Annex I DEFINITIONS OF TERMS USED IN ANNEXES II TO XIII

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

1. (1)

   ‘acceptable means of compliance (AMC)’ means non-binding standards adopted by the F1competent authority to illustrate means to establish compliance with Regulation (EC) No 216/2008 and its implementing rules;

2. (1A)

   F2‘air-ground communication’ means two-way communication between aircraft and stations or locations on the surface of the Earth;

3. (2)

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

4. (3)

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

5. (4)

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

6. (5)

   ‘aerodrome elevation’ means the elevation of the highest point of the landing area;

7. (6)

   ‘aerodrome flight information service (AFIS)’ means flight information service and alerting service for aerodrome traffic at an aerodrome;

8. (7)

   ‘aerodrome meteorological office’ means an office responsible for providing meteorological service for an aerodrome;

9. (8)

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

10. (9)

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

11. (10)

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

12. (11)

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

13. (12)

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

14. (13)

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

15. (14)

    ‘aerodrome mapping data’ means data collected for the purpose of compiling aerodrome mapping information;

16. (15)

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

17. (16)

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

18. (17)

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

19. (18)

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

20. (19)

    ‘AIRMET message’ means information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and of the development of those phenomena in time and space, and which was not already included in the forecast issued for low-level flights in the flight information region concerned or sub-area thereof;

21. (20)

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

22. (21)

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

23. (22)

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

24. (23)

    ‘F3means of compliance (MOC)’ means those means of compliance that propose an alternative to an existing AMC or those that propose new means to establish compliance with Regulation (EC) No 216/2008 and its Implementing Rules for which no associated AMC have been adopted by the F4competent authority;

25. (24)

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

26. (25)

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

27. (26)

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

28. (26A)

    F5‘aeronautical information circular (AIC)’ means a notice containing information that does not qualify for the origination of a NOTAM or for inclusion in the aeronautical information publication, but which relates to flight safety, air navigation, technical, administrative or legislative matters;

29. (26B)

    ‘aeronautical information management (AIM)’ means the dynamic, integrated management of aeronautical information through the provision and exchange of quality-assured digital aeronautical data in collaboration with all parties;

30. (26C)

    ‘aeronautical information product’ means aeronautical data and aeronautical information provided either as digital data sets or as a standardised presentation in paper or electronic media. Aeronautical information products include:

    • aeronautical information publication, including amendment and supplements;

    • AIC;

    • aeronautical charts;

    • NOTAM;

    • digital data sets;

31. (26D)

    ‘aeronautical information publication (AIP)’ means a publication issued by or with the authority of a State and containing aeronautical information of a lasting character essential to air navigation;

32. (26E)

    ‘AIP amendment’ means a permanent change to the information contained in the AIP;

33. (26F)

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

34. (26G)

    ‘aeronautical information regulation and control’ (AIRAC) means a system aimed at advance notification, based on common effective dates, of circumstances that necessitate significant changes in operating practices;

35. (27)

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

36. (28)

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

37. (29)

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

38. (29A)

    F6‘assemble’ means a process of merging data from multiple sources into a database and establishing a baseline for subsequent processing;

39. (30)

    F7‘ATM network functions’ means the air traffic management (ATM) functions mentioned in Article 6(2) of Regulation (EU) No 551/2004;

40. (30A)

    F8‘ATS route’ means a specified route designated for channelling the flow of traffic as necessary for the provision of ATS;

41. (31)

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

42. (32)

    ‘authoritative source’ means:

    1. (a)

       F9the competent authority: or

    2. (b)

       an organisation formally recognised by the F10competent authority to originate and/or publish data which meets the data quality requirements (DQRs) as specified by F11the Secretary of State;

43. (33)

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

44. (34)

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

45. (35)

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

46. (35A)

    F12‘broadcast’ means a transmission of information relating to air navigation that is not addressed to a specific station or stations;

47. (36)

    ‘certified aircraft application’ means a software application approved by the F13competent authority as part of aircraft subject to Article 4 of Regulation (EC) No 216/2008;

48. (37)

    ‘cloud of operational significance’ means 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;

49. (38)

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

50. (38A)

    F14‘completeness’ means, in relation to data, the degree of confidence that all data needed to support the intended use is provided;

51. (38B)

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

52. (39)

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

53. (39A)

    F15‘control zone’ means a controlled airspace extending upwards from the surface of the Earth to a specified upper limit;

54. (39B)

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

55. (40)

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

56. (40A)

    F16‘cruising level’ means a level maintained during a significant portion of a flight;

57. (40B)

    ‘cyclic redundancy check (CRC)’ means a mathematical algorithm applied to the digital expression of data that provides a level of assurance against loss or alteration of data;

58. (40C)

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

59. (40D)

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

60. (40E)

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

61. (40F)

    ‘data integrity’ means a degree of assurance that aeronautical data and its value has not been lost or altered since the data origination or authorised amendment;

62. (40G)

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

63. (40H)

    ‘data origination’ means the creation of a new data item with its associated value, the modification of the value of an existing data item or the deletion of an existing data item;

64. (40I)

    ‘data product specification’ means a detailed description of a data set or a collection of data sets together with additional information that will enable it to be created, supplied to and used by another party;

65. (40J)

    ‘data set’ means an identifiable collection of data;

66. (41)

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

67. (41A)

    F17‘datum’ means any quantity or set of quantities that may serve as a reference or basis for the calculation of other quantities;

68. (42)

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

69. (43)

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

70. (44)

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

71. (45)

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

72. (46)

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

73. (47)

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

74. (48)

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

75. (48A)

    F18‘feature’ means an abstraction of real world phenomena;

76. (48B)

    ‘feature attribute’ means a characteristic of a feature that has a name, a date type and a value domain associated with it;

77. (48C)

    ‘feature type’ means a class of real world phenomena with common properties, which forms the basic level of classification in a feature catalogue;

78. (48D)

    ‘final approach’ means that part of an instrument approach procedure which:

    1. (a)

       commences at the specified fix or point, or, where such a fix or point is not specified, at either of the following places:

       1. (i)

          at the end of the last procedure turn, base turn or inbound turn of a racetrack procedure, if specified;

       2. (ii)

          at the point of the interception of the last track specified in the approach procedure,

    2. (b)

       ends at a point in the vicinity of an aerodrome from which a landing can be made or a missed approach procedure is initiated;

79. (49)

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

80. (50)

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

81. (51)

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

82. (52)

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

83. (53)

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

84. (54)

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

85. (55)

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

86. (55A)

    F19‘format’ means in relation to data, a structure of data items, records and files arranged to meet standards, specifications or data quality requirements;

87. (56)

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

88. (57)

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

89. (57A)

    F20‘geoid’ means the equipotential surface in the gravity field of the Earth which coincides with the undisturbed mean sea level (MSL) extended continuously through the continents;

90. (57B)

    ‘geoid undulation’ means the distance of the geoid above (positive) or below (negative) the mathematical reference ellipsoid;

91. (58)

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

92. (59)

    ‘guidance material’ means non-binding material developed by the F21competent authority that helps to illustrate the meaning of a requirement or specification and is used to support the interpretation of Regulation (EC) No 216/2008, its implementing rules and AMC;

93. (60)

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

94. (61)

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

95. (62)

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

96. (62A)

    F22‘heliport’ means an aerodrome or a defined area on a structure intended to be used wholly or in part for the arrival, departure and surface movement of helicopters;

97. (62B)

    ‘identification’ means the situation which exists when the position indication of a particular aircraft is seen on a situation display and positively identified;

98. (62C)

    ‘integrity classification’ means, in relation to aeronautical data, a classification based upon the potential risk resulting from the use of corrupted data, defining routine, essential and critical data;

99. (62D)

    ‘international NOTAM office (NOF)’ means an office designated by a State for the exchange of NOTAM internationally;

100. (63)

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

101. (64)

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

102. (65)

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

103. (65A)

     F23‘metadata’ means data about data;

104. (66)

     ‘meteorological bulletin’ means a text comprising meteorological information preceded by an appropriate heading;

105. (67)

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

106. (68)

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

107. (69)

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

108. (70)

     ‘meteorological satellite’ means an artificial Earth satellite making meteorological observations and transmitting these observations to Earth;

109. (71)

     ‘meteorological watch office’ means an office monitoring meteorological conditions affecting flight operations and providing information concerning the occurrence or expected occurrence of specified en-route weather phenomena, natural and other hazards which may affect the safety of aircraft operations within a specified area of responsibility;

110. (72)

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

111. (72A)

     F24‘movement area’ means that part of an aerodrome to be used for the take-off, landing and taxiing of aircraft, consisting of the manoeuvring area and the apron;

112. (72B)

     ‘navigation aid’ means a facility or system external to the aircraft, which generates electro-magnetic signals to be used by aircraft navigation systems for position determination or flight path guidance;

113. (73)

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

114. (74)

     ‘obstacle’ means all fixed (whether temporary or permanent) and mobile objects, or parts thereof, that:

     1. (a)

        are located on an area intended for the surface movement of aircraft; or

     2. (b)

        extend above a defined surface intended to protect aircraft in flight; or

     3. (c)

        stand outside those defined surfaces and have been assessed as being a hazard to air navigation;

115. (75)

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

116. (76)

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

117. (76A)

     F25‘position’ means, in a geographical context, a set of coordinates (latitude and longitude) referenced to the mathematical reference ellipsoid, which define the position of a point on the surface of the Earth;

118. (77)

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

119. (78)

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

120. (79)

     ‘problematic use of psychoactive substances’ means the use of one or more psychoactive substances by an individual, in a way that:

     1. (a)

        constitutes a direct hazard to the user or endangers the lives, health, or welfare of others; and/or

     2. (b)

        causes or worsens an occupational, social, mental or physical problem or disorder;

121. (80)

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

122. (80A)

     F26‘prohibited area’ means an airspace of defined dimensions, above the land areas or territorial waters of a State, within which the flight of aircraft is prohibited.

123. (81)

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

124. (82)

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

125. (82A)

     F27‘resolution’ means, in relation to data, a number of units or digits to which a measured or calculated value is expressed and used;

126. (83)

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

127. (83A)

     F28‘restricted area’ means 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;

128. (84)

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

129. (85)

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

130. (85A)

     F29‘route stage’ means a route or portion of a route flown without an intermediate landing;

131. (86)

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

132. (87)

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

133. (88)

     ‘safety directive’ means a document issued or adopted by F30the competent authority which mandates actions to be performed on a functional system or sets restrictions to its operational use to restore safety when evidence shows that aviation safety may otherwise be compromised;

134. (89)

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

135. (90)

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

136. (91)

     ‘selected volcano observatory’ means a provider, selected by the competent authority, that observes the activity of a volcano or a group of volcanoes and makes these observations available to an agreed list of aviation recipients;

137. (92)

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

138. (93)

     ‘SIGMET’ means information concerning en-route weather phenomena, which may affect the safety of aircraft operations;

139. (94)

     ‘SIGMET message’ means information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of aircraft operations and of the development of those phenomena in time and space;

140. (94A)

     F31‘SNOWTAM’ means a special series NOTAM given in a standard format, which provides a surface condition report notifying the presence or cessation of hazardous conditions due to snow, ice, slush, frost or water associated with snow, slush, ice, or frost on the movement area;

141. (95)

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

142. (96)

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

143. (97)

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

144. (98)

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

145. (99)

     ‘take-off alternate aerodrome’ means an alternate aerodrome at which an aircraft can land should this become necessary shortly after take-off and if it be not possible to use the aerodrome of departure;

146. (99A)

     F32‘taxiing’ means movement of an aircraft on the surface of an aerodrome or an operating site under its own power, excluding take-off and landing;

147. (100)

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

148. (101)

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

149. (102)

     ‘threshold’ means the beginning of that portion of the runway usable for landing;

150. (102A)

     F33‘timeliness’ means, in relation to data, the degree of confidence that the data is applicable to the period of its intended use;

151. (103)

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

152. (103A)

     F34‘traceability’ means, in relation to data, the degree to which a system or data product can provide a record of the changes made to that product and thereby enable an audit trail to be followed from the end-user to the party originating data;

153. (103B)

     ‘track’ means the projection on the Earth’s surface of the path of an aircraft, the direction of which path at any point is usually expressed in degrees from North (true, magnetic or grid);

154. (103C)

     ‘transition altitude’ means the altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes;

155. (103D)

     ‘transition level’ means the lowest flight level available for use above the transition altitude;

156. (104)

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

157. (105)

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

158. (105A)

     F35‘validation’ means, in relation to data, the process of ensuring that data meets the requirements for the specified application or intended use;

159. (105B)

     ‘verification’ means, in relation to data, the evaluation of the output of an aeronautical data process to ensure correctness and consistency with respect to the inputs and applicable data standards, rules and conventions used in that process;

160. (106)

     ‘visibility’ means visibility for aeronautical purposes, which is the greater of:

     1. (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;

     2. (b)

        the greatest distance at which lights in the vicinity of 1 000 candelas can be seen and identified against an unlit background;

161. (106A)

     F36‘visual approach’ means an approach by an IFR flight when either part or all of an instrument approach procedure is not completed and the approach is executed in visual reference to terrain;

162. (106B)

     ‘visual flight rules flight’ or ‘VFR flight’ means a flight conducted in accordance with the visual flight rules;

163. (107)

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

164. (107A)

     F37‘waypoint’ means a specified geographical location used to define an area navigation route or the flight path of an aircraft employing area navigation. Waypoints are identified as either:

     1. (a)

        fly-by waypoint – a waypoint which requires turn anticipation to allow tangential interception of the next segment of a route or procedure, or

     2. (b)

        fly-over waypoint – a waypoint at which a turn is initiated in order to join the next segment of a route or procedure;

165. (108)

     ‘world area forecast centre (WAFC)’ means a meteorological centre preparing and issuing significant weather forecasts and upper-air forecasts in digital form on a global basis direct to the F38United Kingdom by appropriate means as part of the aeronautical fixed service;

166. (109)

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