CIVIL AVIATION: SUBSIDIARY LEGISLATION: CIVIL AVIATION (RADIO NAVIGATION AIDS) REGULATIONS
(section 89)
(21st June, 2022)
ARRANGEMENT OF REGULATIONS
REGULATION
PART I
Preliminary
1. Citation
2. Interpretation
3. Application
PART II
General Requirements
4. Requirements for radio navigation aids facilities
PART III
Radio Navigation Aids
5. Standard radio navigation aids
6. GNSS – specific provisions
7. Precision approach radar
8. Composition of precision approach radar system
9. Specifications for precision approach radar elements
10. Specifications for Surveillance Radar Element
11. Ground and flight testing
12. Operational status of radio navigation aids
13. Power supply for radio navigation aids and communication systems
14. Human factor considerations
(a) Instrument Landing System
15. Basic requirements for instrument landing system – composition
16. Basic requirements for instrument landing system – construction and adjustment
17. Localizer and glide path components of facility performance categories
18. ILS level of safety
19. Two ILS facilities serving opposite ends of single runway
(b) VHF Localizer and Associated Monitor
20. VHF localizer and associated monitor specifications
21. VHF localizer radio frequency
22. VHF localizer coverage
23. VHF localizer course structure
24. VHF localizer carrier modulation
25. VHF localizer course alignment accuracy
26. VHF localizer displacement sensitivity
27. VHF localizer voice
28. VHF localizer identification
29. VHF localizer siting
30. VHF localizer monitoring
31. VHF localizer integrity and continuity of service requirements
32. Interference immunity performance for ILS localizer receiving systems
(c) UHF Glide Path Equipment and Associated Monitor
33. UHF glide path and associated monitor specifications
34. UHF glide path radio frequency
35. UHF glide path coverage
36. UHF glide path structure
37. UHF glide path carrier modulation
38. UHF glide path displacement sensitivity
39. UHF glide path monitoring
40. UHF glide path integrity and continuity of service requirements
41. Localizer and glide path frequency pairing
(d) VHF Marker Beacon
42. VHF marker beacons
43. VHF marker radio frequency
44. VHF marker coverage
45. VHF marker modulation
46. VHF marker identification
47. VHF marker siting
48. VHF marker monitoring
(e) Specification for Precision Approach Radar System
49. Specification for precision approach radar system
(f) The Precision Approach Radar Element (PAR)
50. PAR coverage
51. PAR siting
52. PAR accuracy
(g) The Surveillance Radar Element (SRE)
53. The Surveillance Radar Element (SRE)
54. SRE coverage
55. SRE accuracy
(h) Specification for VHF Omnidirectional Radio Range (VOR)
56. VHF omnidirectional range (VOR)
57. VOR radio frequency
58. VOR polarisation and pattern accuracy
59. VOR coverage
60. VOR modulations of navigation signals
61. VOR voice and identification
62. VOR monitoring
63. Interference immunity performance for VOR receiving systems
(i) Specification for Non-directional Radio Beacon (NDB)
64. NDB coverage
65. NDB limitations in radiated power
66. NDB radio frequencies
67. NDB identification
68. NDB characteristics of emissions
69. NDB siting of locators
70. NDB monitoring
(j) Specification for UHF Distance Measuring Equipment (DME)
71. UHF distance measuring equipment
72. Association of DME with ILS
73. UHF DME performance
74. UHF DME coverage
75. UHF DME accuracy
76. UHF DME radio frequencies and polarisation
77. UHF DME channelling
78. UHF DME interrogation pulse repetition frequency
79. UHF DME aircraft handling capacity of system
80. UHF DME transponder identification
81. UHF DME identification implementation
(k) Characteristics of Transponder and Associated Monitor
82. DME transponder transmission component
83. DME transponder pulse spacing
84. DME transponder peak power output
85. DME transponder receiver
86. DME transponder sensitivity
87. DME transponder load limiting
88. DME transponder noise
89. DME transponder bandwidth
90. DME transponder recovery time
91. DME transponder spurious radiations
92. DME transponder CW and echo suppression
93. DME transponder protection against interference
94. DME transponder decoding
95. DME transponder time delay
96. DME transponder accuracy
97. DME transponder efficiency
98. DME transponder monitoring and control
(l) Technical Characteristics of Interrogator
99. DME interrogator transmitter
100. DME interrogator pulse spacing
101. DME interrogator pulse repetition frequency
102. DME interrogator spurious radiation
103. DME interrogator time delay
104. DME interrogator receiver
105. DME interrogator receiver sensitivity
106. DME interrogator bandwidth
107. DME interrogator interference rejection
108. DME interrogator decoding
109. DME interrogator accuracy
(m) Specification for En Route VHF Marker Beacons (75 MHz)
110. En route VHF marker equipment
111. En route VHF marker characteristics of emissions
112. En route VHF marker identification
113. En route VHF marker coverage and radiation pattern
114. En route VHF marker determination of coverage
115. En route VHF marker radiation pattern
116. En route VHF marker monitoring
(n) Requirements for the Global Navigation Satellite System (GNSS)
117. GNSS functions
118. GNSS elements
119. GNSS space reference
120. GNSS time reference
121. GNSS signal-in-space performance
(o) GPS Standard Positioning Service (SPS) (L1)
122. GPS space and control segment accuracy
123. GPS range domain accuracy
124. GPS availability
125. GPS reliability
126. GPS continuity
127. GPS coverage
(p) Radio Frequency (RF) Characteristics
128. GPS carrier frequency
129. GPS signal spectrum
130. GPS polarisation
131. GPS signal power level
132. GPS modulation
133. GPS time
134. GPS co-ordinate system
135. GPS navigation information
(q) GLONASS Channel of Standard Accuracy (CSA) (L1)
136. GLONASS space and control segment accuracy
137. GLONASS availability
138. GLONASS reliability
139. GLONASS coverage
140. GLONASS carrier frequency
141. GLONASS signal spectrum
142. GLONASS polarisation
143. GLONASS signal power level
144. GLONASS modulation
145. GLONASS time
146. GLONASS co-ordinate system
147. GLONASS navigation information
(r) Aircraft-based Augmentation System (ABAS)
148. ABAS performance
(s) Satellite-based Augmentation System (SBAS)
149. SBAS performance
150. SBAS functions
151. SBAS ranging
152. SBAS carrier frequency
153. SBAS signal spectrum
154. SBAS satellite signal power level
155. SBAS polarisation
156. SBAS modulation
157. SBAS network time (SNT)
158. SBAS navigation information
(t) Ground-based Augmentation System (GBAS) and Ground-based Regional Augmentation System (GRAS)
159. GBAS performance
160. GBAS functions
161. GBAS service volume
162. GBAS approach services supporting auto land and guided take-off
163. GBAS positioning service
164. GBAS carrier frequency
165. GBAS access technique
166. GBAS modulation
167. GBAS data broadcast RF field strength and polarisation
168. GBAS power transmitted in adjacent channels
169. GBAS unwanted emissions
170. GBAS navigation information
171. Aircraft GNSS receiver
172. GNSS resistance to interference
173. GNSS database
(u) System Characteristics of Airborne ADF Receiving Systems
174. Accuracy of bearing indication
PART IV
Exemptions
175. Requirements for application for exemption
176. Review and publication
177. Evaluation of the request
PART V
General Provisions
178. Drug and alcohol testing and reporting
179. Reports of violation
180. Failure to comply with direction
181. Aeronautical fees
PART VI
Offences and Penalties
182. Contravention of Regulations
183. Penalties
184. Appeal
PART VII
Savings and Transitions
185. Savings and transition
S.I. 76, 2022.
PART I
Preliminary (regs 1-3)
These Regulations may be cited as the Civil Aviation (Radio Navigation Aids) Regulations.
In these Regulations, unless the context otherwise requires—
"aircraft-based augmentation system (ABAS)" means an augmentation system that augments and/or integrates the information obtained from the other GNSS elements with information available on board the aircraft;
"air navigation services facility" means any facility used, available for use, or designed for use in aid of navigation of aircraft, including airports, landing fields, any structures, mechanisms, lights, beacons, marks, communicating systems, or other instruments or devices used or useful as an aid to the safe taking off, navigation, and landing of aircraft and any combination of such facilities;
"alert" means an indication provided to other aircraft systems or annunciation to the pilot to identify that an operating parameter of a navigation system is out of tolerance;
"alert limit" means the error tolerance not to be exceeded without issuing an alert for a given parameter measurement;
"altitude" means the vertical distance of a level, a point or an object considered as a point, measured from mean sea level (MSL);
"air navigation services provider" means an entity established for the purpose of providing one or more of the air navigation services as defined in these Regulations;
"angular displacement sensitivity" means the ratio of measured DDM to the corresponding angular displacement from the appropriate reference line;
"antenna port" means a point where the received signal power is specified. For an active antenna, the antenna port is a fictitious point between the antenna elements and the antenna pre-amplifier. For a passive antenna, the antenna port is the output of the antenna itself;
"area navigation" 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 these;
"Authority" means the Civil Aviation Authority of Botswana established under the Civil Aviation Act (Cap. 70:01);
"average radius of rated coverage" means the radius of a circle having the same area as the rated coverage;
"axial ratio" means the ratio, expressed in decibels, between the maximum output power and the minimum output power of an antenna to an incident linearly polarised wave as the polarisation orientation is varied over all directions perpendicular to the direction of propagation;
"back course sector" means the course sector which is situated on the opposite side of the localizer from the runway;
"carrier energy" means the average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle under conditions of no modulation;
"certificate" means the certificate for the provision of air navigation services issued by the Authority under the Civil Aviation (Certification of Air Navigation Services Providers) Regulations, 2021, Statutory No. 144 of 2021;
"channel of standard accuracy" means the specified level of positioning, velocity and timing accuracy that is available to any GLONASS user on a continuous, worldwide basis;
"CNS" means radio navigation aids, communication procedures including those with PANS (Procedures for Air Navigation Services), communication systems, surveillance and collision avoidance systems and aeronautical radio frequency spectrum utilisation;
"control motion noise (CMN)" means that portion of the guidance signal error which causes control surface, wheel and column motion and could affect aircraft attitude angle during coupled flight, but does not cause aircraft displacement from the desired course and/or glide path;
"core satellite constellation(s)" means the GPS and GLONASS;
"course line" means the locus of points nearest to the runway centre line in any horizontal plane at which the DDM is zero;
"coupling" means the association of two circuits or systems in such a way that power may be transferred from one to the other;
"course sector" means a sector in a horizontal plane containing the course line and limited by the loci of points nearest to the course line at which the DDM is 0.155;
"displacement sensitivity (localizer)" means the ratio of measured DDM to the corresponding lateral displacement from the appropriate reference line;
"DME" means Distance Measuring Equipment;
"dead time" means a period immediately following the decoding of a valid interrogation during which a received interrogation will not cause a reply to be generated;
"DME/N" means distance measuring equipment, primarily serving operational needs of en route or Terminal Control Area navigation, where the "N" stands for narrow spectrum characteristics;
"DME/P" means the distance measuring element of the MLS, where the "P" stands for precise distance measurement. The spectrum characteristics are those of DME/N;
"effective adjacent channel rejection" means the rejection that is obtained at the appropriate adjacent channel frequency when all relevant receiver tolerances have been taken into account;
"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;
"essential radio navigation service" means a radio navigation service whose disruption has a significant impact on operations in the affected airspace or aerodrome;
"equivalent isotropically radiated power (EIRP)" means 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);
"Facility Performance Category I – ILS" means an ILS which provides guidance information from the coverage limit of the ILS to the point at which the localizer course line intersects the ILS glide path at a height of 60 metres (200 ft) or less above the horizontal plane containing the threshold;
"Facility Performance Category II – ILS" means an ILS which provides guidance information from the coverage limit of the ILS to the point at which the localizer course line intersects the ILS glide path at a height of 15 metres (50 ft) or less above the horizontal plane containing the threshold;
"Facility Performance Category III – ILS" means an ILS which, with the aid of ancillary equipment where necessary, provides guidance information from the coverage limit of the facility to, and along, the surface of the runway;
"fan marker beacon" means a type of radio beacon, the emissions of which radiate in a vertical fan-shaped pattern;
"final approach (FA) mode" means the condition of DME/P operation which supports flight operations in the final approach and runway regions;
"front course sector" means the course sector which is situated on the same side of the localizer as the runway;
"GBAS/E" means a ground-based augmentation system transmitting an elliptically-polarised VHF data broadcast;
"GBAS/H" means a ground-based augmentation system transmitting a horizontally-polarised VHF data broadcast;
"global navigation satellite system (GNSS)" means 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 require navigation performance for the intended operation;
"global navigation satellite system (GLONASS)" means the satellite navigation system operated by the Russian Federation;
"GNSS position error" means the difference between the true position and the position determined by the GNSS receiver;
"ground-based augmentation system (GBAS)" means an augmentation system in which the user receives augmentation information directly from a ground-based transmitter;
"ground-based regional augmentation system (GRAS)" means an augmentation system in which the user receives augmentation information directly from one of a group of ground-based transmitters covering a region;
"half course sector" means the sector, in a horizontal plane containing the course line and limited by the loci of points nearest to the course line at which the DDM is 0.0775;
"height" means the vertical distance of a level, a point or an object considered as a point, measured from a specified datum;
"Human Factors Principles" means principles which apply to design, certification, training, operations and maintenance and which seek safe interface between the human and other system components by proper consideration to human performance;
"ILS" means an Instrument Landing System;
"ILS glide path" means that locus of points in the vertical plane containing the runway centre line at which the DDM is zero, which, of all such loci, is the closest to the horizontal plane;
"ILS glide path angle" means the angle between a straight line which represents the mean of the ILS glide path and the horizontal;
"ILS glide path sector" means the sector in the vertical plane containing the ILS glide path and limited by the loci of points nearest to the glide path at which the DDM is 0.175;
"ILS Point "B"" means a point on the ILS glide path measured along the extended runway centre line in the approach direction a distance of 1050 metres (3 500 ft) from the threshold;
"initial approach (IA) mode" means the condition of DME/P operation which supports those flight operations outside the final approach region and which is interoperable with DME/N;
"integrity" means a measure of the trust that can be placed in the correctness of the information supplied by the total system and includes the ability of a system to provide timely and valid warnings to the user (alerts);
"key down time" means the time during which a dot or dash of a Morse character is being transmitted;
"LF/MF" means low frequency/medium frequency;
"locator" means an LF/MF NDB used as an aid to final approach; conditions;
"mode X, Y," means a method of coding the DME transmissions by time spacing pulses of a pulse pair, so that each frequency can be used more than once;
"NDB" means a radio transmitter at a known location, used as a radio navigation aid;
"path following error (PFE)" means that portion of the guidance signal error which could cause aircraft displacement from the desired course and/or glide path;
"pseudo-range" means the difference between the time of transmission by a satellite and reception by a GNSS receiver multiplied by the speed of light in a vacuum, including bias due to the difference between a GNSS receiver and satellite time reference;
"pulse code" means the method of differentiating between W, X, Y and Z modes and between FA and IA modes;
"pulse decay time" means the time as measured between the 10 and 90 per cent amplitude points on the trailing edge of the pulse envelope;
"pulse duration" means the time interval between the 50 per cent amplitude point on leading and trailing edges of the pulse envelope;
"pulse rise time" means the time as measured between the 10 and 90 per cent amplitude points on the leading edge of the pulse envelope;
"radio navigation service" means a service providing guidance information or position data for the efficient and safe operation of aircraft supported by one or more radio navigation aids;
"rated coverage" means the area surrounding an NDB within which the strength of the vertical field of the ground wave exceeds the minimum value specified for the geographical area in which the radio beacon is situated;
"receiver" means a subsystem that receives GNSS signals and includes one or more sensors;
"reply efficiency" means the ratio of replies transmitted by the transponder to the total of received valid interrogations;
"reserved (bits/words/fields)" means bits/words/fields that are not allocated, but which are reserved for a particular GNSS application;
"search" means the condition which exists when the DME interrogator is attempting to acquire and lock onto the response to its own interrogations from the selected transponder;
"satellite-based augmentation system (SBAS)" means a wide coverage augmentation system in which the user receives augmentation information from a satellite-based transmitter;
"spare (bits/words/fields)" means bits/words/fields that are not allocated or reserved, and which are available for future allocation;
"standard positioning service (SPS)" means the specified level of positioning, velocity and timing accuracy that is available to any global positioning system (GPS) user on a continuous, worldwide basis;
"Surveillance Radar Element" means a component of a GCA (ground-controlled approach) system—
(a) which vectors incoming traffic until it is handed over to the precision approach radar (PAR) controller or established on the ILS (Instrument Landing System);
(b) which provides target information in the range and the azimuth while information on target information is not available; and
(c) in which a pilot can be vectored onto the final approach so that he or she can be handed over to the PAR controller or can carry out the ILS approach;
"time-to-alert" means the maximum allowable time elapsed from the onset of the navigation system being out of tolerance until the equipment enunciates the alert;
"track" means the condition which exists when the DME interrogator has locked onto replies in response to its own interrogations and is continuously providing a distance measurement;
"touchdown" means the point where the nominal glide path intercepts the runway;
"transmission rate" means the average number of pulse pairs transmitted from the transponder per second;
"two-frequency glide path system" means an ILS glide path in which coverage is achieved by the use of two independent radiation field patterns spaced on separate carrier frequencies within the particular glide path channel;
"VOR" means Very High Frequency (VHF) Omnidirectional Radio Range; and
"Z marker beacon" means type of radio beacon, the emissions of which radiate in a vertical cone-shaped pattern.
These Regulations shall apply to a person providing radio navigation aids services within designated airspace and at aerodromes.
PART II
General Requirements (reg 4)
4. Requirements for radio navigation aids facilities
The minimum requirements for planning, installation, commissioning, training, operations and maintenance of the radio navigation aids facilities shall conform to these Regulations.
PART III
Radio Navigation Aids (regs 5-174)
5. Standard radio navigation aids
(1) Standard radio navigation aids to be used for air navigation shall be—
(a) the Instrument Landing System (ILS);
(b) the global navigation satellite system (GNSS);
(c) the VHF Omnidirectional Radio Range (VOR);
(d) the Non-Directional Radio Beacon (NDB);
(e) the Distance Measuring Equipment (DME);
(f) the En Route VHF Marker Beacon; and
(g) microphone landing system (MLS).
(2) Differences in radio navigation aids specified in subregulation (1) shall be published in an Aeronautical Information Publication (AIP).
(3) The ANS shall publish in an (AIP) any radio navigation aid that is not an ILS, but which may be used in whole or in part with aircraft equipment designed for use with an ILS.
(1) A service provider shall terminate a GNSS satellite service, provided by one of its elements under the Requirements for the global navigation satellite system, on the basis of at least a six-year advance notice.
(2) The Authority shall, upon approving the GNSS-based operations ensure that GNSS data relevant to those operations are recorded.
(3) The Authority shall retain recordings for a period of at least 30 days.
(4) Where the recordings are pertinent to accident and incident investigations, the Authority shall retain such recordings for longer periods until it is evident that they will no longer be required.
(1) A precision approach radar (PAR) system, where installed and operated as a radio navigation aid together with equipment for two-way communication with aircraft and facilities for the efficient co-ordination of these elements with air traffic control, shall conform to regulation 49.
(2) Where a radio navigation aid is provided to support precision approach and landing, it shall be supplemented, as necessary, by a source or sources of guidance information which, when used in conjunction with appropriate procedures, will provide effective guidance to, and efficient coupling with, the desired reference path.
8. Composition of precision approach radar system
(1) The precision approach radar system shall comprise the following elements—
(a) the Precision Approach Radar element (PAR); and
(b) the Surveillance Radar Element (SRE).
(2) Where the Precision Approach Radar only is used, the installation shall be identified by the term "precision approach radar" and not by the term "precision approach radar system".
9. Specifications for precision approach radar elements
The specifications for precision approach radar shall be as contained in Schedule 1.
10. Specifications for Surveillance Radar Element
A surveillance radar used as the SRE of a precision approach radar system shall satisfy the performance requirements as contained in Schedule 1.
Radio navigation aids of the types covered by the specifications in regulations 5 to 174 and available for use by aircraft engaged in international air navigation, shall be the subject of periodic ground and flight tests as contained in Schedule 4.
12. Operational status of radio navigation aids
Aerodrome control towers and units providing approach control service shall be provided with information on the operational status of radio navigation services essential for approach, landing and take-off at the aerodrome with which they are concerned, on a timely basis consistent with the use of the service involved.
13. Power supply for radio navigation aids and communication systems
Radio navigation aids and ground elements of communication systems shall be provided with suitable power supplies and means to ensure continuity of service, consistent with the use of the service involved.
14. Human factor considerations
Human Factors Principles shall be observed in the design and certification of radio navigation aids.
(a) Instrument Landing System (regs 15-19)
15. Basic requirements for instrument landing system – composition
(1) The ILS shall comprise the following basic components—
(a) VHF localizer equipment, associated monitor system, remote control and indicator equipment;
(b) UHF glide path equipment, associated monitor system, remote control and indicator equipment; and
(c) DME or VHF Markers as a means to enable glide path verification checks.
(2) Distance to threshold information shall be provided by either VHF marker beacons or Distance Measuring Equipment (DME) to enable glide path verification checks together with associated monitor systems and remote control and indicator equipment.
(3) If one or more VHF marker beacons are used to provide distance to threshold information, the equipment shall conform to the specifications in regulations 42 to 48.
(4) Facility Performance Categories I, II and III – ILS shall provide indications at designated remote-control points of the operational status of all ILS ground system components, as follows—
(a) for all Category II and Category III – ILS, the air traffic services unit involved in the control of aircraft on the final approach shall be one of the designated remote control points and shall receive information on the operational status of the ILS, with a delay commensurate with the requirements of the operational environment; and
(b) for a Category I – ILS, if that ILS provides an essential radio navigation service, the air traffic services unit involved in the control of aircraft on the final approach shall be one of the designated remote control points and shall receive information on the operational status of the ILS, with a delay commensurate with the requirements of the operational environment.
16. Basic requirements for instrument landing system – construction and adjustment
The ILS shall be constructed and adjusted so that, at a specified distance from the threshold, similar instrumental indications in the aircraft represent similar displacements from the course line or ILS glide path as appropriate, irrespective of the particular ground installation in use.
17. Localizer and glide path components of facility performance categories
(1) The localizer and glide path components specified in regulation 15(1)(a) and (b) which form part of a Facility Performance Category I – ILS shall comply with regulations 20 to 41 respectively, except those in which the application to Facility Performance Category II – ILS is prescribed.
(2) The localizer and glide path components specified in regulation 15(1)(a) and (b) which form part of a Facility Performance Category II – ILS shall comply with the standards applicable to these components in a Facility Performance Category I – ILS, as supplemented or amended by regulations 20 to 41 in which the application to Facility Performance Category II – ILS is prescribed.
(3) The localizer and glide path components and other ancillary equipment specified in regulation 15(1)(a) and (b), which form part of a Facility Performance Category III – ILS, shall otherwise comply with the standards applicable to these components in Facility Performance Categories I and II – ILS, except as supplemented by the standards in regulations 20 to 41 in which application to Facility Performance Category III – ILS is prescribed.
The ILS shall be so designed and maintained that the probability of operation within the performance requirements specified is of a high value, consistent with the category of operational performance concerned.
19. Two ILS facilities serving opposite ends of single runway
(1) Where two separate ILS facilities serve opposite ends of a single runway, an interlock shall ensure that only the localizer serving the approach direction in use shall radiate, except where the localizer in operational use is Facility Performance Category I – ILS and not operationally harmful interference results.
(2) Where two separate ILS facilities serve opposite ends of a single runway and where a Facility Performance Category I – ILS is to be used for auto-coupled approaches and landings in visual conditions an interlock shall ensure that only the localizer serving the approach direction in use radiates:
Provided the other localizer serving the approach direction in use, radiates.
(3) Where ILS facilities serving opposite ends of the same runway or different runways at the same airport, use the same paired frequencies, an interlock shall ensure that only one facility shall radiate at a time.
(4) Where there is a switching from one ILS facility to another, radiation from both facilities shall be suppressed for not less than 20 seconds.
(b) VHF Localizer and Associated Monitor (regs 20-32)
20. VHF localizer and associated monitor specifications
(1) The specifications of the VHF localizer and associated monitor shall be as set out in Schedule 2.
(2) The radiation from the localizer antenna system shall produce a composite field pattern which is amplitude modulated by a 90 Hz and a 150 Hz tone.
(3) The radiation field pattern shall produce a course sector with one tone predominating on one side of the course and with the other tone predominating on the opposite side.
(4) Where an observer faces the localizer from the approach end of a runway, the depth of modulation of the radio frequency carrier due to the 150 Hz tone shall predominate on the observer's right hand and that due to the 90 Hz tone shall predominate on the observer's left hand.
(5) All horizontal angles employed in specifying the localizer field patterns shall originate from the centre of the localizer antenna system which provides the signals used in the front course sector.
21. VHF localizer radio frequency
(1) The localizer shall—
(a) operate in the band 108 MHz to 111.975 MHz; and
(b) where a single radio frequency carrier is used, the frequency tolerance shall not exceed 0.005 per cent.
(2) Where two radio frequency carriers are used—
(a) the frequency tolerance shall not exceed 0.002 per cent;
(b) the nominal band occupied by the carriers shall be symmetrical about the assigned frequency; and
(c) with all tolerances applied, the frequency separation between the carriers shall not be less than 5 kHz nor more than 14 kHz.
(3) The emission from the localizer shall—
(a) be horizontally polarised; and
(b) the vertically polarised component of the radiation on the course line shall not exceed that which corresponds to a DDM error of 0.016 when an aircraft is positioned on the course line and is in a roll attitude of 20 degrees from the horizontal.
(4) For Facility Performance Category II localizers, the vertically polarised component of the radiation on the course line shall not exceed that which corresponds to a DDM error of 0.008 when an aircraft is positioned on the course line and is in a roll attitude of 20 degrees from the horizontal.
(5) For Facility Performance Category III localizers, the vertically polarised component of the radiation within a sector bounded by 0.02 DDM either side of the course line shall not exceed that which corresponds to a DDM error of 0.005 when an aircraft is in a roll attitude of 20 degrees from the horizontal.
(6) For Facility Performance Category III localizers, signals emanating from the transmitter shall contain no components which result in an apparent course line fluctuation of more than 0.005 DDM peak to peak in the frequency band 0.01 Hz to 10 Hz.
(1) The localizer shall provide signals sufficient to allow satisfactory operation of a typical aircraft installation within the localizer and glide path coverage sectors.
(2) —
(1) The localizer coverage sector shall extend from the centre of the localizer antenna system to distances of—
(a) 46.3 km (25 NM) within plus or minus 10 degrees from the front course line;
(b) 31.5 km (17 NM) between 10 degrees and 35 degrees from the front course line; and
(c) 18.5 km (10 NM) outside of plus or minus 35 degrees from the front course line if coverage is provided.
(2) In all parts of the coverage volume specified in subregulation (1), other than as specified in subregulations (3), (4) and (5), the field strength shall not be less than 40 microvolts (µv) per metre (minus 114 dBW/m2'>).
(3) For Facility Performance Category I localizers, the minimum field strength on the ILS glide path and within the localizer course sector from a distance of 18.5 km (10 NM) to a height of 60 m (200 ft) above the horizontal plane containing the threshold shall hot be less than 90 µv per metre (minus 107 dBW/m2'>).
(4) For Facility Performance Category II localizers, the minimum field strength on the ILS glide path and within the localizer course sector shall—
(a) not be less than 100 µv per metre (minus 106 dBW/m2'>) at a distance of 18.5 km (10 NM) increasing to not less than 200 µv per metre (minus 100 dBW/m2'>); and
(b) at a height of 15 m (50 ft) above the horizontal plane containing the threshold.
(5) For Facility Performance Category III localizers, the minimum field strength on the ILS glide path and within the localizer course sector shall—
(a) not be less than 100 µv per metre (minus 106 dBW/m2'>) at a distance of 18.5 km (10 NM);
(b) not increase to less than 200 µv per metre (minus 100 dBW/m2'>) at 6 m (20 ft) above the horizontal plane containing the threshold;
(c) from this point to a further point 4 m (12 ft) above the runway centre line, and 300 m (1 000 ft) from the threshold in the direction of the localizer; and
(d) thereafter at a height of 4 m (12 ft) along the length of the runway in the direction of the localizer, the field strength shall not be less than 100 µv per metre (minus 106 dBW/m2'>).
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