Publication: Magyar Közlöny
Issue: MK-2007-70 (Year: 2007, Number: 70)
Era: 2004-2010
Section: Melléklet a 2007. évi XLVI. törvényhez
Paragraph Index: 3891

b) 6.5 degrees from 0.0 to 1.0 rad/s and 10 degrees at 1.5 rad/s for the elevation function. 7.4.3 Minimum glide path. When there is capability of selecting the approach elevation angle, a suitable warning is to be issued if the selected angle is lower than the minimum glide path as provided in basic data word 2. 7.4.4 Status bits. A suitable warning is to be provided when the function status bits in acquired basic data indicate that the respective function is not being radiated or is being radiated in test mode. 7.5 Use of back azimuth guidance for missed approaches and departures 7.5.1 sable back azimuth angles 7.5.1.1 Flight test results indicated that back azimuth angles of up to ±30 degrees from the runway centre line can be used for navigation guidance for missed approaches and departures. With appropriate interception techniques, larger angle offsets might be acceptable up to the flyable limits of back azimuth coverage. Departure guidance can utilize the back azimuth signal for centre line guidance throughout the take-off roll and initial departure. It is intended that a turn to intercept the back azimuth is initiated at an operationally acceptable altitude, and the prescribed procedure is protected according to appropriate obstacle clearance criteria. 7.5.2 Back azimuth deviation scale 7.5.2.1 The scaling of back azimuth deviations must be sufficient to support back azimuth departures and missed approaches not aligned with the approach azimuth, as well as missed approach and departure tracks aligned with the approach azimuth. Deviation scaling effects are most pronounced when manoeuvring to intercept a back azimuth. Very sensitive scaling will cause lateral overshoots and limit flyability of the signal, whereas very insensitive scaling will result in the large consumption of airspace. A nominal course width sensitivity of ±6 degrees provides for an acceptable interception of back azimuth during missed approach and departure. ATT G-27 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I 7.5.3 Approach azimuth to back azimuth switching 7.5.3.1 Following initiation of a missed approach using back azimuth guidance, the guidance must switch from approach azimuth to back azimuth. The switching, either automatically or manually, from approach azimuth to back azimuth guidance is intended to provide continuous flyable guidance throughout the missed approach sequence. Switching is not expected to occur until the aircraft receives a validated back azimuth signal, but it is intended to occur before the approach azimuth guidance becomes too sensitive to fly. Switching based on loss of approach azimuth may not occur until the aircraft is very close to the approach azimuth antenna resulting in unflyable guidance. Switching based only on loss of elevation guidance may occur prior to the aircraft receiving a valid back azimuth signal. However, switching might be based on loss of elevation guidance once the back azimuth signal has been validated. Automatic switching at or near the mid-point between azimuth antennas will provide a method which results in continuous guidance during the transition. The mid-point switching methodology may require the use of DME information by the MLS receiver. Precautions are to be taken so that approach to back azimuth switching does not automatically occur unless a missed approach has been initiated. 8. Operations at the limits of and outside the promulgated MLS coverage sectors 8.1 The limits of the azimuth proportional guidance sectors are transmitted in basic data words 1 and 5. These limits do not indicate the maximum flyable MLS approach and back azimuth angles which will normally be at some angle inside these limits. For example, for an approach azimuth providing a proportional guidance sector of ±40 degrees, flyable MLS approach azimuth angles with a full course width of ±3 degrees will exist to approximately ±37 degrees. For a back azimuth, flyable back azimuth angles with full course width will exist to within 6 degrees of the proportional guidance sector limits. 8.2 The basic MLS antenna designs should preclude the generation of unwanted signals outside coverage. Under some unusual siting conditions, MLS signals might be reflected into regions outside the promulgated coverage with sufficient strength to cause erroneous guidance information to be presented by the receiver. As in current procedure the implementing authority would specify operational procedures based on the use of other navaids to bring the aircraft into landing system coverage without transiting the area of concern or may publish advisories which alert pilots to the condition. In addition, the MLS signal format permits the use of two techniques to further reduce the probability of encountering erratic flag activity. 8.2.1 If the undesired MLS signals are reflections and if operational conditions permit, the coverage sector can be adjusted (increased or decreased) such that, at the receiver, either the direct signal is greater than any reflection or the reflector is not illuminated. This technique is referred to as coverage control. 8.2.2 Out-of-coverage indication signals can be transmitted into the out-of-coverage sectors for use in the receiver to ensure a flag whenever an undesired angle guidance signal is present. This is accomplished by transmitting an out-ofcoverage indication signal into the region which is greater in magnitude than the undesired guidance signal. 8.3 If it is operationally required to confirm the selected MLS channel outside the promulgated coverage sectors of the MLS, it is intended that this confirmation be derived from the identification of the associated DME. MLS status information is not available outside the promulgated MLS coverage sectors. 9. Separation criteria in terms of signal ratios and propagation losses 9.1 Geographical separation 9.1.1 The separation criteria are provided in 9.2 and 9.3 as desired signal-to-noise ratios and when combined with appropriate propagation losses allow evaluation of MLS C-Band frequency assignments as regards on-channel and adjacent 23/11/06 ATT G-28 2007/70/II. szám Attac ment G Annex 10 — Aeronautical Communications channel interference. When selecting frequencies for MLS facilities, a similar criteria for the DME/P element or an associated DME/N as provided in Attachment C to this Part need to be considered. 9.2 Co-frequency requirements 9.2.1 Co-frequency MLS channel assignments should be made to preclude the acquisition of DPSK preambles of an undesired co-channel facility. The required level of the undesired signal is less than minus 120 dBm, which is 2 dB below a sensitive MLS airborne system, as shown below: — receiver sensitivity = –112 dBm — margin for aircraft antenna gain above minimum = –6 dBm –118 dBm Considering the system power budget in Table G-1, which shows the minimum signal level at the aircraft is required to be at least minus 95 dBm, the minus 120 dBm requirement is achieved by placing the undesired co-channel at a geographic separation which exceeds the radio horizon distance at any point in the promulgated coverage sector of the desired facility. Note.— The PS signal requires more protection than the scanning beam so that by limiting the undesired co-channel signal to minus 120 dBm, interference from the scanning beam is negligible. 9.3 Adjacent frequency requirements 9.3.1 Considering the absence of requirements on transmitter spectrum characteristics for the first and second adjacent channels, the ground stations operating at these frequencies should be placed at a geographical separation that exceeds the radio horizon distance at any point in the promulgated coverage sector of the desired facility. Note.— here for specific reasons (for example, ILS/MLS/ ME pairing channels) the first or second ad acent channels need to be assigned, a less conservative method to assure receiver protection is to guarantee that the minimum SNR values as quoted in 3.11.6.1.4 are available at any point in the promulgated coverage sector of the desired facility while the undesired facility is transmitting. 9.3.2 For the third and subsequent adjacent channels, the ground stations operating at these frequencies should be placed at a geographical separation which guarantees that the minimum SNR values as quoted in Chapter 3, 3.11.6.1.4 are available at any point in the promulgated coverage sector of the desired facility while undesired facilities are transmitting. 9.3.2.1 If there is no undesired MLS transmission situated at less than 4 800 m from any point of the promulgated coverage, the –94.5 dBW/m maximum power of Chapter 3, 3.11.4.1.4.2 compared to the minimum power density of Chapter 3, 3.11.4.10.1 assures that the SNR minimum values will be met. No constraints are anticipated. 9.3.2.2 If there is an undesired MLS transmission situated at less than 4 800 m from a point of the promulgated coverage, the maximum power produced by this transmission and measured, during transmission time for angle and data signals, in a 150 kHz band centred on the desired nominal frequency has to be assessed taking into account the frequency separation, spectrum performances and antenna pattern of the transmitter and the appropriate propagation losses. This maximum power has then to be compared to the desired angle and data level to check that the minimum SNR values defined in 3.11.6.1.4 are met. If not, another channel offering a larger frequency separation has to be assigned in order to reduce this maximum undesired power taking benefit of the spectrum characteristic of the transmitter. ATT G-29 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I 9.4 Development of frequency planning criteria 9.4.1 The controlling factor when developing adjacent channel frequency planning criteria is the radiated spectrum from the MLS ground station. When developing frequency planning criteria for the third adjacent channel and above, ideally, the radiated spectrum output of individual MLS ground stations should be considered. However it may be possible in a eographic region to use a generic MLS transmitter mark which meets the requirements of that region. g 10. Material concerning MLS installations at special locations 10.1 MLS facility performance throughout the coverage volume 10.1.1 It is recognized that at some locations the requirements for MLS specified in Chapter 3, 3.11 cannot be met throughout the whole volume of coverage due to environmental effects on the signal. It is expected that at such locations the requirements of Chapter 3, 3.11 are to be met at least in the guidance sector for all published instrument procedures to a defined point beyond which the MLS guidance is not used for intended operations. To assist appropriate authorities with the initial appraisal of the suitability of such individual MLS installations for the intended operations, relevant coverage estrictions need to be promulgated. r

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