Publication: Magyar Közlöny
Issue: MK-2007-70 (Year: 2007, Number: 70)
Era: 2004-2010
Section: Melléklet a 2007. évi XLVI. törvényhez
Paragraph Index: 3602

d) variation of the obstacle clearance limit to cater for the offending obstacle. 2.4.7 To enable more effective use of land adjacent to Category III — ILS glide path sites and to reduce siting requirements and sensitive areas at these sites, it is desirable that the signals forming the horizontal radiation pattern from the Category III — ILS glide path antenna system be reduced to as low a value as practicable outside the azimuth coverage limits specified in Chapter 3, 3.1.5.3. Another acceptable method is to rotate in azimuth the glide path antennas away from multipath sources thus reducing the amount of radiated signals at specific angles while still maintaining the azimuth coverage limits. ATT C-21 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I 2.4.8 ILS glide path curvature. In many cases the ILS glide path is formed as a conic surface originating at the glide path aerial system. Owing to the lateral placement of the origin of this conic surface from the runway centre line, the locus of the glide path in the vertical plane along the runway centre line is a hyperbola. Curvature of the glide path occurs in the threshold region and progressively increases until touchdown. 2.4.9 Relationship between siting of glide path antenna and glide path threshold crossing height. The longitudinal position of the glide path antenna should be selected so as to meet the recommendation made in Chapter 3, 3.1.5.1.4, in respect to the height of the ILS reference datum above the runway threshold. The height of the ILS reference datum above the runway threshold is then a function of the longitudinal position of the glide path antenna, of the longitudinal slope of the glide path reflection plane and of the position of the runway threshold in respect to the glide path reflection plane. This situation is described pictorially in Figure C-5. The longitudinal position of the glide path antenna is then calculated as follows: + tan (ș + Į) where = the horizontal distance between O and P; = the nominal threshold crossing height; = the vertical height of the runway threshold above P ; ș = the nominal ILS glide path angle; Į = the longitudinal downslope of the glide path reflection plane. Note.— In the above formula Į is to be taken as positive in the case of a downslope from the antenna towards the threshold. Y is taken as positive if the threshold is above the reflection plane intersection line. 2.4.10 The foregoing guidance material in respect of the longitudinal placement to the glide path antenna in relation to the runway threshold, which takes into account the fact that the runway may not be in the glide path reflection plane, and that the glide path reflection plane may be sloped, is based on geometrical abstractions. The material implicitly assumes that the glide path locus in the vertical plane, containing the runway centre line, is a perfect hyperbola; consequently, the glide path extension is implicitly assumed as the asymptote to this hyperbola. 2.4.11 In fact, however, the glide path is often quite irregular. The mean ILS glide path angle can be ascertained only by flight tests; the mean observed position of that part of the glide path between ILS Points A and B being represented as a straight line, and the ILS glide path angle being the angle measured between that straight line and its vertical projection on the horizontal plane. 2.4.12 It is important to recognize that the effect of glide path irregularities if averaged within the region between the middle marker and the threshold will likely tend to project a reference datum which is actually different from the ILS reference datum. This reference datum, defined here as the achieved ILS reference datum, is considered to be of important operational significance. The achieved ILS reference datum can only be ascertained by flight check, i.e. the mean observed position of that portion of the glide path typically between points 1 830 m (6 000 ft) and 300 m (1 000 ft) from the threshold being represented as a straight line and extended to touchdown. The point at which this extended straight line meets the line drawn vertically through the threshold at the runway centre line is the achieved ILS reference datum. Note.— Further guidance on the measurement of the glide path angle and the achieved ILS reference datum is given in oc 071. 23/11/06 ATT C-22 2007/70/II. szám Attac ment C Annex 10 — Aeronautical Communications A lide path antenna Threshold P orizontal un ay Straight line extension of glide path D ine of glide path reflection plane Figure C-5. Glide path siting for sloping runway 2.4.13 Chapter 3, 3.1.5.3.1 indicates the glide path coverage to be provided to allow satisfactory operation of a typical aircraft installation. The operational procedures promulgated for a facility must be compatible with the lower limit of this coverage. It is usual for descents to be made to the intercept altitude and for the approach to continue at this altitude until a fly-down signal is received. In certain circumstances a cross-check of position may not be available at this point. Automatic flight control systems will normally start the descent whenever a fly-up signal has decreased to less than about 10 microamperes. 2.4.14 The objective is, therefore, to provide a fly-up signal prior to intercepting the glide path. Although under normal conditions, approach procedures will be accomplished in such a way that glide path signals will not be used below 0.45 ș, or beyond 18.5 km (10 NM) from the runway, it is desirable that misleading guidance information should not be radiated in this area. Where procedures are such that the glide path guidance may be used below 0.45 ș, adequate precautions must be taken to guard against the radiation of misleading guidance information below 0.45 ș, under both normal conditions and during a malfunction, thus preventing the final descent being initiated at an incorrect point on the approach. Some precautions which can be employed to guard against the radiation of misleading guidance include the radiation of a supplementary clearance signal such as provided for in Chapter 3, 3.1.5.2.1, the provision of a separate clearance monitor and appropriate ground inspection and setting-up procedures. 2.4.15 To achieve satisfactory monitor protection against below-path out-of-tolerance DDM, depending on the antenna system used, the displacement sensitivity monitor as required in Chapter 3, 3.1.5.7.1 e) may not be adequate to serve also as a ATT C-23 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I clearance monitor. In some systems, e.g. those using multi-element arrays without supplementary clearance, a slight deterioration of certain antenna signals can cause serious degradation of the clearance with no change or only insignificant changes within the glide path sector as seen by the deviation sensitivity monitor. It is important to ensure that monitor alarm is achieved for any or all possible deteriorated antenna and radiated signal conditions, which may lead to a reduction of clearance to 0.175 DDM or less in the below-path clearance coverage. 2.5 Diagrams (Figures C-6 to C-12 illustrate certain of the Standards contained in Chapter 3) 90 Hz 90 Hz 150 Hz 150 Hz 20 degrees at 150 Hz (370 microseconds) 10 degrees at 150 Hz (185 microseconds) P = 1.749 P = 1.806 P = 1.936 P = 1.900 = 0.903 = 0.951 +1 +1 -1 -1 +2 +2 +1 +1 -1 -1 -2 -2 Time Time Facility performance Categories I and II localizers and glide paths Facility performance Category III localizers and glide paths Amplitude Amplitude The accompanying graphs illustrate a method that can be used to measure the relative phase relationship between the 90 Hz and 150 Hz tones. The upper portion of each graph shows the individual waveforms and their relationship at the limit of phase differences allowed by Chapter 3, 3.1.3.5.3.3 and 3.1.5.5.3. The lower portion shows the combined waveforms as would be seen on an oscilloscope. By taking the ratio of P and P , which gives a value equal to or less than unity, it is possible to determine if the phasing is within tolerance. For Categories I and II ILS theratio should be greater than 0.903 and for Category III the ratio should be greaterthan0.951. Figure C-6. ILS wave forms illustrating relative audio phasing of the 90 Hz and 150 Hz tones 23/11/06 ATT C-24 2007/70/II. szám Attac ment C Annex 10 — Aeronautical Communications Figure C-7. Localizer coverage with respect to azimuth Figure C-9. Difference in depth of modulation and displacement sensitivity Figure C-8. Localizer coverage with respect to elevation Figure C-10. Glide path coverage Course line 10° 10° 25° 25° 18.5 km (10 NM) 31.5 km (17 NM) Centre of localizer antenna system Centre of localizer antenna system When topographical features dictate or operational requirements and alternative navigation facilities permit, the following coverage may be provided: Course line 10° 10° 25° 25° 18.5 km Note.— If coverage as prescribed in Chapter 3, 3.1.3.3.1 is required outside the plus or minus 35-degree sector, this is provided to 18.5 km (10 NM), as indicated by the broken arc above. 46.3 km (25 NM) 18.5 km (10 NM) 33.4 km (18 NM) (10 NM) P or D = Distances and azimuths specified in 3.1.3.3.1 Note.— The point P is either 600 metres (2 000 ft) above the elevation of the threshold, or 300 metres (1 000 ft) above the elevation of the highest point within theintermediateandfinal approach areas,whichever is the higher. 7° 300 m (1 000 ft) 600 m (2 000 ft) (See Note) D 8° 8° Centre line R 18.5 km (10 NM) (a) Azimuthal cover (b) Elevation cover R Back course (if provided) Centre of localizer antenna system (-90°) (+90°) DDM 0.155 (if coverage provided) ½ DDM 0.155 (if coverage provided) ½ DDM 0.155 ½ DDM = 0.155 DDM = 0.155 DDM = 0 DDM 0.155 ½ 25° 25° ILS reference datum 10° 10° C A B A — Course sector 6 degrees B — Displacement sensitivity = 0.00145 DDM/metre (0.00044 DDM/foot) at the ILS reference datum ¿ C — DDM increases linearly from zero to value of 0.180, and then ½0.180 ATT C-25 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I DDM = 0 A C B Category I Category III Category II DDM = 0 DDM = 0.0 75 DDM = 0.0 75 q DDM = 0.0 75 DDM = 0 DDM = 0.0 75 DDM = 0.0 75 DDM = 0 DDM = 0.0 75 Figure C-11. Glide path — difference in depth of modulation 23/11/06 ATT C-26 2007/70/II. szám Attac ment C Annex 10 — Aeronautical Communications DDM = 0 Nominal glide path Monitoring provisions of Chapter 3, 3.1.5.7.1 a) Monitoring provisions of Chapter 3, 3.1.5.7.1 d) Monitoring provisions of Chapter 3, 3.1.5.7.1 e) Monitoring provisions of Chapter 3, 3.1.5.7.1 f) Change of displacement sensitivity by more than 25 from normal DDM = 0.0 75 DDM = 0 DDM = 0.0 75 DDM = 0 DDM = 0 DDM = 0.0 75 Figure C-12. Glide path monitoring provisions ATT C-27 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I 2.6 Deployment of ILS frequencies 2.6.1 In using the figures listed in Table C-1, it must be noted that these are related to ensuring freedom from interference to a point at the protection height and at the limit of service distance of the ILS in the direction of the front beam. If there is an operational requirement for back beam use, the criteria would also be applied to a similar point in the back beam direction. Frequency planning will therefore need to take into account the localizer azimuthal alignment. It is to be noted that the criteria must be applied in respect of each localizer installation, in the sense that while of two localizers, the first may not cause interference to the use of the second, nevertheless the second may cause interference to the use of the first. 2.6.2 The figures listed in Table C-1 are based on providing an environment within which the airborne receivers can operate correctly. Table C-1. Required distance separations Minimum separation between second facility and the protection point of the first facility km (NM) Frequency separation List A List B List C Localizer Co-channel 148 (80) 148 (80) 148 (80) 50 kHz — 37 (20) 9 (5) 100 kHz 65 (35) 9 (5) 150 kHz — 200 kHz 11 (6) Glide path Co-channel 93 (50) 93 (50) 93 (50) 150 kHz — 20 (11) 2 (1) 300 kHz 46 (25) 2 (1) 450 kHz — 600 kHz 9 (5) List A refers to the use of localizer receivers designed for 200 kHz channel spacing coupled with glide path receivers designed for 600 kHz channel spacing and applicable only in regions where the density of facilities is low. List B refers to the use of localizer receivers designed for 100 kHz channel spacing coupled with glide path receivers designed for 300 kHz channel spacing. List C refers to the use of localizer receivers designed for 50 kHz channel spacing coupled with glide path receivers designed for 150 kHz channel spacing. Note 1.— The above figures are based on the assumption of protection points for the localizer at 46 km (25 NM) distance and 1 900 m (6 250 ft) height and for the ILS glide path at 1 .5 km (10 NM) distance and 760 m (2 500 ft) height. Note 2.— States, in applying the separations shown in the table, have to recognize the necessity to site the ILS and VOR facilities in a manner which will preclude the possibility of airborne receiver error due to overloading by high unwanted signal levels when the aircraft is in the initial and final approach phases. Note 3.— States, in applying the separations shown in the table, have to recognize the necessity to site the ILS glide path facilities in a manner which will preclude the possibility of erroneous glide path indications due to reception of ad acent channel signals when the desired signal ceases to radiate for any reason while the aircraft is in the final approach phase. 23/11/06 ATT C-28 2007/70/II. szám Attac ment C Annex 10 — Aeronautical Communications 2.6.2.1 ILS localizer receivers 2.6.2.1.1 In order to protect receivers designed for 50 kHz channel spacing, minimum separations are chosen in order to provide the following minimum signal ratios within the service volume:

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