OPERATION

Aviation has reshaped the world we live in—allowing for affordable and rapid travel to almost any point on the globe. In recent years, economic growth and rapid globalization have made air travel affordable to an even larger part of the global population. In this context, demand for aviation, in terms of passenger-miles flown, has grown at a rapid pace. In China, for example, domestic air transport grew at 15.5 percent annually from 2000 to 2006. Globally, the rate of air travel increased at 3.8 percent per year over the same time period.This growing demand for air travel has resulted in increasing levels of greenhouse gas (GHG) emissions from the aviation sector, despite efficiency improvements. Currently, the aviation sector—including both domestic and international travel—accounts for approximately 1.5 percent of global anthropogenic GHG emissions per year.The U.S. accounts for nearly 40 percent of the global GHG emissions from aviation.Barring policy intervention, GHG emissions from aviation are projected to quadruple by 2050.

OPERATIONS

Operatıonal Improvements To Reduce Global Emıssıons By Icao Secretarıat

INTRODUCTION

Operational improvements are an important element of the basket of mitigation measures to limit or reduce CO2 emissions from international aviation. Assembly Resolution A37-19 requested that ICAO undertake further work to develop and facilitate the implementation of operational measures, including the development of tools to assess the benefits associated with air traffic management (ATM) improvements and guidance material on operational measures to reduce international aviation emissions.

The ICAO Committee on Aviation Environmental Protection (CAEP) continues to serve as the key technical forum for the development and enhancement of guidance on operational opportunities to save fuel and reduce emissions, as well as methodologies to assess the environmental benefits accrued from changes in operational measures. At its ninth meeting         (CAEP/9) in February 2013, CAEP recommended a new set of guidance materials and tools that will provide States and the aviation community with state-of-the-art information on these areas.

GUIDANCE AND TOOLS

ICAO has put significant effort in delivering meaningful guidance and practical tools to support the assessment of environmental benefits related to operational measures.

Leading to CAEP/9, Working Group 2–Airports    and Operations (WG2), which undertakes work to address aircraft noise and emissions linked to airport and aircraft operations, was tasked with completing two crucial  ICAO publications.

The first was an update to ICAO Circular 303, which is to be published as a new ICAO manual entitled, Operational Opportunities to Reduce Fuel Burn and Emissions. The new manual contains information on current operational practices being implemented by aircraft operators, airport operators, air navigation service providers (ANSPs), other industry organizations and ICAO Member States. It  includes information on airport operations, maintenance, weight reduction, the effect of payload on fuel efficiency, air traffic management, flight and route planning, and other aircraft operations.

The second publication contains guidance material on conducting CNS/ATM environmental assessments, to be issued as the new ICAO manual, Environmental Assessment Guidance for Proposed Air Traffic Management Operational Changes. This document focuses on environmental impact assessments (including both engine emissions and noise), related to proposed changes to operational procedures, airspace re-designs, and other related operational aspects. The information contained in this new guidance document was made      available to States in 2011 on a          preliminary basis to assist in the development of State action plans on CO2 emissions reduction activities.

The ICAO Secretariat has continued to create new tools to assess the environmental impact of international aviation operations. Most recently, the ICAO Fuel Savings Estimation Tool (IFSET) was developed by the Secretariat, with support from States and international organizations, to estimate fuel savings resulting from the implementation of operational measures, in a manner consistent with the models approved by CAEP, and in line with the ICAO Global Air Navigation Plan (GANP). IFSET is not intended to replace the use of detailed measurement or modelling of fuel savings, where those capabilities exist. Rather, it is provided to assist those States without such capabilities to estimate the benefits from operational improvements in a harmonized way. In addition, this tool can be used by States in the development of their action plans on CO2 emissions reduction activities (see article States’ Action Plans to Reduce Aviation CO2 emissions, Chapter 5 in this report).

FUEL BURN OPERATIONAL GOALS

Common terms and definitions of fuels are necessary for countries to describe emissions from fuel combustion activities, consistently. A list of fuel types based primarily on the definitions of the International Energy Agency (IEA) is provided below.

Consistent with its mandate to develop fuel burn operational goals, CAEP’s Independent Experts on Operational Goals Group (IEOGG) undertook a comprehensive review of the operation of civil aircraft, across all gate-to-gate phases of a flight, both in the air and on the ground, in order to develop challenging aspirational operational environmental goals. During the CAEP/9 meeting, operational goals for fuel burn (for 2020, 2030 and 2040) were recommended.

These operational goals represent fuel savings that can be achieved by new operations, and reflect the percentage of fuel usage and emissions that can be reduced relative to 2010   by eliminating inefficient operational practices.To be achieved, they also require technology investments and changes in policies. The operational goals are 3.25% in 2020, 6.75% in 2030, and 9% for 2040.CAEP/9 agreed to publish the fuel burn operational goals, which were included in the future CAEP environmental trends analysis as a new scenario.

There are three Tiers presented in the 2006 IPCC Guidelines for estimating emissions from fossil fuel combustion. In addition a Reference Approach is presented. It can be used as an independent check of the sectoral approach and to produce a first-order estimate of national greenhouse gas emissions if only very limited resources and data structures are available to the inventory compiler. The 2006 IPCC Guidelines estimate carbon emissions in terms of the species which are emitted. During the combustion process, most carbon is immediately emitted as CO2. However, some carbon is released as carbon monoxide (CO), methane (CH4) or non-methane volatile organic compounds (NMVOCs). Most of the carbon emitted as these non-CO2 species eventually oxidises to CO2 in the atmosphere. This amount can be estimated from the emissions estimates of the non-CO2 gases. In the case of fuel combustion, the emissions of these non-CO2 gases contain very small amounts of carbon compared to the CO2 estimate and, at Tier 1, it is more accurate to base the CO2 estimate on the total carbon in the fuel. This is because the total carbon in the fuel depends on the fuel alone, while the emissions of the nonCO2 gases depend on many factors such as technologies, maintenance etc which, in general, are not well known. At higher tiers, the amount of carbon in these non-CO2 gases can be accounted for. Since CO2 emissions are independent of combustion technology whilst CH4 and N2O emissions are strongly dependent on the technology, this chapter only provides default emission factors for CO2 that are applicable to all combustion processes, both stationary and mobile. Default emission factors for the other gases are provided in subsequent chapters of this volume, since combustion technologies differ widely between source categories within the source sector “Combustion” and hence will vary between these subsectors.

AS BU STRATEGY

The ASBU framework is ICAO’s systems engineering approach to achieve global ATM interoperability and harmonisation. The Block Upgrades are the product of inclusive and prolonged collaboration between ICAO, ANSPs, member States and industry stakeholders from around the world. A number of air navigation improvement programmes undertaken by ICAO member States – namely SES, NextGen, CARATS, SIRIUS, and others in Canada, China, India, and the Russian Federation – are planned to be implemented with the ASBU framework. The Block Upgrades present target implementation time frames for sets of operational improvements, referred to as modules. A single module defines a single capability (operational improvement) and its required technologies and procedures. Each Block Upgrade has been organised into a set of unique modules that are linked to one of four aviation performance improvement areas (PIAs).

A key challenge for the aviation community in recent years has been to prioritize and build consensus around the latest technologies, procedures and operational concepts. This is because such a wide variety of national and regional ATM modernization programmes have been emerging worldwide. The multidisciplinary and interrelated aspects of these modernization efforts require ongoing collaboration among stakeholders representing every aspect and component of the international air transport system.

In an effort to assist with this effort, ICAO has developed the Aviation System Block Upgrade (ASBU) strategy. Created with its industry partners and based on extensive feedback from States, this strategy forms a critical element of the implementation planning mechanism of ICAO’s Global Air Navigation Plan.

This also includes work by CAEP to develop a compendium of illustrated “best practice” environmental assessment case studies that demonstrate the application of the principles outlined in the document Environmental Assessment Guidance for Proposed Air Traffic Management Operational Changes.

Minimizing Adverse Environmental Effects Of Civil Aviation Activities By Icao Secretarıat

Air traffic growth expands two-fold every 15 years1. If not properly supported by the necessary regulatory and infrastructure framework, this kind of growth can lead to an increase in safety risks and negative environmental impacts. A careful balance between these factors is critical for maintaining continued air traffic growth. The real challenge for the aviation community lies in achieving safety and operational improvements on a globally harmonized basis, while being environmentally responsible  and cost-effective.

In order to meet this challenge, ICAO collaborated with States, industry and international organizations to develop the Aviation System Block Upgrades (ASBU) concept. This concept aims to ensure that aviation safety is maintained and enhanced, that air traffic management improvement programmes are effectively harmonized, and that barriers to future aviation efficiency and environmental gains are removed, at reasonable cost.

As shown in Figure 1, at the core of the Block Upgrade concept is a pragmatic system of Modules – each one comprised of technologies and procedures that are organized towards achieving a specific performance capability. Each of these modules is then linked to one of four specific and interrelated performance improvement areas: airport operations;globally interoperable systems and data; optimum capacity and flexible    flights;  and efficient flight paths.This concept allows for a flexible global systems approach, enabling all States to advance their Air Navigation capabilities based on their specific operational requirements.            

The implementation of many of these modules can minimize the adverse environmental effects of civil aviation activities. For example, modules that allow for improved flexibility and efficiency in descent and departure operations significantly reduce fuel burn and therefore provide fuel savings and reduced CO2 emissions.

Modules which apply the concept of continuous descent operations (CDO) feature optimized profile descents that allow aircraft to descend from the cruise to the final approach to the airport at minimum thrust settings. Besides the significant fuel savings achieved, CDO decrease aircraft noise levels, significantly benefiting local communities. In addition to the general benefits in this regard, derived from less thrust being employed, the use of performance-based navigation (PBN) ensures that the lateral path can also be routed to avoid more noise-sensitive areas.

As depicted in Figure 3,  CDOs feature optimized profiles that allow aircraft to descend from high altitudes to the airport at minimum thrust settings, thus decreasing noise in local communities and using up to 30% less fuel than standard “stepped” approaches.

Continuous climb operations (CCO) do not require a  specific air or ground technology. They are derived from aircraft operating techniques aided by the appropriate airspace and procedure design. Since a large proportion of fuel burn occurs during the climb phase, enabling an aircraft to reach and maintain its optimum flight level without interruption will optimize fuel efficiency and reduce emissions. CCO can also provide for a reduction in noise, while increasing flight stability and the predictability of flight paths for both controllers and pilots.

Another good example is the use of collaborative decisionmaking (CDM) to improve airport operations, also known as A-CDM. Modules relating to A-CDM allow for the implementation of a collaborative set of applications and

permit the sharing of surface operations data among the different operators at the airport. A-CDM aims to improve the management of surface  traffic,  leading  to reduced delays on movement and maneuvering areas. Apart from the enhanced safety, efficiency and situational awareness gained,A-CDM contributes to reduced taxi time, reduced fuel and carbon emissions, and reduced aircraft engine run time.

Several  other modules are expected to deliver benefits through fuel savings and reduced CO2 emissions. The Committee on Aviation Environmental Protection (CAEP) has undertaken an initiative to quantify these reductions, in order to provide States and stakeholders with a better assessment of the expected environmental benefits.

Two New ICAO Manuals On Reducıng Emıssıons  Usıng Enhanced Aırcraft Operatıons By Kevın Morrıs And Shannon Scott

There is a range of options to reduce the impact of aviation emissions, including changes in aircraft and engine technology, fuel, operational practices, and regulatory and economic measures. These could be implemented either singly or in combination by the public and/or private sector. Substantial aircraft and engine technology advances and the air traffic management improvements described in this report are already incorporated in the aircraft emissions scenarios used for climate change calculations. Other operational measures, which have the potential to reduce emissions, and alternative fuels were not assumed in the scenarios. Further technology advances have the potential to provide additional fuel and emissions reductions. In practice, some of the improvements are expected to take place for commercial reasons. The timing and scope of regulatory, economic, and other options may affect the introduction of improvements and may affect demand for air transport. Mitigation options for water vapor and cloudiness have not been fully addressed.

Safety of operation, operational and environmental performance, and costs are dominant considerations for the aviation industry when assessing any new aircraft purchase or potential engineering or operational changes. The typical life expectancy of an aircraft is 25 to 35 years. These factors have to be taken into account when assessing the rate at which technology advances and policy options related to technology can reduce aviation emissions.

The structure of the Committee on Aviation Environmental Protection (CAEP1) leading to the ninth meeting of CAEP (CAEP/9) consisted of three specialized Working Groups (see article Committee on Aviation Environmental Protection: Outcomes from CAEP/9, Introduction in this report).

During the last CAEP cycle,   Working Group 2 Airports and Operations (WG2), which undertakes work to address aircraft noise and emissions linked to airport and aircraft operations, was tasked with completing two crucial ICAO publications2. The first was an update to ICAO Circular 303,which is to be published as a new ICAO manual titled, “Operational Opportunities to Reduce Fuel Burn and Emissions”. The second publication was guidance material on conducting CNS/ATM3 environmental assessments, to be issued as the new ICAO manual, “Environmental Assessment Guidance for Proposed Air Traffic Management Operational Changes”.

BACKGROUND

At the eighth meeting of CAEP (CAEP/8) in February 2010, WG2 was tasked with the completion of updates to chapters previously             contained in ICAO Circular 303. Four chapters were completed and approved at the CAEP Steering Group meeting      in November 2010. Then in September 2011, it was decided to make the approved chapters available on the ICAO public website. The draft manual was subsequently reviewed by the ICAO Operations Panel (OPSP), which reports to the Air Navigation Commission (ANC).

In addition, two tasks initiated at the CAEP/8 meeting in 2010 aimed at the development of CNS/ATM environmental assessment guidance material, with an associated programme plan. These tasks were directed towards WG2, and were completed at CAEP/9 in February 2013.            

The first of these tasks was to draft a programme plan to develop CNS/ATM environmental assessment guidance material. The plan required compiling information on current best practices in use for environmental assessments and identifying high-level guiding principles to inform States, airports, Air Navigation Service Providers (ANSPs) and others. The second task was to draft the actual guidance document itself, including the CNS/ATM environmental assessment guidance material, information on environmental assessment best practices, and high-level principles 

Manual: “ Operatıonal Opportunıtıes  To Reduce Fuel Burn And Emıssıons ” Introduction In  2004,       

ICAO published Circular  303,Operational Opportunities to Minimize Fuel Use and Reduce Emissions. That circular, developed by CAEP, reviewed a wide range of operational opportunities and techniques for minimizing fuel consumption, and therefore reducing emissions, in civil aviation operations. It was based on the premise that the most effective way to minimize aircraft emissions is to minimize the amount of fuel used in operating each flight. The circular was aimed at airlines, airport operators, air traffic management and air traffic control service providers, airworthiness authorities, environmental agencies, other government bodies, and other interested parties, and has since become an essential reference document.

Since the publication of Circular 303, the aviation industry has developed and implemented many new techniques to reduce fuel usage. As a result, CAEP agreed to update the material in Circular 303 and convert it into a new ICAO manual.         

To undertake that task, CAEP established a multi-disciplinary team comprised of experts from States, the airport sector, airline sector, air navigation service providers (ANSPs), aircraft manufacturers, other industry organizations, and the ICAO Secretariat. The resulting ICAO manual, titled “Operational Opportunities to Reduce Fuel Burn and Emissions”, will replace  Circular 303 when it is published.

There would not appear to be any practical alternatives to kerosene-based fuels for commercial jet aircraft for the next several decades. Reducing sulfur content of kerosene will reduce SOxO emissions and sulfate particle formation.

Jet aircraft require fuel with a high energy density, especially for long-haul flights. Other fuel options, such as hydrogen, may be viable in the long term, but would require new aircraft designs and new infrastructure for supply. Hydrogen fuel would eliminate emissions of carbon dioxide from aircraft, but would increase those of water vapor. The overall environmental impacts and the environmental sustainability of the production and use of hydrogen or any other alternative fuels have not been determined.

The formation of sulfate particles from aircraft emissions, which depends on engine and plume characteristics, is reduced as fuel sulfur content decreases. While technology exists to remove virtually all sulfur from fuel, its removal results in a reduction in lubricity.

The New Manual

The manual contains information on current practices followed by aircraft operators, airport operators, ANSPs, other industry organizations, and States. The information is intended to help any group that uses it to reduce fuel use and emissions from civil air transport.

The objectives of the manual are to:

a) Document industry experience and the benefits in terms of reduced emissions resulting from optimizing the use of current aircraft and infrastructure, and other related benefits of infrastructure improvements;

b) Identify improvements that could result in measurable fuel savings;

c) Demonstrate that the more efficient use of infrastructure is an effective means of reducing civil aviation emissions, and therefore promote the enhanced use of the capabilities inherent in existing aircraft, ground service equipment and infrastructure.

The manual is not intended to be the basis for regulatory action, and the particular choice of operational procedures can depend on many factors other than environmental benefits.For example, safety must always be the overriding consideration in all civil aviation operations. Another important consideration is that many operational opportunities require collaboration and cooperation among all civil aviation stakeholders for effective planning and implementation.

The structure of the manual features some differences from the original Circular 303. Three of the chapters from the circular were not incorporated into the manual, as they covered material that was considered to be better provided elsewhere. Chapters on the phases of flight were merged into a single chapter addressing opportunities across the full flight envelope.

The final manual reviews the fuel burn reduction opportunities related to:

•  airports;

•  maintenance;

•  reducing the aircraft dry operating weight;

•  air traffic management  (ATM);

•  across all phases of flight.

It also includes chapters on the effects of payload on fuel efficiency, and a review of flight planning and related issues from the aircraft operator’s point of view, as well as background information with respect to global emissions and climate change issues.

Operational techniques and opportunities will continue to evolve into the future, and readers are encouraged to submit comments on the manual to ICAO. These comments will be taken into account in the preparation of subsequent editions.

Manual: “ Environmental Assessment Guidance For Proposed Air Traffic Management Operational Changes ” 

Introduction 

At CAEP/8 in 2010, it was agreed to develop a document that provides guidance for assessing the environmental impacts of Air Traffic Management operational changes. As the task progressed, it became clear that the guidance would be useful to assist ICAO Member States in developing action plans for CO2 emissions reductions, and the task group was asked to move forward its completion. The drafting process was subsequently accelerated in an  effort to produce usable material, ahead of the original 2013 target completion date.

To accelerate the process, the task group worked using WG2 meetings, email, and dual conference calls (one Eastern hemisphere, and one Western hemisphere) to fast track the production of a draft document, without appendices, which was then duly submitted to the 2011 CAEP Steering Group meeting, and published on the ICAO Action Plan Emissions Reduction (APER) secure website for States to use. The process of finishing the remaining material continued, and a completed draft was presented at the 2012 Steering Group meeting. After final editing and conversion into the standard ICAO format, the final document “Environmental Assessment Guidance For Proposed Air Traffic Management Operational Changes”, with appendices and a form for reporting future examples, was approved at    the CAEP/9 meeting in February 2013.

The Guidance 

The document itself contains high-level principles for environmental assessment to guide States to ensure that a consistent approach can be maintained to support sound and informed decision making.

The recommended process is outlined in Figure 1. The manual also provides advice on preparatory work including: criteria for triggering assessments; environmental parameters; potential methodologies; and the type of documentation and communication that may be required.

Advice is also given on describing: proposed changes and investigating alternatives; how to determine the scope and extent   required;               whether appropriate “short-cuts” are possible; conducting the assessment;       and analysing and communicating the results.

Finally, the document notes the importance of considering and evaluating interdependencies, both environmental (e.g. noise vs. fuel burn, etc.) and non-environmental (e.g. fuel efficiency vs. airspace capacity, etc.) to ensure that, to the extent possible, an achievable and acceptable compromise can be made.

Four appendices are included in the guidance, containing:

•             examples of formal requirements;           

•             assessment methods and key environmental parameters;             

•             advice for avoiding common mistakes;

•             assessment examples.   

A standard reporting form is also provided to help keep the document up to date.

A living document to build on for the future The guidance was always intended to be a “living document” that could be updated as more experience was gained. To start the process, assessment examples for local, nonlocal, intercontinental, and oceanic regions were included in the initial guidance document and users are encouraged to submit their own experiences to ICAO for potentially inclusion in future updates.

An important example is one that used the 2011 draft guidance material and “road-tested” it on a Functional Airspace Block proposal. The results were very encouraging, and experiences from this study were fed back into the Task Group to refine the final guidance. In the future it is hoped that more examples and experiences can be used to continually refine the document.

Operatıons Impact Of Operatıonal Changes on Global Emıssıon Levels — Fındıngs Of The Operatıonal Goals Group By Lee Merry Brown

IntroductIon

Operational improvements, in conjunction with aircraft technology improvements, are key elements that contribute to the achievement of ICAO’s environmental sustainability goals for the aviation sector. ICAO therefore requires the thorough assessment             and        definition               of           potential             environmental   goals.    The        high-level purpose of operational goals is to inform decisionmakers     of           achievable          environmental   benefits               if            the         potential             improvements are implemented.

The Independent Expert (IE) review process was originated in support of the Committee on Aviation Environmental Protection (CAEP) work programme during the CAEP/7 cycle (2004-2007) when     the         first        IE           group    was        established         to           develop mediumterm and long-term technology goals for oxides of nitrogen (NOx) emissions. Various IE review groups and processes were established during the CAEP/8 cycle (2007-2010) including: noise technology goals review, second NOx technology goals review, fuel burn technology goals review, and operational goals review.

The operational goals IE review conducted during the CAEP/8 cycle produced a report summarizing future environmental goals for         air          traffic    management     (ATM)               operations.         CAEP     requested           that the group further elaborate the goals. A second operational goals review was conducted under the CAEP/9 cycle (20102013). The second Independent Expert Operational Goals Group (IEOGG) was established to undertake this task.

Independent Expert Operational  Goals Group Composition

 As with the first operational goals IE review, IEOGG  members were selected as individual experts.In contrast to the first IE review, nominees could not be direct representatives of a national service authority. The CAEP/9 IEOGG consisted of eight members from a variety of industry groups, bringing relevant knowledge of a number of relevant disciplines, including: air traffic    system  performance; airspace design;  airline operations; airport management; air transport and international affairs;  aircraft system  engineering; and system  modernization programmes (SESAR  and NextGen). Similar   to the first operational goals IE review, because the IEOGG membership represented a wide variety of different expertise domains, their consensus is considered as being fairly representative of the overall expert community perspective on the related issues covered.

Scope And Analysıs

The IEOGG’s scope was defined to address the impact  of  operations-based changes. The Terms of Reference for the IEOGG defined Operations as  “...  encompass[ing] the direct facilitation of the utilization of civil aircraft in any phase of the Gate-to-Gate regime, both in the air and on the ground”. Future activities that did not directly affect gate-to-gate operations were not included in the IEOGG’s analyses. However, the IEOGG attempted to include the potential impact of these actions in the context of other in-scope activities.

The Group’s scope was also defined to include  a baseline year of 2010, with two target    goal years 2020 (mid-term) and 2030 (long-term). At the inaugural workshop, the IEOGG was asked to add the year 2040 in order to coincide with the modelling timeframes planned for CAEP/10.

The analysis approach used by IEOGG was devised to take advantage of a variety of recent research, demonstration projects and studies  that estimate both potential benefit  pools, and also benefits that could be achieved using certain  technologies and procedures.

Summary Of Fuel And  Atmospheric Emission Goals

The operational fuel and atmospheric goals express the degree to which fuel usage and emissions can be reduced by eliminating inefficient fuel-usage operational practices. The IEOGG first       

estimated an associated “benefit pool”, which represents the 2010 level of fuel-usage inefficiency. The IEOGG  goals express the degree  to which    these inefficiencies can be eliminated by implementing new operational practices for the years in question. Thus, the associated benefit  pool is the level of  fuelusage inefficiency.

Based on its analyses, the IEOGG estimates the 2010 worldwide operational fuel        and atmospheric emissions benefit  pool to be 12.75%.If the ultimate goal is to be 100%     efficient, this corresponds to a worldwide system  efficiency level of 87.25%. The lower limit of the IEOGG confidence range for the benefit  pool is 10.25%, which corresponds to a worldwide efficiency level of 89.75%.         

The size of this benefit  pool is larger than the size estimated by the prior IEOGG and earlier Civil Air Navigation Services Organization (CANSO) estimates. The IEOGG used an alternate methodology compared with the prior work so there could be many       reasons for differences; however three factors  stand out: 

1.   The IEOGG   estimated the benefit  pool for those regions based on limited  data       availability.For example, the figures used for Middle East, China, India, South America and Africa were larger than the pools estimated previously. This difference was based on access to additional data and also anecdotal evidence obtained in discussions with local experts. 

2. IEOGG considers all taxi-in and taxi-out emissions to be part of the benefit pool due to the potential for electric taxi systems to eliminate the majority of these emissions. 

3. The IEOGG analysis took into account recent research that estimated           inefficiencies in typical cruise speed and altitude values.

The following table lists the IEOGG worldwide operational fuel usage and atmospheric emissions reduction goals.

The goals shown in Table 1 indicate a reduction in fuel usage/ emissions relative to 2010 levels. For example, the estimated emissions reduction goal for the year 2030 is 6.75% from the 2010 levels. As these are estimates,  a  lower confidence limit is also provided, or a 4.5% reduction from the 2010 levels.

As the previous IEOGG analysis observed, under a static ATM system congestion levels would increase and this increased congestion would lead to less        efficient operations. This would lead tomore excess fuel usage    on a per flight basis and an overall  degradation of the worldwide system  efficiency level. As depicted by the blue line in Figure 1 below, the IEOGG estimates that, under a static ATM system, overall system  efficiency would degrade by 2%    by 2020 and an additional  2% in each of  the succeeding decades, so  that the 2010 87.5% efficiency level mentioned above would decrease to 81.5% by 2040.Thus, the goals listed in Table 1 represent even greater emissions reductions relative to a static ATM system. Specifically, the IEOGG worldwide operational fuel usage and atmospheric emissions goals expressed as reductions in overall fuel usage and atmospheric emissions relative to a static ATM system are: 2020: 5.25%, 2030: 10.75%, 2040: 15%, as represented by the difference between the red and blue lines in Figure 1.

The IEOGG   analysis produced a benefit  pool and goals for each phase of flight:taxi-out, climb,cruise, descent, and taxi-in. The phase-of-flight  specific benefit  pool and goals are given below.  

Mechanisms To Achieve Goals

The stated goals are aspirational ones that the IEOGG believes are feasible. However, in order to achieve them the international aviation community must make strong and concerted efforts. To be achieved, a variety of performance enhancing measures must be implemented over time. The specific measures underlying the goals by phase-of-flight are given below.

• Taxi-Out: Minimum engine taxi and better surface management, especially reduction in physical taxi- outqueues in the near-term; electric taxi in the longer term.

• Climb: Dynamic airspace configuration; denser terminal area               operations, including performance-based navigation; better traffic flow       management, especially coordination between surface and airspace;time-based metering; trajectory-based operations.

• Cruise/Speed And Altitude Optimization:Satellite-based surveillance and               datalink; better traffic flow management, especially relative to reducing overall  congestion; performancebased navigation;               increased carrier priority/attention to fueloptimal speed control.

• Cruise/2-D Trajectory Optimization: Satellite-based surveillance and        datalink; better traffic flow management; improved weather information and prediction, including wind forecasts; trajectory-based operations; better access to special use airspace.

• Descent: Optimized profile descents; speed control  en route to reduce  congestion in terminal in near term; timebased metering in intermediate      term; performance-based trajectories and full trajectory-based operations in longer term; dynamic airspace configuration; denser terminal area operations, including             performance-based navigation; better traffic flow management,    especially coordination between surface and airspace.

• Taxi-in: Minimum engine taxi and better surface management in near term;     in North America, some move toward  common use gates in mid-term; electric taxi in longer term.

lIMItatIons and Further consIderatIons The goals developed by IEOGG are contingent on improvements in operational efficiency at the individual flight level. To illustrate, the IEOGG 2040        goal could be interpreted as follows: on the average, an equivalent flight, 

e.g. a B737-800 from ATL to ORD, should   use 9% less fuel in 2040  than the same flight     would use in 2010 (see Table 1). Specifically, these goals do not account for growth  in the overall number of flights,nor on changes in the characteristics of an “average” flight, which will likely become longer and use a larger aircraft.

The emissions reduction goal is expressed as a reduction in fuel usage, implicitly assuming that total emissions (all else being equal) are proportional to total fuel usage. In the case of CO2, this is a  reasonable assumption, however, for NOx the relationship between emissions and fuel usage may be more complex.

The IEOGG goals represent savings that can be achieved by new operational practices. However, in many cases these will require new technology investments on the part of both Air Navigation Service  Providers and flight operators, such as those associated with modernization efforts such as the Next Generation Air Transportation System (NextGen) and Single European Sky Aviation Research (SESAR). In addition, it is important to note that achieving the goals will require substantial reduction in taxi-in and taxi-out emissions through efficient queuing and by the eventual use of electric taxi systems.

The goals, at least in part, may require changes in policies and practices, not only for Air Navigation Service Providers (ANSPs), but also for flight operators            and States. For example, achieving certain  cruise benefits may require  flight     operators to give higher   priority  to the use of fuel-efficient speeds. Also, some cruise benefits may require that States provide additional access to special use airspace.

In addition to CO2 from fuel combustion, airplanes can also emit methane (CH4), nitrous oxide (N2O), hydrocarbons (HC), particulate matter (PM), sulfur oxides (SOx), and nitrogen oxides (NOx). Moreover, certain high-altitude aviation emissions can spur heat-trapping cloud formation. Compared to these non-CO2 emissions and cloud formation, there is more scientific certainty regarding the impacts of CO2 emissions from aviation and greater consensus on the optimal policies for reducing aviation’s CO2 emissions.

  

AND

INTERNATIONAL STANDARDS AND RECOMMENDED PRACTICES   

DEFINITIONS   

Where the following expressions are used in Volume II of this Annex, they have the meanings ascribed to them below: 

Afterburning. A mode of engine operation wherein a combustion system fed (in whole or part) by vitiated air is used. 

Approach phase. The operating phase defined by the time during which the engine is operated in the approach operating mode. 

Climb phase. The operating phase defined by the time during which the engine is operated in the climb operating mode. 

Date of manufacture. The date of issue of the document attesting that the individual aircraft or engine as appropriate conforms to the requirements of the type or the date of an analogous document. 

Derivative version. An aircraft gas turbine engine of the same generic family as an originally type-certificated engine and having features which retain the basic core engine and combustor design of the original model and for which other factors, as judged by the certificating authority, have not changed. 

 Note.— Attention is drawn to the difference between the definition of Aderived version of an aeroplane@ in Volume I of Annex 16 and the definition of Aderivative 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. 

Oxides of nitrogen. The sum of the amounts of the nitric oxide and nitrogen dioxide contained in a gas sample calculated as if the nitric oxide were in the form of nitrogen dioxide. 

Rated thrust. For engine emissions purposes, the maximum take-off thrust approved by the certificating authority for use under normal operating conditions at ISA sea level static conditions, and without the use of water injection. Thrust is expressed in kilonewtons. 

Reference pressure ratio. The ratio of the mean total pressure at the last compressor discharge plane of the compressor to the mean total pressure at the compressor entry plane when the engine is developing take-off thrust rating in ISA sea level static conditions. 

 Note.— Methods of measuring reference pressure ratio are given in Appendix 1. 

Smoke. The carbonaceous materials in exhaust emissions which obscure the transmission of light.

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Smoke Number. The dimensionless term quantifying smoke emissions (see 3 of Appendix 2). 

Take-off phase. The operating phase defined by the time during which the engine is operated at the rated thrust. 

Taxi/ground idle. The operating phases involving taxi and idle between the initial starting of the propulsion engine(s) and the initiation of the take-off roll and between the time of runway turn-off and final shutdown of all propulsion engine(s). 

Unburned hydrocarbons. The total of hydrocarbon compounds of all classes and molecular weights contained in a gas sample, calculated as if they were in the form of methane.    

Energy systems are for most economies largely driven by the combustion of fossil fuels. During combustion the carbon and hydrogen of the fossil fuels are converted mainly into carbon dioxide (CO2) and water (H2O), releasing the chemical energy in the fuel as heat. This heat is generally either used directly or used (with some conversion losses) to produce mechanical energy, often to generate electricity or for transportation. The energy sector is usually the most important sector in greenhouse gas emission inventories, and typically contributes over 90 percent of the CO2 emissions and 75 percent of the total greenhouse gas emissions in developed countries. CO2 accounts typically for 95 percent of energy sector emissions with methane and nitrous oxide responsible for the balance. Stationary combustion is usually responsible for about 70 percent of the greenhouse gas emissions from the energy sector. About half of these emissions are associated with combustion in energy industries mainly power plants and refineries. Mobile combustion (road and other traffic) causes about one quarter of the emissions in the energy sector.

SYMBOLS

Where the following symbols are used in Volume II of this Annex, they have the meanings ascribed to them below: 

 CO Carbon monoxide 

 Dp The mass of any gaseous pollutant emitted during the reference emissions landing and take-off cycle 

 F n Thrust in International Standard Atmosphere (ISA), sea level conditions, for the given operating mode 

 F oo Rated thrust 

 F*oo Rated thrust with afterburning applied 

 HC Unburned hydrocarbons (see definition) 

 NO Nitric oxide 

 NO2 Nitrogen dioxide 

 NOx Oxides of nitrogen (see definition) 

 SN Smoke Number (see definition) 

 πoo Reference pressure ratio (see definition)