach fix, outer marker, 1500 feet above runway end elevation, or entry to the vfr pattern, whichever occurs first.
Normal flight zone
Airspace not defined as LFFZ, LCFZ or LSFZ but which must be protected from laser radiation capable of causing biological damage to the eye.
Normal operating zone
Airspace of defined dimensions extending to either side of an ILS localizer course and/or MLS final approach track. Only the inner half of the normal operating zone is taken into account in independent parallel approaches.
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.
The evaluation of one or more meteorological elements.
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 that have been assessed as being a hazard to air navigation.
Obstacle assessment surface
A defined surface intended for the purpose of determining those obstacles to be considered in the calculation of obstacle clearance altitude/height for a specific ILS facility and procedure.
Obstacle clearance altitude or obstacle clearance height
The lowest altitude or the lowest height above the elevation of the relevant runway threshold or the aerodrome elevation as applicable, used in establishing compliance with appropriate obstacle clearance criteria.
Source: ICAO Annex 4; ICAO Annex 6;
Synonyms: obstacle clearance altitude/height; OCA/H
Obstacle free zone
The airspace above the inner approach surface, inner transitional surfaces, and balked landing surface and that portion of the strip bounded by these surfaces, which is not penetrated by any fixed obstacle other than a low-mass and frangibly mounted one required for air navigation purposes.
Obstacle/terrain data collection surface
A defined surface intended for the purpose of collecting obstacle/terrain data.
Off shore flight
A flight for the carriage of passengers or freight or a combination thereof for remuneration to and from an offshore installation.
Includes VIP flights.
Offset frequency simplex
A variation of single channel simplex wherein telecommunication between two stations is effected by using in each direction frequencies that are intentionally slightly different but contained within a portion of the spectrum allotted for the operation.
Operations which routinely have a substantial proportion of the flight conducted over sea areas to or from offshore locations. Such operations include, but are not limited to, support of offshore oil, gas and mineral exploitation and sea-pilot transfer.
The electric resistance between two points of a conductor when a constant difference of potential of 1 volt, applied between these two points, produces in this conductor a current of 1 ampere, this conductor not being the source of any electromotive force.
Open path CDO procedures
Procedures which require that after the DTW, an FM path terminator should be coded. In contrast, if ATC requires a defined path, a VM path terminator can be used instead.
The location from which operational control is exercised.
an organisation responsible for the provision of engineering and technical services supporting air traffic, communication, navigation or surveillance services
An activity or group of activities which are subject to the same or similar hazards and which require a set of equipment to be specified, or the achievement and maintenance of a set of pilot competencies, to eliminate or mitigate the risk of such hazards.
For the purposes of this document, an operational concept is defined as: a) a high-level description of the ATM services necessary to accommodate traffic at a given time horizon; b) a description of the anticipated level of performance required from, and the interaction between, the ATM services, as well as the objects they affect; and c) a description of the information to be provided to agents in the ATM system and how that information is to be used for operational purposes.
Operational concept vision
To achieve an interoperable global ATM system, for all users during all phases of flight, that meets agreed levels of safety, provides for optimum economic operations, is environmentally sustainable and meets national security requirements.
The exercise of authority over the initiation, continuation, diversion or termination of a flight in the interest of the safety of the aircraft and the regularity and efficiency of the flight.
Operational control communications
Communications required for the exercise of authority over the initiation, continuation, diversion or termination of a flight in the interest of the safety of the aircraft and the regularity and efficiency of a flight.
information concerning all phases of flight that are required to take operational decisions by air navigation service providers, airspace users, airport operators and other actors involved
Operational flight plan
The operator's plan for the safe conduct of the flight based on considerations of aeroplane performance, other operating limitations and relevant expected conditions on the route to be followed and at the aerodromes concerned.
The planning of flight operations by an operator.
A statement of the operational attributes of a system needed for the effective and/or efficient provision of air traffic services to users.
the requirements of the network in terms of safety, capacity and efficiency
the civil and military airspace users, civil and military air navigation service providers, airport operators, airport slot coordinators and operating organisations and any additional stakeholder groups considered relevant for the individual functions
Operations in performance Class 1
Operations with performance such that, in the event of a critical engine failure, performance is available to enable the helicopter to safely continue the flight to an appropriate landing area, unless the failure occurs prior to reaching the take-off decision point (TDP) or after passing the landing decision point (LDP), in which cases the helicopter must be able to land within the rejected take-off or landing area.
Operations in performance Class 2
Operations with performance such that, in the event of critical engine failure, performance is available to enable the helicopter to safely continue the flight to an appropriate landing area, except when the failure occurs early during the take-off manoeuvre or late in the landing manoeuvre, in which cases a forced landing may be required.
Operations in performance Class 3
Operations with performance such that, in the event of an engine failure at any time during the flight, a forced landing will be required.
A manual containing procedures, instructions and guidance for use by operational personnel in the execution of their duties.
The authorizations, conditions and limitations associated with the air operator certificate and subject to the conditions in the operations manual.
a person, organisation or enterprise engaged in or offering to engage in an aircraft operation
A person, organization or enterprise engaged in or offering to engage in an aircraft operation.
Operator's maintenance control manual
A document which describes the operator's procedures necessary to ensure that all scheduled and unscheduled maintenance is performed on the operator's aircraft on time and in a controlled and satisfactory manner.
Optimized profile descent
A descent profile normally associated with a published arrival (STAR) and designed to allow maximum practical use of a CDO. It starts from top of descent, taking onto consideration the limitations of the local airport, airspace, environment, traffic and aircraft capabilities, and ATC. To the extent possible the descent profile is comprised of idle-power performance descent profile segments and geometric descent profile segments that maximize altitude, minimize the thrust required to remain on the path, terminate the path at the desired end location and satisfy the altitude and speed constraints along the closed path design. Note.- OPD is one method of facilitating CDO.
When an operational concept (or a technical concept) can be realized through various solutions, each of these solutions is seen as an option. Selecting/retaining an option requires investigated cost-benefit and other analyses. In some cases, only one option can be retained. In other cases, several options can be left to the choice of implementers.
The process of creating a data item or amending the value of an existing data item.
The first organization in the aeronautical data chain that accepts responsibility for the data.
A heavier-than-air aircraft supported in flight chiefly by the reactions of the air on planes to which a flapping motion is imparted.
Height of a point related to the geoid, generally presented as an MSL elevation.
An enclosure used by a single shipper to contain one or more packages and to form one handling unit for convenience of handling and stowage.
Oxides of nitrogen
The sum of the amounts of the nitric oxide and nitrogen dioxide contained in a gas sample calculated as if the nitric oxide were in the form of nitrogen dioxide.
The complete product of the packing operation consisting of the packaging and its contents prepared for transport.
Receptacles and any other components or materials necessary for the receptacle to perform its containment function.
Continuous line along the painted line in the center of a runway connecting the two thresholds.
Parachute drop flight
A flight to carry parachutists.
The pressure or stress of 1 newton per square metre.
Passenger air service
An air service performed primarily for the transport of passengers.
An aircraft that carries any person other than a crew member, an operator's employee in an official capacity, an authorized representative of an appropriate national authority or a person accompanying a consignment or other cargo.
Facilities provided for passengers which are not essential for passenger processing.
Pavement classification number
A number expressing the bearing strength of a pavement for unrestricted operations.
Performance Class 1 helicopter
A helicopter with performance such that, in case of engine failure, it is able to land on the rejected take-off area or safely continue the flight to an appropriate landing area.
Performance Class 2 helicopter
A helicopter with performance such that, in case of engine failure, it is able to safely continue the flight, except when the failure occurs prior to a defined point after take-off or after a defined point before landing, in which cases a forced landing may be required.
Performance Class 3 helicopter
A helicopter with performance such that, in case of engine failure at any point in the flight profile, a forced landing must be performed.
Simple, evaluative statements on the required outcome of the competency element and a description of the criteria used to judge whether the required level of performance has been achieved.
Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace.
Person with disabilities
Any person whose mobility is reduced due to a physical incapacity (sensory or locomotor), an intellectual deficiency, age, illness or any other cause of disability when using transport and whose situation needs special attention and the adaptation to the person's needs of the services made available to all passengers.
A flight to carry out aerial photography.
To manipulate the flight controls of an aircraft during flight time.
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.
Pilot-in-command under supervision
Co-pilot performing, under the supervision of the pilot-in-command, the duties and functions of a pilot-in-command, in accordance with a method of supervision acceptable to the Licensing Authority.
Private flying operations for no specific purpose.
The smallest unit of geometry which has no spatial extent. Points are described by two-dimensional (2D) or three-dimensional (3D) coordinates.
A luminous signal appearing without perceptible length.
The point-in-space approach is based on a basic GNSS non-precision approach procedure designed for helicopters only. It is aligned with a reference point located to permit subsequent flight manoeuvring or approach and landing using visual manoeuvring in adequate visual conditions to see and avoid obstacles.
Point-in-space reference point
Reference point for the point-in-space approach as identified by the latitude and longitude of the MAPt.
Pertaining or relating to the interconnection of two devices, particularly end-user instruments. A communication path of service intended to connect two discrete end-users; as distinguished from broadcast or multipoint service.
A flight carried out by the police
A surface or area described by a closed line.
Presentation of information to humans (ISO 19117).
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.
The visual indication, in non-symbolic and/or symbolic form, on a situation display, of the position of an aircraft, aerodrome vehicle or other object.
The visual indication in symbolic form, on a situation display, of the position of an aircraft, aerodrome vehicle or other object, obtained after automatic processing of positional data derived from any source.
That element of an SSR response which represents the actual position of the associated aircraft on the display.
Any flight flown to position the aircraft to be used on some revenue-earning services.
Post maintenance function check flight
A flight to check functtions after maintenance
Angular or linear distance between two adjacent elevation points.
The phase, in an accident or incident sequence, after the aircraft has collided with the first object, place or person.
A heavier-than-air aircraft capable of vertical take-off, vertical landing, and low-speed flight, which depends principally on engine-driven lift devices or engine thrust for the lift during these flight regimes and on non-rotating aerofoil(s) for lift during horizontal flight.
The system consisting of all the engines, drive system components (if applicable), and propellers (if installed), their accessories, ancillary parts, and fuel and oil systems installed on an aircraft but excluding the rotors for a helicopter.
Pre-flight information bulletin
A presentation of current NOTAM information of operational significance, prepared prior to flight.
The smallest difference that can be reliably distinguished by a measurement process.
Precision approach and landing operations
An instrument approach and landing using precision lateral and vertical guidance with minima as determined by the category of operation.
Precision approach procedure
An instrument approach procedure utilizing azimuth and glide path information provided by ILS or PAR.
Precision approach procedure
An instrument approach procedure using precision lateral and vertical guidance with minima as determined by the category of operation.
Note.- Lateral and vertical guidance refers to the guidance provided either by: a) a ground-based navigation aid; or b) computer generated navigation data.
Precision approach radar
Primary radar equipment used to determine the position of an aircraft during final approach, in terms of lateral and vertical deviations relative to a nominal approach path, and in range relative to touchdown.
Precision approach runway, category 1
An instrument runway served by ILS and/or MLS and visual aids intended for operations with a decision height not lower than 60 m (200 ft) and either a visibility not less than 800 m or a runway visual range not less than 550 m.
Precision approach runway, category II
An instrument runway served by ILS and/or MLS and visual aids intended for operations with a decision height lower than 60 m (200 ft) but not lower than 30 m (100 ft) and a runway visual range not less than 350 m.
Precision approach runway, category III
An instrument runway served by ILS and/or MLS to and along the surface of the runway and: A - intended for operations with a decision height lower than 30 m (100 ft), or no decision height and runway visual range not less than 200 m. B - intended for operations with a decision height lower than 15 m (50 ft), or no decision height and runway visual range less than 200 m but not less than 50 m. C - intended for operations with no decisions height and no runway visual range limitations.
Is a measure of delay variance against a performance dependability target. As the variance of expected delay increases, it becomes a very serious concern for airlines when developing and operating their schedules. Conceptually, predictability metrics should be a comparison of the actual flight time to the scheduled flight time, since the scheduled time includes the amount of expected delay at a targeted dependability performance.
The communication used for the prompt dissemination of data obtained during the early stages of the investigation.
An atmospheric pressure expressed in terms of altitude which corresponds to that pressure in the Standard Atmosphere.
The rate of change in atmospheric pressure.
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.
The greatest visibility value observed 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.
A defined area symmetrically disposed about the nominal flight track in which full obstacle clearance is provided.
The radiotelephony frequency assigned to an aircraft as a first choice for air-ground communication in a radiotelephony network.
Primary means of communication
The means of communication to be adopted normally by aircraft and ground stations as a first choice where alternative means of communication exist.
A radar system which uses reflected radio signals.
Runway(s) used in preference to others whenever conditions permit.
Primary surveillance radar
A surveillance radar system which uses reflected radio signals.
Communications which automatically provide a permanent printed record at each terminal of a circuit of all messages which pass over such circuit.
Any non-State aircraft used for noncommercial purposes.
An airport that serves primarily small privately owned aircraft, flying clubs, etc.
Problematic use of substances
The use of one or more psychoactive substances by aviation personnel 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.
Term used to indicate that information derived from an ATS surveillance system is not required for the provision of air traffic control service.
The separation used when providing procedural control.
as used in the context of the interoperability Regulation,a standard method for either the technical or the operational use of systems, in the context of agreed and validated concepts of operation requiring uniform implementation throughout the EATMN
A specified altitude/height flown operationally at or above the minimum altitude/height and established to accommodate a stabilized descent at a prescribed descent gradient/angle in the intermediate/final approach segment.
A manoeuvre in which a turn is made away from a designated track followed by a turn in the opposite direction to permit the aircraft to intercept and proceed along the reciprocal of the designated track.
The orthogonal projection of a flight path or portion thereof on the vertical surface containing the nominal track.
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.
An airspace of defined dimensions, above the land areas or territorial waters of a State, within which the flight of aircraft is prohibited.
A system consisting of a power-unit and all other equipment utilized to provide those functions necessary to sustain, monitor and control the power/thrust output of any one power-unit following installation on the airframe.
Protected flight zones
Airspace specifically designated to mitigate the hazardous effects of laser radiation.
Protected service volume
A part of the facility coverage where the facility provides a particular service in accordance with relevant SARPs and within which the facility is afforded frequency protection.
An area within a taxi-route and around a helicopter stand which provides separation from objects, the FATO, other taxi-routes and helicopter stands, for safe manoeuvring of helicopters.
The visual indication, in non-symbolic form, on a situation display of the position of an aircraft obtained by primary radar.
The visual indication, in non-symbolic form, on a radar display of the position of an aircraft obtained by primary radar.
Alcohol, opioids, cannabinoids, sedatives and hypnotics, cocaine, other psychostimulants, hallucinogens, and volatile solvents, whereas coffee and tobacco are excluded.
The agencies or officials of a Contracting State responsible for the application and enforcement of the particular laws and regulations of that State which relate to any aspect of these Standards and Recommended Practices.
Public health emergency of international concern
An extraordinary event which is determined, as provided in the International Health Regulations (2005) of the World Health Organization: (i) to constitute a public health risk to other States through the international spread of disease and (ii) to potentially require a coordinated international response.
Public health risk
A likelihood of an event that may affect adversely the health of human populations, with an emphasis on one which may spread internationally or may present a serious and direct danger.
The phase of flight when an aircraft is moving from the gate or parking position, not under its own power, but with the assistance of a tug.
putting into service
the first operational use after the initial installation or an upgrade of a system
Degree to which a set of inherent characteristics fulfils requirements (ISO 9000).
Part of quality management focused on providing confidence that quality requirements will be fulfilled (ISO 9000).
Part of quality management focused on fulfilling quality requirements (ISO 9000).
Coordinated activities to direct and control an organization with regard to quality (ISO 9000).
Documented organizational procedures and policies; internal audit of those policies and procedures; management review and recommendation for quality improvement.
A procedure designed to enable the aircraft to reduce altitude during the initial approach segment and/or establish the aircraft inbound when the entry into a reversal procedure is not practical.
A radio detection device which provides information on range, azimuth and/or elevation of objects.
An approach in which the final approach phase is executed under the direction of a controller using radar.
A generic term for the visual indication, in non-symbolic form, on a radar display of the position of an aircraft obtained by primary or secondary radar.
The visual indication on a situation display of unwanted signals.
The situation which exists when the radar position of a particular aircraft is seen and identified on a situation display.
Term used to indicate that radar-derived information is employed directly in the provision of air traffic control service.
A qualified air traffic controller holding a radar rating appropriate to the functions to which he is assigned.
An electronic display of radar-derived information depicting the position and movement of aircraft.
The visual indication on a radar display of a radar signal reflected from an object.
A magnetic heading given by a controller to a pilot on the basis of radar-derived information for the purpose of providing navigational guidance.
The process of correlating a particular radar blip or radar position symbol with a specific aircraft.
Information superimposed on a radar display to provide ready indication of selected features.
The use of radar for the purpose of providing aircraft with information and advice relative to significant deviations from nominal flight path.
Radar position indication
The visual indication, in non-symbolic and/or symbolic form, on a radar display of the position of an aircraft obtained by primary and/or secondary surveillance radar.
Radar position symbol
A generic term of the visual indication in a symbolic form, on a radar display, of the position of an aircraft obtained after digital computer processing of positional data derived from primary radar and/or SSR.
Radar response (or SSR response)
The visual indication in non-symbolic form, on a radar display, of a radar signal transmitted from an object in reply to an interrogation.
The separation used when aircraft position information is derived from radar sources.
Term used to indicate a service provided directly by means of radar.
Radar track position
An extrapolation of aircraft position by the computer based upon radar information and used by the computer for tracking purposes. Note.- In some cases, information other than radar-derived information is used to assist the tracking processes.
The act, by either a human or a computer, of following the movements of specific aircraft by means of radar for the purpose of ensuring a continuous indication of the identity, position, track and/or height of the aircraft.
That element of an air traffic services unit which uses radar equipment to provide one or more services.
Provision of navigational guidance to aircraft in the form of specific headings, based on the use of radar.
The plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius.
The angle between the apparent direction of a definite source of emission of electro-magnetic waves and a reference direction, as determined at a radio directionfinding station. A true radio bearing is one for which the reference direction is that of true North. A magnetic radio bearing is one for which the reference direction is that of magnetic North.
Radio direction finding
Radiodetermination using the reception of radio waves for the purpose of determining the direction of a station or object.
Radio direction-finding station
A radiodetermination station using radio direction finding.
Radio navigation service
A service providing guidance information or position data for the efficient and safe operation of aircraft supported by one or more radio navigation aids.
The capability of a sensor to discriminate levels or intensity of spectral radiance. In the analogue systems such as photography, the radiometric resolution is measured based on the number of grey levels that can be obtained. In opto-electronic systems, the radiance is recorded in an array of cells. A digit is assigned to each cell proportional to the received level of energy. This is done by an analog to digital converter in the platform. Generally, in modern sensors the range is between zero radiance into the sensor and 255 at saturation response of the detector.
A form of radiocommunication primarily intended for the exchange of information in the form of speech.
A group of radiotelephony aeronautical stations which operate on and guard frequencies from the same family and which support each other in a defined manner to ensure maximum dependability of air-ground communications and dissemination of air-ground traffic.
Random errors of observations refer to the basic inherent property that estimates of a random variable do not agree, in general, with its expectation.
Ranked 4D trajectories
A series of desired 4D trajectories, with tolerances supplied if necessary by the airspace user to define when the next ranked trajectory should be used.
Rapid exit taxiway
A taxiway connected to a runway at an acute angle and designed to allow landing aeroplanes to turn off at higher speeds than are achieved on other exit taxiways thereby minimizing runway occupancy times.
Rated air traffic controller
An air traffic controller holding a licence and valid ratings appropriate to the privileges to be exercised.
For engine emissions purposes, the maximum take-off thrust approved by the certificating authority for use under normal operating conditions at ISA sea level static conditions, and without the use of water injection. Thrust is expressed in kilonewtons.
An authorization entered on or associated with a licence and forming part thereof, stating special conditions, privileges or limitations pertaining to such licence.
A label (e.g. RCP 240) that represents the values assigned to RCP parameters for communication transaction time, continuity, availability and integrity.
A procedure whereby the receiving station repeats a received message or an appropriate part thereof back to the transmitting station so as to obtain confirmation of correct reception.
Air traffic services unit/air traffic controller to which a message is sent.
Certification of an aircraft with or without a revision to its certification noise levels, to a Standard different to that to which it was originally certificated.
Reference datum height
The height of the extended glide path or a nominal vertical path at the runway threshold.
A geometric figure comprising one component of a geodetic datum, usually determined by rotating an ellipse about its shorter (polar) axis, and used as a surface of reference for geodetic surveys. The reference ellipsoid closely approximates the dimensions of the geoid, with certain ellipsoids fitting the geoid more closely for various areas of the earth. Elevations derived directly from satellite observations are relative to the ellipsoid and are called ellipsoid heights.
The relationship between temperature and reference humidity is defined as follows: - at temperatures at and below ISA, 80 per cent relative humidity, - at temperatures at and above ISA + 28�C, 34 per cent relative humidity, - at temperatures between ISA and ISA + 28�C, the relative humidity varies linearly between the humidity specified for those temperatures.
Reference pressure ratio
The ratio of the mean total pressure at the last compressor discharge plane of the compressor to the mean total pressure at the compressor entry plane when the engine is developing take-off thrust rating in ISA sea level static conditions.
Regional air navigation agreement
Agreement approved by the Council of ICAO normally on the advice of a regional air navigation meeting.
Regional air service
An air service offered on routes serving smaller cities within a region or between regions of a State; or an air service offered on secondary routes serving smaller cities in a regional area involving the territories of more than one State.
Generally refers to an airport of a medium or small city that is mainly served by short-haul regional services.
FF-ICE will be based upon global information standards defining a core set of data. Regional extensions on data elements are permitted in accordance with harmonized global practices for defining and referring to these elements.
Regional requirements specify conditions regarding data items within a region if necessary.
A station selected from those forming an en-route air-ground radiotelephony network to communicate with or to intercept communications from aircraft in normal conditions.
An agent, freight forwarder or any other entity who conducts business with an operator and provides security controls that are accepted or required by the appropriate authority in respect of cargo or mail.
Rejected take-off area
A defined area on a heliport suitable for helicopters operating in performance class 1 to complete a rejected take-off.
Rejected take-off distance available (helicopter)
The length of the final approach and take-off area declared available and suitable for performance class 1 helicopters to complete a rejected take-off.
Rejected take-off distance required
The horizontal distance required from the start of the take-off to the point where the helicopter comes to a full stop following a power-unit failure and rejection of the take-off at the take-off decision point.
Release of goods
The action by the customs authorities to permit goods undergoing clearance to be placed at the disposal of the persons concerned.
Time prior to which an aircraft should be given further clearance or prior to which it should notproceed in case of radio failure.
The inequalities in elevation of the surface of the Earth represented on aeronautical charts by contours, hypsometric tints, shading or spot elevations.
Flights operated for humanitarian purposes which carry relief personnel and relief supplies such as food, clothing, shelter, medical and other items during or after an emergency and/or disaster and/or are used to evacuate persons from a place where their life or health is threatened by such emergency and/or disaster to a safe haven in the same State or another State willing to receive such persons.
Removal of a person
Action by the public authorities of a State, in accordance with its laws, to direct a person to leave that State.
A written order served by a State on the operator on whose flight an inadmissible person travelled into that State, directing the operator to remove that person from its territory.
Rendering (a Certificate of Airworthiness) valid
The action taken by a Contracting State, as an alternative to issuing its own Certificate of Airworthiness, in accepting a Certificate of Airworthiness issued by any other Contracting State as the equivalent of its own Certificate of Airworthiness.
Rendering (a licence) valid
The action taken by a Contracting State, as an alternative to issuing its own licence, in accepting a licence issued by any other Contracting State as the equivalent of its own licence.
The restoration of an aeronautical product to an airworthy condition to ensure that the aircraft continues to comply with the design aspects of the appropriate airworthiness requirements used for the issuance of the type certificate for the respective aircraft type, after it has been damaged or subjected to wear.
The closeness with which a measurement upon a given, invariant sample can be reproduced in short-term repetitions of the measurement with no intervening instrument adjustment.
Repetitive flight plan
A flight plan related to a series of frequently recurring, regularly operated individual flights with identical basic features, submitted by an operator for retention and repetitive use by ATS units.
A specified (named) geographical location in relation to which the position of an aircraft can be reported.
Required ATM performance
RASP is the set of criteria, expressed in the form of performance parameters and values of those parameters, that the ATM system needs to meet, with a given probability, in order to support the approved quality of service specified for a particular environment.
Required communication performance
A statement of the performance requirements for operational communication in support of specific ATM functions.
Required communication performance type
A label (e.g. RCP 240) that represents the values assigned to RCP parameters for communication transaction time, continuity, availability and integrity.
Required navigation performance
A statement of the navigation performance necessary for operation within a defined airspace.
Required total system performance
RTSP is the aggregate of criteria, expressed in the form of performance parameters (operational and technical), that the ATM system needs to meet in order to deliver the approved quality of service and RASP specified for a particular environment.
Need or expectation that is stated, generally implied or obligatory (ISO 9000).
An operation to retrieve persons in distress, provide for their initial medical or other needs, and deliver them to a place of safety.
Rescue coordination centre
A unit responsible for promoting efficient organization of search and rescue services and for coordinating the conduct of search and rescue operations within a search and rescue region.
A unit subordinate to a rescue coordination centre, established to complement the latter according to particular provisions of the responsible authorities.
A unit composed of trained personnel and provided with equipment suitable for the expeditious conduct of search and rescue.
A number of units or digits to which a measured or calculated value is expressed and used.
A continuous and defined period of time, subsequent to and/or prior to duty, during which flight or cabin crew members are free of all duties.
An airspace of defined dimensions, above the land areas or territorial waters of a State, within which the flight of aircraft is restricted in accordance with certain specified conditions.
A procedure designed to enable aircraft to reverse direction during the initial approach segment of an instrument approach procedure. The sequence may include procedure turns or base turns.
An assessment by a deporting State of a deportee's suitability for escorted or unescorted removal via commercial air services. The assessment should take into account all pertinent factors, including medical, mental and physical fitness for carriage on a commercial flight, willingness or unwillingness to travel, behavioural patterns and any history of violence.
The systematic application of management policies, procedures and practices to the tasks of establishing the context of, identifying, analysing, evaluating and treating risks; monitoring the implementation of treatments; and communicating about risk.
The systematic application of management procedures and practices which provide border inspection agencies with the necessary information to address movements or consignments which represent a risk.
Risk not determined
The risk classification of an aircraft proximity in which insufficient information was available to determine the risk involved, or inconclusive or conflicting evidence precluded such determination.
Risk of collision
The risk classification of an aircraft proximity in which serious risk of collision has existed.
Aircraft operations using area navigation for RNAV applications.
A navigation system which permits aircraft operation on any desired flight path within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these. An RNAV system may be included as part of a flight management system (FMS).
Aircraft operations using an RNP system for RNP navigation applications.
An ATS route established for the use of aircraft adhering to a prescribed RNP navigation specification.
An area navigation system which supports on-board performance monitoring and alerting.
A containment value expressed as a distance in nautical miles from the intended position within which flights would be for at least 95 per cent of the total flying time.
An established surface route on the movement area meant for the exclusive use of vehicles.
A designated position at which vehicles may be required to hold.
A power-driven heavier-than-air aircraft supported in flight by the reactions of the air on one or more rotors.
The phase of flight when the helicopter is standing with its rotors turning prior to take-off or after landing.
route and traffic orientation
policies and procedures for the use of routes by aircraft
The unambiguous delineation of a route in terms of an ordered sequence of ATS route designators and/or significant points.
a network of specified routes for channelling the flow of general air traffic as necessary for the provision of ATC services
A route or portion of route usually flown without an intermediate stop.
A route or portion of a route flown without an intermediate landing.
the chosen itinerary to be followed by an aircraft during its operation
A defined area encompassing one or more major traffic flows for the purpose of developing a detailed plan for the implementation of interoperable CNS/ATM systems.
A list in a communication centre indicating for each addressee the outgoing circuit to be used.
The phase of flight in which the helicopter lands with power on.
A defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 14; ICAO Annex 2; ICAO Annex 3; ICAO Annex 4;
The number of aircraft movements which aeronautical authorities determine can safely be operated, usually stated as the total number of landings and take-offs per hour, taking into account such factors as the physical characteristics of the runways and the surrounding area, altitude, the types of aircraft involved (larger aircraft may mandate greater separation) and air traffic control (approach and aerodrome control) capabilities.
Runway displaced area
That portion of a runway between the beginning of the runway and the displaced threshold.
Runway end safety area
An area symmetrical about the extended runway centre line and adjacent to the end of the strip primarily intended to reduce the risk of damage to an aeroplane undershooting or overrunning the runway.
Runway exit line
Guidance line painted on the runway exit.
Runway guard lights
A light system intended to caution pilots or vehicle drivers that they are about to enter an active runway.
Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take-off of aircraft.
Runway incursion severity classification calculator
A computer programme that classifies the outcome of runway incursions.
A defined area including the runway and stopway, if provided, intended: a) to reduce the risk of damage to aircraft running off a runway; and b) to protect aircraft flying over it during take-off or landing operations.
Runway turn pad
A defined area on a land aerodrome adjacent to a runway for the purpose of completing a 180-degree turn on a runway.
Runway visual range
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.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 14; ICAO Annex 3; ICAO Annex 4; ICAO Annex 6;
A designated position intended to protect a runway, an obstacle limitation surface, or an ILS/MLS critical/sensitive area at which taxiing aircraft and vehicles shall stop and hold, unless otherwise authorized by the aerodrome control tower.
(Abbreviated RVR) The range [distance] over which the pilot of an aircraft on the center line of a runway can see the runway surface markings or the lights delineating the runway or identifying its center line.
Safe forced landing
Unavoidable landing or ditching with a reasonable expectancy of no injuries to persons in the aircraft or on the surface.
A defined area on a heliport surrounding the FATO which is free of obstacles, other than those required for air navigation purposes, and intended to reduce the risk of damage to helicopters accidentally diverging from the FATO.
Both the argument and the document that contend that the level of safety attained will satisfy the safety requirements. It intelligently and coherently argues the degree of safety achieved at any point of a system's life cycle by making rational and coherent reference to the documented results of the system safety approach defined below.
Safety management system
A systematic approach to managing safety, including the necessary organizational structures, accountabilities, policies and procedures.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 14; ICAO Annex 6; ICAO Annex 8;
Safety not assured
The risk classification of an aircraft proximity in which the safety of the aircraft may have been compromised.
An integrated set of regulations and activities aimed at improving safety.
A proposal of an accident investigation authority based on information derived from an investigation, made with the intention of preventing accidents or incidents and which in no case has the purpose of creating a presumption of blame or liability for an accident or incident. In addition to safety recommendations arising from accident and incident investigations, safety recommendations may result from diverse sources, including safety studies.
Persons who might endanger aviation safety if they perform their duties and functions improperly including, but not limited to, crew members, aircraft maintenance personnel and air traffic controllers.
A set of documents or activities that a Contracting State accepts as sufficient to show compliance with an airworthiness requirement.
An instrument for estimating extinction coefficient by measuring the flux scattered from a light beam by particles present in the atmosphere.
Scheduled air service
An air service open to use by the general public and operated according to a published timetable or with such a regular frequency that it constitutes an easily recognizable systematic series of flights.
Scheduled international air service
a series of flights that possesses all of the following characteristics: it passes through the airspace over the territory of more than one State; it is performed by aircraft for the transport of passengers, mail or cargo for remuneration, in such a manner that each flight is open to use by members of the public; and it is operated so as to serve traffic between the same two or more points, either according to a published timetable or with flights so regular or frequent that they constitute a recognizable systematic series.
schedules facilitated airport
an airport where there is potential for congestion at some periods of the day, week or year which is amenable to resolution by voluntary cooperation between air carriers and where a schedules facilitator has been appointed to facilitate the operations of air carriers operating services or intending to operate services at that airport
either the summer or winter season as used in the schedules of air carriers
The application of technical or other means which are intended to identify and/or detect weapons, explosives or other dangerous devices, articles or substances which may be used to commit an act of unlawful interference.
the operation of the EATMN in such a manner that from the user's perspective it functions as if it were a single entity
Seaplane landing area
A defined area on water at an aerodrome prescribed for the landing and take-off of seaplanes.
Seaplane landing lane
A defined path on water at an aerodrome prescribed for the landing and take-off run of seaplanes along its entire length.
An operation normally coordinated by a rescue coordination centre or rescue subcentre using available personnel and facilities to locate persons in distress.
Search and rescue aircraft
An aircraft provided with specialized equipment suitable for the efficient conduct of search and rescue missions.
Search and rescue facility
Any mobile resource, including designated search and rescue units, used to conduct search and rescue operations.
Search and rescue flight
A flight to carry out search and rescue operations.
Search and rescue region
An area of defined dimensions, associated with a rescue coordination centre, within which search and rescue services are provided.
Search and rescue service
The performance of distress monitoring, communication, coordination and search and rescue functions, initial medical assistance or medical evacuation, through the use of public and private resources, including cooperating aircraft, vessels and other craft and installations.
Search and rescue services unit
A generic term meaning, as the case may be, rescue coordination centre, rescue subcentre or alerting post.
Search and rescue unit
A mobile resource composed of trained personnel and provided with equipment suitable for the expeditious conduct of search and rescue operations.
The temperature of the ocean surface. The term sea surface temperature is generally meant to be representative of the upper few meters of the ocean as opposed to the skin temperature, which is the temperature of the upper few centimeters.
The duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
A defined area on each side of the primary area located along the nominal flight track in which decreasing obstacle clearance is provided.
The radiotelephony frequency assigned to an aircraft as a second choice for air-ground communication in a radiotelephony network.
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
A surveillance radar system which uses transmitters/receivers (interrogators) and transponders.
a scheme combining sectors that are constructed and best placed to satisfy the operational requirements and airspace availability
Safeguarding civil aviation against acts of unlawful interference. This objective is achieved by a combination of measures and human and material resources.
An in-depth compliance examination of all aspects of the implementation of the national civil aviation security programme.
A means by which the introduction of weapons, explosives or other dangerous devices, articles or substances which may be used to commit an act of unlawful interference can be prevented.
Devices of a specialized nature for use, individually or as part of a system, in the prevention or detection of acts of unlawful interference with civil aviation and its facilities.
An examination of the implementation of relevant national civil aviation security programme requirements by an airline, airport, or other entity involved in security.
Security restricted area
Those areas of the airside of an airport which are identified as priority risk areas where in addition to access control, other security controls are applied. Such areas will normally include, inter alia, all commercial aviation passenger departure areas between the screening checkpoint and the aircraft, the ramp, baggage make-up areas, including those where aircraft are being brought into service and screened baggage and cargo are present, cargo sheds, mail centres, airside catering and aircraft cleaning premises.
An evaluation of security needs including the identification of vulnerabilities which could be exploited to carry out an act of unlawful interference, and the recommendation of corrective actions.
A covert or overt trial of an aviation security measure which simulates an attempt to commit an unlawful act.
Segregated parallel operations
Simultaneous operations on parallel or near-parallel instrument runways in which one runway is used exclusively for approaches and the other runway is used exclusively for departures.
Self-sustaining powered sailplane
A powered aeroplane with available engine power which allows it to maintain level flight but not to take-off under its own power.
Semi-automatic relay installation
A teletypewriter installation where interpretation of the relaying responsibility in respect of an incoming message and the resultant settingup of the connections required to effect the appropriate retransmissions require the intervention of an operator but where all other normal operations of relay are carried out automatically.
Air traffic services unit/air traffic controller transmitting a message.
Spacing between aircraft, levels or tracks.
The minimum displacements between an aircraft and a hazard which maintain the risk of collision at an acceptable level of safety.
An approved set of rules, procedures and conditions of application associated with separation minima.
The tactical process of keeping aircraft away from hazards by at least the appropriate separation minima.
Separation provision intervention capability
The quality of humans and/or systems to detect and solve a conflict and to implement and monitor the solution. The communications, navigation and surveillance systems' performance, as well as their situation assessment and problem-solving capabilities, are factors in determining the intervention capability.
The agent responsible for separation provision for a conflict, being either the airspace user or a separation provision service provider.
Series of flights
Series of flights are consecutive flights that: a) begin and end within a period of 24 hours; and b) are all conducted by the same pilot-in-command.
series of slots
at least five slots having been requested for the same time on the same day of the week regularly in the same scheduling period and allocated in that way or, if that is not possible, allocated at approximately the same time
An incident involving circumstances indicating that there was a high probability of an accident and associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time as it comes to rest at the end of the flight and the primary propulsion system is shut down.
An injury which is sustained by a person in an accident and which: a) requires hospitalization for more than 48 hours, commencing within seven days from the date the injury was received; or b) results in a fracture of any bone (except simple fractures of fingers, toes or nose); or c) involves lacerations which cause severe haemorrhage, nerve, muscle or tendon damage; or d) involves injury to any internal organ; or e) involves second or third degree burns, or any burns affecting more than 5 per cent of the body surface; or f) involves verified exposure to infectious substances or injurious radiation.
Part of aerodrome surface that must be used only by service vehicles and is not considered as surface movement areas for aircraft.
A heliport located on a ship that may be purpose or non-purpose-built. A purpose-built shipboard heliport is one designed specifically for helicopter operations. A non-purpose-built shipboard heliport is one that utilizes an area of the ship that is capable of supporting a helicopter but not designed specifically for that task.
A line following the general contour of the shore, except that in cases of inlets or bays less than 30 nautical miles in width, the line shall pass directly across the inlet or bay to intersect the general contour on the opposite side.
An area adjacent to the edge of a pavement so prepared as to provide a transition between the pavement and the adjacent surface.
The electric conductance of a conductor in which a current of 1 ampere is produced by an electric potential difference of 1 volt.
The unit of radiation dose equivalent corresponding to 1 joule per kilogram.
Sight seeing flight
A flight for the carriage of passengers by air for remuneration which returns to the departure point.
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 aircraft operations.
a) Fixed message sign. A sign presenting only one message. b) Variable message sign. A sign capable of presenting several predetermined messages or no message, as applicable.
Sign a maintenance release (to)
To certify that maintenance work has been completed satisfactorily in accordance with the applicable Standards of airworthiness, by issuing the maintenance release referred to in Annex 6.
An area on an aerodrome used for the display of ground signals.
In the context of the medical provisions in Chapter 6, significant means to a degree or of a nature that is likely to jeopardize flight safety.
Any natural terrain feature or man-made fixed object, permanent or temporary, which has vertical significance in relation to adjacent and surrounding features and which is considered a potential hazard to the safe passage of aircraft in the type of operation for which the individual procedure is designed.
A specified geographical location used in defining an ATS route or the flight path of an aircraft and for other navigation and ATS purposes.
A method in which telecommunication between two stations takes place in one direction at a time.
A mode of ATS data interchange where information extracted from the filed flight plan is sent simultaneously in a filed flight plan message to all ATS units concerned along the route of flight.
Single channel simplex
Simplex using the same frequency channel in each direction.
An electronic display depicting the position and movement of aircraft and other information as required.
The perception of elements in the environment, the comprehension of their meaning, and the projection of their status into the near future. [Endsley, 1990] For example, for pilots, the elements of the environment include, but are not limited to, the crew, passengers, aircraft systems, time, position, weather, traffic, and ATC constraints.
Slant visual range
The visual range of a specified object or light along a line of sight which differs significantly from the horizontal; for example, the visual range of ground objects or lights as seen from an aircraft on the approach (metre, m).
the permission given by a coordinator in accordance with this Regulation to use the full range of airport infrastructure necessary to operate an air service at a coordinated airport on a specific date and time for the purpose of landing or take-off as allocated by a coordinator in accordance with this Regulation
A random access strategy whereby multiple users access the same communications channel independently, but each communication must be confined to a fixed time slot. The same timing slot structure is known to all users, but there is no other coordination between the users.
Water-saturated snow which with a heel-and-toe slap-down motion against the ground will be displaced with a splatter; specific gravity: 0.5 up to 0.8.
An aeroplane of a maximum certificated take-off mass of 5 700 kg or less.
The carbonaceous materials in exhaust emissions which obscure the transmission of light.
The dimensionless term quantifying smoke emissions (see 3 of Appendix 2).
Snow (on the ground)
a) Dry snow. Snow which can be blown if loose or, if compacted by hand, will fall apart again upon release; specific gravity: up to but not including 0.35. b) Wet snow. Snow which, if compacted by hand, will stick together and tend to or form a snowball; specific gravity: 0.35 up to but not including 0.5. c) Compacted snow. Snow which has been compressed into a solid mass that resists further compression and will hold together or break up into lumps if picked up; specific gravity: 0.5 and over.
A special series NOTAM notifying the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush and ice on the movement area, by means of a specific format.
A flight in which a student pilot is the sole occupant of an aircraft.
Solo flight time
Flight time during which a student pilot is the sole occupant of an aircraft.
Any application of a distance or time between an aircraft and a hazard at or above separation minima in order to maintain a safe and orderly flow of traffic.
Articles, including engines and propellers, of a repair or replacement nature for incorporation in an aircraft.
The capacity of the system (lens, sensor, emulsion, electronic components, etc.) to define the smallest possible object in the image. Historically, this has been measured as the number of lines pair per millimetre that can be resolved in a photograph of a bar chart. This is the so-called analogue resolution. For the modern photogrammetric cameras equipped with forward motion compensation (FMC) devices and photogrammetric panchromatic black and white emulsions, the resolution could (depending on contrast) be 40 to 80 lp/mm (line pairs per millimetre).
Special VFR flight
A VFR flight cleared by air traffic control to operate within a control zone in meteorological conditions below VMC.
Document which establishes the requirements the product or service should be compliant with.
The capability of a sensor to discriminate the detected radiance in different intervals of wavelengths of the electromagnetic spectrum. Hence, the spectral resolution is determined by the number of bands that a particular sensor is capable to capture and by the corresponding spectral bandwidth.
The visual indication, in non-symbolic form, on a situation display, of a response from an SSR transponder in reply to an interrogation.
Standard altimeter setting
A pressure setting of 1013.2 hPa (1013.1 mb) which, when set on the subscale of the sensitive altimeter, will cause the altimeter to read zero when at mean sea level in the ICAO standard atmosphere.
An atmosphere defined as follows: a) the air is a perfect dry gas; b) the physical constants are: � Sea level mean molar mass: M0 = 28.964 420 � 10�3 kg mol�1 � Sea level atmospheric pressure: P0 = 1 013.250 hPa � Sea level temperature: t0 = 15�C T0 = 288.15 K � Sea level atmospheric density: ?0 = 1.225 0 kg m�3 � Temperature of the ice point: Ti = 273.15 K � Universal gas constant: R* = 8.314 32 JK�1mol�1 c) the temperature gradients are: Geopotential altitude (km) Temperature gradient (Kelvin per standard From To geopotential kilometre) �5.0 11.0 �6.5 11.0 20.0 0.0 20.0 32.0 +1.0 32.0 47.0 +2.8 47.0 51.0 0.0 51.0 71.0 �2.8 71.0 80.0 �2.0
Standard instrument arrival
A designated instrument flight rule (IFR) arrival route linking a significant point, normally on an ATS route, with a point from which a published instrument approach procedure can be commenced.
Standard instrument departure
A designated instrument flight rule (IFR) departure route linking 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.
Standard isobaric surface
An isobaric surface used on a worldwide basis for representing and analysing the conditions in the atmosphere.
A defined period during which a crew member may be called for a duty with minimum notice.
The phase of flight from the time the first person boards the aircraft with the intention of flight until push-back or, if pushback does not apply, until taxiing from the gate or parking position is commenced. subsequently, from engine shut down upon reaching the gate or parking position after flight until the last person has exited the aircraft.
The phase of flight, while the aircraft is parked with the intention of flight, during which the first engine is started.
An internationally recognized geographic entity that provides aeronautical information service.
Aircraft used for military, customs, police or other law enforcement services of a State. (see Article 3 of the Convention on International Civil Aviation).
State of Design
The State having jurisdiction over the organization responsible for the type design.
State of Manufacture
The State having jurisdiction over the organization responsible for the final assembly of the aircraft.
State of Occurrence
The State in the territory of which an accident or incident occurs.
State of Origin
The State in the territory of which the consignment was first loaded on an aircraft.
State of Registry
The State on whose register the aircraft is entered.
State of the Operator
The State in which the operator's principal place of business is located or, if there is no such place of business, the operator's permanent residence.
State safety programme
An integrated set of regulations and activities aimed at improving safety.
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 13; ICAO Annex 14; ICAO Annex 6; ICAO Annex 8;
Static load-bearing surface
A surface capable of supporting the mass of a helicopter situated upon it.
An alignment variation between the zero degree radial of a VOR and true north, determined at the time the VOR station is calibrated.
A mode of ATS data interchange where each ATS unit, as the flight progresses, transmits a current flight plan message to the next unit.
The solid angle which, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.
Sterile flight deck
Any period of time when the flight crew should not be disturbed, except for matters critical to the safe operation of the aircraft.
An airport specifically designed for STOL aircraft separate from conventional airport facilities.
A defined rectangular area on the ground at the end of take-off run available prepared as a suitable area in which an aircraft can be stopped in the case of an abandoned take-off.
a) Stores (supplies) for consumption; and b) Stores (supplies) to be taken away.
Stores for consumption
Goods, whether or not sold, intended for consumption by the passengers and the crew on board aircraft, and goods necessary for the operation and maintenance of aircraft, including fuel and lubricants.
Stores to be taken away
Goods for sale to the passengers and the crew of aircraft with a view to being landed.
Strategic action describes "action", i.e. initiatives of a general nature, which shall be launched in order to support one or several strategic objectives.
Any system which is associated with the air traffic control system as a provider and/or recipient of information relating to the provision of air traffic control service.
An aeroplane incapable of sustaining level flight at speeds exceeding flight Mach number of 1.
Suitable alternate aerodrome
A suitable alternate aerodrome is an adequate aerodrome where, for the anticipated time of use, weather reports, or forecasts, or any combination thereof, indicate that the weather conditions will be at or above the required aerodrome operating minima, and the runway surface condition reports indicate that a safe landing will be possible.
Lighting within a movement area.
A heliport located on the ground or on the water.
Radar equipment used to determine the position of an aircraft in range and azimuth.
those facilities and services used to determine the respective positions of aircraft to allow safe separation
Survey control point
A monumented survey control point.
An ELT which is removable from an aircraft, stowed so as to facilitate its ready use in an emergency, and manually activated by survivors.
Switch-over time (light)
The time required for the actual intensity of a light measured in a given direction to fall from 50 per cent and recover to 50 per cent during a power supply changeover, when the light is being operated at intensities of 25 per cent or above.
A display of computer-generated information, normally comprising aircraft positions and associated data presented in alphanumeric or symbolic form.
the aggregation of airborne and ground-based constituents, as well as space-based equipment, that provides support for air navigation services for all phases of flight
System safety approach
A systematic and explicit approach defining all activities and resources (people, organizations, policies, procedures, time spans, milestones, etc.) devoted to the management of safety. This approach starts before the fact, is documented, planned and explicitly supported by documented organizational policies and procedures endorsed by the highest executive levels. The system safety approach uses systems theory, systems engineering and management tools to manage risk formally, in an integrated manner, across all organizational levels, all disciplines and all system life-cycle phases.
Systematic errors affect all repeated observations in the same way. Systematic errors are often referred to as bias errors. These effects can be minimized via instrument calibration and/or the use of the appropriate math model.
A display of information in the form of a table.
The phase of flight from the application of take-off power until reaching the first prescribed power reduction, or until reaching the vfr pattern or 1,500 feet (450 metres) above runway end elevation, whichever comes first or the termination (abort) of the take-off.
An alternate aerodrome at which an aircraft can land should this become necessary shortly after take-off and it is not possible to use the aerodrome of departure.
Take-off and initial climb phase
That part of the flight from the start of take-off to 300 m (1 000 ft) above the elevation of the FATO, if the flight is planned to exceed this height, or to the end of the climb in the other cases.
Take-off decision point
The point used in determining take-off performance from which, an engine failure occurring at this point, either a rejected take-off may be made or a take-off safely continued.
Take-off distance available
The length of the take-off run available plus the length of the clearway, if provided.
Take-off distance available (helicopter)
The length of the final approach and take-off area plus the length of helicopter clearway (if provided) declared available and suitable for helicopters to complete the take-off.
Take-off distance required (helicopter)
The horizontal distance required from the start of the take-off to the point at which Vtoss, a height of 10.7 m (35 ft) above the take-off surface, and a positive climb gradient are achieved, following failure of the critical power-unit at TDP, the remaining power-units operating within approved operating limits.
The operating phase defined by the time during which the engine is operated at the rated thrust.
The phase of flight from the application of take-off power, through the take-off roll and rotation up to 50 feet [15 metres] above runway end elevation.
Take-off run available
The length of runway declared available and suitable for the ground run of an aeroplane taking off.
A runway intended for take-off only.
That part of the surface of an aerodrome which the aerodrome authority has declared available for the normal ground or water run of aircraft taking off in a particular direction.
In radar, 1) generally, any discrete object which reflects or retransmits energy back to the radar equipment; 2) specifically, an object of radar search or surveillance.
Target level of safety
A generic term representing the level of risk which is considered acceptable in particular circumstances.
The phase of flight in which movement of an aircraft on the surface of an aerodrome under its own power occurs, excluding take-off and landing.
A defined path established for the movement of helicopters from one part of a heliport to another. A taxi-route includes a helicopter air or ground taxiway which is centred on the taxi-route.
The operating phases involving taxi and idle between the initial starting of the propulsion engine(s) and the initiation of the take-off roll and between the time of runway turn-off and final shutdown of all propulsion engine(s).
Movement of an aircraft on the surface of an aerodrome under its own power, excluding take-off and landing and, in the case of helicopters, operation over the surface of an aerodrome within a height band associated with ground effect and at speeds associated with taxiing, i.e. air-taxiing.
Taxiing to/from runway
The phase of flight, after reaching the movement area, when the aircraft progresses under its own power to the departure runway, or post-flight moves under its own power after leaving the landing runway.
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, including: a) Aircraft stand taxilane. A portion of an apron designated as a taxiway and intended to provide access to aircraft stands only. b) Apron taxiway. A portion of a taxiway system located on an apron and intended to provide a through taxi route across the apron. c) Rapid exit taxiway. A taxiway connected to a runway at an acute angle and designed to allow landing aeroplanes to turn off at higher speeds than are achieved on other exit taxiways thereby minimizing runway occupancy times.
Taxiway guidance line
Guidance line painted on a taxiway.
Taxiway holding position
A designated position at which taxiing aircraft and vehicles must stop and hold position, unless otherwise authorized by the aerodrome control tower.
A junction of two or more taxiways.
Taxiway intersection marking
Taxiway intersection marking painted across a taxiway.
An area including a taxiway intended to protect an aircraft operating on the taxiway and to reduce the risk of damage to an aircraft accidentally running off the taxiway.
The Technical Instructions for the Safe Transport of Dangerous Goods by Air (Doc 9284), approved and issued periodically in accordance with the procedure established by the ICAO Council.
Any transmission, emission, or reception of signs, signals, writing, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems.
A tape on which signals are recorded in the 5-unit Start-Stop code by completely severed perforations (Chad Type) or by partially severed perforations (Chadless Type) for transmission over teletypewriter circuits.
The periodicity through which a sensor can acquire a new image of the same spot of the Earth's surface.
The customs procedure under which certain goods can be brought into a customs territory conditionally relieved totally or partially from payment of import duties and taxes; such goods must be imported for a specific purpose and must be intended for re-exportation within a specified period and without having undergone any change except normal depreciation due to the use made of them.
Terminal area sequencing
The process of organizing traffic entering and departing from a terminal area into an orderly flow.
Terminal arrival altitude
The lowest altitude that will provide a minimum clearance of 300 m (1 000 ft) above all objects located in an arc of a circle defined by a 46 km (25 NM) radius centred on the initial approach fix (IAF), or where there is no IAF on the intermediate approach fix (IF), delimited by straight lines joining the extremity of the arc to the IF. The combined TAAs associated with an approach procedure shall account for an area of 360 degrees around the IF.
The number of passengers and tonnes of cargo per hour which can be processed in a terminal building (sometimes referred to as passenger throughput or cargo throughput).
Terminal control area
A control area normally established at the confluence of ATS routes in the vicinity of one or more major aerodromes.
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.
The magnetic flux density given by a magnetic flux of 1 weber per square metre.
A flight for the purpose of testing aircraft (e.g. after maintenance, to obtain type certificates etc.).
non-Member States that are members of Eurocontrol or have concluded an agreement with the Union on the implementation of the single European sky or are participating in a functional airspace block
Events or errors that occur beyond the influence of an operational person, increase operational complexity and must be managed to maintain the margin of safety.
The process of detecting and responding to threats with countermeasures that reduce or eliminate the consequences of threats and mitigate the probability of errors or undesired states.
The beginning of that portion of the runway usable for landing.
A particular operation of aircraft, identified by the operator by the use throughout of the same symbol, from point of origin via any intermediate points to point of destination.
Time division multiple access
A multiple access scheme based on time-shared use of an RF channel employing: (1) discrete contiguous time slots as the fundamental shared resource; and (2) a set of operating protocols that allows users to interact with a master control station to mediate access to the channel.
Time division multiplex
A channel sharing strategy in which packets of information from the same source but with different destinations are sequenced in time on the same channel.
to operate an ATM functionality
means that the ATM functionality in question is put in service and that it is fully used in daily operations
The mass equal to 1 000 kilograms.
Torn-tape relay installation
A teletypewriter installation where messages are received and relayed in teletypewriter tape form and where all operations of relay are performed as the result of operator intervention.
Total estimated elapsed time
For IFR flights, the estimated time required from take-off to arrive over that designated point, defined by reference to navigation aids, from which it is intended that an instrument approach procedure will be commenced, or, if no navigation aid is associated with the destination aerodrome, to arrive over the destination aerodrome. For VFR flights, the estimated time required from take-off to arrive over the destination aerodrome.
Total vertical error
The vertical geometric difference between the actual pressure altitude flown by an aircraft and its assigned pressure altitude (flight level).
Total amount of precipitation measured over a defined period.
Rate of total precipitation.
The point where the nominal glide path intercepts the runway.
Touchdown and lift-off area
A load bearing area on which a helicopter may touch down or lift off.
The portion of a runway, beyond the threshold, where it is intended landing aeroplanes first contact the runway.
A flight to tow another aircraft (e.g. glider towing).
Ability to trace the history, application or location of that which is under consideration (ISO 9000).
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).
Source: ICAO Annex 1; ICAO Annex 11; ICAO Annex 2; ICAO Annex 4;
Synonyms: flight track; ground track
Traffic avoidance advice
Advice provided by an air traffic services unit specifying manoeuvres to assist a pilot to avoid a collision.
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.
Traffic information service - broadcast OUT
A function on the ground that periodically broadcasts the surveillance information made available by ground sensors in a format suitable for TIS-B IN capable receivers.
Traffic information service - broadcast IN
A surveillance function that receives and processes surveillance data from TIS-B OUT data sources.
Traffic synchronization concerns the management of the flow of traffic through merging and crossing points, such as traffic around major aerodromes or airway crossings. It currently includes the management and provision of queues both on the ground and in the air. Traffic synchronization, as a function, is closely related to both demand/capacity balancing and separation provision and may in the future be indistinguishable from them. Traffic synchronization also concerns the aerodrome "service" part of the concept.
A non-revenue flight carried out for the purpose of flight crew training or check.
Trajectory or profile
This is a description of the movement of an aircraft, both in the air and on the ground, including position, time and, at least via calculation, speed and acceleration.
Trajectory update requirement
The trajectory update requirement specifies displacement values that require an aircraft, when it is displaced by at least one of these values from the last trajectory advised to ATM, to provide updated trajectory information to the ATM system.
Transfer of control
Transfer of responsibility for providing air traffic control service. Note. - When the word "process" is used as a suffix to this term, it signifies the series of actions taken by two air traffic control units for the purpose of effecting transfer of responsibility from one unit to the other.
Transfer of control point
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.
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 along the route of flight.
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 along the route of flight.
In packet data systems, the elapsed time between a request to transmit an assembled data packet and an indication at the receiving end that the corresponding packet has been received and is ready to be used or forwarded.
The altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes.
The airspace between the transition altitude and the transition level.
The lowest flight level available for use above the transition altitude.
Transmissivity (or transmission coefficient)
The fraction of luminous flux which remains in a beam after traversing an optical path of a unit distance in the atmosphere (dimensionless).
An instrument that takes a direct measurement of the transmittance between two points in space, i.e. over a specified path length or baseline.
Transmissivity within an optical path of a given length b in the atmosphere (dimensionless).
A receiver/transmitter which will generate a reply signal upon proper interrogation; the interrogation and reply being on different frequencies.
Aircraft that are designed for the purpose of transporting persons and/or cargo.
A passport or other official document of identity issued by a State or organization, which may be used by the rightful holder for international travel.
An aeronautical fixed station that may receive or transmit messages and/or digital data but which does not relay except for the purpose of serving similar stations connected through it to a communication centre.
Generic term for a non-frontal synoptic-scale cyclone originating over tropical or sub-tropical waters with organized convection and definite cyclonic surface wind circulation.
Tropical cyclone advisory centre
A meteorological centre designated by regional air navigation agreement to provide 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.
Cyclone of tropical origin of small diameter (some hundreds of kilometres) with minimum surface pressure in some cases less than 900 hPa, very violent winds and torrential rain; sometimes accompanied by thunderstorms. It usually contains a central region, known as the �eye� of the storm, with a diameter of the order of some tens of kilometres, and with light winds and more or less lightly clouded sky.
The speed of the aeroplane relative to undisturbed air.
The time spent on the ground during a flight duty period between two flight sectors.
A document issued by a Contracting State to define the design of an aircraft type and to certify that this design meets the appropriate airworthiness requirements of that State.
The limit load multiplied by the appropriate factor of safety.
The four-digit number assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods to identify a substance or a particular group of substances.
Baggage that is transported as cargo and may or may not be carried on the same aircraft with the person to whom it belongs.
The total of hydrocarbon compounds of all classes and molecular weights contained in a gas sample, calculated as if they were in the form of methane.
A situation wherein uncertainty exists as to the safety of an aircraft and its occupants.
Baggage that arrives at an airport and is not picked up or claimed by a passenger.
The phase of flight in which an uncontrolled descent from a previously normal manoeuvre occurs.
Uncontrolled descent during an approach
The phase of flight in which a previously normal descent during an approach becomes uncontrolled.
Uncontrolled descent during take-off
The phase of flight in which any uncontrolled descent occurs after rotation but before the first prescribed power reduction, on reaching 1500 feet (450 metres) or the vfr pattern, whichever comes first.
Uncontrolled descent en-route
The phase of flight in which an uncontrolled descent is made en-route.
An aeroplane on the surface of the water is 'under command' when it is able to execute manoeuvres as required by the International Regulations for Preventing Collisions at Sea for the purpose of avoiding other vessels.
An aeroplane on the surface of the water is 'under way' when it is not aground or moored to the ground or to any fixed object on the land or in the water.
Baggage at an airport, with or without a baggage tag, which is not picked up by or identified with a passenger.
Unit load device
Any type of freight container, aircraft container, aircraft pallet with a net, or aircraft pallet with a net over an igloo.
Universe of discourse
View of the real or hypothetical world that includes everything of interest.
The removal of cargo, mail, baggage or stores from an aircraft after a landing.
Unlimited route concept
A concept of controlled airspace organization which allows an operator complete freedon to choose the route to be taken by a flight from one point to another provided that the route is adequately defined in the flight plan and adhered to as accurately as circumstances permit.
Unmanned aerial vehicle
An unmanned aerial vehicle is a pilotless aircraft, in the sense of Article 8 of the Convention on International Civil Aviation, which is flown without a pilot-in-command on-board and is either remotely and fully controlled from another place (ground, another aircraft, space) or programmed and fully autonomous.
Unmanned free balloon
A non-power-driven, unmanned, lighter-than-air aircraft in free flight.
updated flight position
aircraft position, updated by surveillance data, flight plan data or position reports
any modification that changes the operational characteristics of a system
A meteorological chart relating to a specified upper-air surface or layer of the atmosphere.
The percentage of time during which the use of a runway or system of runways is not restricted because of the crosswind component.
User of aeronautical data
The group or organization using the system that contains the delivered aeronautical data on an operational basis, such as the airline operator.
user required route
the desirable routing that is declared by the aircraft operators at the airspace design stage to meet their needs.
Global Solar UVI is formulated using the International Commission on Illumination (CIE) reference action spectrum for UV-induced erythema on the human skin. It is a measure of the UV radiation that is relevant to and defined for a horizontal surface.
Confirmation, through the provision of objective evidence, that the requirements for a specific intended use or application have been fulfilled (ISO 9000).
Variable message sign
A sign capable of presenting several pre-determined messages or no message, as applicable.
Provision of navigational guidance to aircraft in the form of specific headings, based on the use of an ATS surveillance system.
Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled (ISO 9000).
A point that defines a line structure, curvature, or shape.
Vertical line structure
Line structure of a defined vertical extend that is located within an area that extends from the edge(s) of the runway(s) to 90 m from the runway centreline(s) and for all other parts of the aerodrome movement area(s), 50 m from the edge(s) of the defined area(s).
An object with vertical extent that is within the designated buffer area.
Vertical path angle
Angle of the published final approach descent in baro-VNAV procedures.
Planes perpendicular to the horizontal plane.
Vertical point structure
Point structure of a defined vertical extend that is located within an area that extends from the edge(s) of the runway(s) to 90 m from the runway centreline(s) and for all other parts of the aerodrome movement area(s), 50 m from the edge(s) of the defined area(s).
Vertical polygonal structure
Polygonal structure of a defined vertical extend that is located within an area that extends from the edge(s) of the runway(s) to 90 m from the runway centreline(s) and for all other parts of the aerodrome movement area(s), 50 m from the edge(s) of the defined area(s).
Separation between aircraft expressed in units of vertical distance.
Vertical visibility is defined as the vertical visual range into an obscuring medium.
The symbol used to designate the visual flight rules.
A flight conducted in accordance with the visual flight rules.
VHF digital link
A constituent mobile subnetwork of the aeronautical telecommunication network (ATN), operating in the aeronautical mobile VHF frequency band. In addition, the VDL may provide non-ATN functions such as, for instance, digitized voice.
Visibility for aeronautical purposes is the greater of: a) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognized 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.
The greatest distance that prominent objects can be seen and identified by unaided, normal eyes. Unless otherwise stated, visibility is determined in the horizontal plane at the ground surface.
Visibility for aeronautical purposes; 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 1000 candelas can be seen and identified against an unlit background. Note that visibility for aeronautical purposes is a more rigorously defined than general visibility.
Visible on a dark night with a clear atmosphere.
Any person who disembarks and enters the territory of a Contracting State other than that in which that person normally resides; remains there lawfully as prescribed by that Contracting State for legitimate non-immigrant purposes, such as touring, recreation, sports, health, family reasons, religious pilgrimages, or business; and does not take up any gainful occupation during his stay in the territory visited.
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 approach procedure
A series of predetermined manoeuvres by visual reference, 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, a go-around procedure can be carried out.