AMENDMENT 22 to INTERNATIONAL STANDARDS AND RECOMMENDED PRACTICES AERONAUTICAL TELECOMMUNICATIONS ANNEX 10 TO THE CONVENTION ON INTERNATIONAL CIVIL AVIATION FOURTH EDITION - APRIL 1955 INTRODUCTION Amendment 22 was adopted by the Council of ICAO with a date for application of 1 December 1956. The text of the amendment has, therefore, been incor- porated into tha attached replacement pages which should be inserted into the Fourth Edition of Annex 10. The amendment is incorporated intoparagraph 3.1.5 of Part1 of Annex 10 which provides for the method of pairing ILS localizer and glide path frequencies. INTERNATIONAL CIVIL AVIATION ORGANIZATION
Part I - Equipment and Systems Annex 10 - Aeronautical Tdccommunications used and.identihcation signal shall con- provide safe guidance over obstruction 18.104.22.168.4 The 90 cjs. modulating tinue to be radiated when possible. during an approach for landing and also tone shall be phase locked to the 150 cis. to a touchdowi point that will permit of modulating tone. 22.214.171.124.2 Means shall be provided BO that any of the conditions a, b and cI in 126.96.36.199.1 can persist for a certain period before the warning is transmitted and navigational components are removed. 'This period shall be as low as practicable within the limits of 4 and 10 seconds con- sistent with the need for avoiding inter- ruption, due to transient effccts, of the navigation service provided by the local- izer. Provision lor adjustment of the period. between these limits shall be available. safe and efficient use of the runway served. Note.-Material lhal muy be used as u guide in the selection of the ILS refirence point and for riling the glide path equipmenl appeurs in 2.4 of Attachment C lo Part I. 188.8.131.52 Radio frequency. 184.108.40.206.1 The glide path equipment shall operate in the band 328.6 Mcjs. to 335.4 Mc/s. The frequency tolerance' of the carrier shall be lus or minus 0.005 220.127.116.11.5 The glide path equipment shall be so desigled and adjusted that a DDM of 0.175 is realized both above and below the glide path for an angular displacement from the glide path between 0.11 8 and 0.33 8 where 8 is the glide path angle. The DDM. below the glide pnth shall increase smoothly for decreasing angle of elevation, and at no time be less than 0.250 at an angle of 0.3 8 above the horizontal. per cent. Note - The limits of glide path equip- ment adjustment are pictorMlly represevfed 18.104.22.168.3 Failure of the monitor it- in Atlachmd C to Yarl I Fig. C-12. self shalt automatically rcnlove the naviga- 22.214.171.124.2 The emission from the tional components from the localizer glide path equipnlent shall be horizontally radiaiion. polarized. 126.96.36.199 Monitoring. AND ASSOCIATED MONITOR Nok-The ILS reference pmnl referred to in this parugruph is a seleded oint on the cetttre line oj tie muoy snwt It corrts- ponds to the point designated us the optimum oinl of contact in the final reporls of the hird Session of lhe Communications DiG- F sion Doc 6625-COMj521 aid lhe Firs1 Session of the Special Radio Technical Division COT DOC 2553-COTI26. 3,1.4.1 General. 188.8.131.52.1 The UHF glide pnth equipment shall radiate two radio fre- quency held patterns. One of tliese pat- terns shall be due to a radio frequency carrier modulated by a 150 cjs. tone and the other shall be due to the same radio frequency carrier modulated by a 90 c/s. tone. The two patterns shall be arranged to intersect so as to provide a straight de- scent path in the vertical plane containing the centre line of the runway. 184.108.40.206.2 At any point below the glide path the 150 c/s. modulation of the radio frequency carrier shall pre- dominate. 220.127.116.11.3 RIICOMMIINDATION,- The UHF glide poth equipment should he cup able of adjuslmenl to prduce a glide path from 2 4 degrees wilh respect to lhe horieonlul. 18.104.22.168.4 The glide pnth shall pass through a point 6 tn 20 feet above the 1L.S reference point. 22.214.171.124.5 The 1I.S referclcc poirit shall be wlected m that tlic glidc path will 126.96.36.199 Coveruge. The glide path equipment shall provide signals sufficient to allow satisfactory operation of a typical aircraft installation in sectors of 8 degrees on each side of the centre line of the glide path, up to a distance of at least 10 nautical miles and between an angle above the horizontal equal to 0.3 times the glide path angle, and an angle above the glide path equal to 0.8 times the glide path angle. Note.-The requiremtnls .in lh foregoing paragruph are bused on the assumplion that lhe aircrufi is heading directly loward ths facility. 188.8.131.52 Carrier modulalion. 184.108.40.206.1 The depth of modulation of the radio frequency carrier due to each of the 90 C/S. and 150 cjs. tones shall be nominally 47.5 per cent along the glide path. This value shall not deviate ontside the limits of 45 per cent to 50 per cent. 220.127.116.11.2 ECOMMENDATION.- The modulalion depth should be held as close to 47.5 per cent us practicable in order to uchime the maximun benejit from the air- borne receiver jlng alarm system. 18.104.22.168.3 The foHowiag tolerances shall be applied to the modllating tones u tile nodiating tones shall be 90 c/s. arid 150 c/s. within 2.5 per cent b tlre total harmonic content of the 90 c/s. torre shall not exceed 10 per cent c the total hilrmonic content of the 150 C/R. tone filnll not cxcced 10 pr cent. 22.214.171.124.1 Suitable equipment lo- cated in the radiation field at a distance in front of the glide path antenna system shall provide signals for the operation of an automatic monitor. The monitor shall transmit a warning to a control point, and cause radiation from the glide path equip- ment to cease if any of the following condi- tions arise a shift of the nth angle by more than 0.1 0 from the published glide path angle '0' b reduction of power output to less than 50 per cent of normal G increase of the glide path sector width of more than 10 per cent over the maximum width implied in 126.96.36.199.5. 188.8.131.52.2 RECOMMENDATION.- Munibring of th lower edge of the sector to smulIer tolerances should be orranged in cases where, with standard monitoring toler- ance, an vnacceplably high glide path would otherwise bs required. 184.108.40.206.3 Means shall be provided BO that any of the cotditions prescribed in a, b and c of 220.127.116.11.1 can persist for a certain period before the warning is trans- mitted and radiation ceases. This period shall be as low as practicable within the litnits of from 2 to 6 seconds having regard to the need for avoiding interrtrption, due to transient effects, of the nnvigitiot serv- ice provided by the facility. hfennv of adjustnent between 2 and 6 seconds shall be available. 18.104.22.168.4 Failure of the monitor it- self slrali autonatically cwsc ratlintion from the glide path facility to cease.
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