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)
