(22 pages) 

 

COMMITTEE ON AVIATION ENVIRONMENTAL PROTECTION (CAEP) 

EIGHTH MEETING 

Montréal, 1 to 12 February 2010 

AGENDA ITEM 2 

PART TWO 

The attached constitutes the report on Agenda Item 2 and should be 

inserted at the appropriate place in the yellow report folder. 

CAEP/8-WP/80 

9/2/10 

CAEP/8-WP/80

 Report on Agenda Item 2 2-25

Agenda Item 2: Review of technical proposals relating to aircraft engine emissions 

... 

2.6 EMISSIONS – OPERATIONS RELATED ISSUES 

2.6.1 Prior to the discussion on Agenda Item 2, D/ATB briefly presented the role of ATB in 

support of CAEP activities and, in particular, on the ongoing coordination with ANB on operational 

measures to address aviation emissions, assuring the commitment of both herself and D/ANB to continue 

this coordination and cooperation between these Bureaux. D/ATB then introduced D/ANB who provided 

a presentation on overall initiatives undertaken under ANB and suggested next steps and specific areas 

where CAEP and the operational community could benefit from further collaboration. 

2.6.2 She emphasised that Secretariat would do its part and presented concrete steps put in 

place to ensure coordination and transparency. She proposed next steps for pursuing the collaboration 

between the environmental and operational “talent” and offered to brief CAEP on the developments in the 

operational efforts that benefit environment. The main area where the support of the committee was 

sought was on the development of methods to assess environmental benefits of operational measures. She 

proposed to establish a “measures” sub-group of the Regional Planning and Implementation Groups 

(PIRGS) and develop a training programme in this area. 

2.6.3 A member stressed that ICAO has several panels, dedicated for safety, economic and 

security aspects but that there is a committee with the remit on environmental-related issues and that all 

environmental considerations are tasked within CAEP. She added that it was obvious that while 

performing these activities, coordination between the other panels was necessary. 

2.6.4 Several members and observers welcomed the presentation made by D/ANB and stressed 

the importance of non-duplication, coordination and cooperation among ATB, ANB and CAEP. A 

member suggested that ANB provide updates to CAEP and SG meetings on the operational work. An 

observer suggested that when discussing these issues under the Future Work agenda item, members from 

ANB attend the meeting. 

2.6.5 The Chair summarized by saying that he heard many magic “Cs” in the presentation, i.e. 

commitment, collaboration, cooperation, coordination and CAEP, and that the Committee was pleased to 

hear that it could count on the support from ANB for the development of some of its tasks. He further 

stated that the suggestions for next steps proposed by D/ANB would be brought to the attention of the 

meeting during the consideration of future work under agenda item 5. He also thanked both D/ATB and 

D/ANB for their contributions. 

2.6.6 Next, a representative from the UNFCCC Secretariat provided the meeting with a brief 

update on the climate change negotiations under the UNFCCC, in particular the result of COP/15. He 

mentioned that, although bunker fuels were not directly addressed in the Copenhagen Accord, it 

recognized the scientific view to hold the increase in global temperature below 2 degrees Celsius and that 

it would be important for ICAO and CAEP to explore what this goal meant for international aviation. He 

also referred to the Accord’s goals for mobilizing new and additional finance which would come from a 

variety of sources, including “alternative sources of funding” and that some might look to funding from 

international aviation in this regard. 
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2.6.7 He informed that to date 38 Annex I Parties provided information on their economy-wide 

emission reduction targets for 2020, but specific targets on international aviation were not included in the 

submissions. 23 non-Annex I Parties provided information on mitigation actions, and seven of them 

mentioned the transport sector, but no specific activities on international aviation were mentioned. 

2.6.8 He concluded that the year 2010 provides an opportunity for ICAO and UNFCCC to 

further advance their work on a robust and efficient GHG regime for international aviation which will 

benefit the global environment and future generations. 

2.6.9 Report of Working Group 2 

2.6.9.1 The Co-Rapporteurs of WG2 presented the Group’s report on activities since CAEP/7. 

The detailed work of the Group had been undertaken by four Task Groups as follows: 

a) Task Group 1 (TG1): Land use planning and noise management; 

b) Task Group 2 (TG2): Air Traffic Management; 

c) Task Group 3 (TG3): Operational measures; and 

d) Task Group 4 (TG4): Local air quality. 

2.6.9.2 Ad hoc activities on the update and conversion of ICAO Circular 303 into an ICAO 

guidance manual and on the ICAO carbon emissions calculation methodology were also undertaken. 

2.6.10 TG1 – Land Use Planning and Noise Management Task Group 

2.6.10.1 The group continued to develop updates to the concept of a Balanced Approach to 

Aircraft Noise Management and to estimate the environmental impact of curfews on destination airports. 

It also investigated the use of Environmental Management Systems (EMS) among aviation organisations. 

2.6.11 TG2 – Air Traffic Management Task Group 

2.6.11.1 The group investigated approaches to environmental impact assessment as applied to 

CNS/ATM. It began development of ICAO guidance on computing, assessing and reporting on aviation 

emissions at national and global levels and the development of environmental indicators (EI). It also 

supported the IE efforts to make recommendations for noise, NOx and fuel burn with respect to air traffic 

operational goals in the mid and long terms. 

2.6.12 TG3 – Operational Measures Task Group 

2.6.12.1 The group assessed the potential reductions of noise and gaseous emissions through the 

use of reduced takeoff thrust and deeper cutback and by the use of the Continuous Descent Operations 

(CDO). It contributed to the development of the CDO manual in cooperation with the IFPP and also 

studied the potential changes in noise exposure associated with steeper approaches. 
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 Report on Agenda Item 2 2-27

2.6.13 TG4 – Airport Local Air Quality Task Group 

2.6.13.1 The group completed development of new and updated chapters for ICAO Doc 9889, 

“Airport Air Quality Guidance Manual.” It also had coordinated with FESG and MODTF on aircraft 

times-in-mode, and developed a report to CAEP and web text on the role of market based measures in a 

management framework for local emissions.

2.6.14 Environmental Indicators 

2.6.14.1 The WG2 TG2 Environmental Indicators Ad-Hoc Group was tasked with conducting a 

review of the present guidance and practices in environmental performance indicators (EI). 

2.6.14.2 While the guidance material is still not mature, key findings have been made and the 

basis for the development of ICAO EI guidance has been identified. However, there was a lack of 

consensus within the group on if and how this material should be used or further developed. 

Findings 

2.6.14.3 Differing purposes for EIs were identified: 

• Regulatory and policy (decision support); 

• Overarching environmental performance tracking (reporting); 

• Support to (and harmonising of) local environmental performance tracking; and 

• Support to and harmonising of confidential benchmarking 

2.6.14.4 ISO environmental management system standards (e.g. 14031 & 14032) offer a sound 

basis for any overarching EI work within aviation and are the basis for the ICAO EI development. 

Consistency in the definitions of EI and in the quality of “feed data” collection and management are 

considered to be essential. The development and promulgation of simple EI tests would also help the 

industry to minimise unnecessary, poorly designed or inappropriate EI. 

Proposed ICAO approach to Environmental Indicators 

2.6.14.5 If EI guidance is to be developed through CAEP, it is proposed to: 

a) only specify EIs to a level of detail that it (or its States or Institutions) wishes to 

monitor actively; 

b) publish these EIs as those that Civil Aviation stakeholders are required to support; 

c) publish generic aviation relevant Environmental Performance Management guidance 

complimenting the guidance already developed in the ISO international standards; 

and 

d) establish a process to be led by WG2 – the existing EI ad-hoc group may suffice but 

an independent expert process may also be a possible solution, which would have a 

significant cost. 
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Discussion and Conclusions 

2.6.14.6 The meeting congratulated the ad-hoc group of this task on its effort and progress in spite 

of the complexity of the task, and several members expressed the need to continue this task, subject to 

taking into account the priority and resources necessary for various tasks. Another member commented 

that they learned a lot from the report; including the complexity of indicators and that they are Statespecific. As such, the work can inform ICAO, but cannot be published as is, and any potential future 

work needs to be weighed carefully given other priorities and lack of WG2 consensus – likely due to 

feasibility and lack of resources. 

2.6.14.7 A member expressed the need to ensure non-duplication with other tasks, and informed 

that CANSO has been working on a similar task from a global perspective and coordination with this 

work should be explored in the future work programme. 

2.6.14.8 The Chair concluded that there was general support for the necessity of this task, and that 

the future work of this task, including further development of an ICAO EI guidance; development of 

specific EIs with a focus on operational fuel efficiency and CO2 emissions; and development of EI inputs 

to the work of Circular 303 replacement, would be further discussed in Agenda Item 5. 

2.6.15 Environmental Assessment of CNS/ATM 

Background 

2.6.15.1 The WG2 TG2 Lead noted that the different impacts of aviation, including sustainability 

and socio economics issues, can be classified as having either a Local or a Global effect on the 

environment. CNS/ATM programmes have already demonstrated their capability in reducing significantly 

the environmental impact of aviation. 

2.6.15.2 An agreed Environmental Impact Assessment methodology is needed to ensure the 

consolidation of the environmental studies that will be conducted in Research and Development 

programmes like SESAR and NextGen. It should be an integrated and systematic approach to assess how 

ATM programmes and improvements may impact the environment and should cover all phases of flight 

operation (ground, climb, cruise and descent). The ability to assess, predict, measure and monitor any 

changes in environmental performance allows decision-makers to incorporate information relating to the 

likely environmental impact of a CNS/ATM measure as a complement to other criteria such as safety, 

capacity, security and cost-efficiency, etc. 

2.6.15.3 At present, there is no global and commonly agreed high level framework for conducting 

environmental impact assessment for CNS/ATM activities. 

Progress to Date 

2.6.15.4 A draft text based on guidance that is being developed within Europe was presented, 

based on three sources: 

1) Output from the European Commission project CAATS1

 II (WP1.5); 

 

1

 Co-operative Approach to Air Traffic Services 
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 Report on Agenda Item 2 2-29

2) European Operational Concept Validation Methodology (E-OCVM); and 

3) EUROCONTROL internal guidance material. 

2.6.15.5 The draft material covered background information and guidance in four areas: 

1) Review of Existing Environmental Impact Assessment Methods; 

2) Principles of Environmental Assessment; 

3) Assessment of Environmental Impacts Methodology; and 

4) Validation plan of the Environmental Impact Assessment Method. 

Discussion and Conclusions 

2.6.15.6 Several members expressed their appreciation for the progress made and strongly 

supported the continuation of this task toward a globally acceptable high-level guidance material. 

2.6.15.7 With regard to future work, a member highlighted the need to prioritize this task and 

suggested the scope of this task be clarified to enable specific inputs from more States in the future. 

Another member pointed out that the current report focused only on the assessment of climate change 

impact and suggested the future work should also include the assessment of noise impact. A member 

indicated that much of the material was based on European input and work would be required to make it 

applicable to all States. The member recommended separating the descriptive material from guidance and 

to develop high level material as future work. 

2.6.15.8 Another member commented that CNS/ATM would provide all aviation stakeholders 

with a win-win situation in terms of safety, efficiency and environment, and that CAEP should closely 

monitor the progress of this task in cooperation with ANB. 

2.6.15.9 The Chair concluded that further discussion on the future work and the priority of this 

task would be undertaken in Agenda Item 5, taking into account the views expressed by members. 

2.6.16 Update and Conversion of ICAO Circular 303 into an ICAO 

Manual 

2.6.16.1 Following-up on the discussion of GIACC’s basket of measures in the development of 

the ICAO Programme of Action on international aviation and climate change, the CAEP SG meeting in 

September 2008 agreed that WG2 should streamline and integrate some of its deliverables towards 

updating the material contained in Circular 303 “Operational Opportunities Minimize Fuel Use and 

Reduce Emissions”, concentrating efforts in one single comprehensive document instead of producing 

stand-alone guidance. 

2.6.16.2 A new task was subsequently added to WG2 requesting the group to “produce new 

guidance document replacing Circular 303 with extended scope covering environmental impact 

assessment of CNS/ATM, methods for computing aviation emissions and environmental indicators and 

update existing material, in particular on ATM.” 
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Progress to date 

2.6.16.3 Due to the heavy CAEP workload, the late addition of this task to the work programme, 

and constrained resources, multiple States and Observer Organizations have indicated that they were 

unable to provide timely and substantial input and to complete a comprehensive review in advance of 

CAEP/8. As a result, in its current state, some chapters are limited in scope and not mature enough, and 

will be benefit from including more global perspective. 

2.6.16.4 The ad-hoc group formed by the last SG meeting in June 2009 conducted a thorough 

review of the selected four chapters, as follows, which were presented to CAEP/8: 

— Chapter 2 – Airport Operations; 

— Chapter 6 – Air Traffic Management; 

— Chapter 7 – Non-Revenue Flying; and 

— Chapter 12 – The Effect of Load Factor on Fuel Efficiency. 

2.6.16.5 While the whole of WG2 was involved in the original revisions to these chapters, only 

the ad-hoc group has participated in the detailed review. The meeting noted that the group received 

suggestions for additional revisions to some of the chapters. It was proposed that these comments, along 

with any other comments from WG2, be reviewed early in the CAEP/9 cycle. 

2.6.16.6 The ad-hoc leader explained that the use of ad-hoc group and regular teleconferences 

proved to be an effective approach in progressing the discussions. He proposed that a similar approach be 

used for the work necessary to complete the review and expansion of the remaining chapters, and 

emphasized that the ability of key States and Observer Organizations to contribute to this task would be 

paramount to its completion. 

Discussion and Conclusions 

2.6.16.7 Several members appreciated the ad-hoc group for its leadership and substantial progress 

made in the selected chapters, and stressed the importance of this task in terms of providing States with 

updated guidance in this area. A member commented that Circular 303 is a very valuable material for use 

by all aviation stakeholders to reduce aviation fuel burn and welcomed the continuation of this task. 

2.6.16.8 The Secretary added that Circular 303 was one of the bases for discussion of GIACC’s 

basket of measures in the development of the ICAO Programme of Action on international aviation and 

climate change, and CAEP has a timely opportunity to review the document and showcase the 

information to the world aviation community. She also pointed out that the updated information could 

provide the basis for the preparation of States’ Action Plans in line with the outcome of the High-level 

Meeting. 

2.6.16.9 The meeting recognized that commitments from key States and Observer Organizations 

would be paramount to establishing the timelines and milestones in the production of the guidance. The 

meeting also noted the proposal for the use of a specialized group to continue the development of the 

guidance and that it proposed a web-based approach for its dissemination. Further discussion on this task 

will be undertaken in Agenda Item 5. 
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 Report on Agenda Item 2 2-31

2.6.17 Effect of Takeoff Thrust and Deeper Cutback on Noise, 

Emissions, Fuel Consumption and Climb 

2.6.17.1 WG2 presented at CAEP/7 the assessment on the effects of several variations of the 

PANS-OPS Noise Abatement Departure Procedures (NADP) on noise and emissions and produced 

guidance material (Effects of PANS-OPS Noise Abatement Departure Procedures on Noise and Gaseous 

Emissions, Circ 317). 

2.6.17.2 As a follow-up to this work, CAEP/7 requested a study on noise and gaseous emissions 

effects from variations of takeoff thrust and from deeper cutback for individual aircraft at the same 

takeoff weight using the same Noise Abatement Departure Procedure (NADP). Aircraft evaluated in the 

study include the Airbus A320-200, A330-200, A340-600, and A380-800; the Boeing 737-700, 767-

400ER, and 777-300; and the Bombardier CRJ900ER. The WG2 TG3 Lead presented the results of the 

study to the meeting. 

Thrust Variation 

2.6.17.3 ICAO PANS-OPS, Volume 1, Flight Procedures, Part I, Section7, Chapter 3 provides 

guidance with respect to noise abatement departure procedures. It discusses the conditions in which noise 

abatement procedures can be safely used and the envelope within which main flight parameters defining 

the procedure can be safely adapted for airport noise mitigation. Examples of such flight parameters are 

the minimum height at which engine thrust can be reduced and the minimum height at which flap/slat 

retraction and acceleration can be initiated. 

2.6.17.4 The guidance includes two examples of noise abatement departure procedures. One 

procedure, called NADP1, is designed to mitigate noise at relatively short distances from the brake 

release point; and another procedure, called NADP2, is designed to reduce noise at relatively greater 

distances from the brake release point. Takeoff thrust variations and deeper climb thrust cutbacks for both 

NADP1 and NADP2 procedures were assessed in this study. 

2.6.17.5 This study evaluates takeoff thrust effects at the same takeoff weight; and deeper cutback 

effect, with a minimum climb thrust, compared to the standard climb thrust. 

2.6.17.6 For this study, the first case assumes a performance-limited takeoff weight associated 

with a 10-12% reduced takeoff thrust setting. The reduced thrust setting should correspond to a case 

halfway between full takeoff thrust and maximum permitted takeoff thrust reduction. According to an 

earlier study, this takeoff thrust setting value is believed to be close to the average thrust settings used in 

daily practice by the airlines. 

2.6.17.7 The second case assumes a performance-limited takeoff weight associated with a 25% 

reduced takeoff thrust setting for some Airbus aircraft. This case is considered more representative of 

short stage length A320 operations in Europe. 

2.6.17.8 The WG2 TG3 Lead highlighted that the flight procedures studied for this task were 

included for comparative purposes only: not all respective manufacturer’s operations manuals include all 

the flight procedures presented in the study, and some of them therefore cannot be used in actual 

operations. Noise abatement flight procedures must be developed with advice from the appropriate 

manufacturer and approved by the State of the operator; and must comply with the safety criteria 

contained in PANS OPS. The specification of noise abatement procedures for a given airport requires 
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2-32 Report on Agenda Item 2 

dedicated environmental and safety studies that determine the need for such procedures and ensure the 

required levels of flight safety are maintained. 

2.6.17.9 An operational and safety assessment of the procedures was not incorporated in this 

analysis. 

Assessment of Noise and Gaseous Emissions Effects 

2.6.17.10 The study found that reduced takeoff thrust result generally in a small increase in 

“close-in” noise, a decrease in NOx, and in no change to CO2. The effect on “distant” noise is 

inconclusive and/or airplane dependent. The study found that climb thrust generally has an impact on 

noise away from the airport, but this impact varies from one airplane to another and from one weight to 

another. Emissions results, both in terms of NOx and CO2, were also inconclusive and generally very 

small in magnitude. 

2.6.17.11 For the thrust variations included in this study, no single departure procedure minimized 

overall noise and emissions simultaneously. Tradeoffs may be required between noise impacts close-in or 

further away from the airport, levels of NOx versus CO2 emissions, and finally noise abatement versus 

reductions in gaseous emissions. 

2.6.17.12 An observer presented the view that the selection of takeoff thrust and deeper climb 

thrust cutback are not flight parameters that can be freely varied to optimise a NADP as stated in 

PANS-OPS. The observer explained that the selection of takeoff must balance economics, performance, 

maintenance requirements, aircraft status, weather, and runway conditions. Typically, the minimum 

takeoff thrust is used to relieve the engine from high combustion temperatures and reduce the 

maintenance overhaul costs while providing sufficient performance margins. However, full takeoff thrust 

may be selected because of runway contaminants, aircraft dispatch status, onboard systems status, and the 

weather conditions. 

2.6.17.13 The observer expressed a concern that take-off thrust restrictions and reduced climb 

thrust selection for environmental reasons will have a very severe interference with the flight execution 

and is likely to reduce margins to safety, and asked this task to be refrained from its continuation. 

Discussion and Conclusions 

2.6.17.14 The meeting expressed its appreciation to WG2 for their analysis of this task. Regarding 

the concern expressed by the observer, several members were of the view that the scope of CAEP should 

continue to be for the environmental assessment aspects, while safety aspects should continue to be fully 

coordinated with other ICAO bodies and experts. 

2.6.17.15 The Chair commented that safety is paramount for aviation and any safety concerns 

should be dealt with in the relevant bodies. CAEP should undertake the environmental assessment. 

2.6.17.16 The Secretary clarified that ICAO is responsible for safety, security and environment of 

international aviation, and therefore all the work under ICAO must fully consider these three aspects 

before a final decision is made. CAEP was no exception and while CAEP is responsible for the 

environmental aspects, CAEP’s constituency includes experts representing all aviation stakeholders and it 

is expected that they would bring other specific concerns to CAEP while participating in the development 

of the work. If any recommendation from CAEP could raise safety concerns, that should be properly 
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 Report on Agenda Item 2 2-33

flagged and brought to the attention of the relevant groups at an early stage. That is how CAEP has 

always operated and will continue to operate. 

2.6.17.17 The meeting took note of the concern of the observer on safety, however regarding his 

statement that to “note the near impossibility to develop effective environmental operational procedures 

for close-in noise and emissions due to the inevitable safety implications and complex interaction with the 

dynamic state and operative limitations of the aircraft”, the meeting could only note that this was the view 

of the observer but there was no concurrence from the meeting to such a statement. The meeting decided 

that this task was fully accomplished without further work being envisaged and no further work should be 

conducted until safety concerns have been evaluated and eliminated. 

2.6.18 Assess and validate noise and emissions reductions accrued 

from the use of Continuous Descent Operations (CDO) 

2.6.18.1 The WG2 TG3 Continuous Descent Operations (CDO)2

 task leader explained that 

CAEP/7 was informed of the benefits from the use of CDO and that these procedures were being 

developed locally on a widespread scale. CAEP/7 was also informed that there was not an internationally 

agreed definition or concept of CDA, and therefore the CAEP/7 requested the Secretariat to address it 

with ANC with a view to progressing this work in an appropriate ICAO body. As a result, work on a 

CDO manual was initiated by CAEP and a panel of the ICAO Air Navigation Commission: the 

Instrument Flight Procedures Panel (IFPP), and the draft manual will be submitted for approval of the 

ANC in 2010. 

2.6.18.2 In addition, WG2 was tasked during CAEP/8 to update the assessment of noise and 

emissions reductions accrued from the use of CDO based on the definitions proposed by the IFPP. The 

results from early CDO trials in Europe and the US were previously reported and had identified 

environmental benefits from CDO that are of similar orders of magnitude across several airports. 

Estimated Global CDO Benefits 

Global Fuel and CO2 Benefit Estimation 

2.6.18.3 The approach taken for this very high level assessment was to pro-rate the typical range 

of fuel and emissions benefits so far found in CDO trials, to the calculated annual civil aircraft 

movements for 2006 for each aircraft category. The global movement numbers for each aircraft type were 

extrapolated from data for a single day in 2006 to a full year. An assumption of a 50 per cent achievement 

of CDO was taken to reflect the current disparities in achieving CDO. The aircraft movement data used 

only included medium and heavy civil fixed-wing turbojet aircraft. 

2.6.18.4 Results from the estimate of the potential fuel and CO2 benefits were given for 27 million 

calculated annual global movements in 2006 as follows (respectively in the case of the low and high 

benefit scenarios): between 500 thousand and 2.3 million of global tonnes fuel saved, between $250 

million and $1.1 billion of global fuel saved and between 1.5 and 7 million of global tonnes CO2 saved. 

 

2

 Formerly continuous descent arrivals / approaches (CDA). 
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Global CDO Noise Benefit Estimation 

2.6.18.5 Most of the CDO noise benefits arise at approximately 10 to 25 miles from touchdown 

and vary depending on base-case and the location of population centres. The noise reductions range from 

1 to 5 dB. Thus the noise benefits can therefore be considered important, but would not normally be 

critical to an airport’s mitigation regime. 

Global NOx Benefit Estimation 

2.6.18.6 Unlike CO2, NOx emission is not proportional to fuel burn and any reduction in thrust 

produces a larger reduction in NOx than from reduced fuel use alone. Since CDOs do provide a fuel burn 

reduction, a NOx savings can be assumed, but could not be quantified in this analysis. 

Other CDO Assessment Aspects 

2.6.18.7 Implementation of CDO is accelerating in the US, Europe, Australia and Asia-Pacific. 

This will be further facilitated by the forthcoming ICAO CDO guidance manual. 

Global CDO Performance Monitoring 

2.6.18.8 Although there was no consensus, it is believed by some States and observers that ICAO 

should monitor CDO implementation and that CAEP should therefore consider adopting a performance 

monitoring role through its working arrangements and using one or more of the assessment approaches 

considered above. 

Issues Identified 

2.6.18.9 The group identified a number of issues related to the global assessment of CDO. The 

baseline (pre-CDO case) is different at every airport, in particular the population distribution and the fact 

that some amount of CDO happens naturally at most airports. This makes the validation of the results 

difficult, especially combined with the lack of global detailed information on CDO implementation. The 

task leader explained, however, that some local CDO assessments were made using data collected from 

actual operations, making those results reasonably consistent. 

2.6.18.10 The task leader explained that local implementation of CDO is accelerating, which 

underscored the emerging need for a harmonized local assessment methodology and capability. The task 

leader suggested the document be the initial basis for further development of the harmonized 

methodology. In addition, some local, State, and international interests require a consistent performance 

monitoring capability. 

Discussion and Conclusions 

2.6.18.11 The meeting congratulated WG2 on the development of the CDO guidance manual in 

coordination with IFPP and the continued analysis of CDO. It noted the accelerated adoption of CDO 

procedures in many regions. 

2.6.18.12 An observer enquired whether more inputs on the environmental benefits from CDO 

would be necessary and welcomed the possibility of having a more global perspective, and the task leader 
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 Report on Agenda Item 2 2-35

expressed appreciation for further inputs from worldwide regions to assess the environmental benefits of 

global international aviation operations. 

2.6.18.13 Another observer sought clarification regarding coordination between this task and the 

development of CDO guidance manual, which the observer believed to be very important, and the task 

leader confirmed that there was coordination and that the analysis was based on the definitions in the 

CDO Manual. 

2.6.18.14 The meeting noted the assessment of environmental benefits from CDO as a first order 

approximation and the different CDO performance assessment options identified, and will consider the 

need to continue with the task on the future assessment and harmonization of assessment methodology of 

CDO in Agenda Item 5. 

2.6.19 Computing, Assessing and Reporting Aviation Emissions 

2.6.19.1 The WG2 TG2 Lead presented on the development of ICAO guidance for computing, 

assessing and reporting on aviation emissions at national and global levels. 

2.6.19.2 A review of applications and methodologies for computing, assessing and reporting civil 

aviation fuel burn and CO2 emissions was presented and should be considered a work in progress. A 

refined version of the report could also serve as input material for the update of ICAO Circular 303. 

2.6.19.3 Along with the different applications, methodologies were described for computing fuel 

burn (and hence CO2 emissions) from operating aircraft on a gate-to-gate basis. Where appropriate the 

methodology included the turn-around phase to include APU fuel burn. 

Development 

2.6.19.4 Although the original geographical scope was for national and global fuel burn, CAEP 

SG meeting in 2008 accepted to add the local level (fuel burn in the LTO phase below 3000ft) in the 

guidance on the basis that: 

a) Local CO2 emissions form part of the carbon inventory reporting applications such as 

EMEP3

/CORINAIR4 where CO2 is reported for LTO and ‘Cruise’5; 

b) Airport authorities need to be able to calculate their carbon footprint to demonstrate 

“their slice of the pie”; and 

c) Quantifying the emissions that result from airports often being the constraining point 

in the air traffic system. 

d) The guidance was not intended to rival other publications that address the subject of 

computing aviation emissions. Instead, this guidance drew on work developed, 

reported and promoted by industry, standards organisations and international bodies. 

As such, there was some concern regarding the duplicative nature of the draft 

guidance. 

 

3

 EMEP - European Monitoring and Evaluation Programme

4

 CORINAIR - The Core Inventory of Air Emissions in Europe (http://www.eea.europa.eu/publications/EMEPCORINAIR) 5

 Cruise: All phases of a flight above 3000ft with respect to Aerodrome Elevation. 
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2.6.19.5 Guidance on the calculation of other categories of aircraft emissions, i.e. NOx, HC, CO, 

SOx, PM from main engines, APU or brake/tire wear was outside the scope of this work for CAEP/8. 

Scope and limitations 

2.6.19.6 The scope of the task was restricted to the compilation of methods and tools for 

calculating and reporting aircraft fuel burn and CO2 emissions and their possible applications. The term 

aviation could include all emissions from all sources related to air transport activities during all life-cycle 

phases. Other pollutants could be covered in a future issue. 

2.6.19.7 The geographical scope of the guidance covers aviation CO2 emissions at local (within 

the limits of the ICAO LTO certification cycle), State, and global (worldwide or ICAO region) scales. 

2.6.19.8 The guidance document should allow a reader to choose the aircraft fuel burn calculation 

method that is most suitable for a particular application. 

Report Structure 

2.6.19.9 The global layout and structure of the draft guidance is as follows: 

a) review of application themes: An inventory of aviation emissions applications; 

b) gap analysis; 

c) methods catalogue; and 

d) reporting. 

2.6.19.10 The TG leader informed that the bulk of the material was had been developed (around 

90 per cent) and that a few more items needed to be completed. The final review would still need to be 

undertaken. He suggested that the material could be used as part of the new guidance replacing Circ. 303. 

2.6.19.11 An observer presented ACI’s new manual, providing guidance material for airport 

operators wishing to manage greenhouse gas emissions. The document draws the threads of some 

guidance documents and should assist airport operators with allowing comparisons of airport inventories 

and achievements. 

Discussion and Conclusions 

2.6.19.12 The meeting congratulated WG2 on the development of the draft guidance document. 

Several members commented on its usefulness and suggested incorporation into the manual replacing 

Circular 303. A member suggested the continuation of this task under MODTF. Another member 

commented that 90 per cent of the work was completed with remaining 10 per cent of the work to be 

devoted to its review, and the material should be left for inclusion in Circular 303. 

2.6.19.13 In concluding, the Chair re-emphasized that 90 per cent of the work was completed, and 

that further discussion on the continuation of this task, including which working group would undertake 

this task and possible future work for Circular 303, would be undertaken in Agenda Item 5. 
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2.6.20 Update of Airport Air Quality Guidance 

2.6.20.1 The WG2 TG4 lead presented on the development of airport air quality guidance 

information to assist States in implementing best practices. This group was also tasked with providing 

continued coordination with FESG on “times-in-mode” in relation to modelling capabilities, and 

preparing a report and web material that describes the various technical, operational, mitigation and 

market-based measures available to address aircraft emissions impacting local air quality. 

Coordination with FESG on “Times-in-Mode” 

2.6.20.2 The use of performance based times-in-mode (TIM) versus the certification values task 

did not require coordination with FESG, but WG2 TG4 did monitor the work of MODTF. Although no 

specific modification to the Guidance Manual was identified, the group noted that the MODTF NOx

stringency policy assessment activity includes a sensitivity test for performance based TIMs. 

Develop and update the Airport Air Quality Guidance (Doc 9889) to 

include dispersion modelling, measurements, and revision of the 

inventory chapter 

2.6.20.3 ICAO published a preliminary edition of Doc 9889 in 2007, including the Introduction, 

State Requirements, Emissions Inventory, and the Spatial and Temporal Distribution of Emissions. 

2.6.20.4 Updates to the Aircraft Inventory and Road Vehicle chapters have been prepared and two 

new chapters on Dispersion Modelling and Air Quality Measurements have been completed. The new text 

was presented to the meeting for approval. 

2.6.20.5 The updated document provides detailed information on regulatory air quality drivers, 

which aircraft and non-aircraft emissions sources to address, how to calculate the emissions, how to 

calculate the resulting air pollutant concentrations, and how to measure airport ambient air quality and use 

modelling calculations to confirm the local air quality situation. 

Development of remaining chapters 

2.6.20.6 The task leader informed that the two remaining chapters: Mitigation and 

Interrelationships were proposed to be developed during the early part of CAEP/9, subject to resources. 

2.6.20.7 An observer reported that a case study has been done for Zurich airport to investigate the 

effects of applying different levels of information for emission inventory calculations and concentration 

modelling. The results of this study could be used to inform any decision making process for users who 

would wish to conduct similar assessments. He informed that the development of material for the chapters 

on Mitigation and Interrelationships had been initiated and that these final two key chapters of the manual 

are fundamental and to the usefulness of the document. 

2.6.20.8 Two observers offered to provide resources to ensure the completion of this task. They 

also proposed to deliver a draft of these two chapters to the first Steering Group Meeting of CAEP/9 

expected in November 2010. 
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2-38 Report on Agenda Item 2 

Discussion and Conclusions 

2.6.20.9 Two members expressed a concern regarding the approaches and models used in Chapter 

4 (Dispersion Modelling), and requested that another approach and model currently used by these States 

(PolEmiCa model) be incorporated in a balanced manner. 

2.6.20.10 The Chair and the WG2 TG4 lead responded that, since the draft guidance manual was 

the outcome of three-year thorough discussions since CAEP/7 and all inputs were incorporated before 

reporting back to this meeting, additional inputs could be incorporated only if necessary in the future 

work. 

2.6.20.11 An observer pointed out that the approaches described in Chapter 4 of the guidance do 

not refer to a specific model, instead, they only provide a generic description, and therefore any model in 

use would be covered in this Chapter. The observer also pointed out that the TG4 only analyzed models 

that were already reviewed and in use within CAEP, and therefore prior to incorporation of a new specific 

model in the guidance, it would need to be sent to MODTF for review. 

2.6.20.12 The meeting approved the additional and revised guidance manual chapters proposed by 

TG4, and decided to make the updated manual available through the ICAO public website. It also 

concluded that the possible update of Chapter 4 in the future would be discussed in Agenda Item 5. 

Recommendation 

2.6.20.13 In light of the foregoing discussions the meeting developed the following 

recommendation: 

 Recommendation 2/4 — Update to Airport Air Quality 

Guidance Manual (Doc 9889)

That the ICAO Airport Air Quality Guidance Manual (Doc 9880) 

be updated with the material contained in Appendix C to the 

report on this agenda item, and that it be published on the ICAO 

public website free of charge. 

2.6.20.14 Regarding the development of the Mitigation and Interrelationships chapters during the 

CAEP/9 cycle, several members and an observer expressed their support for the development of these 

new chapters. A member expressed concerns with the development of an Interrelationship chapter, in 

particular the relevance of addressing the interrelationship between LAQ and climate change, and 

reminded the meeting of the issue of resources for completion and review of the guidance material. 

2.6.20.15 The Chair concluded that the development of new chapters would also be discussed in 

Agenda Item 5. 

2.6.21 Environmental Management Systems 

2.6.21.1 The WG2 TG1 EMS Task leader noted that at the last CAEP meeting in February 2007, 

WG2 was assigned a task under the CAEP/8 work programme to deliver a report providing information 
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 Report on Agenda Item 2 2-39

on the use of EMS and, as appropriate, make recommendations on how the Committee could promote the 

use of EMS within the aviation system. 

2.6.21.2 To complete these two tasks successfully, a questionnaire was proposed and developed to 

gather information for the report, to be distributed to aviation organizations worldwide. The Secretariat 

sent the questionnaire and an accompanying introductory State letter in May 2008. The questionnaire and 

letter were then widely distributed by States and industry associations. The information collected through 

this questionnaire forms the basis of the report to CAEP/8. 

Survey response and results 

2.6.21.3 Over a six month time period, responses were received via mail, fax, e-mail, or through 

the questionnaire software program (interactive electronic tool). At the end, all questionnaire responses 

were input into the questionnaire software program. Initially, 254 responses were received from 

organizations worldwide. As a result of the data validation process, which consisted in reviewing data and 

resolving inconsistencies, 233 responses were selected to form the basis of the report. 

2.6.21.4 117 questionnaire respondents apply EMS Standards or guidelines, with the majority 

having an ISO 14001 v2004 certified EMS in place. Among them, 96 percent recommended that other 

organizations implement one. Many of the remaining 116 respondents use other types of environmental 

programs and procedures mainly because of unfamiliarity with EMS approaches. Among them, 79 plan to 

implement one. 

2.6.21.5 As a result, EMS implementation guidance specific to the aviation industry was 

requested. 

Task report and recommendations 

2.6.21.6 Based on survey responses, TG1 developed a Report on Environmental Management 

System Practices in the Aviation Sector that contains aggregated questionnaire responses and two 

recommendations agreed from WG2 TG1: 

a) disseminate report information. Within the first year of the CAEP/9 cycle, ICAO 

should make the information contained in this report publicly available; and 

b) develop EMS guidance. A standalone EMS guidance document should be developed 

for the end of the CAEP/9 cycle. 

Report dissemination proposal 

2.6.21.7 WG2 TG1 developed and presented a proposal for disseminating the final report to 

States, respondents, and the public in a manner consistent with the confidentiality statement provided in 

the questionnaire. It was recommended that the report be disseminated in the following ways: 

a) publish on the ICAO public website free-of-charge; and 

b) distribute by letter to CAEP States and observers, and to all survey respondents. 
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Discussion and conclusions 

2.6.21.8 The meeting welcomed the completion of the report, approved the report, and accepted 

the dissemination proposal presented by WG2 TG1. 

Recommendation 

2.6.21.9 In light of the foregoing discussions the meeting developed the following 

recommendation: 

 Recommendation 2/5 — Report on Environmental 

Management Systems Practices in the Aviation Sector

That the report contained in Appendix D to the report on this 

agenda item be published as an ICAO document on the ICAO 

public website free of charge. 

2.6.22 Creation of an AIRE-like Partnership to Focus on Main 

Traffic Flows and Reduce Emissions between Europe and 

South America 

2.6.22.1 A member on behalf of four European CAEP members and an observer presented the 

European interest in encouraging the development of activities to reduce the environmental impact of 

aviation at international level and to broaden and extend the experience and benefits from ongoing 

initiatives such as AIRE and ASPIRE to other world regions such as the Europe - South America oceanic 

routing areas (South Atlantic routes) with a further perspective to cover the entire trans-Atlantic area. 

2.6.22.2 Several members welcomed and supported this initiative, and the meting acknowledged 

the need for collaboration and establishment of synergies between different countries and authorities to 

improve aviation efficiency and reduce fuel burn hence CO2 emissions. 

2.6.22.3 The Secretariat suggested the presentation of the working paper to the South Atlantic 

Regional Group. The Secretary emphasized that, as more and more initiatives emerge, the global 

harmonization on the design, implementation and environmental assessment of these initiatives would be 

crucial before we spread-out initiatives to different areas in order to obtain maximum synergy. 

2.6.23 ICAO Carbon Emissions Calculator 

2.6.23.1 The Aviation Carbon Calculator Support (ACCS) ad hoc group lead presented a review 

of the progress made in the development of an aviation carbon emission calculator methodology both by 

this group and its predecessor, the Aviation Carbon Estimation (ACE) ad hoc group, and a proposal for 

future enhancements. 

2.6.23.2 The group successfully developed an impartial, transparent methodology for computing 

the CO2 emissions from passenger air travel. In June 2008, ICAO posted on their website a Carbon 

Emissions Calculator that estimates the CO2 emissions from air travel based on this methodology for use 

in offset programs. The Calculator allows passengers to estimate the emissions attributed to their air 

travel through a simple interface that requires the user to enter only their origin and destination airports, 

and their class of service. The methodology used by the calculator applies the best publicly available 
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 Report on Agenda Item 2 2-41

industry data to account for various factors such as aircraft types, route specific data, passenger load 

factors and cargo carried. The ICAO Carbon Emissions Calculator can be accessed through the ICAO 

website: www.icao.int by clicking the link labelled “ICAO Calculator” on the left side of the homepage. 

The ICAO website provides the public with access to documentation of the methodology used by the 

Calculator and answers to a set of frequently asked questions. 

2.6.23.3 The UN Environment Management Group (EMG), who is responsible for the Climate 

Neutral UN initiative, formally adopted the Calculator as the tool for computing CO2 emissions from air 

travel. With a view to facilitating the use of the ICAO Calculator by other UN agencies and organizations, 

in August 2009, ICAO provided them with an enhanced interface to the carbon emissions calculator, 

which has since received positive feedback. To further facilitate inventory preparation, ICAO facilitated 

the integration of the Calculator directly into three UN Organizations’ travel approval systems. 

2.6.23.4 The ACCS group also explored the development of a methodology to compute the CO2

emissions from air freight. The group suggested that potential methodologies used to compute emissions 

from cargo carried onboard a passenger aircraft will need to be distinct from that used to compute 

emissions from cargo carried on a dedicated freight aircraft. It was noted that transport routes and modes 

for cargo are not always clear, hence, leading to potential inaccuracy in emission estimation. The 

following approach for developing a cargo emissions calculator was proposed: 

1) (For belly cargo only). Use the passenger/cargo ratio with the existing passenger 

calculator methodology to attribute CO2 emissions to the cargo being carried. This 

could initially be done on a weight basis to be refined to incorporate a DIM 

(dimensional weight) factor, if appropriate. This will allow an initial calculator to be 

made available in the very near term. In support of this activity, IATA will 

investigate with its airline offset program partners their willingness to develop cargo 

carbon emissions (per freight weight) based on actual airline data and assess if they 

would be willing disclose these results as a means of refining these results. This 

level of information will also enable an assessment of the margin of error associated 

with this approach. 

2) (For dedicated freight aircraft only). In the near term, CAEP should develop a 

distance-based methodology for computing cargo emissions. In doing so, it will seek 

support from IATA to help with an assessment of the level of accuracy achieved. An 

assessment of the range of errors from using this method should be undertaken, 

including an assessment of the errors associated with segments of the trip being 

carried by a mode of other than aviation. When introduced to the public, the 

documentation of the errors and limitations of the methodology should be 

transparent. The ACCS lead noted that the CAEP experts would be unable to 

comment on emissions from other transport modes and that another source for this 

information would need to be identified. It was also noted that this approach 

would allow for those shippers with more detailed information on the route/mode 

taken by their cargo to apply that information to refine their result. This approach 

was known internally to the ACCS group as “Option 1” of the cargo methodology. 

3) (For belly cargo and dedicated freight aircraft). Over the longer term, develop a 

route and aircraft type independent methodology through the use of top-down 

modelled or measured fuel consumption data. This approach was known internally to 

the ACCS group as “Option 2.” Again, full disclosure regarding the accuracy of the 
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result given the inability of the consumer to know the route taken by the cargo would 

be required before making the calculator available to the public. IATA will pursue 

obtaining the necessary data from its member airlines, and noted that the ability to 

implement this approach will depend on data availability and airlines’ willingness to 

disclose it. 

2.6.23.5 While the existing passenger methodology has been widely accepted, it is not without 

limitations. One area in particular is its current dependence on the CORINAIR data set for aircraft fuel 

consumption information. Because the CORINAIR data set has not been updated to reflect the latest 

generation of aircraft, improvement of the Calculator would be sought to compute CO2 emissions for the 

Airbus A380, the current generation Boeing 737 aircraft, and the Embraer E190 and E195, among others. 

2.6.23.6 With the objective of continuous improvement of the existing passenger methodology, 

the following approach for improvement was proposed that follows 3 parallel tracks: 

Update the current database 

— Incorporate city-pair level load factor data collected by ICAO and pursue filling 

gaps through IATA; 

— Incorporate air carrier level seating configuration data, where available; 

— Pursue obtaining CORINAIR-like data for the missing aircraft types from the 

aircraft manufacturers; and 

— Consider refining the premium/economy multiplier used as well as its basis 

(space vs. weight). 

Update the methodology and underlying data sources (modelled) 

— Pursue obtaining flight-level global emissions inventories generated by 

AEDT/SAGE, AEM III, Aero2K, and FAST (the aviation GHG models 

evaluated by CAEP) on a regular basis. These results would be merged into a 

single ICAO database of modelled fuel consumption (or CO2 emissions) 

Transition from modelled estimates of fuel consumption/CO2 to measured values 

— Pursue obtaining measured fuel consumption (including type of fuel consumed – 

i.e. alternative fuels) data at the city pair level from IATA and IBAC, and other 

relevant bodies such as the European Low Fares Airline Association (ELFAA). 

In support of this step, IATA will be asked to confirm whether airlines are 

willing to disclose such information to ICAO, noting that any data sharing by 

IATA member airlines will be subject to an assessment of appropriate disclosure 

levels including data confidentiality issues and intellectual property rights. 

2.6.23.7 An observer presented their views regarding various aspects of the ACCS activity on the 

Calculator, notably the proposed approach to enhance the passenger methodology and the extension of 

this methodology to air freight. In addition, concerns were raised about the specific use of the Calculator 

by third parties. 
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2.6.23.8 The observer believed that the ICAO passenger methodology for estimating CO2 

emissions presents a valuable tool provided it is used for its intended purpose and recognizing that it 

produces more accurate results when used in combination with more accurate input data. For this reason, 

the observer recommended that CAEP continue refining and improving the passenger methodology, 

working with relevant industry bodies. 

2.6.23.9 For the air freight methodology, the observer was unconvinced that either of the Options 

described in paragraph 2.6.23.4 could eventually lead to a useful product that would be sufficiently robust 

and transparent and recommended the development of non-binding guidelines that would enable 

interested parties to develop an air freight methodology based upon specific operational data. 

2.6.23.10 The observer also expressed concern regarding the use of the Calculator for the purposes 

of presenting users with a tool to distinguish between airlines, aircraft types or flights or commercializing 

Calculator data. 

Discussion and Conclusions 

2.6.23.11 The Secretary pointed out that development of the Calculator was very successful and a 

good result of cooperation and harmonization among aviation stakeholders, serving as one of ICAO’s 

tangible results in addressing aviation emissions. She also clarified that the agreement with Amadeus was 

not intended for commercial purposes but aiming at cost-recovery. In addition, she mentioned that ICAO 

would receive information on the amount of air-travel carbon offsets through these systems. 

2.6.23.12 An observer noted that contrary to data requirements for certification standards, data gaps 

can be filled by sources other than the manufacturers, so therefore requested the action item “ICCAIA to 

provide ICAO with compatible data to address the data gaps associated with the aircraft types” be 

changed to “compatible data or advice”, which was agreed upon. 

2.6.23.13 A member expressed a concern with regard to the use of global emissions inventory data 

from the model of the State (AEDT/SAGE) in terms of associated resources that could be necessary to 

cooperate with the activity. Although clarification was made by the ACCS lead on his intention not to put 

burden on the State’s resources, the member was still of the view that providing support to the activities 

especially related to providing data on a regular basis would be unlikely, but she had no objection to 

further cooperation between ICAO, States and the industry on the further development of the Calculator’s 

methodologies as resources permit. 

2.6.23.14 Another member pointed out that future work could be accelerated considering the fact 

that the original Calculator was developed within a half year of intensive work; any update on Calculator 

should be conducted in a transparent manner; and the work on Calculator would be important in terms of 

possible carbon offsetting schemes in the future. The member suggested these points be considered for the 

discussions of the Calculator’s future work. 

2.6.23.15 An observer expressed the need to decide on the update of an average passenger weight 

of 100 kg assumed in the Calculator while MODTF assumed 91 kg. 

2.6.23.16 The meeting confirmed that the purpose of the ICAO Carbon Emissions Calculator is not 

to present users with a tool to distinguish between airlines, aircraft types, or flights. 
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2-44 Report on Agenda Item 2 

2.6.23.17 The Chair concluded that further discussion on future work on the Calculator would be 

undertaken in Agenda Item 5, while a small informal group would continue its discussion during the 

meeting, in particular on the issues of air freight methodology and STA/10’s fuel data collection form. 

2.6.23.18 A member presented an overview of carbon footprinting work being carried out by his 

government. This work indicated robust carbon footprinting of aircraft operational networks can be 

carried out using Great Circle computations. Valuable carbon footprint information can be obtained using 

relatively basic datasets and commonly available software. Initial visualisation concepts to present a rapid 

transparent picture of carbon footprints have been developed. It was seen that over the FY 2008/9 the 

cumulative difference between actual and computed fuel use was just over 2%. 

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