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′>).
(6) The signals shall be reduced to as low a value as seven degrees.
(7) —
(1) Where coverage is achieved by a localizer using two radio frequency carriers, one carrier shall provide a radiation field pattern in the front course sector and the other shall provide a radiation field pattern outside that sector.
(2) The ratio of the two carrier signal strengths in space within the front course sector to the coverage limits specified in subregulation (1), shall not be less than 10 dB.
(8) For Facility Performance Category III localizers, the ratio of the two carrier signal strengths in space within the front course sector shall not be less than 16 dB.
23. VHF localizer course structure
(1) For Facility Performance Category I localizers, bends in the course line shall not have amplitudes which exceed the following—
| Zone
|
Amplitude (DDM) (95% probability)
|
| Outer limit of coverage to ILS Point “A”
|
0.031
|
| ILS Point “A” to ILS Point “B”
|
0.031 at ILS Point “A” decreasing at a linear rate to 0.015 at ILS Point “B”
|
| ILS Point “B” to ILS Point “C”
|
0.015
|
(2) For Facility Performance Categories II and III localizers, bends in the course line shall not have amplitudes which exceed the following—
| Zone
|
Amplitude (DDM) (95% probability)
|
| Outer limit of coverage to ILS Point “A”
|
0.031
|
| ILS Point “A” to ILS Point “B”
|
0.03 at ILS Point “A” decreasing at a linear rate to 0.005 at ILS Point “B”
|
| ILS Point “B” to the ILS reference datum
|
0.005
|
| and, for Category III only—
|
|
| ILS reference datum to ILS Point “D”
|
0.005
|
| ILS Point “D” to ILS Point “E”
|
0.005 at ILS Point “D” increasing at a liner rate to 0.010 at ILS Point “E”
|
24. VHF localizer carrier modulation
(1) The nominal depth of modulation of the radio frequency carrier due to each of the 90 Hz and 150 Hz tones shall be 20 per cent along the course line.
(2) The depth of modulation of the radio frequency carrier due to each of the 90 Hz and 150 Hz tones shall be within the limits of 18 and 22 per cent.
(3) The following tolerances shall be applied to the frequencies of the modulating tones—
(a) the modulating tones shall be 90 Hz and 150 Hz within plus or minus 2.5 per cent;
(b) the modulating tones shall be 90 Hz and 150 Hz within plus or minus 1.5 per cent for Facility Performance Category II installations;
(c) the modulating tones shall be 90 Hz and 150 Hz within plus or minus one per cent for Facility Performance Category III installations;
(d) the total harmonic content of the 90 Hz tone shall not exceed 10 per cent;
(e) additionally, for Facility Performance Category III localizers, the second harmonic of the 90 Hz tone shall not exceed five per cent; and
(f) the total harmonic content of the 150 Hz tone shall not exceed 10 per cent.
(4) For Facility Performance Category I – ILS, the modulating tones shall be—
(a) 90 Hz; and
(b) 150 Hz within plus or minus 1.5 per cent where practicable.
(5) —
(1) For Facility Performance Category III localizers, the depth of amplitude modulation of the radio frequency carrier at the power supply frequency or its harmonics, or by other unwanted components, shall not exceed 0.5 per cent.
(2) Harmonics of the supply, or other unwanted noise components that may intermodulate with the 90 Hz and 150 Hz navigation tones or their harmonics to produce fluctuations in the course line, shall not exceed 0.05 per cent modulation depth of the radio frequency carrier.
(6) The modulation tones shall be phase-locked so that within the half course sector, the demodulated 90 Hz and 150 Hz wave forms pass through zero in the same direction within—
(a) for Facility Performance Categories I and II localizers: 20 degrees; and
(b) for Facility Performance Category III localizers: 10 degrees, of phase relative to the 150 Hz component, every half cycle of the combined 90 Hz and 150 Hz wave form.
(7) —
(1) With two-frequency localizer systems, subregulation (6) shall apply to each carrier and the 90 Hz modulating tone of one carrier shall be phase-locked to the 90 Hz modulating tone of the other carrier so that the demodulated wave forms pass through zero in the same direction—
(a) for Categories I and II localizers: 20 degrees; and
(b) for Category III localizers: 10 degrees, of phase relative to 90 Hz.
(2) Similarly, the 150 Hz tones of the two carriers shall be phase-locked so that the demodulated wave forms pass through zero in the same direction—
(a) for Categories I and II localizers: 20 degrees; and
(b) for Category III localizers: 10 degrees, of phase relative to 150 Hz.
(8) —
(1) The Authority shall authorise the use of alternative two-frequency localizer systems that employ audio phasing different from the normal in-phase conditions described in subregulation (7).
(2) Subject to subregulation (8) the 90 Hz to 90 Hz phasing and the 150 Hz to 150 Hz phasing shall be adjusted to their nominal values to within limits equivalent to those stated in subregulation (7).
(9) The sum of the modulation depths of the radio frequency carrier due to the 90 Hz and 150 Hz tones shall—
(a) not exceed 60 per cent; or
(b) be less than 30 per cent within the required coverage.
(10) For equipment first installed after 1st January 2000, the sum of the modulation depths of the radio frequency carrier due to the 90 Hz and 150 Hz tones shall—
(a) not exceed 60 per cent; or
(b) be less than 30 per cent within the required coverage.
(11) When utilising a localizer for radiotelephone communications, the sum of the modulation depths of the radio frequency carrier due to the 90 Hz and 150 Hz tones shall not exceed—
(a) 65 per cent within 10 degrees of the course line; and
(b) 78 per cent at any other point around the localizer.
(12) When utilising a localizer for radiotelephone communications, the sum of the modulation depths of the radio frequency carrier due to the 90 Hz and 150 Hz tones shall—
(a) not exceed 65 per cent within 10 degrees of the course line; and
(b) not exceed 78 per cent at any other point around the localizer.
(13) Undesired frequency and phase modulation on ILS localizer radio frequency carriers that can affect the displayed DDM values in localizer receivers shall be minimised to such extent as is practical.
25. VHF localizer course alignment accuracy
The mean course line shall be adjusted and maintained within limits equivalent to the following displacements from the runway centre line at the ILS reference datum—
(a) for Facility Performance Category I localizers: plus or minus 10.5 m (35 ft), or the linear equivalent of 0.015 DDM, whichever is less;
(b) for Facility Performance Category II localizers: plus or minus 7.5 m (25 ft); and
(c) for Facility Performance Category III localizers: plus or minus 3 m (10 ft).
26. VHF localizer displacement sensitivity
(1) The nominal displacement sensitivity within the half course sector shall be the equivalent of 0.00145 DDM/m (0.00044 DDM/ft) at the ILS reference datum except that for Category I localizers, where the specified nominal displacement sensitivity cannot be met, the displacement sensitivity shall be adjusted as near as possible to that value.
(2) For Facility Performance Category I localizers on runway codes 1 and 2, the nominal displacement sensitivity shall—
(a) be achieved at the ILS Point “B”; and
(b) maximum course sector angle shall not exceed six degrees.
(3) The lateral displacement sensitivity shall be adjusted and maintained within the limits of plus or minus—
(a) 17 per cent of the nominal value for Facility Performance Categories I and II;
(b) 10 per cent of the nominal value for Facility Performance Category III.
(4) For Facility Performance Category II – ILS, displacement sensitivity shall be adjusted and maintained within the limits of plus or minus 10 per cent where practicable.
(5) The increase of DDM shall be substantially linear with respect to angular displacement from the front course line (where DDM is zero), up to an angle on either side of the front course line where the DDM is 0.180.
(6) From that angle to plus or minus 10 degrees, the DDM shall not be less than 0.180 and from plus or minus 10 degrees to plus or minus 35 degrees, the DDM shall not be less than 0.155.
(7) Where coverage is required outside of the plus or minus 35 degrees sector, the DDM in the area of the coverage, except in the back-course sector, shall not be less than 0.155.
(1) Facility Performance Categories I and II localizers may provide a ground-to-air radiotelephone communication channel to be operated simultaneously with the navigation and identification signals:
Provided that such operation shall not interfere in any way with the basic localizer function.
(2) Category III localizers shall not provide such a radiotelephone communication channel, except where extreme care has been taken in the design and operation of the facility to ensure that there is no possibility of interference with the navigational guidance.
(3) If the radiotelephone communication channel is provided, it shall conform with the following standards—
(a) the channel shall be on the same radio frequency carrier or carriers as used for the localizer function, and the radiation shall be horizontally polarised;
(b) where two carriers are modulated with speech, the relative phases of the modulations on the two carriers shall be such as to avoid the occurrence of nulls within the coverage of the localizer; and
(c) the peak modulation depth of the carrier or carriers due to the radiotelephone communications shall not exceed 50 per cent but shall be adjusted so that—
(i) the ratio of peak modulation depth due to the radiotelephone communications to that due to the identification signal is approximately 9:1, and
(ii) the sum of modulation components due to use of the radiotelephone channel, navigation signals and identification signals shall not exceed 95 per cent; and
(d) the audio frequency characteristics of the radiotelephone communication channel shall be flat to within 3 dB relative to the level at 1000 Hz over the range 300 Hz to 3000 Hz.
28. VHF localizer identification
(1) The localizer shall—
(a) provide for the simultaneous transmission of an identification signal;
(b) be specific to the runway and approach direction, on the same radio frequency carrier or carriers as used for the localizer function; and
(c) the transmission of the identification signal shall not interfere in any way with the basic localizer function.
(2) The identification signal shall—
(a) be produced by Class A2A modulation of the radio frequency carrier; or
(b) carriers using a modulation tone of 1020 Hz within plus or minus 50 Hz.
(3) The depth of modulation shall be between the limits of 5 and 15 per cent except that where a radiotelephone communication channel is provided, the depth of modulation shall be adjusted so that the ratio of peak modulation depth due to radiotelephone communications to that due to the identification signal modulation is approximately 9:1.
(4) The emissions carrying the identification signal shall—
(a) be horizontally polarised; and
(b) where two carriers are modulated with identification signals, the relative phase of the modulations shall be such as to avoid the occurrence of nulls within the coverage of the localizer.
(5) The identification signal shall—
(a) employ the International Morse Code which consist of two or three letters; or
(b) be preceded by the International Morse Code signal of the letter “I”, followed by a short pause where it is necessary to distinguish the ILS facility from other navigational facilities in the immediate area.
(6) The identification signal shall—
(a) be transmitted by dots and dashes at a speed corresponding to approximately seven words per minute; and
(b) shall be repeated at approximately equal intervals, not less than six times per minute, at all times during which the localizer is available for operational use.
(7) Where the transmissions of the localizer are not available for operational use after removal of navigation components, or during maintenance or test transmissions, the identification signal shall be suppressed and the dots shall have a duration of 0.1 second to 0.160 second.
(8) The dash duration shall—
(a) be typically three times the duration of a dot;
(b) the interval between dots or dashes shall be equal to that of one dot plus or minus ten per cent; and
(c) the interval between letters shall not be less than the duration of three dots.
(1) For Facility Performance Categories II and III—
(a) the localizer antenna system shall be located on the extension on the centre line of the runway at the stop end;
(b) the equipment shall be adjusted so that the course lines will be in a vertical plane containing the centre line of the runway served; and
(c) the antenna height and location shall be consistent with safe obstruction clearance practices.
(2) For Facility Performance Category I, the localizer antenna system shall be located and adjusted as in subregulation (1), unless site constraints dictate that the antenna be offset from the centre line of the runway.
(1) The automatic monitor system shall provide a warning to the designated control points and cause one of the following to occur, within the period specified in subregulation (5), if any of the conditions stated in subregulation (2) persist—
(a) radiation to cease; and
(b) removal of the navigation and identification components from the carrier.
(2) The conditions requiring initiation of monitor action shall be the following—
(a) for Facility Performance Category I localizers, a shift of the mean course line from the runway centre line equivalent to more than 10.5 m (35 ft), or the linear equivalent to 0.015 DDM, whichever is less, at the ILS reference datum;
(b) for Facility Performance Category II localizers, a shift of the mean course line from the runway centre line equivalent to more than 7.5 m (25 ft) at the ILS reference datum;
(c) for Facility Performance Category III localizers, a shift of the mean course line from the runway centre line equivalent to more than 6 m (20 ft) at the ILS reference datum;
(d) in the case of localizers in which the basic functions are provided by the use of a single-frequency system, a reduction of power output to a level such that any of the requirements of regulation 22, 23 or 24 are no longer satisfied, or to a level that is less than 50 per cent of the normal level (whichever occurs first);
(e) in the case of localizers in which the basic functions are provided by the use of a two-frequency system, a reduction of power output for either carrier to less than 80 per cent of normal, except that a greater reduction to between 80 per cent and 50 per cent of normal may be permitted, provided the localizer continues to meet the requirements of regulations 22, 23 and 24; and
(f) change of displacement sensitivity to a value differing by more than 17 per cent from the nominal value for the localizer facility.
(3) In the case of localizers in which the basic functions are provided by the use of a two-frequency system, the conditions requiring initiation of monitor action shall include the case where the DDM in the required coverage beyond plus or minus 10 degrees from the front course line, except in the back course sector, decreases below 0.155.
(4) The total period of radiation, including period(s) of zero radiation, outside the performance limits specified in subregulation (2) shall be as short as practicable, consistent with the and need for avoiding interruptions of the navigation service provided by the localizer.
(5) The total period referred to under subregulation (4) shall not exceed under any circumstances—
(a) 10 seconds for Category I localizers;
(b) five seconds for Category II localizers; and
(c) two seconds for Category III localizers.
(6) Where practicable, the total period under subregulation (5) shall be reduced so as not to exceed two seconds for Category II localizers and one second for Category III localizers.
(7) Design and operation of the monitor system shall be consistent with the requirement that navigation guidance and identification will be removed and a warning provided at the designated remote-control points in the event of failure of the monitor system itself.
31. VHF localizer integrity and continuity of service requirements
(1) The probability of not radiating false guidance signals shall not be less than 1 – 0.5 x 109 ‘>in any one landing for Facility Performance Categories II and III localizers.
(2) The probability of not radiating false guidance signals shall not be less than 1 – 1.0 x 106′> in any one landing for Facility Performance Category I localizers.
(3) The probability of not losing the radiated guidance signal shall be greater than—
(a) 1 – 2 x 106′> in any period of 15 seconds for Facility Performance Category II localizers or localizers intended to be used for Category IIIA operations (equivalent to 2 000 hours mean time between outages); and
(b) 01 – 2 x 106′> in any period of 30 seconds for Facility Performance Category III localizers intended to be used for the full range of Category III operations (equivalent to 4000 hours mean time between outages).
(4) The probability of not losing the radiated guidance signal shall exceed 1 – 4 x 106′> in any period of 15 seconds for Facility Performance Category I localizers (equivalent to 1000 hours mean time between outages).
32. Interference immunity performance for ILS localizer receiving systems
(1) The ILS localizer receiving system shall provide adequate immunity to interference from two-signal, third order inter modulation products caused by VHF FM broadcast signals having levels in accordance with the following—
(2) The ILS localizer receiving system shall not be desensitised in the presence of VHF FM broadcast signals having levels in accordance with the following table—
| Maximum level of unwanted frequency signal at receiver input
|
|
| Frequency (MHz)
|
Maximum level of unwanted signal at receiver input (dBm)
|
| 88-102
|
+15
|
| 104
|
+10
|
| 106
|
+5
|
| 107.9
|
–10
|
(c) UHF Glide Path Equipment and Associated Monitor (regs 33-41)
33. UHF glide path and associated monitor specifications
(1) The specifications of the UHF glide path and associated monitor shall be as set out in the Schedule 3.
(2) The radiation from the UHF glide path antenna system shall produce a composite field pattern which is amplitude modulated by a—
(a) 90 Hz; and
(b) a 150 Hz tone.
(3) The composite field pattern shall—
(a) be arranged to provide a straight line descent path in the vertical plane containing the centre line of the runway;
(b) be the 150 Hz tone predominating below the path;
(c) and be 90 Hz tone predominating above the path to at least an angle equal to 1.75 q.
(4) The ILS glide path angle shall—
(a) be three degrees;
(b) ILS glide path angles in excess of three degrees shall not be used except where alternative means of satisfying obstruction clearance requirements are impracticable.
(5) The glide path angle shall be adjusted and maintained within—
(a) 0.075 q from q for Facility Performance Categories I and II – ILS glide paths;
(b) 0.04 q from q for Facility Performance Category III – ILS glide paths.
(6) The downward extended straight portion of the ILS glide path shall pass through the ILS reference datum at a height ensuring safe guidance over obstructions and also safe and efficient use of the runway served.
(7) The height of the ILS reference datum for Facility Performance Categories II and III – ILS shall be 15 m (50 ft) and a tolerance of plus 3 m (10 ft) is permitted.
(8) The height of the ILS reference datum for Facility Performance Category I – ILS shall be 15 m (50 ft). A tolerance of plus 3 m (10 ft) shall be permitted.
(9) The height of the ILS reference datum for Facility Performance Category I – ILS used on short precision approach runway codes 1 and 2 shall be 12 m (40 ft). A tolerance of plus 6 m (20 ft) is permitted.
34. UHF glide path radio frequency
(1) The glide path equipment shall operate in the band 328.6 MHz to 335.4 MHz where a single radio frequency carrier is used and the frequency tolerance shall not exceed 0.005 per cent.
(2) Where two carrier glide path systems 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 4 kHz nor more than 32 kHz.
(3) The emission from the glide path equipment shall be horizontally polarised.
(4) For Facility Performance Category III – ILS glide path equipment, signals emanating from the transmitter shall contain no components which result in apparent glide path fluctuations of more than 0.02 DDM peak to peak in the frequency band 0.01 Hz to 10 Hz.
(1) The glide path equipment shall provide signals sufficient to allow satisfactory operation of a typical aircraft installation in sectors of 8 degrees in azimuth on each side of the centre line of the ILS glide path, to a distance of at least 18.5 km (10 NM) up to 1.75 q and down to 0.45 q above the horizontal or to such lower angle, down to 0.30 q, as required to safeguard the promulgated glide path intercept procedure.
(2) In order to provide the coverage for glide path performance specified in subregulation (1)—
(a) the minimum field strength within this coverage sector shall be 400 microvolts per metre minus 95 dBW/m2; and
(b) for Facility Performance Category I glide paths, this field strength shall be provided down to a height of 30 m (100 ft) above the horizontal plane containing the threshold.
(3) For Facility Performance Categories II and III glide paths, the field strength shall be provided down to a height of 15 m (50 ft) above the horizontal plane containing the threshold.
(1) For Facility Performance Category I – ILS glide paths, bends in the glide path shall not have amplitudes which exceed the following—
| Zone
|
Amplitude (DDM) (95% probability)
|
| Outer limit of coverage to ILS Point “C”
|
0.035
|
(2) For Facility Performance Categories II and III — ILS glide paths, bends in the glide path shall not have amplitudes which exceed the following—
37. UHF glide path carrier modulation
(1) The nominal depth of modulation of the radio frequency carrier due to each of the 90 Hz and 150 Hz tones shall be 40 per cent along the ILS glide path.
(2) The depth of modulation shall not deviate outside the limits of 37.5 per cent to 42.5 per cent.
(3) The following tolerances shall be applied to the frequencies of the modulating tones—
(a) the modulating tones shall be 90 Hz and 150 Hz within 2.5 per cent for Facility Performance Category I – ILS;
(b) the modulating tones shall be 90 Hz and 150 Hz within 1.5 per cent for Facility Performance Category II – ILS;
(c) the modulating tones shall be 90 Hz and 150 Hz within one per cent for Facility Performance Category III – ILS;
(d) the total harmonic content of the 90 Hz tone shall not exceed 10 per cent and additionally and for Facility Performance Category III equipment, the second harmonic of the 90 Hz tone shall not exceed 5 per cent; and
(e) the total harmonic content of the 150 Hz tone shall not exceed 10 per cent.
(4) For Facility Performance Category I – ILS, the modulating tones shall be 90 Hz and 150 Hz within plus or minus 1.5 per cent where practicable.
(5) For Facility Performance Category III glide path equipment, the depth of amplitude modulation of the radio frequency carrier at the power supply frequency or harmonics, or at other noise frequencies, shall not exceed one per cent.
(6) The modulation shall be phase-locked so that within the ILS half glide path sector, the demodulated 90 Hz and 150 Hz wave forms pass through zero in the same direction—
(a) for Facility Performance Categories I and II – ILS glide paths: 20 degrees; and
(b) for Facility Performance Category III – ILS glide paths: 10 degrees, of phase relative to the 150 Hz component, every half cycle of the combined 90 Hz and 150 Hz wave form.
(7) With two-frequency glide path systems, subregulation (5) shall apply to each carrier and in addition, the 90 Hz modulating tone of one carrier shall be phase-locked to the 90 Hz modulating tone of the other carrier so that the demodulated wave forms pass through zero in the same direction—
(a) for Categories I and II – ILS glide paths: 20 degrees;
(b) for Category III – ILS glide paths: 10 degrees, of phase relative to 90 Hz; and
(c) similarly, the 150 Hz tones of the two carriers shall be phase-locked so that the demodulated wave forms pass through zero in the same direction—
(i) for Categories I and II – ILS glide paths: 20 degrees,
(ii) for Category III – ILS glide paths: 10 degrees, of phase relative to 150 Hz.
(8) The Authority may permit alternative two-frequency glide path systems that employ radio phasing, different from the normal in-phase condition described in subregulation (6).
(9) Where alternate two-frequency glide path systems are permitted, the 90 Hz to 90 Hz phasing and the 150 Hz to 150 Hz phasing shall be adjusted to their nominal values to within limits equivalent to those stated in subregulation (6).
(10) Undesired frequency and phase modulation on ILS glide path radio frequency carriers that can affect the displayed DDM values in glide path receivers shall be minimised to such an extent as is practical.
38. UHF glide path displacement sensitivity
(1) For Facility Performance Category I – ILS glide paths, the nominal angular displacement sensitivity shall correspond to a DDM of 0.0875 at angular displacements above and below the glide path between 0.07 q and 0.14 q.
(2) For Facility Performance Category II – ILS glide paths, the angular displacement sensitivity shall be as symmetrical as practicable and the nominal angular displacement sensitivity shall correspond to a DDM of 0.0875 at an angular displacement of—
(a) 0.12 q below path with a tolerance of plus or minus 0.02 q; and
(b) 0.12 q above path with a tolerance of plus 0.02 q and minus 0.05 q.
(3) For Facility Performance Category III – ILS glide paths—
(a) the nominal angular displacement sensitivity shall correspond to a DDM of 0.0875; and
(b) at angular displacements above and below the glide path of 0.12 q with a tolerance of plus or minus 0.02 q.
(4) The DDM below the ILS glide path shall increase smoothly for decreasing angle until a value of 0.22 DDM is reached.
(5) The value referred to in subregulation (4), shall be achieved at an angle not less than 0.30 q above the horizontal.
(6) If the DDM below the ILS glide path is achieved at an angle above 0.45 q, the DDM value shall—
(a) not be less than 0.22;
(b) at least down to 0.45 q or to such lower angle; and
(c) be down to 0.30 q, as required to safeguard the promulgated glide path intercept procedure.
(7) The angular displacement sensitivity shall be adjusted and maintained within plus or minus 25 per cent of the nominal value selected, for Facility Performance Category I – ILS glide paths.
(8) The angular displacement sensitivity shall be adjusted and maintained within plus or minus 20 per cent of the nominal value selected, for Facility Performance Category II – ILS glide paths.
(9) The angular displacement sensitivity shall be adjusted and maintained within plus or minus 15 per cent of the nominal value selected, for Facility Performance Category III – ILS glide paths.
(1) The automatic monitor system shall provide a warning to the designated control points and cause radiation to cease within the periods specified in subregulation (4) if any of the following conditions persist—
(a) shift of the mean ILS glide path angle equivalent to more than minus 0.075 q to plus 0.10 q from q;
(b) in the case of ILS glide paths in which the basic functions are provided by the use of a single-frequency system, a reduction of power output to less than 50 per cent of normal:
Provided the glide path continues to meet the requirements of regulations 35, 36 and 37;
(c) the case of ILS glide paths in which the basic functions are provided by the use of two-frequency systems, a reduction of power output for either carrier to less than 80 per cent of normal, except that a greater reduction to between 80 per cent and 50 per cent of normal may be permitted: provided the glide path continues to meet the requirements of regulations 35, 36 and 37;
(d) for Facility Performance Category I – ILS glide paths. A change of the angle between the glide path and the line below the glide path (150 Hz predominating), at which a DDM of 0.0875 is realised by more than the greater of—
(i) plus, or minus 0.0375 q, or
(ii) an angle equivalent to a change of displacement sensitivity to a value differing by 25 per cent from the nominal value;
(e) for Facility Performance Categories II and III – ILS glide paths, a change of displacement sensitivity to a value differing by more than 25 per cent from the nominal value;
(f) lowering of the line beneath the ILS glide path at which a DDM of 0.0875 is realised to less than 0.7475 q from horizontal; and
(g) a reduction of DDM to less than 0.175 within the specified coverage below the glide path sector.
(2) Monitoring of the ILS glide path characteristics to smaller tolerances shall be arranged in those cases where operational penalties would otherwise exist.
(3) The total period of radiation, including period(s) of zero radiation, outside the performance limits specified in subregulation (1) shall be as short as practicable, consistent with the need for avoiding interruptions of the navigation service provided by the ILS glide path.
(4) The total period referred to under subregulation (3), shall not exceed under any circumstances—
(a) six seconds for Category I — ILS glide paths; and
(b) two seconds for Categories II and III — ILS glide paths.
(5) Where practicable, the total period specified under subregulation (4) for Categories II and III — ILS glide paths, shall not exceed one second.
(6) Design and operation of the monitor system shall be consistent with the requirement that radiation shall cease and a warning shall be provided at the designated remote-control points, in the event of failure of the monitor system.
40. UHF glide path integrity and continuity of service requirements
(1) The probability of not radiating false guidance signals shall not be less than 1 – 0.5 x 109′>, in any one landing for Facility Performance Categories II and III glide paths.
(2) The probability of not radiating false guidance signals shall not be less than 1 – 1.0 x 107′> in any one landing for Facility Performance Category I glide paths.
(3) The probability of not losing the radiated guidance signal shall be greater than 1 – 2 x 107′>, in any period of 15 seconds for Facility Performance Categories II and III glide paths (equivalent to 2 000 hours mean time between outages).
(4) The probability of not losing the radiated guidance signal, shall exceed 1 – 4 x 106′> in any period of 15 seconds for Facility Performance Category I glide paths (equivalent to 1 000 hours mean time between outages).
41. Localizer and glide path frequency pairing
(1) The pairing of the runway localizer and glide path transmitter frequencies of an instrument landing system shall be taken from the following list in accordance with regulation 35 and the provisions of Statutory Instrument No. 44 Civil Aviation (Radio Frequency Spectrum Utilisation) Regulations, 2022 (S.I. No. 44 of 2022).
|
Localizer |
Glide path |
Localizer |
Glide path |
|
108.1 |
334.7 |
110.1 |
334.4 |
|
108.15 |
334.55 |
110.15 |
334.25 |
|
108.3 |
334.1 |
110.3 |
335.0 |
|
108.35 |
333.95 |
110.35 |
334.85 |
|
108.5 |
329.9 |
110.5 |
329.6 |
|
108.55 |
329.75 |
110.55 |
329.45 |
|
108.7 |
330.5 |
110.7 |
330.2 |
|
108.75 |
330.35 |
110.75 |
330.05 |
|
108.9 |
329.3 |
110.9 |
330.8 |
|
108.95 |
329.15 |
110.95 |
330.65 |
|
109.1 |
331.4 |
111.1 |
331.7 |
|
109.15 |
331.25 |
111.15 |
331.55 |
|
109.3 |
332.0 |
111.3 |
332.3 |
|
109.35 |
331.85 |
111.35 |
332.15 |
|
109.5 |
332.6 |
111.5 |
332.9 |
|
109.55 |
332.45 |
111.55 |
332.75 |
|
109.7 |
333.2 |
111.7 |
333.5 |
|
109.75 |
333.05 |
111.75 |
333.35 |
|
109.9 |
333.8 |
111.9 |
331.1 |
|
109.95 |
333.65 |
111.95 |
330.95 |
(2) In those regions where the requirements for runway localizer and glide path transmitter frequencies of an instrument landing system do not justify more than 20 pairs, they shall be selected sequentially, as required, from the following list—
|
Sequence number |
Localizer |
Glide path |
|
1 |
110.3 |
335.0 |
|
2 |
109.9 |
333.8 |
|
3 |
109.5 |
332.6 |
|
4 |
110.1 |
334.4 |
|
5 |
109.7 |
333.2 |
|
6 |
109.3 |
332.0 |
|
7 |
109.1 |
331.4 |
|
8 |
110.9 |
330.8 |
|
9 |
110.7 |
330.2 |
|
10 |
110.5 |
329.6 |
|
11 |
108.1 |
334.7 |
|
12 |
108.3 |
334.1 |
|
13 |
108.5 |
329.9 |
|
14 |
108.7 |
330.5 |
|
15 |
108.9 |
329.3 |
|
16 |
111.1 |
331.7 |
|
17 |
111.3 |
332.3 |
|
18 |
111.5 |
332.9 |
|
19 |
111.7 |
333.5 |
|
20 |
111.9 |
331.1 |
(3) Where existing ILS localizers meeting national requirements are operating on frequencies ending in even tenths of a megahertz, they shall be reassigned frequencies, conforming with regulation 41 or subregulation (2) as soon as practicable and may continue operating on their present assignments only until this reassignment can be effected.
(4) Existing ILS localizers in the international service operating on frequencies ending in odd tenths of a megahertz shall—
(a) not be assigned new frequencies ending in odd tenths plus one-twentieth of a megahertz; and
(b) where, by regional agreement, general use may be made of any of the channels listed in regulation 41 of the Civil Aviation (Radio Frequency Spectrum Utilisation) Regulations, 2020.
(d) VHF Marker Beacon (regs 42-48)
(1) There shall be two marker beacons in each installation except where, in the opinion of the Authority, a single marker beacon is considered to be sufficient.
(2) A third marker beacon may be added whenever, in the opinion of the Authority, an additional beacon is required because of operational procedures at a particular site.
(3) A marker beacon shall conform to the requirements prescribed in regulations 15 to 19 of these Regulations.
(4) Where the installation comprises only two marker beacon, the requirements applicable to the middle marker and to the outer marker shall be complied with.
(5) Where the installation comprises only one marker beacon, the requirements applicable to either the middle or the outer marker shall be complied with and if marker beacons are replaced by DME, the requirements of regulation 47(10) shall apply.
(6) The marker beacons shall produce radiation patterns to indicate predetermined distance from the threshold along the ILS glide path.
(7) Where a marker beacon is used in conjunction with the back course of a localizer, it shall conform to the marker beacon characteristics specified in regulations 15 to 19 of these Regulations.
(8) Identification signals of marker beacons used in conjunction with the back course of a localizer shall be clearly distinguishable from the inner, middle and outer marker beacon identifications, as prescribed in regulation 46.
43. VHF marker radio frequency
The marker beacons shall operate at 75 MHz with a frequency tolerance of plus or minus 0.005 per cent and shall utilise horizontal polarisation.
The marker beacon system shall be adjusted to provide coverage over the following distances, measured on the ILS glide path and localizer course line—
(a) inner marker: 150 m plus or minus 50 m (500 ft plus or minus 160 ft);
(b) middle marker: 300 m plus or minus 100 m (1 000 ft plus or minus 325 ft); and
(c) outer marker: 600 m plus or minus 200 m (2 000 ft plus or minus 650 ft).
(1) The modulation frequencies shall be as follows—
(a) inner marker: 3 000 Hz;
(b) middle marker: 1 300 Hz; and
(c) outer marker: 400 Hz.
(2) The frequency tolerance of the above frequencies shall be plus or minus 2.5 per cent, and the total harmonic content of each of the frequencies shall not exceed 15 per cent.
(3) The depth of modulation of the markers shall be 95 per cent plus or minus 4 per cent.
A carrier energy shall not be interrupted and the audio frequency modulation shall be keyed as follows—
(a) inner marker: six dots per second continuously;
(b) middle marker: a continuous series of alternate dots and dashes, the dashes keyed at the rate of two dashes per second, and the dots at the rate of six dots per second; and
(c) outer marker: two dashes per second continuously.
These keying rates shall be maintained to within plus or minus 15 per cent.
(1) An inner marker shall be located so as to indicate in low visibility conditions the imminence of arrival at the runway threshold.
(2) If the radiation pattern is vertical, the inner marker, when installed, shall be located between 75 m (250 ft) and 450 m (1 500 ft) from the threshold and at not more than 30 m (100 ft) from the extended centre line of the runway.
(3) If the radiation pattern is other than vertical, the equipment shall be located so as to produce a field within the course sector and ILS glide path sector that is substantially similar to that produced by an antenna radiating a vertical pattern and located as prescribed in subregulation (2).
(4) The middle marker shall be located so as to indicate the imminence, in low visibility conditions, of visual approach guidance.
(5) Where the radiation pattern is vertical, the middle marker shall be located 1050 m (3 500 ft) plus or minus 150 m (500 ft), from the landing threshold at the approach end of the runway and at not more than 75 m (250 ft) from the extended centre line of the runway.
(6) Where the radiation pattern is other than vertical, the equipment shall be located so as to produce a field within the course sector and ILS glide path sector that is substantially similar to that produced by an antenna radiating a vertical pattern and located as prescribed in subregulation (5).
(7) The outer marker shall be located so as to provide height, distance and equipment functioning checks to aircraft on intermediate and final approach.
(8) The outer marker shall be located 7.2 km (3.9 NM) from the threshold except that, where for topographical or operational reasons this distance is not practicable, the outer marker may be located between 6.5 and 11.1 km (3.5 and 6 NM) from the threshold.
(9) Where the radiation pattern is vertical, the outer marker shall not be more than 75 m (250 ft) from the extended centre line of the runway.
(10) Where the radiation pattern is not vertical, the equipment shall—
(a) be located so as to produce a field within the course sector; and
(b) shall have an ILS glide path sector that is substantially similar to that produced by an antenna radiating a vertical pattern.
(11) The positions of marker beacons, or where applicable, the equivalent distance(s) indicated by the DME when used as an alternative to part or all of the marker beacon component of the ILS shall be published in accordance with the provisions of Civil Aviation (Aeronautical Information Services) Regulations, 2020.
(12) When so used, the DME shall provide distance information operationally equivalent to that furnished by marker beacon(s).
(13) When used as an alternative for the middle marker, the DME shall be frequency paired with the ILS localizer and sited so as to minimise the error in distance information.
(14) The DME referred to in subregulation (10) shall conform to the specification in regulations 71 to 81.
(1) Suitable equipment shall provide signals for the operation of an automatic monitor and the monitor shall transmit a warning to a control point if either of the following conditions arise—
(a) failure of the modulation or keying; and
(b) reduction of power output to less than 50 per cent of normal.
(2) For each marker beacon, suitable monitoring equipment shall be provided which will indicate at the appropriate location a decrease of the modulation depth below 50 per cent.
(e) Specification for Precision Approach Radar System (reg 49)
49. Specification for 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 PAR only is used, the installation shall be identified by the term PAR or precision approach radar and not by the term “precision approach radar system”.
(f) The Precision Approach Radar Element (PAR) (regs 50-52)
The PAR shall be capable of detecting and indicating the position of an aircraft of 15 m2′> echoing area or larger, which is within a space bounded by a 20-degree azimuth sector and a 7-degree elevation sector, to a distance of at least 16.7 km (9 NM) from its respective antenna.
The PAR shall be sited and adjusted so that it gives complete coverage of a sector with its apex at a point 150 m (500 ft) from the touchdown in the direction of the stop end of the runway and extending plus or minus 5 degrees about the runway centre line in azimuth and from minus 1 degree to plus 6 degrees in elevation.
(1) Azimuth information shall be displayed in such a manner that—
(a) left-right deviation from the on-course line shall be easily observable;
(b) the maximum permissible error with respect to the deviation from the on-course line shall be either 0.6 per cent of the distance from the PAR antenna plus 10 per cent of the deviation from the on-course line or 9 m (30 ft), whichever is greater;
(c) the equipment shall be so sited that the error at the touchdown shall not exceed 9 m (30 ft) and the equipment shall be so aligned and adjusted that the displayed error at the touchdown shall be a minimum and shall not exceed 0.3 per cent of the distance from the PAR antenna or 4.5 m (15 ft), whichever is greater; and
(d) it shall be possible to resolve the positions of two aircraft which are at 1.2 degrees in azimuth of one another.
(2) Elevation information shall be displayed in such a manner that—
(a) up-down deviation from the descent path for which the equipment is set shall be easily observable;
(b) the maximum permissible error with respect to the deviation from the on-course line shall be 0.4 per cent of the distance from the PAR antenna plus 10 per cent of the actual linear displacement from the chosen descent path or 6 m (20 ft), whichever is greater;
(c) the equipment shall be so sited that the error at the touchdown shall not exceed 6 m (20 ft) and the equipment shall be so aligned and adjusted that the displayed error at the touchdown shall be a minimum and shall not exceed 0.2 per cent of the distance from the PAR antenna or 3 m (10 ft), whichever is greater; and
(d) it shall be possible to resolve the positions of two aircraft that are at 0.6 degree in elevation of one another.
(3) The error in indication of the distance from the touchdown shall—
(a) not exceed 30 m (100 ft) plus three per cent of the distance from the touchdown; and
(b) be possible to resolve the positions of two aircraft which are at 120 m (400 ft) of one another on the same azimuth.
(4) Information shall—
(a) be made available to permit the position of the controlled aircraft to be established with respect to other aircraft and obstructions;
(b) also permit appreciation of ground speed and rate of departure from or approach to the desired flight path; and
(c) be completely renewed at least once every second.
(g) The Surveillance Radar Element (SRE) (regs 53-55)
53. The Surveillance Radar Element (SRE)
A surveillance radar used as the SRE of a precision approach radar system shall satisfy at least the following broad performance requirements.
(1) The SRE shall be capable of detecting aircraft of 15m2′> echoing area and larger, which are in line of sight of the antenna within a volume described as follows—
The rotation through 360 degrees about the antenna of a vertical plane surface bounded by a line at an angle of 0.5 degrees above the horizontal plane of the antenna, extending from the antenna to 46.3 km (25 NM)—
(a) by a vertical line at 46.3 km (25 NM) from the intersection with the 0.5-degree line up to 3 000 m (10 000 ft) above the level of the antenna;
(b) by a horizontal line at 3 000 m (10 000 ft) from 46.3 km (25 NM) back towards the antenna to the intersection with a line from the antenna at 20 degrees above the horizontal plane of the antenna; and
(c) and by a 30-degree line from the intersection with the 3 000 m (10 000 ft) line to the antenna.
(1) The indication of position in azimuth shall—
(a) be within plus or minus two degrees of the true position; and
(b) be possible to resolve the positions of two aircraft which are at four degrees of azimuth of one another.
(2) The error in distance indication shall—
(a) not exceed five per cent of true distance or 150 m (500 ft), whichever is the greater; and
(b) shall be possible to resolve the positions of two aircraft that are separated by a distance of one per cent of the true distance from the point of observation or 230 m (750 ft), whichever is the greater.
(3) The error in distance indication shall not exceed three per cent of the true distance or 150 m (500 ft), whichever is the greater.
(4) The equipment shall be capable of completely renewing the information concerning the distance and azimuth of any aircraft within the coverage of the equipment at least once every four seconds.
(5) Efforts shall be made to reduce, as far as possible, the disturbance caused by ground echoes or echoes from clouds and precipitation.
(h) Specification for VHF Omnidirectional Radio Range (VOR) (regs 56-63)
56. VHF omnidirectional radio range (VOR)
(1) The VOR shall—
(a) be constructed and adjusted so that similar instrumental indications in aircraft represent equal clockwise angular deviations (bearings), degree for degree from magnetic North as measured from the location of the VOR; and
(b) radiate a radio frequency carrier with which are associated two separate 30 Hz modulations.
(2) Subject to subregulation (1)—
(a) these modulations shall be such that its phase is independent of the azimuth of the point of observation (reference phase); and
(b) the other modulation (variable phase) shall be such that its phase at the point of observation differs from that of the reference phase by an angle equal to the bearing of the point of observation with respect to the VOR.
(1) The VOR shall—
(a) operate in the band 111.975 MHz to 117.975 MHz; and
(b) operate in frequencies in the band 108 MHz to 111.975 MHz in accordance with the provisions of the Civil Aviation (Radio Frequency Spectrum Utilisation) Regulations, regulations 35 and 36(4).
(2) The highest assignable frequency shall—
(a) be 117.950 MHz and the channel separation shall be in increments of 50 kHz referred to the highest assignable frequency; and
(b) in areas where 100 kHz or 200 kHz channel spacing is in general use, the frequency tolerance of the radio frequency carrier shall be plus or minus 0.005 per cent.
(3) The frequency tolerance of the radio frequency carrier of all new installations implemented after 23 May 1974 in areas where 50 kHz channel spacing is in use, shall be plus or minus 0.002 per cent.
(4) In areas where new VOR installations are implemented and are assigned frequencies spaced at 50 kHz from existing VORs in the same area, priority shall be given to ensuring that the frequency tolerance of the radio frequency carrier of the existing VORs is reduced to plus or minus 0.002 per cent.
58. VOR polarisation and pattern accuracy
(1) The emission from the VOR shall—
(a) be horizontally polarised; and
(b) the vertically polarised component of the radiation shall be as small as possible.
(2) The ground station contribution to the error in the bearing information conveyed by the horizontally polarised radiation from the VOR for all elevation angles between 0 and 40 degrees, measured from the centre of the VOR antenna system, shall be within plus or minus 2 degrees.
(1) The VOR shall provide signals such as to permit satisfactory operation of a typical aircraft installation at the levels and distances required for operational reasons, and up to an elevation angle of 40 degrees.
(2) The field strength or power density in space of VOR signals required to permit satisfactory operation of a typical aircraft installation at the minimum service level at the maximum specified service radius shall be 90 microvolts per metre or minus 107 dBW/m2′>.
60. VOR modulations of navigation signals
(1) The radio frequency carrier as observed at any point in space shall be amplitude modulated by two signals as follows—
(a) subcarrier of 9 960 Hz of constant amplitude, frequency modulated at 30 Hz—
(i) for the conventional VOR, the 30 Hz component of this FM subcarrier is fixed without respect to azimuth and is termed the “reference phase” and shall have a deviation ratio of 16 plus or minus 1, and
(ii) for the Doppler VOR, the phase of the 30 Hz component varies with azimuth and is termed the “variable phase” and shall have a deviation ratio of 16 plus or minus 1 when observed at any angle of elevation up to 5 degrees, with a minimum deviation ratio of 11 when observed at any angle of elevation above 5 degrees and up to 40 degrees; and
(b) a 30 Hz amplitude modulation component—
(i) for the conventional VOR, this component results from a rotating field pattern, the phase of which varies with azimuth, and is termed the “variable phase”, and
(ii) for the Doppler VOR, this component, of constant phase with relation to azimuth and constant amplitude, is radiated omnidirectionally and is termed the “reference phase”.
(2) The nominal depth of modulation of the radio frequency carrier due to the 30 Hz signal or the subcarrier of 9 960 Hz shall be within the limits of 28 per cent and 32 per cent.
(3) The depth of modulation of the radio frequency carrier due to the 30 Hz signal, as observed at any angle of elevation up to five degrees, shall be within the limits of 25 to 35 per cent.
(4) The depth of modulation of the radio frequency carrier due to the 9 960 Hz signal, as observed at any angle of elevation up to five degrees, shall be within the limits of 20 to 55 per cent on facilities without voice modulation, and within the limits of 20 to 35 per cent on facilities with voice modulation.
(5) The variable and reference phase modulation frequencies shall be 30 Hz within plus or minus one per cent.
(6) The subcarrier modulation mid-frequency shall be 9 960 Hz within plus or minus one per cent.
(7) Percentage of amplitude modulation for the—
(a) the conventional VOR, the percentage of amplitude modulation of the 9 960 Hz subcarrier shall not exceed five per cent;
(b) Doppler VOR, the percentage of amplitude modulation of the 9960 Hz subcarrier shall not exceed 40 per cent when measured at a point at least 300 m (1 000 ft) from the VOR.
(8) Where 50 kHz VOR channel spacing is implemented, the sideband level of the harmonics of the 9 960 Hz component in the radiated signal shall not exceed the following levels referred to the level of the 9 960 Hz sideband—
61. VOR voice and identification
(1) Where the VOR provides a simultaneous communication channel ground-to-air, it shall be on the same radio frequency carrier as used for the navigational function.
(2) The radiation on the simultaneous communications channel shall be horizontally polarised.
(3) The peak modulation depth of the carrier on the simultaneous communication channel shall not be greater than 30 per cent.
(4) The audio frequency characteristics of the speech channel shall be within 3 dB relative to the level at 1000 Hz over the range 300 Hz to 3000 Hz.
(5) The VOR shall provide for the simultaneous transmission of a signal of identification on the same radio frequency carrier as that used for the navigational function.
(6) The identification signal radiation shall—
(a) be horizontally polarised; and
(b) the identification signal shall employ the International Morse Code and consist of two or three letters and shall be sent at a speed corresponding to approximately seven words per minute.
(7) The identification signal shall be repeated at least once every 30 seconds and the modulation tone shall be 1020 Hz within plus or minus 50 Hz.
(8) The identification signal shall be transmitted at least three times each 30 seconds, spaced equally within that time period.
(9) One of these identification signals may take the form of a voice identification.
(10) The depth to which the radio frequency carrier is modulated by the code identification signal shall be close to, but not in excess of 10 per cent:
Provided that, where a communication channel is not provided, it shall be permissible to increase the modulation by the code identification signal to a value not exceeding 20 per cent.
(11) Where the VOR provides a simultaneous communication channel ground-to-air, the modulation depth of the code identification signal shall be five plus or minus one per cent in order to provide a satisfactory voice quality.
(12) The transmission of speech shall—
(a) not interfere in any way with the basic navigational function; and
(b) when speech is being radiated, the code identification shall not be suppressed.
(13) The VOR receiving function shall permit positive identification of the wanted signal under the signal conditions encountered within the specified coverage limits, and with the modulation parameters specified at subregulations (5), (6) and (7).
(1) Suitable equipment located in the radiation field shall provide signals for the operation of an automatic monitor.
(2) The monitor shall transmit a warning to a control point, and either remove the identification and navigation components from the carrier or cause radiation to cease if any one or a combination of the following deviations from established conditions arises—
(a) change in excess of one degree at the monitor site of the bearing information transmitted by the VOR; and
(b) a reduction of 15 per cent in the modulation components of the radio frequency signals voltage level at the monitor of either the subcarrier, or 30 Hz amplitude modulation signals, or both.
(3) Failure of the monitor itself shall transmit a warning to a control point and either—
(a) remove the identification and navigation components from the carrier; or
(b) cause radiation to cease.
63. Interference immunity performance for VOR receiving systems
(1) The VOR receiving system shall provide adequate immunity to interference from two signal, third-order intermodulation products caused by VHF FM broadcast signals having levels in accordance with the following—
for VHF FM sound broadcasting signals below 107.7 MHz.
(2) Where the frequencies of the two VHF FM sound broadcasting signals produce, within the receiver, a two signal, third-order intermodulation product on the desired VOR frequency.
(3) N2′> are the levels (dBm) of the two VHF FM sound broadcasting signals at the VOR receiver input and neither level shall exceed the desensitisation criteria set forth in subregulation (2).
(4) Df = 108.1 – f1′>, where f1′> is the frequency of N1′>, the VHF FM sound broadcasting signal closer to 108.1 MHz.
(5) The VOR receiving system shall not be desensitised in the presence of VHF FM broadcast signals having levels in accordance with the following table—
| Frequency (MHz)
|
Maximum level of unwanted signal at receiver input (dBm)
|
| 88-102
|
+15
|
| 104
|
+10
|
| 106
|
+5
|
| 107.9
|
–10
|
(i) Specification for Non-directional Radio Beacon (NDB) (regs 64-70)
(1) The minimum value of field strength in the rated coverage of an NDB shall be 70 microvolts per metre.
(2) All notifications or promulgations of NDBs shall be based upon the average radius of the rated coverage.
(3) Where the rated coverage of an NDB is materially different in various operationally significant sectors, its classification shall be expressed in terms of the average radius of rated coverage and the angular limits of each sector as follows—
(a) radius of coverage of sector/angular limits of sector expressed as magnetic bearing clockwise from the beacon; and
(b) where it is desirable to classify an NDB in such a manner, the number of sectors shall be kept to a minimum and preferably shall not exceed two.
65. NDB limitations in radiated power
The power radiated from an NDB shall not exceed by more than 2 dB than necessary to achieve its agreed rated coverage, except that this power may be increased if co-ordinated regionally or if no harmful interference to other facilities will result.
(1) The radio frequencies assigned to NDBs shall be selected from those available in that portion of the spectrum between 190 kHz and 1 750 kHz.
(2) The frequency tolerance applicable to NDBs shall be 0.01 per cent except that, for NDBs of antenna power above 200 W using frequencies of 1 606.5 kHz and above, the tolerance shall be 0.005 per cent.
(3) Where two locators are used as supplements to an ILS, the frequency separation between the carriers of the two shall be not less than 15 kHz to ensure correct operation of the radio compass, and preferably not more than 25 kHz in order to permit a quick tuning shift in cases where an aircraft has only one radio compass.
(4) Where locators associated with ILS facilities serving opposite ends of a single runway are assigned a common frequency, provision shall be made to ensure that the facility not in operational use cannot radiate.
(1) Each NDB shall be individually identified by a two or three letter International Morse Code group transmitted at a rate corresponding to approximately seven words per minute.
(2) The complete identification shall be transmitted at least once every 30 or so seconds.
(3) Where the beacon is effected by on and off keying of the carrier the identification shall—
(a) be at approximately one minute intervals; or
(b) except that a shorter interval may be used at particular NDB stations where this is found to be operationally desirable; and
(c) except for those cases where the beacon identification is effected by on/off keying of the carrier, the identification signal shall be transmitted at least three times each 30 seconds, spaced equally within that time period.
(4) —
(1) For NDBs with an average radius of rated coverage of 92.7 km (50 NM) or less that are primarily approaches and holding aids in the vicinity of an aerodrome.
(2) The identification shall—
(a) be transmitted at least three times each 30 seconds; and
(b) spaced equally within that time period.
(5) The frequency of the modulating tone used for identification shall be 1020 Hz plus or minus 50 Hz or 400 Hz plus or minus 25 Hz.
68. NDB characteristics of emissions
(1) Except as provided in subregulation (2), all NDBs shall radiate an uninterrupted carrier and be identified by on/off keying of an amplitude modulating tone (NON/A2A).
(2) NDBs other than those wholly or partly serving as holding, approach and landing aids, or those having an average radius of rated coverage of less than 92.7 km (50 NM), may be identified by on and off keying of the unmodulated carrier (NON/A1A) if they are in areas of high beacon density or where the required rated coverage is not practicable of achievement because of—
(a) radio interference from radio stations;
(b) high atmospheric noise; and
(c) local conditions.
(3) For each NDB identified by on/off keying of an audio modulating tone, the depth of modulation shall be maintained as near to 95 per cent as practicable.
(4) For each NDB identified by on/off keying of an audio modulating tone, the characteristics of emission during identification shall be such as to ensure satisfactory identification at the limit of its rated coverage.
(5) The carrier power of an NDB with NON/A2A emissions shall not fall when the identity signal is being radiated except that, in the case of an NDB having an average radius of rated coverage exceeding 92.7 km (50 NM), a fall of not more than 1.5 dB may be accepted.
(6) Unwanted audio frequency modulations shall total less than five per cent of the amplitude of the carrier.
(7) The bandwidth of emissions and the level of spurious emissions shall be kept at the lowest value that the state of technique and the nature of the service permit.
(1) Where locators are used as a supplement to the ILS, they shall—
(a) be located at the sites of the outer and middle marker beacons; and
(b) where only one locator is used as a supplement to the ILS, preference shall be given to location at the site of the outer marker beacon.
(2) Where locators are employed as an aid to final approach in the absence of an ILS, equivalent locations to those applying when an ILS is installed shall be selected, taking into account the relevant obstacle clearance provisions of the PANS-OPS (ICAO Doc 8168 – Aircraft Operations).
(3) Where locators are installed at both the middle and outer marker positions, they shall be located, where practicable, on the same side of the extended centre line of the runway in order to provide a track between the locators which will be more nearly parallel to the centre line of the runway.
(1) For each NDB, suitable means shall be provided to enable detection of any of the following conditions at an appropriate location—
(a) a decrease in radiated carrier power of more than 50 per cent below that required for the rated coverage;
(b) failure to transmit the identification signal; and
(c) malfunctioning or failure of the means of monitoring itself.
(2) Where—
(a) an NDB is operated from a power source having a frequency which is close to airborne ADF equipment switching frequencies; and
(b) the design of the NDB is such that the power supply frequency is likely to appear as a modulation product on the emission.
(3) Subject to subregulation (2) the means of monitoring shall be capable of detecting such power supply modulation on the carrier in excess of five per cent.
(4) During the hours of service of a locator, the means of monitoring shall provide for a continuous check on the functioning of the locator as prescribed in subregulation (1).
(5) During the hours of service of an NDB other than a locator, the means of monitoring shall provide for a continuous check on the functioning of the NDB as prescribed in subregulation (1).
(j) Specification for UHF Distance Measuring Equipment (DME) (regs 71-81)
71. UHF distance measuring equipment
(1) The DME system shall provide for continuous and accurate indication in the cockpit of the slant range distance of an equipped aircraft from an equipped ground reference point.
(2) The system shall comprise two basic components, one fitted in the aircraft and the other installed on the ground.
(3) The aircraft component shall be referred to as the interrogator and the ground component as the transponder.
(4) In operation, interrogators shall interrogate transponders which shall, in turn, transmit to the interrogator replies synchronised with the interrogations, thus providing means for accurate measurement of distance.
(5) When a DME is associated with an ILS or VOR for the purpose of constituting a single facility, they shall—
(a) be operated on a standard frequency pairing in accordance with regulation 78(3);
(b) be collocated within the limits prescribed for associated facilities in subregulation (5) and (6); and
(c) comply with the identification provisions of regulation 81(4).
(6) Associated VOR and DME facilities shall be collocated in accordance with the following—
(a) for those facilities used in terminal areas for approach purposes or other procedures where the highest position fixing accuracy of system capability is required, the separation of the VOR and DME antennas does not exceed 80 m (260 ft); and
(b) for purposes other than those indicated in (a), the separation of the VOR and DME antennas does not exceed 600 m (2 000 ft).
72. Association of DME with ILS
The association of DME with ILS shall be in accordance with the guidelines set out in ICAO Annex 10, Volume 1, Attachment C, section 2.11.
The system shall provide a means of measurement of slant range distance from an aircraft to a selected transponder to the limit of coverage prescribed by the operational requirements for the selected transponder.
(1) When associated with a VOR, DME/N coverage shall be at least that of the VOR to the extent practicable.
(2) When associated with an ILS, DME/N coverage shall be at least that of the respective ILS guidance coverage sectors.
(1) The accuracy standards specified in regulations 97 and 110 shall be met on a 95 per cent probability basis.
(2) The path following error (PFE) shall be comprised of those frequency components of the DME/P error at the output of the interrogator which lie below 1.5 rad/s.
(3) The control motion noise (CMN) shall be comprised of those frequency components of the DME/P error at the output of the interrogator which lie between 0.5 rad/s and 10 rad/s.
(4) Errors on the extended runway centre line shall not exceed the values given in Table B under Schedule 2.
76. UHF DME radio frequencies and polarisation
The system shall operate with vertical polarisation in the frequency band 960 MHz to 1 215 MHz and the interrogation and reply frequencies shall be assigned with 1 MHz spacing between channels.
(1) DME operating channels shall be formed by pairing interrogation and reply frequencies and by pulse coding on the paired frequencies.
(2) DME operating channels shall be chosen from Table A under Schedule 2 of 352 channels in which the channel numbers, frequencies, and pulse codes are assigned.
(3) Where a DME transponder is intended to operate in association with a single VHF navigation facility in the 108 MHz to 117.95 MHz frequency band, the DME operating channel shall be paired with the VHF channel as given in Table A order Schedule 2.
78. UHF DME interrogation pulse repetition frequency
(1) The interrogator average pulse repetition frequency (PRF) shall not exceed 30 pairs of pulses per second, based on the assumption that at least 95 per cent of the time is occupied for tracking.
(2) If it is desired to decrease the time of search, the PRF may be increased during search but shall not exceed 150 pairs of pulses per second.
(3) After 15 000 pairs of pulses have been transmitted without acquiring indication of distance, the PRF shall not exceed 60 pairs of pulses per second thereafter, until a change in operating channel is made or a successful search is completed.
(4) Where, after a time period of 30 seconds, tracking has not been established, the pulse pair repetition frequency shall not exceed 30 pulse pairs per second thereafter.
79. UHF DME aircraft handling capacity of system
(1) The aircraft handling capacity of transponders in an area shall be adequate for the peak traffic of the area or 100 aircraft, whichever is the lesser.
(2) Where the peak traffic in an area exceeds 100 aircraft, the transponder shall be capable of handling that peak traffic.
80. UHF DME transponder identification
(1) A transponder shall transmit an identification signal in one of the following forms as required by regulation 82—
(a) an “independent” identification consisting of coded (International Morse Code) identity pulses which can be used with all transponders; and
(b) an “associated” signal which can be used for transponders specifically associated with a VHF navigation facility which itself transmits an identification signal.
(2) Both systems of identification shall use signals, which shall consist of the transmission for an appropriate period of a series of paired pulses transmitted at a repetition rate of 1 350 pulse pairs per second, and shall temporarily replace all reply pulses that would normally occur at that time, except as in paragraph (b).
(3) The pulse referred to under subregulation (2), shall have similar characteristics to the other pulses of the reply signals in the following manner—
(a) reply pulses shall be transmitted between key down times; and
(b) if it is desired to preserve a constant duty cycle, an equalising pair of pulses, having the same characteristics as the identification pulse pairs, shall be transmitted 100 microseconds plus or minus 10 microseconds after each identity pair.
(4) The characteristics of the “independent” identification signal shall be as follows—
(a) the identity signal shall consist of the transmission of the beacon code in the form of dots and dashes (International Morse Code) of identity pulses at least once every 40 seconds, at a rate of at least 6 words per minute;
(b) the identification code characteristic and letter rate for the DME transponder shall conform to the following to ensure that the maximum total key down time does not exceed six seconds per identification code group;
(c) the dots shall be a time duration of 0.1 second to 0.160 second. The dashes shall be typically three times the duration of the dots and the duration between dots and/or dashes shall be equal to that of one dot plus or minus 10 per cent; and
(d) the time duration between letters or numerals shall not be less than three dots and the total period for transmission of an identification code group shall not exceed 10 seconds.
(5) The characteristics of the “associated” signal shall be as follows—
(a) where associated with a VHF facility, the identification shall be transmitted in the form of dots and dashes (International Morse Code) as in subregulation (3) and shall be synchronised with the VHF facility identification code; and
(b) each 40-second interval shall be divided into four or more equal periods, with the transponder identification transmitted during one period only and the associated VHF facility identification, where these are provided, transmitted during the remaining periods.
81. UHF DME identification implementation
(1) The “independent” identification code shall be employed wherever a transponder is not specifically associated with a VHF navigational facility.
(2) Wherever a transponder is specifically associated with a VHF navigational facility, identification shall be provided by the “associated” code.
(3) Where voice communications are being radiated on an associated VHF navigational facility, an “associated” signal from the transponder shall not be suppressed.
(k) Characteristics of Transponder and Associated Monitor (regs 82-98)
82. DME transponder transmission component
(1) The transponder shall transmit on the reply frequency appropriate to the assigned DME channel.
(2) The radio frequency of operation shall not vary more than plus or minus 0.002 per cent from the assigned frequency.
(3) The following shall apply to all radiated pulses—
(a) pulse rise time shall not exceed three microseconds;
(b) pulse duration shall be 3.5 microseconds plus or minus 0.5 microsecond;
(c) pulse decay time shall nominally be 2.5 microseconds but shall not exceed 3.5 microseconds;
(d) the instantaneous amplitude of the pulse shall not, at any instant between the point of the leading edge which is 95 per cent of maximum amplitude and the point of the trailing edge which is 95 per cent of the maximum amplitude, fall below a value which is 95 per cent of the maximum voltage amplitude of the pulse;
(e) the spectrum of the pulse modulated signal shall be such that during the pulse the EIRP contained in a 0.5 MHz band centred on frequencies 0.8 MHz above and 0.8 MHz;
(f) below the nominal channel frequency in each case shall not exceed 200 mW, and the EIRP contained in a 0.5 MHz band centred on frequencies 2 MHz above and 2 MHz;
(g) below the nominal channel frequency in each case shall not exceed 2 mW. The EIRP contained within any 0.5 MHz band shall decrease monotonically as the band centre frequency moves away from the nominal channel frequency;
(h) to ensure proper operation of the thresholding techniques, the instantaneous magnitude of any pulse turn-on transients which occur in time prior to the virtual origin shall be less than one per cent of the pulse peak amplitude; and
(i) initiation of the turn-on process shall not commence sooner than one microsecond prior to the virtual origin.
83. DME transponder pulse spacing
(1) The spacing of the constituent pulses of transmitted pulse pairs shall be as given in the table in regulation 96.
(2) The tolerance on the pulse spacing shall be plus or minus 0.25 microsecond.
(3) The tolerance on the DME/N pulse spacing shall be plus or minus 0.10 microsecond.
(4) The pulse spacings shall be measured between the half voltage points on the leading edges of the pulses.
84. DME transponder peak power output
(1) The peak EIRP shall not be less than that required to ensure a peak pulse power density of approximately minus 83 dBW/m2′> at the maximum specified range and level.
(2) The peak equivalent isotropically radiated power shall not be less than that required to ensure a peak pulse power density of minus 89 dBW/m2′> under all operational weather conditions at any point within coverage specified in regulation 75.
(3) The peak power of the constituent pulses of any pair of pulses shall not differ by more than 1 dB.
(4) The reply capability of the transmitter shall be such that the transponder shall be capable of continuous operation at a transmission rate of 2 700 plus or minus 90 pulse pairs per second (if 100 aircraft are to be served).
(5) The transmitter shall operate at a transmission rate, including randomly distributed pulse pairs and distance reply pulse pairs, of not less than 700 pulse pairs per second except during identity.
(6) The minimum transmission rate shall be as close as practicable to 700 pulse pairs per second and for DME/P, in no case shall it exceed 1 200 pulse pairs per second.
(7) —
(1) During intervals between transmission of individual pulses the spurious power received and measured in a receiver shall have the same characteristics as a transponder receiver.
(2) When tuned to any DME, interrogation or reply frequency, shall—
(a) be more than 50 dB below the peak pulse power received and measured in the same receiver tuned to the reply frequency in use during the transmission of the required pulses; and
(b) this provision refers to all spurious transmissions, including modulator and electrical interference.
(8) The spurious power level specified in subregulation (6) shall be more than 80 dB below the peak pulse power level.
(9) The spurious output of the DME transponder transmitter shall not exceed minus 40 dBm in any of kHz receiver bandwidth at all frequencies from 10 to 1500 MHz, but band of frequencies from 960 to 1245 MHz.
(10) The equivalent isotropically radiated power of any CW harmonic of the carrier frequency on any DME operating channel shall not exceed minus 10 dBm.
(1) The receiver centre frequency shall be the interrogation frequency appropriate to the assigned DME operating channel.
(2) The centre frequency of the receiver shall not vary more than plus or minus 0.002 per cent from the assigned frequency.
86. DME transponder sensitivity
(1) In the absence of all interrogation pulse pairs, with the exception of those necessary to perform the sensitivity measurement, interrogation pulse pairs with the correct spacing and nominal frequency shall trigger the transponder if the peak power density at the transponder antenna is at least—
(a) minus 103 dBW/m2′> for DME/N with coverage range greater than 56 km (30 NM); and
(b) minus 93 dBW/m2′> for DME/N with coverage range not greater than 56 km (30 NM).
(2) The minimum power densities specified in subregulation (1) shall cause the transponder to reply with an efficiency of at least—
(a) 70 per cent for DME/N;
(b) 70 per cent for DME/PIA mode; and
(c) 80 per cent for DME/P FA mode.
(3) The performance of the transponder shall be maintained when the power density of the interrogation signal at the transponder antenna has any value between the minimum specified in subregulation (1) up to a maximum of minus 22 dBW/m2′> when installed with ILS and minus 35 dBW/m2′> when installed for other applications.
(4) The transponder sensitivity level shall not vary by more than 1 dB for transponder loadings between 0 and 90 per cent of its maximum transmission rate.
(5) When the spacing of an interrogator pulse pair varies from the nominal value by up to plus or minus one microsecond, the receiver sensitivity shall not be reduced by more than 1 dB.
87. DME transponder load limiting
When transponder loading exceeds 90 per cent of the maximum transmission rate, the receiver sensitivity shall be automatically reduced in order to limit the transponder replies, so as to ensure that the maximum permissible transmission rate is not exceeded. (The available range of sensitivity reduction shall be at least 50 dB.)
When the receiver is interrogated at the power densities specified in regulation 87 to produce a transmission rate equal to 90 per cent of the maximum, the noise generated pulse pairs shall not exceed 5 per cent of the maximum transmission rate.
(1) The minimum permissible bandwidth of the receiver shall be such that the transponder sensitivity level shall not deteriorate by more than 3 dB when the total receiver drift is added to an incoming interrogation frequency drift of plus or minus 100 kHz.
(2) The receiver bandwidth shall be sufficient to allow compliance with regulation 76 when the input signals are those specified in regulation 100(3).
(3) Signals greater than 900 kHz removed from the desired channel nominal frequency and having power densities up to the values specified in regulation 87(3) DME/N shall not trigger the transponder. Signals arriving at the intermediate frequency shall be suppressed at least 80 dB. All other spurious response or signals within the 960 MHz to 1 215 MHz band and image frequencies shall be suppressed at least 75 dB.
90. DME transponder recovery time
(1) Within eight microseconds of the reception of a signal between 0 dB and 60 dB above minimum sensitivity level, the minimum sensitivity level of the transponder to a desired signal shall be within 3 dB of the value obtained in the absence of signals.
(2) The minimum sensitivity level referred to in under subregulation (1) shall be met with echo suppression circuits, if any, rendered inoperative.
(3) The eight microseconds are to be measured between the half voltage points on the leading edges of the two signals, both of which conform in shape, with the specifications in regulation 100(3).
91. DME transponder spurious radiations
Radiation from any part of the receiver or allied circuits shall meet the requirements stated in regulation 85(6).
92. DME transponder CW and echo suppression
Carrier wave (CW) and echo suppression shall be adequate for the sites at which the transponders will be used.
93. DME transponder protection against interference
Protection against interference outside the DME frequency band shall be adequate for the sites at which the transponders will be used.
(1) The transponder shall include a decoding circuit such that the transponder can be triggered only by pairs of received pulses having pulse duration and pulse spacings appropriate to interrogator signals as described in regulations 100(3) and 101(1).
(2) The decoding circuit performance shall not be affected by signals arriving before, between, or after, the constituent pulses of a pair of the correct spacing.
(3) An interrogation pulse pair with a spacing of plus or minus two microseconds, or more, from the nominal value and with any signal level up to the value specified in regulation 87(3) shall not exceed the transmission rate, does not exceed the value obtained when interrogations are absent.
95. DME transponder time delay
(1) Where a DME is associated only with a VHF facility, the time delay shall—
(a) be the interval from the half voltage point on the leading edge of the second constituent pulse of the interrogation pair and the half voltage point on the leading edge of the second constituent pulse of the reply transmission; and
(b) this delay shall be consistent with the following table, when it is desired that aircraft interrogators are to indicate the distance from the transponder site.
| Pulse pair sparing (µs)
|
Time delay (µs) |
||||
| Channel suffix
|
Operating mode
|
Interrogation
|
Reply
|
1st pulse timing
|
2nd pulse timing
|
| X
|
DME/N
|
12
|
12
|
50
|
50
|
| DME/P IA M
|
12
|
12
|
50
|
–
|
|
| DME/P FA M
|
18
|
12
|
56
|
–
|
|
| Y
|
DME/N
|
36
|
30
|
56
|
50
|
| DME/P IA M
|
36
|
30
|
56
|
–
|
|
| DME/P FA M
|
42
|
30
|
62
|
–
|
|
| W
|
DME/N
|
–
|
–
|
–
|
–
|
| DME/P IA M
|
24
|
24
|
50
|
–
|
|
| DME/P FA M
|
30
|
24
|
56
|
–
|
|
| Z
|
DME/N
|
–
|
–
|
–
|
–
|
| DME/P IA M
|
21
|
15
|
56
|
–
|
|
| DME/P FA M
|
27
|
15
|
62
|
–
|
(2) Where a DME is associated with an angle facility, the time delay shall—
(a) be the interval from the half voltage point on the leading edge of the first constituent pulse of the interrogation pair; and
(b) the half voltage point on the leading edge of the first constituent pulse of the reply transmission.
(3) This delay shall—
(a) be 50 microseconds for mode X channels; and
(b) be 56 microseconds for mode Y channels, when it is desired that aircraft interrogators are to indicate distance from the transponder site.
(4) The transponder time delay shall—
(a) be capable of being set to an appropriate value between the nominal value of the time delay minus 15 microseconds; and
(b) the nominal value of the time delay, to permit aircraft interrogators to indicate zero distance at a specific point remote from the transponder site.
(5) The time delay shall—
(a) be the interval from the half voltage point on the leading edge of the first constituent pulse of the interrogation pair; and
(b) be the half voltage point on the leading edge of the first constituent pulse of the reply transmission.
(1) The transponder shall not contribute more than plus or minus one microsecond (150 m (500 ft)) to the overall system error.
(2) The contribution to the total system error due to the combination of the transponder errors, transponder location co-ordinate errors, propagation effects and random pulse interference effects shall be not greater than plus or minus 340 m (0.183 NM) plus 1.25 per cent of distance measure.
(3) The combination of the transponder errors, transponder location co-ordinate errors, propagation effects and random pulse interference effects shall not contribute more than plus or minus 185 m (0.1 NM) to the overall system error.
(4) A transponder associated with a landing aid shall not contribute more than plus or minus 0.5 microsecond (75 m (250 ft)) to the overall system error.
97. DME transponder efficiency
(1) The transponder reply efficiency shall be at least 70 per cent for DME/N at all values of transponder loading up to the loading corresponding to regulation 80 and at the minimum sensitivity level specified in regulation 87(1) and (4).
(2) The transponder shall be rendered inoperative for a period normally not to exceed 60 microseconds after a valid interrogation decode has occurred and in extreme cases when the geographical site of the transponder is such as to produce undesirable reflection problems, the dead time may be increased but only by the minimum amount necessary to allow the suppression of echoes for DME/N.
98. DME transponder monitoring and control
(1) Means shall be provided at each transponder site for the automatic monitoring and control of the transponder in use.
(2) In the event that any of the conditions specified in subregulation (3) occur, the monitor shall cause the following action to take place—
(a) a suitable indication shall be given at a control point;
(b) the operating transponder shall be automatically switched off; and
(c) the standby transponder, if provided, shall be automatically placed in operation.
(3) The monitor shall cause the actions specified in subregulation (2) if—
(a) the transponder delay differs from the assigned value by one microsecond (150 m (500 ft)) or more; and
(b) in the case of a DME/N associated with a landing aid, the transponder delay differs from the assigned value by 0.5 microsecond (75 m (250 ft)) or more.
(4) The monitor shall cause the actions specified in subregulation (2) if the spacing between the first and second pulse of the transponder pulse pair differs from the nominal value specified in the table specified in regulation 96 by one microsecond or more.
(5) The monitor shall also cause a suitable indication to be given at a control point if any of the following conditions arise—
(a) a fall of 3 dB or more in transponder transmitted power output;
(b) a fall of 6 dB or more in the minimum transponder receiver sensitivity (provided that this is not due to the action of the receiver automatic gain reduction circuits);
(c) the spacing between the first and second pulse of the transponder reply pulse pair differs from the normal value specified in regulation 84 by one microsecond or more; and
(d) variation of the transponder receiver and transmitter frequencies beyond the control range of the reference circuits (if the operating frequencies are not directly crystal controlled).
(6) —
(1) Means shall be provided so that any of the conditions and malfunctioning enumerated in regulations 99(3), 99(4) and 99(5) which are monitored shall persist for a certain period before the monitor takes action.
(2) This period shall be as low as practicable, but shall not exceed 10 seconds, consistent with the need for avoiding interruption, due to transient effects, of the service provided by the transponder.
(7) The transponder shall not be triggered more than 120 times per second for either monitoring or automatic frequency control purposes, or both.
(l) Technical Characteristics of Interrogator (regs 99-109)
99. DME interrogator transmitter
(1) The interrogator shall transmit on the interrogation frequency appropriate to the assigned DME channel as specified in regulation 78.
(2) The radio frequency of operation shall not vary more than plus or minus 100 kHz from the assigned value—
(a) pulse rise time shall not exceed three microseconds;
(b) pulse duration shall be 3.5 microseconds plus or minus 0.5 microsecond;
(c) pulse decay time shall nominally be 2.5 microseconds, but shall not exceed 3.5 microseconds;
(d) the instantaneous amplitude of the pulse shall not, at any instant between the point of the leading edge which is 95 per cent of maximum amplitude and the point of the trailing edge which is 95 per cent of the maximum amplitude, fall below a value which is 95 per cent of the maximum voltage amplitude of the pulse;
(e) the spectrum of the pulse modulated signal shall be such that at least 90 per cent of the energy in each pulse shall be within 0.5 MHz in a band centred on the nominal channel frequency; and
(f) to ensure proper operation of the thresh holding techniques, the instantaneous magnitude of any pulse turn-on transients which occur in time prior to the virtual origin shall be less than one per cent of the pulse peak amplitude and the initiation of the turn-on process shall not commence sooner than one microsecond prior to the virtual origin.
100. DME interrogator pulse spacing
(1) The spacing of the constituent pulses of transmitted pulse pairs shall be as given in the table in regulation 96.
(2) The tolerance on the pulse spacing shall be plus or minus 0.5 microsecond.
(3) The tolerance on the pulse spacing shall be plus or minus 0.25 microsecond.
(4) The pulse spacing shall be measured between the half voltage points on the leading edges of the pulses.
101. DME interrogator pulse repetition frequency
The variation in time between successive pairs of interrogation pulses shall be sufficient to prevent false lock-on.
102. DME interrogator spurious radiation
(1) During intervals between transmission of individual pulses, the spurious pulse power received and measured in a receiver having the same characteristics of a DME transponder receiver, but tuned to any DME interrogation or reply frequency, shall—
(a) be more than 50 dB below the peak pulse power received; and
(b) be measured in the same receiver tuned to the interrogation frequency in use during the transmission of the required pulses.
(2) Subregulation (1) shall apply to all spurious pulse transmissions. The spurious CW power radiated from the interrogator on any DME interrogation or reply frequency shall not exceed 20 microwatts (minus 47 dBW).
(3) The spurious pulse power received and measured under the conditions stated in subregulation (1) shall be 80 dB below the required peak pulse power received.
103. DME interrogator time delay
(1) The time delay shall be consistent with the table in regulation 96.
(2) The time delay shall be the interval between the time of the half voltage point on the leading edge of the second constituent interrogation pulse and the time at which the distance circuits reach the condition corresponding to zero distance indication.
(3) The time delay shall be the interval between the time of the half voltage point on the leading edge of the first constituent interrogation pulse and the time at which the distance circuits reach the condition corresponding to zero distance indication.
104. DME interrogator receiver
The receiver centre frequency shall be the transponder frequency appropriate to the assigned DME operating channel specified in regulation 78.
105. DME interrogator receiver sensitivity
(1) The airborne equipment sensitivity shall be sufficient to acquire and provide distance information to the accuracy specified in regulation 110 and for the signal power density specified in regulation 85(2).
(2) The performance of the interrogator shall be maintained when the power density of the transponder signal at the interrogator antenna is between the minimum values given in regulation 85 and a maximum of minus 18 dBW/m2′>.
106. DME interrogator bandwidth
Where there is a ratio of desired to undesired co-channel DME signals of at least 8 dB at the input terminals of the airborne receiver, the interrogator shall display distance information and provide unambiguous identification from the stronger signal.
107. DME interrogator interference rejection
(1) Where there is a ratio of desired to undesired co-channel DME signals of at least 8 dB at the input terminals of the airborne receiver, the interrogator shall display distance information and provide unambiguous identification from the stronger signal.
(2) DME signals greater than 900 kHz removed from the desired channel nominal frequency and having amplitudes up to 42 dB above the threshold sensitivity shall not be used.
108. DME interrogator decoding
(1) The interrogator shall include a decoding circuit such that the receiver can be triggered only by pairs of received pulses having pulse duration and pulse spacings appropriate to transponder signals as described in regulation 84.
(2) A reply pulse pair with a spacing of plus or minus two microseconds, or more, from the nominal value and with any signal level up to 42 dB above the receiver sensitivity shall be rejected.
109. DME interrogator accuracy
The interrogator shall not contribute more than plus or minus 315 m (plus or minus 0.17 NM) or 0.25 per cent of indicated range, whichever is greater, to the overall system error.
(m) Specification for En Route VHF Marker Beacons (75 MHz) (regs 110-116)
110. En route VHF marker equipment
The emissions of an en route VHF marker beacon shall have a radio frequency of 75 MHz plus or minus 0.005 per cent.
111. En route VHF marker characteristics of emissions
(1) Radio marker beacons shall radiate an uninterrupted carrier modulated to a depth of not less than 95 per cent or more than 100 per cent and the total harmonic content of the modulation shall not exceed 15 per cent.
(2) The frequency of the modulating tone shall be 3 000 Hz plus or minus 75 Hz.
(3) The radiation shall be horizontally polarised.
112. En route VHF marker identification
If a coded identification is required at a radio marker beacon, the modulating tone shall be keyed so as to transmit dots or dashes or both in an appropriate sequence. The mode of keying shall be such as to provide a dot-and-dash duration together with spacing intervals corresponding to transmission at a rate equivalent to approximately six to ten words per minute. The carrier shall not be interrupted during identification.
113. En route VHF marker coverage and radiation pattern
The most desirable radiation pattern would be one that—
(a) in the case of fan marker beacons, results in lamp operation only when the aircraft is within a rectangular parallelepiped, symmetrical about the vertical line through the marker beacon and with the major and minor axes adjusted in accordance with the flight path served; and
(b) in the case of a Z marker beacon, results in lamp operation only when the aircraft is within a cylinder, the axis of which is the vertical line through the marker beacons.
114. En route VHF marker determination of coverage
The limits of coverage of marker beacons shall be determined on the basis of the field strength specified in regulation 44(2).
115. En route VHF marker radiation pattern
The radiation pattern of a marker beacon normally shall be such that the polar axis is vertical, and the field strength in the pattern is symmetrical about the polar axis in the plane or planes containing the flight paths for which the marker beacon is intended.
116. En route VHF marker monitoring
For each marker beacon, suitable monitoring equipment shall be provided which will show at an appropriate location—
(a) a decrease in radiated carrier power below 50 per cent of normal;
(b) a decrease of modulation depth below 70 per cent; and
(c) a failure of keying.
(n) Requirements for the Global Navigation Satellite System (GNSS) (regs 117-121)
The GNSS shall provide position and time data to the aircraft.
The GNSS navigation service shall be provided using various combinations of the following elements installed on the ground, on satellites and/or on board the aircraft—
(a) Global Positioning System (GPS) that provides the standard positioning service (SPS) as defined in regulations 123 to 136;
(b) global navigation satellite system (GLONASS) that provides the channel of standard accuracy (CSA) navigation signal as defined in regulations 137 to 148;
(c) aircraft-based augmentation system (ABAS) as defined in regulation 149;
(d) satellite-based augmentation system (SBAS) as defined in regulations 150 to 159;
(e) ground-based augmentation system (GBAS) as defined in regulations 160 to 171;
(f) ground-based regional augmentation system (GRAS) as defined in regulations 160 to 171; and
(g) aircraft GNSS receiver as defined in regulation 172.
The position information provided by the GNSS to the user shall be expressed in terms of the World Geodetic System – 1984 (WGS-84) geodetic reference datum.
The time data provided by the GNSS to the user shall be expressed in a time scale that takes the Universal Time Coordinated (UTC) as reference.
121. GNSS signal-in-space performance
The combination of GNSS elements and a fault-free GNSS user receiver shall meet the signal-in-space requirements defined in table 3.7.2.4-1 under Schedule 1.
(o) GPS Standard Positioning Service (SPS) (L1) (regs 122-127)
122. GPS space and control segment accuracy
(1) The GPS SPS position errors shall not exceed the following limits—
| Global average 95% of time
|
Worst site 95% of time
|
|
| Horizontal position error
|
9 m (30 ft)
|
17 m (56 ft)
|
| Vertical position error
|
15 m (49 ft)
|
37 m (121 ft)
|
(2) The GPS SPS time transfer errors shall not exceed 40 nanoseconds 95 per cent of the time.
123. GPS range domain accuracy
The range domain error shall not exceed the following limits—
(a) range error of any satellite – 30 m (100 ft) with reliability specified in regulation 126;
(b) 95th percentile range rate error of any satellite – 0.006 m (0.02 ft) per second (global average);
(c) 95th percentile range acceleration error of any satellite – 0.002 m (0.006 ft) per second-squared (global average); and
(d) 95th percentile range error for any satellite over all time differences between time of data generation and time of use of data – 7.8 m (26 ft) (global average).
The GPS SPS availability shall be as follows—
(a) 99 per cent horizontal service availability, average location (17 m 95 per cent threshold);
(b) 99 per cent vertical service availability, average location (37 m 95 per cent threshold);
(c) 90 per cent horizontal service availability, worst-case location (17 m 95 per cent threshold); and
(d) 90 per cent vertical service availability, worst-case location (37 m 95 per cent threshold).
(1) The GPS SPS reliability shall be within the following limits—
(a) reliability – at least 99.94 per cent (global average); and
(b) reliability – at least 99.79 per cent (worst single point average).
(2) The probability that the user range error (URE) of any satellite will exceed 4.42 times the upper bound on the user range accuracy (URA) broadcast by that satellite without an alert received at the user receiver antenna within 10 seconds, shall not exceed 1×105′> per hour.
The probability of losing GPS SPS signal-in-space (SIS) availability from a slot of the nominal 24-slot constellation due to unscheduled interruption shall not exceed 2×104′> per hour.
The GPS SPS shall cover the surface of the earth up to an altitude of 3 000 kilometres.
(p) Radio Frequency (RF) Characteristics (regs 128-135)
Each GPS satellite shall broadcast an SPS signal at the carrier frequency of 1575.42 MHz (GPS L1) using code division multiple access (CDMA).
The GPS SPS signal power shall be contained within a ±12 MHz band (1563.42 – 1587.42 MHz) centred on the L1 frequency.
The transmitted RF signal shall be right-hand (clockwise) circularly polarised.
Each GPS satellite shall broadcast SPS navigation signals with sufficient power such that, at all unobstructed locations near the ground from which the satellite is observed at an elevation angle of five degrees or higher, the level of the received RF signal at the antenna port of a 3 dBi linearly-polarised antenna is within the range of -158.5 dBW to -153 dBW for all antenna orientations orthogonal to the direction of propagation.
(1) The SPS L1 signal shall—
(a) be bipolar phase shift key (BPSK);
(b) modulated with a pseudo random noise (PRN) 1.023 MHz coarse/acquisition (C/A) code; and
(c) the C/A code sequence shall be repeated each millisecond.
(2) The transmitted PRN code sequence shall be the Modulo-2 addition of a 50 bits per second navigation message and the C/A code.
GPS time shall be referenced to UTC (as maintained by the U.S. Naval Observatory).
The GPS co-ordinate system shall be WGS-84.
135. GPS navigation information
The navigation data transmitted by the satellites shall include the necessary information to determine—
(a) satellite time of transmission;
(b) satellite position;
(c) satellite health;
(d) satellite clock correction;
(e) propagation delay effects;
(f) time transfer to UTC; and
(g) constellation status.
(q) GLONASS Channel of Standard Accuracy (CSA) (L1) (regs 136-147)
136. GLONASS space and control segment accuracy
(1) The GLONASS CSA position errors shall not exceed the following limits—
| Global average 95% of the time
|
Worst site 95% of the time
|
|
| Horizontal position error
|
5 m (17 ft)
|
12 m (40 ft)
|
| Vertical position error
|
9 m (29 ft)
|
25 m (97 ft)
|
(2) The GLONASS CSA time transfer errors shall not exceed 700 nanoseconds, 95 per cent of the time.
(3) The range domain error shall not exceed the following limits—
(a) range error of any satellite – 18 m (59.7 ft);
(b) range rate error of any satellite – 0.02 m (0.07 ft) per second;
(c) range acceleration error of any satellite – 0.007 m (0.023 ft) per second squared; and
(d) root-mean-square range error over all satellites – 6 m (19.9 ft).
The GLONASS CSA availability shall be as follows—
(a) ³99 per cent horizontal service availability, average location (12 m, 95 per cent threshold);
(b) ³99 per cent vertical service availability, average location (25 m, 95 per cent threshold);
(c) ³90 per cent horizontal service availability, worst-case location (12 m, 95 per cent threshold); and
(d) ³90 per cent vertical service availability, worst-case location (25 m, 95 per cent threshold).
The GLONASS CSA reliability shall be within the following limits—
(a) frequency of a major service failure – not more than three per year for the constellation (global average); and
(b) reliability – at least 99.7 per cent (global average).
The GLONASS CSA shall cover the surface of the earth up to an altitude of 2 000 km.
140. GLONASS carrier frequency
Each GLONASS satellite shall broadcast CSA navigation signal at its own carrier frequency in the L1 (1.6 GHz) frequency band using frequency division multiple access (FDMA).
GLONASS CSA signal power shall be contained within a ±5.75 MHz band centred on each GLONASS carrier frequency.
The transmitted RF signal shall be right-hand circularly polarised.
143. GLONASS signal power level
Each GLONASS satellite shall broadcast CSA navigation signals with sufficient power such that, at all unobstructed locations near the ground from which the satellite is observed at an elevation angle of 5 degrees or higher, the level of the received RF signal at the antenna port of a 3 dBi linearly polarized antenna is within the range of -161 dBW to -155.2 dBW for all antenna orientations orthogonal to the direction of propagation.
(1) Each GLONASS satellite shall transmit at its carrier frequency the navigation RF signal using a BPSK modulated binary train.
(2) The phase shift keying of the carrier shall be performed at p-radians with the maximum error ±0.2 radian and the pseudo-random code sequence shall be repeated each millisecond.
(3) The modulating navigation signal shall be generated by the Modulo-2 addition of the following three binary signals—
(a) ranging code transmitted at 511 kbits/s;
(b) navigation message transmitted at 50 bits/s; and
(c) 100 Hz auxiliary meander sequence.
GLONASS time shall be referenced to UTC (SU) (as maintained by the National Time Service of Russia).
146. GLONASS co-ordinate system
The GLONASS co-ordinate system shall be PZ-90.
147. GLONASS navigation information
The navigation data transmitted by the satellite shall include the necessary information to determine—
(a) satellite time of transmission;
(b) satellite position;
(c) satellite health;
(d) satellite clock correction;
(e) time transfer to UTC; and
(f) constellation status.
(r) Aircraft-based Augmentation System (ABAS) (reg 148)
The ABAS function combined with one or more of the other GNSS elements and both a fault free GNSS receiver and fault-free aircraft system used for the ABAS function shall meet the requirements for accuracy, integrity, continuity and availability as stated in regulation 122.
(s) Satellite-based Augmentation System (SBAS) (regs 149-158)
(1) SBAS combined with one or more of the other GNSS elements and a fault-free receiver shall meet the requirements for system accuracy, integrity, continuity and availability for the intended operation as stated in regulation 122, throughout the corresponding service area in regulation 152(6).
(2) SBAS combined with one or more of the other GNSS elements and a fault-free receiver shall meet the requirements for signal-in-space integrity as stated in regulation 122, throughout the SBAS coverage area.
SBAS shall perform one or more of the following functions—
(a) ranging; provide an additional pseudo-range signal with an accuracy indicator from an SBAS satellite (regulation 152 and Schedule 3, section 3.5.7.2);
(b) GNSS satellite status: determine and transmit the GNSS satellite health status (Schedule 3, section 3.5.7.3);
(c) basic differential correction: provide GNSS satellite ephemeris and clock corrections (fast and long-term) to be applied to the pseudo-range measurements from satellites (Schedule 3, section 3.5.7.4); and
(d) precise differential correction: determine and transmit the ionospheric corrections (Schedule 3, section 3.5.7.5).
(1) Excluding atmospheric effects, the range error for the ranging signal from SBAS satellites shall not exceed 25 m (82 ft) (95 per cent).
(2) The probability that the range error exceeds 150 m (490 ft) in any hour shall not exceed 105′>.
(3) The probability of unscheduled outages of the ranging function from an SBAS satellite in any hour shall not exceed 103′>.
(4) The range rate error shall not exceed 2 m (6.6 ft) per second.
(5) The range acceleration error shall not exceed 0.019 m (0.06 ft) per second-squared.
(6) An SBAS service area for any approved type of operation shall be a declared area within the SBAS coverage area where SBAS meets the corresponding requirements of regulation 122.
The carrier frequency shall be 1 575.42 MHz.
At least 95 per cent of the broadcast power shall be contained within a ±12 MHz band centred on the L1 frequency. The bandwidth of the signal transmitted by an SBAS satellite shall be at least 2.2 MHz.
154. SBAS satellite signal power level
(1) Each SBAS satellite placed in orbit before 1st January, 2014 shall broadcast navigation signals with sufficient power such that, at all unobstructed locations near the ground from which the satellite is observed at an elevation angle of 5 degrees or higher, the level of the received RF signal at the antenna port of a 3 dBi linearly polarised antenna is within the range of -161 dBW to -153 dBW for all antenna orientations orthogonal to the direction of propagation.
(2) Each SBAS satellite placed in orbit after 31 December, 2013 shall comply with the following requirements—
(a) the satellite shall broadcast navigation signals with sufficient power such that, at all unobstructed locations near the ground from which the satellite is observed at or above the minimum elevation angle for which a trackable GEO signal needs to be provided, the level of the received RF signal at the antenna port of the antenna specified in Schedule 3, Table A-88, is at least -164.0 dBW;
(b) the minimum elevation angle used to determine GEO coverage shall not be less than five degrees for a user near the ground;
(c) the level of a received SBAS RF signal at the antenna port of a 0 dBic antenna located near the ground shall not exceed -152.5 dBW; and
(d) the elasticity of the broadcast signal shall be no worse than 2 dB for the angular range of ±9.1Â℃ from bore sight.
The broadcast signal shall be right-hand circularly polarised.
The transmitted sequence shall—
(a) the Modulo-2 addition of the navigation message be at a rate of 500 symbols per second and the 1 023 bit pseudo-random noise code; and
(b) it shall then be BPSK-modulated onto the carrier at a rate of 1.023 megachips per second.
The difference between SNT and GPS time shall not exceed 50 nanoseconds.
158. SBAS navigation information
The navigation data transmitted by the satellites shall include the necessary information to determine—
(a) SBAS satellite time of transmission;
(b) SBAS satellite position;
(c) corrected satellite time for all satellites;
(d) corrected satellite position for all satellites;
(e) ionospheric propagation delay effects;
(f) user position integrity;
(g) time transfer to UTC; and
(h) service level status.
(t) Ground-based Augmentation System (GBAS) and Ground-based Regional Augmentation System (GRAS) (regs 159-173)
GBAS combined with one or more of the other GNSS elements and a fault-free GNSS receiver shall meet the requirements for system accuracy, continuity, availability and integrity for the intended operation as stated in regulation 122 within the service volume for the service used to support the operation as defined in regulation 162.
GBAS shall perform the following functions—
(a) provide locally relevant pseudo-range corrections;
(b) provide GBAS-related data;
(c) provide final approach segment data when supporting precision approach;
(d) provide predicted ranging source availability data; and
(e) provide integrity monitoring for GNSS ranging sources.
The minimum GBAS guidance approach service volume shall be as follows, except where topographical features dictate, and operational requirements permit—
(a) laterally, beginning at 140 m (450 ft) each side of the landing threshold point/fictitious threshold point (LTP/FTP) and projecting out ±35 degrees either side of the final approach path to 28 km (15 NM) and ±10 degrees either side of the final approach path to 37 km (20 NM);
(b) vertically, within the lateral region, up to the greater of seven degrees or 1.75 promulgated glide path angle (GPA) above the horizontal with an origin at the glide path interception point (GPIP) and 0.45 GPA above the horizontal or to such lower angle, down to 0.30 GPA, as required, to safeguard the promulgated glide path intercept procedure and this coverage applies between 30 m (100 ft) and 3 000 m (10 000 ft) height above threshold (HAT); and
(c) vertically, within the lateral region, up to the greater of seven degrees or 1.75 promulgated glide path angle (GPA) above the horizontal with an origin at the glide path interception point (GPIP) to an upper bound of 3 000 m (10 000 ft) height above threshold (HAT) and 0.45 GPA above the horizontal or to such lower angle, down to 0.30 GPA, as required, to safeguard the promulgated glide path intercept procedure and the lower bound is half the lowest decision height supported or 3.7 m (12 ft), whichever is larger.
162. GBAS approach services supporting auto land and guided take-off
The minimum additional GBAS service volume to support approach operations that include automatic landing and rollout, including during guided take-off, shall be as follows, except where operational requirements permit—
(a) horizontally within a sector spanning the width of the runway beginning at the stop end of the runway and extending parallel with the runway centre line towards the LTP to join the minimum service volume as described in regulation 162; and
(b) vertically, between two horizontal surfaces one at 3.7 m (12 ft) and the other at 30 m (100 ft) above the runway centre line to join the minimum service volume as described in regulation 162.
The minimum additional GBAS service volume to support approach operations that include automatic landing and rollout, including during guided take-off, shall be as follows, except where operational requirements permit—
(a) horizontally within a sector spanning the width of the runway beginning at the stop end of the runway and extending parallel with the runway centre line towards the LTP to join the minimum service volume as described in regulation 162; and
(b) vertically, between two horizontal surfaces one at 3.7 m (12 ft) and the other at 30 m (100 ft) above the runway centre line to join the minimum service volume as described in regulation 162.
(1) The data broadcast radio frequencies used shall be selected from the radio frequencies in the band 108 to 117.975 MHz.
(2) The lowest assignable frequency shall be 108.025 MHz and the highest assignable frequency shall be 117.950 MHz and the separation between assignable frequencies (channel spacing) shall be 25 kHz.
(1) A time division multiple access (TDMA) technique shall be used with a fixed frame structure.
(2) The data broadcast shall be assigned one to eight slots.
GBAS data shall be transmitted as 3-bit symbols, modulating the data broadcast carrier by D8PSK, at a rate of 10 500 symbols per second.
167. GBAS data broadcast RF field strength and polarisation
(1) GBAS/H – A horizontally polarised signal shall be broadcast.
(2) The effective radiated power (ERP) shall—
(a) provide for a horizontally polarised signal with a minimum field strength of 215 microvolts per metre (-99 dBW/m2′>); and
(b) a maximum field strength of 0.350 volts per metre (-35 dBW/m2′>) within the GBAS coverage volume.
(3) The field strength shall—
(a) be measured as an average over the period of the synchronisation; and
(b) be such that the RF phase asset between the HPOL and any VPOL components, achieve the minimum signal power as defined in Schedule 3, section 3.6.8.2.2.3, and as such be achieved for HPOL users throughout the coverage volume.
(4) GB AS/E – An elliptically polarised signal shall be broadcast whenever practical.
(5) —
(1) Where an elliptically polarised signal is broadcast, the horizontally polarised component shall meet the requirements in regulation 168(2), and the effective radiated power (ERP) shall provide for a vertically polarised signal with a minimum field strength of 136 microvolts per metre (-103 dBW/m2′>) and a maximum field strength of 0.221 volts per metre (-39 dBW/m2′>) within the GBAS coverage volume.
(6) The field strength shall—
(a) be measured as an average over the period of the synchronisation and ambiguity resolution field of the burst; and
(b) be such that the RF phase offset between the HPOL and any VPOL components achieve the minimum signal power as defined in Schedule 3, section 3.6.8.2.2.3 and as such be achieved for HPOL and VPOL users throughout the coverage volume.
168. GBAS power transmitted in adjacent channels
The amount of power during transmission under all operating conditions when measured over a 25 kHz bandwidth centred on the ith adjacent channel shall not exceed the values shown in Schedule 1, table 3.7.3.5-1.
Unwanted emissions, including spurious and out-of-band emissions, shall be compliant with the levels shown in Schedule 1, table 3.7.3.5-2 and the total power in any VDB harmonic or discrete signal shall not be greater than -53 dBm.
170. GBAS navigation information
The navigation data transmitted by GBAS shall include the following information—
(a) pseudo-range corrections, reference time and integrity data;
(b) GBAS-related data;
(c) final approach segment data when supporting precision approach; and
(d) predicted ranging source availability data.
The aircraft GNSS receiver shall process the signals of those GNSS elements that it intends to use as specified in Schedule 3, section 3.1 (for GPS), third schedule, section 3.2 (for GLONASS), Schedule 3, section 3.3 (for combined GPS and GLONASS), Schedule 3, section 3.5 (for SBAS) and Schedule 3, section 3.6 (for GBAS and GRAS).
172. GNSS resistance to interference
GNSS shall comply with performance requirements defined in regulation 122 and Schedule 3, section 3.7 in the presence of the interference environment defined in Schedule 3, section 3.7.
Aircraft GNSS equipment that uses a database shall provide a means to—
(a) update the electronic navigation database; and
(b) determine the Aeronautical Information Regulation and Control (AIRAC) effective dates of the aeronautical database.
(u) System Characteristics of Airborne ADF Receiving Systems (reg 174)
174. Accuracy of bearing indication
The bearing given by the ADF system shall not be in error by more than plus or minus five degrees with a radio signal from any direction having a field strength of 70 microvolts per metre or more radiated from an LF/MF NDB or locator operating within the tolerances permitted by these Regulations and in the presence also of an unwanted signal from a direction 90 degrees from the wanted signal and shall be—
(a) on the same frequency and 15 dB weaker;
(b) plus or minus 2 kHz away and 4 dB weaker; and
(c) plus or minus 6 kHz or more away and 55 dB stronger.
PART IV
Exemptions (regs 175-177)
175. Requirements for application for exemption
A request for an exemption must be in writing and specify the time when the aviation service provider is expected by the Authority to fully comply.
(1) The Authority shall—
(a) review the application for exemption made under regulation 175 for accuracy and compliance; and
(b) if the application is satisfactory, the Authority shall publish a detailed summary of the application for comments, within a prescribed time, in either—
(i) the Government Gazette,
(ii) aeronautical information circular, and
(iii) a daily newspaper with national circulation in Botswana.
(2) Where application requirements have not been fully complied with, the Authority shall request the applicant in writing, to comply prior to publication or making a decision under subregulation (3).
(3) If the request is for emergency relief, the Authority shall publish the decision as soon as possible after processing the application.
177. Evaluation of the request
Where the application requirements have been satisfied, the Authority shall conduct an evaluation of the request to include—
(a) determination of whether an exemption would be in the public interest;
(b) a determination, after a technical evaluation of whether the applicant’s proposal would provide a level of safety equivalent to that established by these Regulations:
Provided that, where the Authority decides that a technical evaluation of the request would impose a significant burden on the Authority’s technical resource, the Authority may deny the exemption on that basis;
(c) a determination of whether a grant of the exemption would contravene these Regulations; and
(d) a recommendation based on the preceding elements, of whether the request should be granted or denied, and of any conditions or limitations that should be part of the exemption.
PART V
General Provisions (regs 178-181)
178. Drug and alcohol testing and reporting
(1) Any person who performs any function prescribed by these Regulations directly or by contract may be tested for drug or alcohol usage.
(2) A person who—
(a) refuses to submit to a test to indicate the percentage by weight of alcohol in the blood; or
(b) refuses to submit to a test to indicate the presence of narcotic drugs, marijuana, or depressant or stimulant drugs or substances in the body,
when requested by a law enforcement officer or the Authority, or refuses to furnish or to authorise the release of the test results requested by the Authority shall—
(i) be denied any licence, certificate, rating, qualification, or authorisation issued under these Regulations for a period of up to one year from the date of that refusal, or
(ii) have their licence, certificate, rating, qualification, or authorisation issued under these Regulations suspended or revoked.
(3) Any person who is convicted for the violation of any local or national statute relating to the growing, processing, manufacture, sale, disposition, possession, transportation, or importation of narcotic drugs, marijuana, or depressant or stimulant drugs or substances, shall—
(a) be denied any licence, certificate, rating, qualification, or authorisation issued under these Regulations for a period of up to one year after the date of conviction; or
(b) have their licence, certificate, rating, qualification, or authorisation issued under these Regulations suspended or revoked.
(1) Any person who knows of a violation of the Act, or any regulations, rules, or orders issued thereunder, shall report it to the Authority.
(2) The Authority may determine the nature and type of investigation or enforcement action that need to be taken.
180. Failure to comply with direction
Any person who fails to comply with any direction given to him by the Authority or by any authorised person under any provision of these Regulations shall be deemed for the purposes of these Regulations to have contravened that provision.
(1) The Authority shall notify, in writing the fees to be charged in connection with the issue, renewal or variation of any certificate, test, inspection or investigation required by, or for the purpose of these Regulations, any orders, notices or proclamations made thereunder.
(2) Upon an application being made in connection with which any fee is chargeable in accordance with the provisions of subregulation (1), the applicant shall be required, before the application is accepted, to pay the fee so chargeable.
(3) If, after that payment has been made, the application is withdrawn by the applicant or otherwise ceases to have effect or is refused, the Authority shall not refund the payment made.
PART VI
Offences and Penalties (regs 182-184)
182. Contravention of Regulations
A person who contravenes any provision of these Regulations may have his certificate or exemption cancelled or suspended.
(1) A person who contravenes any provision of these Regulations, orders, notices or proclamations made thereunder shall, upon conviction, be liable to a fine or imprisonment or both, and in the case of a continuing contravention, each day of the contravention shall constitute a separate offence.
(2) Any person who contravenes any provision of these Regulations shall be liable to a fine not exceeding P 100 000 or to imprisonment for a term not more than six months, or to both.
A person aggrieved by the decision of the Authority under these Regulations may, within 14 days of such decision, appeal to the Tribunal established under section 79 of the Civil Aviation Act.
PART VII
Savings and Transitions (reg 185)
(1) The Authority may require all facilities and equipment installed and operated before the coming into force of these Regulations be subjected to an assessment to determine the extent to which they comply with the provisions of these Regulations.
SCHEDULE 1
SPECIFICATIONS FOR RADIO NAVIGATION AIDS
(regs 9, 10, 121, 168 and 169)
SCHEDULE 2
VHF LOCALIZER AND ASSOCIATED MONITOR SPECIFICATIONS
(regs 20, 75 and 77)
SCHEDULE 3
TECHNICAL SPECIFICATIONS FOR THE GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)
(regs 33, 150, 154, 167, 171 and 172)
SCHEDULE 4
REQUIREMENTS OF FLIGHT INSPECTION OF RADIO NAVIGATION AIDS
(reg 11)
