Air Navigation (Noise Certification and Limitation) Order, 1984.

S.I. No. 13 of 1984. I, JIM MITCHELL, Minister for Communications, in exercise of the powers conferred on me by sections 5 11 16 of the (No. 23 of 1946) (as amended by section 9 of the (No. 4 of 1950)), and the Ministers and Secretaries (Amendment) Act, 1983 , (No. 40 of 1983), hereby order as follows: 1 Short title and Commencement. 1. (2) This Order shall come into operation on the 20th day of January, 1984. 2 .. 2. S.I. No. 250 of 1976 ) is hereby revoked. 3 Definitions. 3. In this Order— "aeroplane" means a power-driven heavier-than-air aircraft deriving its lift in flight chiefly from aerodynamic reactions on surfaces which remain fixed under given conditions of flight; "authorised person" means a person authorised under section 64 of the , (No. 40 of 1936); "by-pass ratio" means the ratio of the air mass flow passing through the by-pass ducts of a gas turbine engine to the air mass flow passing through the combustion chambers of that engine, calculated at maximum thrust when the engine is stationary in the Standard Atmosphere at sea level as defined in Annex 8 to the Chicago Convention; "Chicago Convention" has the meaning assigned to it by section 2 of the , (No. 23 of 1946), and includes any annex to the Chicago Convention relating to international standards and recommended practices and adopted in accordance with the Chicago Convention, and any amendment of any such annex made in accordance with the Chicago Convention; "derived version of an aeroplane" means an aeroplane which from the point of view of airworthiness is similar to the noise certificated original version but incorporates changes in type design which may affect its noise characteristics; "maximum certificated take-off mass" means the maximum total mass of the aeroplane and its contents at which the aeroplane may take off anywhere in the world in the most favourable circumstances in accordance with the certificate of airworthiness in force in respect of the aeroplane; "the Minister" means the Minister for Communications; "subsonic jet aeroplane" means an aeroplane incapable of sustaining level flight at speeds exceeding the speed propagation of sound pressure waves in the air. 4 Purpose of Order. 4. This Order is for the purposes of:— (i) giving effect to Annex 16 — first edition, 1981 to the Chicago Convention in respect of noise certification of aeroplanes, and (ii) making such directions as may be necessary from time to time in respect of procedures for the limitation of noise made by aeroplanes in certain locations and in certain circumstances. 5 Application of Order. 5. This Order applies to:— (1) Every subsonic jet aeroplane for which either the application for a certificate of airworthiness for the prototype was accepted or another equivalent procedure was effected by the certification authorities before the 6th day of October, 1977, except those aeroplanes: ) requiring a runway length of 610 metres or less at maximum certificated mass for airworthiness; or ) powered by engines with a by-pass ratio of 2 or more and for which a certificate of airworthiness for the individual aeroplane was first issued before the 1st day of March 1972; or ) powered by engines with a by-pass ratio of less than 2, and for which either the application for certificate of airworthiness for the prototype was accepted or another equivalent procedure was carried out by the certificating authorities, before the 1st day of January, 1969, and for which a certificate of airworthiness for the individual aeroplane was first issued before the 1st day of January, 1976. (2) Derived versions of any aeroplane specified in paragraph (1) of this Article for which the application for certification of a change in type design was accepted or another equivalent procedure was effected by the certificating authorities on or after the 26th day of November, 1981. (3) Every subsonic jet aeroplane including any derived version, other than an aeroplane which requires a runway length of 610 metres or less at maximum certificated take-off mass for airworthiness in respect of which either the application for certificate of airworthiness for the prototype was accepted or another equivalent procedure was effected by the certificating authorities on or after the 6th day of October, 1977. (4) Every propeller-driven aeroplane, including any derived version, except an aeroplane specifically designed for fire-fighting and agricultural purposes, of maximum certificated take-off mass exceeding 5,700 kilograms, other than an aeroplane which requires a runway length of 610 metres or less at maximum certificated mass for airworthiness— ) for which the application for a certificate of airworthiness for the prototype was accepted or another equivalent procedure was effected by the certificating authorities on or after the 6th day of October, 1977; or ) derived versions and individual aeroplanes of the types for which the application for the prototype was accepted or another equivalent procedure was effected by the certificating authorities before 6th October, 1977, and for which a certificate of airworthiness for the individual aeroplane was first issued on or after the 26th day of November, 1981. (5) Every propeller-driven aeroplane, except those aeroplanes specifically designed for aerobatic purposes or agricultural or fire-fighting uses, of a maximum certificated take-off mass not exceeding 5,700 kilograms (but in the case of an application for a change in type design, the maximum certificated take-off mass may not exceed 6,500 kilograms, provided that the prototype has been certificated at a maximum certificated take-off mass not exceeding 5,700 kilograms) for which— ) application for the certificate of airworthiness for the prototype was accepted, or another equivalent procedure was effected by the certificating authorities on or after the 1st day of January, 1975; or ) a certificate of airworthiness for the individual aeroplane was first issued on or after the 1st day of January, 1980. 6 Requirement of a noise certificate. 6. Within the State, no person shall land or take-off, or cause to be landed or to be taken off, an aeroplane to which this Order applies unless— ) there is in force in respect of that aeroplane a noise certificate issued by the Minister under Article 7 of this Order or (in the case of an aeroplane not registered in the State) issued by the competent authority of the state in which the aeroplane is registered and acceptable to the Minister as having been issued in compliance with, or containing requirements substantially equivalent to, the requirements of the Schedule to this Order, and ) any conditions subject to which the noise certificate was issued are complied with. 7 Issue of a Noise Certificate. 7. (1) The Minister may issue (or, in the case of a noise certificate issued by the competent authority of another state, may validate) a noise certificate in respect of any aeroplane to which this Order applies if he is satisfied that the noise made by the aeroplane is not greater than the noise levels specified for the aeroplane in the Schedule to this Order. (2) An applicant for the issue or validation of a noise certificate shall furnish such evidence and shall submit the said aeroplane to such tests (which may include tests in flight) as the Minister may require, for the purpose of proving compliance with the requirements of the Schedule to this Order. (3) The Minister may issue every noise certificate subject to a condition as to the maximum total mass at which the aeroplane may take-off and land and may issue such a certificate subject to such other conditions relating to standards as to noise as he thinks fit. S.I. No. 141 of 1964 ). (5) Subject to this Article and to Article 9 of this Order, a noise certificate shall remain in force without limit of time. (6) A noise certificate issued, or a noise certificate validated, under this Article shall cease to have effect if the aeroplane is modified in any way which affects its compliance with the noise standards required by this Order. 8 Noise Certificate. 8. (1) A noise certificate may take the form of a separate noise certificate or a suitable statement in another document approved of by the state of registration of the aeroplane concerned and required by that state to be carried in the aeroplane. The certificate or statement, as the case may be, shall include the following information, namely:— ) the state in which the aeroplane is registered and the national registration number or mark thereof; ) the manufacturer's serial number; ) the manufacturer's type and model designation for the aeroplane, engine and propeller; ) a statement of any additional modification to the aeroplane made for the purpose of ensuring compliance with the applicable noise certification requirements; ) the maximum mass at which compliance with the applicable noise certification requirements has been demonstrated; ) in the case of aeroplanes for which application for certification is submitted on or after the 6th day of October, 1977, the noise levels and their 90 per cent confidence limits at the reference points for which compliance with the applicable noise certification standards has been demonstrated; ) any provisions prescribed by the Minister in respect of different classes of aeroplanes and with respect to different circumstances. (2) A noise certificate shall be carried in the aeroplane to which it applies, save that if a flight by that aeroplane is intended to begin and to end at the same aerodrome without an intermediate landing at another aerodrome, the noise certificate may be kept at the first-mentioned aerodrome. (3) The pilot-in-command of an aeroplane, on being required by an authorised person to produce or cause to be produced for inspection by the authorised person the noise certificate in force in respect of the said aeroplane, shall produce or cause to be produced the said noise certificate. 9 Suspension, revocation and variation of noise certificates. 9. (1) The Minister may suspend, revoke, or vary any noise certificate, validation, approval, or other document issued under this Order after an investigation at which the person, to whom the noise certificate, validation, approval, or other document has been issued, has been given an opportunity of being heard. (2) The holder or any person having possession or custody of any noise certificate, validation, approval or other document which has been revoked, suspended or varied under this Order shall surrender it to the Minister within a reasonable time after being required to do so by him. (3) The breach of any condition subject to which any noise certificate, validation, approval or other document has been issued under this Order shall render the document invalid during the continuance of the breach. 10 Offences in relation to noise certificates. 10. A person shall not— ) forge or fraudulently alter, or procure to be forged or fraudulently altered, or assist in forging or fraudulently altering a noise certificate; ) use any noise certificate required under this Order which has been forged, fraudulently altered, revoked or suspended or has ceased to be in force; ) give or lend any noise certificate to any other person or allow or permit it to be used by any other person; or ) make, procure to be made or assist in making, any false representation for the purpose of procuring for himself or for any other person the issue, validation, renewal or variation of a noise certificate. 11 Right of access to and detention of aeroplanes. 11. (1) Whenever it appears to the Minister or an authorised person that an aeroplane is intended or likely to be flown from any place in the State in such circumstances that the flight would be a contravention of Article 6 of this Order or of any other provision of this Order or any direction made thereunder, the Minister or authorised person may give to the operator of the aeroplane or to the pilot-in-command thereof such instructions, and take such steps for the detention of the aeroplane or otherwise, as appear to him to be necessary in order to prevent the flight. (2) The operator or pilot-in-command of the aeroplane shall, unless he has reasonable grounds not to do, comply with every instruction given to him pursuant to paragraph (1) of this Article. (3) For the purposes of paragraph (1) of this Article, the Minister or authorised person may enter upon and inspect any aeroplane. 12 Right of access to aerodrome and other places. 12. The Minister or an authorised person may, for the purpose of ascertaining compliance with the provisions of this Order, have access at all reasonable times to any aerodrome or place within the State for the purpose of inspecting either any aeroplane on the said aerodrome or place or any document which under this Order he has power to demand or for the purpose of detaining any aeroplane under this Order, but access to an aerodrome under the control of the Minister for Defence shall be obtained only with the permission of the person in charge of the aerodrome. 13 Obstruction of authorised persons. 13. A person shall not wilfully obstruct or impede an authorised person acting in the exercise of his powers or the performance of his duties under this Order. 14 Enforcement of directions. 14. Any person who fails to comply with the direction given to him by the Minister or an instruction given by an authorised person under any provision of this Order shall be deemed for the purpose of this Order to have contravened that provision. 15 Exemptions. 15. The Minister may, by direction, exempt from any of the provisions of this Order any classes of aeroplanes. 16 Directions under this Order. 16. (1) The Minister may give directions for carrying out the purposes of this Order in respect of any matter or thing provided for by this Order. (2) Directions under this Order may be given in the form of Notices to Airmen (otherwise known as NOTAMS), Notices to Aircraft Owners and Aircraft Engineers, Aeronautical Information Circulars or by notice sent by registered post to the person affected. PART I Requirements for the issue of a noise certificate for aeroplanes specified in Articles 5 (1), 5 (2) and 5 (4b) of this Order. 1. The noise evaluation method for aeroplanes specified in Articles 5 (1) and 5 (2) shall be that prescribed in Appendix 1 of Annex 16 — first edition, 1981 to the Chicago Convention. 2. The noise evaluation method for aeroplanes specified in Article 5 (4b) shall be that prescribed in Appendix 2 of Annex 16 — first edition, 1981 to the Chicago Convention. 3. The noise evaluation measure for aeroplanes specified in Articles 5 (1) and 5 (2) shall be the effective perceived noise level expressed in units of EPNdB as described in Appendix 1 of Annex 16 — first edition, 1981 to the Chicago Convention. 4. The noise evaluation measure for aeroplanes specified in Article 5 (4b) shall be the effective perceived noise level expressed in units of EPNdB as described in Appendix 2 of Annex 16 — first edition, 1981 to the Chicago Convention. 5. Aeroplanes specified in Articles 5 (1) and 5 (2) shall be tested for noise certification in accordance with the test procedures specified in Part II, Chapter 2 of Annex 16— first edition, 1981 to the Chicago Convention. 6. Aeroplanes specified in Article 5 (4b) shall be tested for noise certification in accordance with the test procedures specified in Part II, Chapter 5 of Annex 16 — first edition, 1981 to the Chicago Convention. 7. (1) An aeroplane of the type specified in paragraphs 5 (1) and 5 (4b) of this Order when tested in accordance with the test procedure prescribed in paragraphs 5 and 6 of this Part of this Schedule shall not exceed the following maximum noise levels:— ) at lateral and approach noise measurement points: 108 EPNdB for aeroplanes with maximum certificated take-off mass of 272,000 kgs, or over, decreasing linearly with the logarithm of the mass at the rate of 2 EPNdB per halving of the mass down to 102 EPNdB at 34,000 kgs, after which the limit remains constant; ) at flyover noise measurement point: 108 EPNdB for aeroplanes with maximum certificated take-off mass of 272,000 kgs or over, decreasing linearly with the logarithm of the mass at the rate of 5 EPNdB per halving of the mass down to 93 EPNdB at 34,000 kgs after which the limit remains constant. (2) A derived version of an aeroplane of the type specified in paragraph 5 (2) of this Order when tested in accordance with the test procedure prescribed in paragraph 5 of this Part of this Schedule shall not exceed the following maximum noise levels:— ) at lateral noise measurement point: 106 EPNdB for aeroplanes with maximum certificated take-off mass of 400,000 kgs, or over, decreasing linearly with the logarithm of the mass down to 97 EPNdB at 35,000 kgs, after which the limit remains constant; ) at flyover noise measurement point:— (i) in the case of aeroplanes with two engines or less: 104 EPNdB for aeroplanes with maximum certificated take-off mass of 325,000 kgs, or over, decreasing linearly with the logarithm of the mass at the rate of 4 EPNdB per halving of mass down to 93 EPNdB, after which the limit remains constant; (ii) in the case of aeroplanes with three engines: ) 107 EPNdB for aeroplanes with maximum certificated take-off mass of 325,000 kgs, or over, decreasing linearly with the logarithm of the mass at the rate of 4 EPNdB per halving of the mass down to 93 EPNdB after which the limit remains constant, or ) 108 EPNdB for aeroplanes with maximum certificated take-off mass of 272,000 kgs, or over, decreasing linearly with the logarithm of the mass at the rate of 5 EPNdB per halving of the mass down to 93 EPNdB at 34,000 kgs, after which the limit remains constant, whichever is the lesser; (iii) in the case of aeroplanes with four engines or more: ) 108 EPNdB for aeroplanes with maximum certificated take-off mass of 325,000 kgs, or over, decreasing linearly with the logarithm of the mass at the rate of 4 EPNdB per halving of mass down to 93 EPNdB after which the limit remains constant, or ) 108 EPNdB for aeroplanes with maximum certificated take-off mass of 272,000 kgs, or over, decreasing linearly with the logarithm of the mass at the rate of 5 EPNdB per halving of the mass down to 93 EPNdB at 34,000 kgs, after which the limit remains constant, whichever is the lesser, ) At the approach noise measurement point: 108 EPNdB for aeroplanes with maximum certificated take-off mass of 280,000 kgs, or over, decreasing linearly with the logarithm of the mass down to 101 EPNdB at 35,000 kgs, after which the limit remains constant. 8. (1) The lateral noise measurement point is the point on a line parallel to and 650 m from the runway centre line, or extended runway centre line, where the noise level is a maximum during take-off. (2) The flyover noise measurement point is the point on the extended centre line of the runway and at a distance of 6.5 km from the start of roll. (3) The approach noise measurement point is the point on the ground, on the extended centre line of the runway, 120 m vertically below the 3° descent path originating from a point 300 m beyond the threshold. On level ground this corresponds to a position 2,000 m from the threshold. 9. If the maximum noise levels are exceeded at one or two measurement points:— ) the sum of excesses shall not be greater than 4 EPNdB, except that in respect of four-engined aeroplanes powered by engines with by-pass ratio of 2 or more and for which the application for certificate of airworthiness for the prototype was accepted or another equivalent procedure was effected by the certificating authorities before the 1st day of December, 1969, the sum of any excesses shall not be greater than 5 EPNdB; ) any excess at any single point shall not be greater than 3 EPNdB; ) any excesses shall be offset by corresponding reductions at the other point or points. PART II Requirements for the issue of a noise certificate for aeroplanes specified in Article 5 (3) of this Order. 1. The noise evaluation method shall be that prescribed in Appendix 2 of Annex 16 — first edition, 1981 to the Chicago Convention. 2. The noise evaluation measure shall be the effective perceived noise level in EPNdB as described in Appendix 2 of Annex 16 — first edition, 1981 to the Chicago Convention. 3. An aeroplane shall be tested for noise certification in accordance with the reference procedures outlined in Part II Chapter 3 of Annex 16 — first edition, 1981 to the Chicago Convention. 4. An aeroplane shall be tested for noise certification in accordance with the test procedures outlined in Part II Chapter 3 of Annex 16 — first edition, 1981 to the Chicago Convention. 5. An aeroplane when tested in accordance with the procedures laid down in paragraphs 3 and 4 of this Part of this Schedule shall not exceed the following maximum noise levels. (1) At the lateral reference noise measurement point: 103 EPNdB for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested, of 400,000 kgs, and over and decreasing linearly with the logarithm of the mass down to 94 EPNdB at 35,000 kgs after which the limit remains constant. (2) At the flyover reference noise measurement point: ) in the case of aeroplanes with two engines or less:—101 EPNdB for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested, of 385,000 kgs, and over, and decreasing linearly with the logarithm of the aeroplane mass at the rate of 4 EPNdB per halving of mass down to 89 EPNdB, after which the limit is constant; ) in the case of aeroplanes with three engines:—104 EPNdB for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested of 385,000 kgs, and over, and decreasing linearly with the logarithm of the aeroplane mass at the rate of 4 EPNdB per halving of mass down to 89 EPNdB after which the limit is constant; ) in the case of aeroplanes with four engines or more:—106 EPNdB for aeroplanes with maximum certificated take-off mass at which the noise certification is requested, of 385,000 kgs, and over, and decreasing linearly with the logarithm of the aeroplane mass at the rate of 4 EPNdB per halving of mass down to 89 EPNdB, after which the limit is constant. (3) At the approach reference noise measurement point: 105 EPNdB for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested, of 280,000 kgs, or over, and decreasing linearly with the logarithm of the mass down to 98 EPNdB at 35,000 kgs, after which the limit remains constant. (4) If a reference ambient air temperature of 15°C is used, 1 EPNdB shall be added to the measured (and adjusted) noise level obtained at the flyover measurement point before it is compared with the maximum noise level of paragraph 5 (2). 6. (1) The lateral reference noise measurement point is the point on a line parallel to and 450 m from the runway centre line, where the noise level is at a maximum during take-off. (2) The flyover reference noise measurement point is the point on the extended centre line of the runway and at a distance of 6.5 km from the start of roll. (3) The approach reference noise measurement point is the point on the ground on the extended centre line of the runway 2,000 m from the threshold. On level ground this corresponds to a position 120 m vertically below the 3° descent path originating from a point 300 m beyond the threshold. 7. (1) If the test noise measurement points are not located at the reference noise measurement points, any corrections for the difference in position shall be made in the same manner as the corrections for the difference between test and reference flight paths. (2) Sufficient lateral test noise measurement points shall be used to demonstrate to the Minister that the maximum noise level on the appropriate lateral line has been clearly determined. Simultaneous measurements shall be made at one test noise measurement point at a symmetrical position on the other side of the runway. (3) The applicant shall demonstrate to the Minister that, during flight tests, lateral and flyover noise levels were not separately optimized at the expense of each other. 8. If the maximum noise levels are exceeded at one or two measurement points: ) the sum of excesses shall not be greater than 3 EPNdB; ) any excess at any single point shall not be greater than 2 EPNdB; and ) any excesses shall be offset by corresponding reductions at the other point or points. PART III Requirements for the issue of a noise certificate for aeroplanes specified in Article 5 (4) ( ) of this Order. 1. The noise evaluation method shall be that prescribed in Appendix 2 of Annex 16 — first edition, 1981 to the Chicago Convention. 2. The noise evaluation measure shall be the effective perceived noise level in EPNdB as described in Appendix 2 to Annex 16 — first edition, 1981 to the Chicago Convention. 3. An aeroplane shall be tested for noise certification in accordance with the reference procedures laid down in Part II Chapter 5 of Annex 16 — first edition, 1981 to the Chicago Convention. 4. An aeroplane shall be tested for noise certification in accordance with the test procedures outlined in Part II Chapter 5 of Annex 16 — first edition, 1981 to the Chicago Convention. 5. An aeroplane when tested in accordance with the procedures laid down in paragraphs 3 and 4 of this Part of this Schedule shall not exceed the following maximum noise levels. (1) At the lateral reference noise measurement point: 96 EPNdB constant limit for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested, up to 34,000 kgs and increasing linearly with the logarithm of aeroplane mass at the rate of 2 EPNdB per doubling of mass from that point until the limit of 103 EPNdB is reached, after which the limit is constant; (2) At the flyover reference noise measurement point: 89 EPNdB constant limit for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested, up to 34,000 kgs and increasing linearly with the logarithm of aeroplane mass at the rate of 5 EPNdB per doubling of mass from that point until the limit of 106 EPNdB is reached, after which the limit is constant; and (3) At the approach reference noise measurement point: 98 EPNdB constant limit for aeroplanes with maximum certificated take-off mass, at which the noise certification is requested, up to 34,000 kgs and increasing linearly with the logarithm of aeroplane mass at the rate of 2 EPNdB per doubling of mass from that point until the limit of 105 EPNdB is reached, after which the limit is constant. 6. If the maximum noise levels specified in paragraph 5 are exceeded at one or two measurement points: ) the sum of excesses shall not be greater than 3 EPNdB; ) any excess at any single point shall not be greater than 2 EPNdB; and ) any excesses shall be offset by corresponding reductions at the other point or points. 7. (1) The lateral reference noise measurement point is the point on a line parallel to and 450 m from the runway centre line or extended runway centre line, where the noise level is a maximum during take-off. (2) The flyover reference noise measurement point is the point on the extended centre line of the runway and at a distance of 6.5 km from the start of roll. (3) The approach reference noise measurement point is the point on the ground, on the extended centre line of the runway 2,000 m from the threshold. On level ground this corresponds to a position 120 m vertically below the 3° descent path originating from a point 300 m beyond the threshold. 8. (1) If the test noise measurement points are not located at the reference noise measurement points, any corrections for the difference in position shall be made in the same manner as the corrections for the differences between test and reference flight paths. (2) Sufficient lateral test noise measurement points shall be used to demonstrate to the Minister that the maximum noise level on the appropriate lateral line has been clearly determined. Simultaneous measurements shall be made at one test noise measurement point at a symmetrical position on the other side of the runway. (3) The applicant shall demonstrate to the Minister that during flight test, lateral and flyover noise levels were not separately optimized at the expense of each other. PART IV Requirements for the issue of a document attesting noise certification for aeroplanes as specified in Article 5 (5) of this Order. 1. The noise evaluation method shall be that prescribed in Appendix 3 of Annex 16 — first edition, 1981 to the Chicago Convention. 2. (1) The noise evaluation measure shall be a weighted overall sound pressure level as defined in International Electrotechnical Commission (IEC) Publication 179 (as amended). The weighting applied to each sinusoidal component of the sound pressure shall be given as a function of frequency by the standard reference curve called "A". The unit is referred to as dB (A). (2) When requested by the Minister, noise data in terms of EPNdB as described in Appendix 1 of Annex 16 — first edition, 1981 to the Chicago Convention shall also be provided. In determining the duration correction as specified in 4.5 of Appendix 1, the time interval shall in each case be taken as the period, to the nearest 1.0 second, over which PNLT (k) remains greater than or equal to PNLTM — 10, the lower limit of 90 TPNdb not being applied. 3. An aeroplane shall be tested for noise certification in accordance with the reference procedures outlined in Part II Chapter 6 of Annex 16 — first edition, 1981 to the Chicago Convention. 4. An aeroplane shall be tested for noise certification in accordance with the test procedures outlined in Part II Chapter 6 of Annex 16 — first edition, 1981 to the Chicago Convention. 5. An aeroplane as specified in Articles 5 (5) ( ) and 5 (5) ( ) of this Order shall not exceed the following maximum noise levels: A 68 dB (A) constant limit up to an aeroplane mass of 600 kgs, varying linearly with mass from that point to 1,500 kgs, after which the limit is constant at 80 dB (A) up to 5,700 kgs (except that in the case of an application for a change in type design, the maximum certificated take-off mass may not exceed 6,500 kgs, provided that the prototype has been certificated at a maximum certificated take-off mass not exceeding 5,700 kgs). GIVEN under my Official Seal, this 20th day of January, 1984. JIM MITCHELL, Minister for Communications. EXPLANATORY NOTE.