Tel.: +1 514-954-8219 ext. 6726 

Ref.: AN 1/62.3-11/20 8 April 2011 

Subject: Adoption of Amendment 7 to Annex 16, 

Volume II 

Action Required: a) Notify any disapproval before 

18 July 2011; b) Notify any differences and compliance 

before 17 October 2011; c) Consider the use of the 

Electronic Filing of Differences System (EFOD) for 

notification of differences and compliance 

Sir/Madam, 

1. I have the honour to inform you that Amendment 7 to the International Standards and 

Recommended Practices, Environmental Protection — Aircraft Engine Emissions (Annex 16, Volume II 

to the Convention on International Civil Aviation) was adopted by the Council at the third meeting of its 

192nd Session on 4 March 2011. Copies of the Amendment and the Resolution of Adoption are available 

as attachments to the electronic version of this State letter on the ICAO-NET (www.icao.int/icaonet). 

2. When adopting the amendment, the Council prescribed 18 July 2011 as the date on which 

it will become effective, except for any part concerning which a majority of Contracting States have 

registered their disapproval before that date. In addition, the Council resolved that Amendment 7, to the 

extent it becomes effective, will become applicable on 17 November 2011. 

3. Amendment 7 arises from the recommendations of the eighth meeting of the Committee 

on Aviation Environmental Protection (CAEP/8). The subjects are given in the amendment to the 

Foreword of Annex 16, Volume II, Third Edition, a copy of which is in Attachment A. 

4. The amendment to Annex 16, Volume II includes an increase in stringency of NOx

emissions Standards and an update to the production cut-off provisions. The terminology of “equivalent 

procedures” has been introduced in order to improve consistency and harmonization within Annex 16, 

Volume II and with the Environmental Technical Manual (Doc 9501), Volume II – Procedures for the 

Emissions Certification of Aircraft Engines. Readability and organization is improved by moving some 

paragraphs to more appropriate places and correcting some editorial issues. 

999 University Street

Montréal, Quebec

Canada H3C 5H7

Tel.: +1 514-954-8219

Fax: +1 514-954-6077

E-mail: icaohq@icao.int

www.icao.int

International

Civil Aviation

Organization

Organisation

de l’aviation civile

internationale

Organización

de Aviación Civil

Internacional

Международная

организация

гражданской

авиации
- 2 - 

5. In accordance with the decision of the 26th Session of the Assembly, I would like to 

bring to your attention the Organization’s long-standing practice of providing documentation to States 

upon request. In this regard, I wish to refer you to the ICAO-NET website (www.icao.int/icaonet) where 

you can access all relevant documentation. The practice of dispatching printed copies of such 

documentation has now been discontinued. 

6. In conformity with the Resolution of Adoption, may I request that: 

a) before 18 July 2011, you inform me if there is any part of the adopted Standards and 

Recommended Practices (SARPs) in Amendment 7, concerning which your 

Government wishes to register disapproval, using the form in Attachment B for this 

purpose. Please note that only statements of disapproval need be registered and if you 

do not reply it will be assumed that you do not disapprove of the amendment; 

b) before 17 October 2011, you inform me of the following, using the form in 

Attachment C for this purpose: 

1) any differences that will exist on 17 November 2011 between the national 

regulations or practices of your Government and the provisions of the whole of 

Annex 16, Volume II, as amended by all amendments up to and including 

Amendment 7, and thereafter of any further differences that may arise; and 

2) the date or dates by which your Government will have complied with the 

provisions of the whole of Annex 16, Volume II, as amended by all amendments 

up to and including Amendment 7. 

7. With reference to the request in paragraph 6 a) above, it should be noted that a 

registration of disapproval of Amendment 7 or any part of it in accordance with Article 90 of the 

Convention does not constitute a notification of differences under Article 38 of the Convention. To 

comply with the latter provision, a separate statement is necessary if any differences do exist, as requested 

in paragraph 6 b) 1). It is recalled in this respect that international Standards in Annexes have a 

conditional binding force, to the extent that the State or States concerned have not notified any difference 

thereto under Article 38 of the Convention. 

8. With reference to the request in paragraph 6 b) above, it should be also noted that the 

Council, at the third meeting of its 192nd Session on 4 March 2011, agreed that pending the development 

of a concrete policy and operational procedures governing the use of EFOD, this system be used as an 

alternative means for filing of differences to all Annexes, except for Annex 9 — Facilitation and 

Annex 17 — Security — Safeguarding International Civil Aviation against Acts of Unlawful Interference. 

EFOD is currently available on the USOAP restricted website (http://www.icao.int/soa) which is 

accessible by all Member States (AN 1/1-11/28 refers) and you are invited to consider using this for 

notification of compliance and differences. 

9. Guidance on the determination and reporting of differences is given in the Note on the 

Notification of Differences in Attachment D. 

10. Please note that a detailed repetition of previously notified differences, if they continue to 

apply, may be avoided by stating the current validity of such differences. 
- 3 - 

11. I would appreciate it if you would also send a copy of your notifications, referred to in 

paragraph 6 b) above, to the ICAO Regional Director accredited to your Government. 

12. As soon as practicable after the amendment becomes effective, on 18 July 2011, 

replacement pages incorporating Amendment 7 will be forwarded to you. 

Accept, Sir/Madam, the assurances of my highest consideration. 

 

Raymond Benjamin 

Secretary General 

Enclosures: 

A — Amendment to the Foreword of Annex 16, 

Volume II 

B — Form on notification of disapproval of all or part of 

Amendment 7 to Annex 16, Volume II 

C — Form on notification of compliance with or 

differences from Annex 16, Volume II 

D — Note on the Notification of Differences 
ATTACHMENT A to State letter AN 1/62.3-11/20 

AMENDMENT TO THE FOREWORD OF 

ANNEX 16, VOLUME II, THIRD EDITION 

Add the following at the end of Table A: 

Amendment Source(s) Subject(s)

Adopted/Approved 

Effective 

Applicable

7 Eighth meeting of the 

Committee on 

Aviation 

Environmental 

Protection (CAEP/8)

a) Increase in stringency of the NOx

emissions Standards; 

b) an update to the references to the 

Environmental Technical Manual

(Doc 9501), Volume II — 

Procedures for the Emissions 

Certification of Aircraft Engines; 

c) updates to the text to replace 

“variations in procedures” by 

“equivalent procedures,” in order to 

improve consistency and 

harmonization within Annex 16, 

Volume II and with the 

Environmental Technical Manual

(Doc 9501), Volume II — 

Procedures for the Emissions 

Certification of Aircraft Engines; 

d) the format of applicability dates in 

Section 2.3.2 made consistent with 

the convention used in Annex 6 and 

Annex 16, Volume I; 

e) improved readability by moving 

some paragraphs to more appropriate 

places; and 

f) minor editorial changes. 

4 March 2011 

18 July 2011 

17 November 2011

— — — — — — — — 
— — — — — — — — 

ATTACHMENT B to State letter AN 1/62.3-11/20 

NOTIFICATION OF DISAPPROVAL OF ALL OR PART OF 

AMENDMENT 7 TO ANNEX 16, VOLUME II

To: The Secretary General 

International Civil Aviation Organization 

999 University Street 

Montreal, Quebec 

Canada H3C 5H7 

(State) hereby wishes to disapprove the following parts of 

Amendment 7 to Annex 16, Volume II: 

Signature

Date

NOTES

1) If you wish to disapprove all or part of Amendment 7 to Annex 16, Volume II, please dispatch this 

notification of disapproval to reach ICAO Headquarters by 18 July 2011. If it has not been received 

by that date it will be assumed that you do not disapprove of the amendment. If you approve of all 

parts of Amendment 7, it is not necessary to return this notification of disapproval.

2) This notification should not be considered a notification of compliance with or differences from 

Annex 16, Volume II. Separate notifications on this are necessary. (See Attachment C.) 

3) Please use extra sheets as required. 
ATTACHMENT C to State letter AN 1/62.3-11/20 

NOTIFICATION OF COMPLIANCE WITH OR DIFFERENCES 

FROM ANNEX 16, VOLUME II 

(including all amendments up to and including Amendment 7) 

To: The Secretary General 

International Civil Aviation Organization 

999 University Street 

Montréal, Quebec 

Canada H3C 5H7 

1. No differences will exist on between the national 

regulations and/or practices of (State) and the provisions 

of Annex 16, Volume II, including all amendments up to and including Amendment 7. 

2. The following differences will exist on between the 

regulations and/or practices of (State) and the provisions 

of Annex 16, Volume II, including Amendment 7 (Please see Note 3) below.) 

a) Annex 

Provision 

b) Difference 

Category 

c) Details of Difference d) Remarks 

(Please give 

exact 

paragraph 

reference) 

(Please indicate 

A, B, or C) 

(Please describe the 

difference clearly and 

concisely) 

(Please indicate 

reasons for the 

difference) 

(Please use extra sheets as required) 
C-2

3. By the dates indicated below, (State) will have 

complied with the provisions of Annex 16, Volume II, including all amendments up to and including 

Amendment 7 for which differences have been notified in 2 above. 

a) Annex Provision b) Date c) Comments 

(Please give exact 

paragraph reference) 

 

 (Please use extra sheets as required) 

Signature

Date

NOTES

1) If paragraph 1 above is applicable to you, please complete paragraph 1 and return this form to ICAO 

Headquarters. If paragraph 2 is applicable to you, please complete paragraphs 2 and 3 and return the 

form to ICAO Headquarters. 

2) Please dispatch the form to reach ICAO Headquarters by 17 October 2011. 

3) A detailed repetition of previously notified differences, if they continue to apply, may be avoided by 

stating the current validity of such differences. 

4) Guidance on the notification of differences from Annex 16, Volume II is provided in the Note on the 

Notification of Differences at Attachment D. 

5) Please send a copy of this notification to the ICAO Regional Director accredited to your 

Government. 

— — — — — — — —
ATTACHMENT D to State letter AN 1/62.3-11/20 

NOTE ON THE NOTIFICATION OF DIFFERENCES TO ANNEX 16, VOLUME II 

AND FORM OF NOTIFICATION 

(Prepared and issued in accordance with instructions of the Council) 

1. Introduction

1.1 The Assembly and the Council, when reviewing the notification of differences by States 

in compliance with Article 38 of the Convention, have repeatedly noted that the state of such reporting is 

not entirely satisfactory. 

1.2 With a view to achieving a more comprehensive coverage, this note is issued to facilitate 

the determination and reporting of such differences and to state the primary purpose of such reporting. 

1.3 The primary purpose of reporting of differences is to promote safety and efficiency in air 

navigation by ensuring that governmental and other agencies, including operators and service providers, 

concerned with international civil aviation are made aware of all national regulations and practices in so 

far as they differ from those prescribed in the ICAO Standards. 

1.4 Contracting States are, therefore, requested to give particular attention to the notification 

before 17 October 2011 of differences with respect to Standards in Annex 16, Volume II. The Council has 

also urged Contracting States to extend the above considerations to Recommended Practices. 

1.5 Contracting States are asked to note further that it is necessary to make an explicit 

statement of intent to comply where such intent exists, or where such is not the intent, of the difference or 

differences that will exist. This statement should be made not only to the latest amendment but to the 

whole Annex, including the amendment.

1.6 If previous notifications have been made in respect of this Annex, detailed repetition may 

be avoided, if appropriate, by stating the current validity of the earlier notification. States are requested to 

provide updates of the differences previously notified after each amendment, as appropriate, until the 

difference no longer exists. 

2. Notification of differences to Annex 16, Volume II, including Amendment 7 

2.1 Past experience has indicated that the reporting of differences to Annex 16, Volume II 

has in some instances been too extensive since some appear merely to be a different manner of expressing 

the same intent. 

2.2 Guidance to Contracting States in the reporting of differences to Annex 16, Volume II 

can only be given in very general terms. Where the national regulations of States call for compliance with 

procedures that are not identical but essentially similar to those contained in the Annex, no difference 

should be reported since the details of the procedures existing are the subject of notification through the 

medium of aeronautical information publications. Although differences to Recommended Practices are 

not notifiable under Article 38 of the Convention, Contracting States are urged to notify the Organization 

of the differences between their national regulations and practices and any corresponding Recommended 

Practices contained in an Annex. States should categorize each difference notified on the basis of whether 

the corresponding national regulation is: 
______________________ 

*The expression “different in character or other means of compliance” in b) would be applied to a national 

regulation which achieves, by other means, the same objective as that of the corresponding ICAO SARPs 

and so cannot be classified under a) or c). 

D-2

 a) More exacting or exceeds the ICAO Standard or Recommended Practice (SARP) 

(Category A). This category applies when the national regulation is more demanding

than the corresponding SARP, or imposes an obligation within the scope of the 

Annex which is not covered by a SARP. This is of particular importance where a 

State requires a higher standard which affects the operation of aircraft of other 

Contracting States in and above its territory; 

b) Different in character or other means of compliance (Category B)*. This category 

applies when the national regulation is different in character from the corresponding 

ICAO SARP, or when the national regulation differs in principle, type or system 

from the corresponding SARP, without necessarily imposing an additional 

obligation; and 

c) Less protective or partially implemented/not implemented (Category C). This 

category applies when the national regulation is less protective than the 

corresponding SARP; or when no national regulation has been promulgated to 

address the corresponding SARP, in whole or in part. 

2.3 For States that have already fully reported differences from Annex 16, Volume II or have 

reported that no differences exist, the reporting of any further differences occasioned by the amendment 

should be relatively straightforward; however, attention is called to paragraph 1.5 wherein it is indicated 

that this statement should be not only to the latest amendment but to the whole Annex, including the 

amendment. 

3. Form of notification of differences

 

3.1 Differences should be notified in the following form: 

a) Reference: The number of the paragraph or subparagraph in Annex 16, 

Volume II as amended which contains the Standard or Recommended Practice to 

which the difference relates; 

b) Category: Indicate the category of the difference as A, B or C in accordance with 

paragraph 2.2 above; 

c) Description of the difference: Clearly and concisely describe the difference and 

its effect; 

d) Remarks: Under “Remarks” indicate reasons for the difference and intentions 

including any planned date for implementation. 
D-3

3.2 The differences notified will be recorded in a Supplement to the Annex, normally in the 

terms used by the Contracting State when making the notification. In the interest of making the 

supplement as useful as possible, please make statements as clear and concise as possible and confine 

remarks to essential points. Comments on implementation, in accordance with paragraph 4 b) 2) of the 

Resolution of Adoption, should not be combined with those concerning differences. The provision of 

extracts from national regulations cannot be considered as sufficient to satisfy the obligation to notify 

differences. General comments that do not relate to specific differences will not be published in 

Supplements. 

— END — 
AMENDMENT No. 7 

TO THE 

INTERNATIONAL STANDARDS 

AND RECOMMENDED PRACTICES 

ENVIRONMENTAL

PROTECTION

ANNEX 16 

TO THE CONVENTION ON INTERNATIONAL CIVIL AVIATION 

VOLUME II 

AIRCRAFT ENGINE EMISSIONS 

The amendment to Annex 16, Volume II, contained in this document was 

adopted by the Council of ICAO on 4 March 2011. Such parts of this 

amendment as have not been disapproved by more than half of the total 

number of Contracting States on or before 18 July 2011 will become effective 

on that date and will become applicable on 17 November 2011 as specified in 

the Resolution of Adoption. (State letter AN 1/62.3-11/20 refers.) 

MARCH 2011

INTERNATIONAL CIVIL AVIATION ORGANIZATION

AMENDMENT 7 TO THE INTERNATIONAL STANDARDS 

AND RECOMMENDED PRACTICES 

ENVIRONMENTAL PROTECTION — AIRCRAFT ENGINE EMISSIONS 

RESOLUTION OF ADOPTION 

The Council 

 Acting in accordance with the Convention on International Civil Aviation, and 

particularly with the provisions of Articles 37, 54 and 90 thereof, 

1. Hereby adopts on 4 March 2011 Amendment 7 to the International Standards and 

Recommended Practices contained in the document entitled International Standards and Recommended 

Practices, Environmental Protection — Aircraft Engine Emissions which for convenience is designated 

Annex 16, Volume II to the Convention; 

2. Prescribes 18 July 2011 as the date upon which the said Amendment shall become 

effective, except for any part thereof in respect of which a majority of the Contracting States have 

registered their disapproval with the Council before that date; 

3. Resolves that the said Amendment or such parts thereof as have become effective shall 

become applicable on 17 November 2011; 

4. Requests the Secretary General: 

a) to notify each Contracting State immediately of the above action and immediately 

after 18 July 2011 of those parts of the amendment which have become effective; 

b) to request each Contracting State: 

1) to notify the Organization (in accordance with the obligation imposed by 

Article 38 of the Convention) of the differences that will exist on 17 November 

2011 between its national regulations or practices and the provisions of the 

Standards in the Annex as hereby amended, such notification to be made before 

17 October 2011, and thereafter to notify the Organization of any further 

differences that arise; 

2) to notify the Organization before 17 October 2011 of the date or dates by which 

it will have complied with the provisions of the Standards in the Annex as hereby 

amended. 

c) to invite each Contracting State to notify additionally any differences between its 

own practices and those established by the Recommended Practices, when the 

notification of such differences is important for the safety of air navigation, following 

the procedure specified in subparagraph b) above with respect to differences from 

Standards. 

— — — — — — — — 

 
2 

NOTES ON THE PRESENTATION OF THE 

AMENDMENT TO ANNEX 16, VOLUME II 

1. The text of the amendment is arranged to show deleted text with a line through it and new text 

highlighted with grey shading, as shown below: 

1. Text to be deleted is shown with a line through it. text to be deleted

2. New text to be inserted is highlighted with grey shading. new text to be inserted

3. Text to be deleted is shown with a line through it followed 

by the replacement text which is highlighted with grey 

shading.

new text to replace existing text

2. The proposed amendment to Annex 16, Volume II arises from Recommendation 2/2 of the eighth 

meeting of the Committee on Aviation Environmental Protection. 

 
3 

TEXT OF AMENDMENT 7 TO THE 

INTERNATIONAL STANDARDS 

AND RECOMMENDED PRACTICES 

ENVIRONMENTAL PROTECTION 

ANNEX 16 

TO THE CONVENTION ON INTERNATIONAL CIVIL AVIATION 

VOLUME II — AIRCRAFT ENGINE EMISSIONS 

. . .

PART I. DEFINITIONS AND SYMBOLS 

CHAPTER 1. DEFINITIONS 

. . .

 Note.— Attention is drawn to the difference between the definition of “derived version of an 

aeroplane” in Volume I of Annex 16 and the definition of “derivative version” in this Volume. 

Exhaust nozzle. In the exhaust emissions sampling of gas turbine engines where the jet effluxes are not 

mixed (as in some turbofan engines for example) the nozzle considered is that for the gas generator 

(core) flow only. Where, however, the jet efflux is mixed the nozzle considered is the total exit 

nozzle.

. . . 

PART III. EMISSIONS CERTIFICATION 

CHAPTER 1. ADMINISTRATION 

. . .

 1.4 Contracting States shall recognize as valid emissions certification granted by the certificating 

authority of another Contracting State provided that the requirements under which such certification was 

granted are not less stringent than the provisions of Volume II of this Annex. 

 1.5 Contracting States shall recognise as valid engine exemptions against an engine production cutoff requirement granted by a certificating authority of another Contracting State provided that the 

exemptions are granted in accordance with the process and criteria defined in the Environmental 

Technical Manual (Doc 9501),Volume II — Procedures for the Emissions Certification of Aircraft 

Engines.
4 

CHAPTER 2. TURBOJET AND TURBOFAN ENGINES INTENDED FOR 

PROPULSION ONLY AT SUBSONIC SPEEDS 

2.1 General 

2.1.1 Applicability 

 2.1.1.1 The provisions of this chapter shall apply to all turbojet and turbofan engines, as further 

specified in 2.2 and 2.3, intended for propulsion only at subsonic speeds, except when certificating 

authorities make exemptions for: 

. . . 

 b) a limited number of engines over a specific period of time beyond the dates of applicability 

specified in 2.2 and 2.3 for the manufacture of the individual engine. 

 2.1.1.2 In such cases, an exemption document shall be issued by the certificating authority, the 

identification plates on the engines shall be marked “EXEMPT,” “EXEMPT NEW” or “EXEMPT 

SPARE” and the grant of exemption shall be noted in the permanent engine record. Exemptions shall be 

reported by engine serial number and made available via an official public register.

 2.1.1.3 The provisions of this chapter shall also apply to engines designed for applications that 

otherwise would have been fulfilled by turbojet and turbofan engines. 

 Note.— In considering exemptions, certificating authorities should take into account the probable 

numbers of such engines that will be produced and their impact on the environment. When such an 

exemption is granted, the certificating authority should consider imposing a time limit on the production 

of such engines for installation on new aircraft or on existing aircraft as spares. Further guidance on 

issuing exemptions is provided in the Environmental Technical Manual (Doc 9501), Volume II —

Procedures for the Emissions Certification of Aircraft Engines.

. . .

2.1.4 Reference conditions 

. . .

2.1.4.4 Fuel specifications 

The fuel used during tests shall meet the specifications of Appendix 4, unless a deviation and any 

necessary corrections have been agreed by the certificating authority. Additives used for the purpose of 

smoke suppression (such as organo-metallic compounds) shall not be present. 

. . .

2.2 Smoke 

. . .

2.2.2 Regulatory Smoke Number 

The Smoke Number at any of the four LTO operating mode thrust settings when measured and computed 

in accordance with the procedures of Appendix 2, or an equivalent procedure as agreed by the 
5 

certificating authority, and converted to a characteristic level by the procedures of Appendix 6 shall not 

exceed the level determined from the following formula: 

 Regulatory Smoke Number = 83.6 (Foo)

–0.274

 or a value of 50, whichever is lower 

 Note.― Guidance material on the definition and the use of equivalent procedures is provided in the 

Environmental Technical Manual (Doc 9501), Volume II — Procedures for the Emissions Certification of 

Aircraft Engines.

2.3 Gaseous emissions 

. . .

2.3.2 Regulatory levels 

Gaseous emission levels when measured and computed in accordance with the procedures of Appendix 3 

and converted to characteristic levels by the procedures of Appendix 6, or an equivalent procedure as 

agreed by the certificating authority, shall not exceed the regulatory levels determined from the following 

formulas: 

. . .

a) for engines of a type or model for which the date of manufacture of the first individual production 

model was on or before 31 December 1995 before 1 January 1996 and for which the date of 

manufacture of the individual engine was on or before 31 December 1999 before 1 January 2000. 

. . . 

b) for engines of a type or model for which the date of manufacture of the first individual production 

model was after 31 December 1995 on or after 1 January 1996 or for which the date of 

manufacture of the individual engine was after 31 December 1999 on or after 1 January 2000. 

. . . 

c) for engines of a type or model for which the date of manufacture of the first individual production 

model was after 31 December 2003 on or after 1 January 2004: 

. . .

2) for engines with a pressure ration of more than 30 but less than 62.5: 

. . .

ii) for engines with a maximum rated thrust of more than 26.7 kN but not more than 89.0 

kN: 

 Dp /Foo = 42.71 + 1.4286πoo – 0.4013Foo + 0.00642πoo × Foo

. . .

 d) for engines of a type or model for which the date of manufacture of the first individual production 
6 

model was after 31 December 2007 on or after 1 January 2008 or for which the date of 

manufacture of the individual engine was on or after 1 January 2013: 

1) for engines with a pressure ratio of 30 or less: 

i) for engines with a maximum rated thrust of more than 89.0 kN: 

 Dp /Foo = 16.72 + (1.4080 * πoo)

 ii) for engines with a maximum rated thrust of more than 26.7 kN but not more than 89.0 

kN: 

 Dp /Foo = 38.5486 + (1.6823 * πoo) – (0.2453 * Foo) – (0.00308 * πoo * Foo)

 2) for engines with a pressure ratio of more than 30 but less than 82.6: 

 i) for engines with a maximum rated thrust of more than 89.0 kN: 

 Dp /Foo = –1.04 + (2.0 * πoo)

 ii) for engines with a maximum rated thrust of more than 26.7 kN but not more than 89.0 

kN: 

 Dp /Foo = 46.1600 + (1.4286 * πoo) – (0.5303 * Foo) + (0.00642 * πoo * Foo)

 3) for engines with a pressure ratio of 82.6 or more: 

 Dp /Foo = 32 + (1.6 * πoo)

e) for engines of a type or model for which the date of manufacture of the first individual production 

model was on or after 1 January 2014:

 1) for engines with a pressure ratio of 30 or less:

 i) for engines with a maximum rated thrust of more than 89.0 kN:

 Dp /Foo = 7.88 + 1.4080πoo

 ii) for engines with a maximum rated thrust of more than 26.7 kN but not more than 89.0 

kN:

 Dp /Foo = 40.052 + 1.5681πoo – 0.3615Foo – 0.0018πooFoo

 2) for engines with a pressure ratio of more than 30 but less than 104.7:

 i) for engines with a maximum rated thrust of more than 89.0 kN:

 Dp /Foo = –9.88 + 2.0πoo

 ii) for engines with a maximum rated thrust of more than 26.7 kN but not more than 89.0 

kN:
7 

 Dp /Foo = 41.9435 + 1.505πoo – 0.5823Foo + 0.005562πoo Foo

 3) for engines with a pressure ratio of 104.7 or more:

 Dp /Foo = 32 + 1.6πoo

Note.― Guidance material on the definition and the use of equivalent procedures is provided the 

Environmental Technical Manual (Doc 9501), Volume II — Procedures for the Emissions Certification of 

Aircraft Engines.

. . .

APPENDIX 2. SMOKE EMISSION EVALUATION 

1. INTRODUCTION AND DEFINITIONS 

Note.— The procedures specified here are concerned with the acquisition of representative exhaust 

samples and their transmission to, and analysis by, the emissions measuring system. 

 1.1 Variations in the procedure Any equivalent procedures to those contained in this Appendix shall 

only be allowed after prior application to and approval by the certificating authority. 

. . .

2. MEASUREMENT OF SMOKE EMISSIONS 

. . . 

2.4 Fuel specifications 

The fuel shall meet the specifications of Appendix 4. Additives used for the purpose of smoke 

suppression (such as organo-metallic compounds) shall not be present.

. . .

3. CALCULATION OF SMOKE NUMBER FROM MEASURED DATA 

. . .

 The masses of the various samples shall be calculated by 

W = 0.348 PV/T × 10–2(kg) 

where P and T are, respectively, the sample pressure in pascals Pascal and the temperature in kelvin

Kelvin, measured immediately upstream of the volume meter. V is the measured sample volume in cubic 

metres. 

. . . 
8 

APPENDIX 3. INSTRUMENTATION AND MEASUREMENT 

TECHNIQUES FOR GASEOUS EMISSIONS 

1. INTRODUCTION 

Note.— The procedures specified in this appendix are concerned with the acquisition of 

representative exhaust samples and their transmission to, and analysis by, the emissions measuring 

system. The procedures do not apply to engines employing afterburning. The methods proposed are 

representative of the best readily available and most established practice. 

Variations in the procedure Any equivalent procedures to those contained in this appendix shall only 

be allowed after prior application to and approval by the certificating authority. 

2. DEFINITIONS 

Exhaust nozzle. In the exhaust emissions sampling of gas turbine engines where the jet effluxes are not 

mixed (as in some turbofan engines for example) the nozzle considered is that for the gas generator 

(core) flow only. Where, however, the jet efflux is mixed the nozzle considered is the total exit 

nozzle.

. . .

APPENDIX 4. SPECIFICATION FOR FUEL TO BE USED IN 

AIRCRAFT TURBINE ENGINE EMISSION TESTING 

The fuel shall meet the specifications of this Appendix 4, unless a deviation and any necessary corrections 

have been agreed by the certificating authority. Additives used for the purpose of smoke suppression 

(such as organo-metallic compounds) shall not be present.

. . . 

— END —