Aviation and the Environment: NextGen and Research and		 
Development Are Keys to Reducing Emissions and Their Impact on	 
Health and Climate (06-MAY-08, GAO-08-706T).			 
                                                                 
Collaboration between the federal government and the aviation	 
industry has led to reductions in aviation emissions, but growing
air traffic has partially offset these reductions. The Federal	 
Aviation Administration (FAA), together with the National	 
Aeronautics and Space Administration (NASA), the Environmental	 
Protection Agency (EPA), and others, is working to increase the  
efficiency, safety, and capacity of the national airspace system 
and at the same time reduce aviation emissions, in part, by	 
transforming the current air traffic control system to the Next  
Generation Air Transportation System (NextGen). This effort	 
involves new technologies and air traffic procedures that can	 
reduce aviation emissions and incorporates research and 	 
development (R&D) on emissions-reduction technologies. Reducing  
aviation emissions is important both to minimize their adverse	 
health and environmental effects and to alleviate public concerns
about them that could constrain the expansion of airport	 
infrastructure and aviation operations needed to meet demand.	 
This testimony addresses (1) the scope and nature of aviation	 
emissions, (2) the status of selected key federal efforts to	 
reduce aviation emissions, and (3) next steps and challenges in  
reducing aviation emissions. The testimony updates prior GAO work
with FAA data, literature reviews, and interviews with agency	 
officials, industry and environmental stakeholders, and selected 
experts.							 
-------------------------Indexing Terms------------------------- 
REPORTNUM:   GAO-08-706T					        
    ACCNO:   A81984						        
  TITLE:     Aviation and the Environment: NextGen and Research and   
Development Are Keys to Reducing Emissions and Their Impact on	 
Health and Climate						 
     DATE:   05/06/2008 
  SUBJECT:   Aerospace industry 				 
	     Air pollution					 
	     Air pollution control				 
	     Air traffic control systems			 
	     Air transportation 				 
	     Aircraft						 
	     Aircraft industry					 
	     Airlines						 
	     Aviation						 
	     Aviation fuels					 
	     Carbon dioxide					 
	     Climate change					 
	     Emerging technologies				 
	     Emissions inspection				 
	     Environmental monitoring				 
	     Fuel conservation					 
	     Fuel consumption					 
	     Fuels						 
	     Greenhouse gases					 
	     Pollutants 					 
	     Program evaluation 				 
	     Research and development				 
	     Standards						 
	     Technology assessment				 
	     Technology research				 
	     Transportation industry				 
	     Transportation planning				 
	     Transportation policies				 
	     Transportation research				 
	     Program goals or objectives			 
	     Next Generation Air Transportation 		 
	     System						 
                                                                 

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GAO-08-706T

   

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material separately. 

Testimony Before the Subcommittee on Aviation, Committee on 
Transportation and Infrastructure, House of Representatives: 

United States Government Accountability Office: 
GAO: 

For Release on Delivery:
Expected at 2:00 p.m. EDT: 
Tuesday, May 6, 2008: 

Aviation And The Environment: 

NextGen and Research and Development Are Keys to Reducing Emissions and 
Their Impact on Health and Climate: 

Statement of Gerald L. Dillingham, Ph.D.
Director, Physical Infrastructure Issues: 

GAO-08-706T: 

GAO Highlights: 

Highlights of GAO-08-706T, a testimony before the Subcommittee on 
Aviation, Committee on Transportation and Infrastructure, House of 
Representatives. 

Why GAO Did This Study: 

Collaboration between the federal government and the aviation industry 
has led to reductions in aviation emissions, but growing air traffic 
has partially offset these reductions. The Federal Aviation 
Administration (FAA), together with the National Aeronautics and Space 
Administration (NASA), the Environmental Protection Agency (EPA), and 
others, is working to increase the efficiency, safety, and capacity of 
the national airspace system and at the same time reduce aviation 
emissions, in part, by transforming the current air traffic control 
system to the Next Generation Air Transportation System (NextGen). This 
effort involves new technologies and air traffic procedures that can 
reduce aviation emissions and incorporates research and development 
(R&D) on emissions-reduction technologies. Reducing aviation emissions 
is important both to minimize their adverse health and environmental 
effects and to alleviate public concerns about them that could 
constrain the expansion of airport infrastructure and aviation 
operations needed to meet demand. 

This testimony addresses (1) the scope and nature of aviation 
emissions, (2) the status of selected key federal efforts to reduce 
aviation emissions, and (3) next steps and challenges in reducing 
aviation emissions. The testimony updates prior GAO work with FAA data, 
literature reviews, and interviews with agency officials, industry and 
environmental stakeholders, and selected experts. 

What GAO Found: 

Aviation contributes a modest but growing proportion of total U.S. 
emissions, and these emissions contribute to adverse health and 
environmental effects. Aircraft and airport operations, including those 
of service and passenger vehicles, emit ozone and other substances that 
contribute to local air pollution, as well as carbon dioxide and other 
greenhouse gases that contribute to climate change. EPA estimates that 
aviation emissions account for less than 1 percent of local air 
pollution nationwide and about 2.7 percent of U.S. greenhouse gas 
emissions, but these emissions are expected to grow as air traffic 
increases. 
 
Two key federal efforts, if implemented effectively, can help to reduce 
aviation emissionsï¿½NextGen initiatives in the near term and research 
and development over the longer term. For example, NextGen technologies 
and procedures, such as satellite-based navigation systems, should 
allow for more direct routing, which could improve fuel efficiency and 
reduce carbon dioxide emissions. Federal research and development 
effortsï¿½led by FAA and NASA in collaboration with industry and 
academiaï¿½have achieved significant reductions in aircraft emissions 
through improved aircraft and engine technologies, and federal 
officials and aviation experts agree that such efforts are the most 
effective means of achieving further reductions in the longer term. 
Federal R&D on aviation emissions also focuses on improving the 
scientific understanding of aviation emissions and developing lower-
emitting aviation fuels. 

Next steps in reducing aviation emissions include managing NextGen 
initiatives efficiently; deploying NextGen technologies and procedures 
as soon as practicable to realize their benefits, including lower 
emissions levels; and managing a decline in R&D funding, in part, by 
setting priorities for R&D on NextGen and emissions-reduction 
technologies. Challenges in reducing aviation emissions include 
designing aircraft that can simultaneously reduce noise and emissions 
of air pollutants and greenhouse gases; encouraging financially 
stressed airlines to purchase more fuel-efficient aircraft and 
emissions-reduction technologies; addressing the impact on airport 
expansion of more stringent EPA air quality standards and growing 
public concerns about the effects of aviation emissions; and responding 
to proposed domestic and international measures for reducing greenhouse 
gases that could affect the financial solvency and competitiveness of 
U.S. airlines. 

Figure: Sources of Aviation Emissions: 

[See PDF for image] 

This figure is a photograph of an aircraft parked at a terminal gate. 

Source: FAA. 

[End of figure] 

To view the full product, including the scope and methodology, click on 
[hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-08-706T]. For more 
information, contact Gerald L. Dillingham at (202) 512-2834 or 
[email protected]. 

[End of section] 

Mr. Chairman and Members of the Subcommittee: 

I appreciate the opportunity to testify before you on aviation 
emissions, one of the key sources of concern about the environmental 
effects of aviation. Over the past 30 years, the federal government, 
the aviation industry, and other private parties have worked 
collaboratively to achieve steady reductions in aircraft emissions. 
[Footnote 1] Nevertheless, increases in air traffic, which have 
enhanced the nation's productivity and mobility, have partially offset 
these reductions, as more flights have produced more emissions and 
congestion has led to flight delays. According to the Federal Aviation 
Administration (FAA), this growth in air traffic will continue, with 
the number of flights increasing 20 percent by 2015 and 60 percent by 
2030.[Footnote 2] In light of these developments, concerns about the 
environmental effects of aviation emissions have persisted. Moreover, 
better scientific understanding of the potential health effects of 
certain aviation emissions and their contribution to climate change has 
intensified the public's concerns. 

To accommodate the expected growth in air traffic, FAA is leading a 
multipronged, multiagency effort to increase the efficiency, safety, 
and capacity of the national airspace system. This effort includes 
transforming the current air traffic control system into the Next 
Generation Air Transportation System (NextGen)[Footnote 3] and will 
require airport and runway expansion. The NextGen initiative 
incorporates research and development (R&D) on emissions-reduction 
technologies, alternative fuels, and cleaner and quieter air traffic 
management procedures. This R&D is necessary both to meet anticipated 
domestic and international environmental standards and to reduce the 
environmental impact of aviation. Meeting environmental standards can 
limit the adverse effects of aviation emissions on air quality and 
climate, and addressing public concerns about aviation emissions is 
necessary to avoid constraints on the expansion of aviation operations 
and airport infrastructure planned under NextGen.[Footnote 4] 

Under the National Environmental Policy Act of 1969, agencies evaluate 
the likely environmental effects of projects they are proposing using 
an environmental assessment or, if the projects likely would 
significantly affect the environment, a more detailed environmental 
impact statement.[Footnote 5] FAA typically carries out one of these 
evaluations for federally financed airport construction projects, 
including the construction of federally subsidized runways. In 
addition, under the Clean Air Act's conformity provision, no federal 
agency may approve or provide financial assistance for any activity 
that does not conform to an applicable state implementation 
plan.[Footnote 6] Therefore, FAA must evaluate whether a proposed 
federal action associated with an airport project conforms with the 
applicable state implementation plan before approving or funding the 
project.[Footnote 7] In addition, the Clean Air Act mandates standards 
for mobile sources of emission, such as aircraft and the equipment that 
service them at airports. EPA sets emissions standards for aircraft and 
has chosen to adopt international emissions standards for aircraft set 
by the International Civil Aviation Organization (ICAO).[Footnote 8] 

As requested, my testimony today focuses on aviation emissions. It will 
address the following questions: (1) What are the scope and nature of 
aviation emissions? (2) What is the status of selected key federal 
efforts to address aviation emissions? and (3) What are some next steps 
and major challenges for the federal government, the aviation industry, 
and Congress related to aviation emissions? My statement is based on 
previous GAO reports[Footnote 9] updated with a synthesis of recent 
empirical literature and interviews with officials from FAA, the 
National Aeronautics and Space Administration (NASA), and the U.S. 
Environmental Protection Agency (EPA); representatives of aviation 
industry and environmental associations, and selected aviation 
emissions experts.[Footnote 10] We balanced the selection of these 
experts to capture the views of the many different groups involved in 
aviation emissions reduction efforts and NextGen. We conducted our work 
from March to May 2008 in accordance with generally accepted government 
auditing standards. Those standards require that we plan and perform 
the study to obtain sufficient, appropriate evidence to provide a 
reasonable basis for our findings and conclusions based on our study 
objectives. We believe that the evidence obtained provides a reasonable 
basis for our findings and conclusions based on our study objectives. 

Summary: 

Currently, aviation contributes a modest proportion of total emissions 
in the United States, but its share could increase in the future, and 
aviation emissions can have a detrimental effect on health and the 
environment. Aircraft are the primary source of aviation emissions, but 
airport operations, including those of service and passenger vehicles, 
also produce emissions. Together, aircraft operations in the vicinity 
of the airport and other airport sources emit nitrogen oxides, which 
lead to the formation of ground-level ozone (also known as smog), and 
other substances that contribute to local air pollution, as well as 
carbon dioxide and other greenhouse gases that rise into the atmosphere 
and contribute to climate change. Aircraft operations in the upper 
atmosphere are, however, the primary aviation-related source of 
greenhouse gas emissions. Currently, according to EPA estimates, 
aviation emissions account for less than 1 percent of local air 
pollution nationwide and about 2.7 percent of U.S. greenhouse gas 
emissions. This proportion is, however, expected to grow with projected 
increases in air traffic, despite expected improvements in fuel 
efficiency. Notably, according to FAA, emissions of nitrogen oxides 
from aviation sources will increase by over 90 percent by 2025 if not 
addressed. This increase is likely to increase ozone, which aggravates 
respiratory ailments. Increases in air traffic also mean increases in 
carbon dioxide emissions and increases in aviation's contribution to 
climate change, according to the International Panel on Climate Change 
(IPCC). 

Two key federal efforts, if implemented effectively, can help to reduce 
aviation emissions--near-term NextGen initiatives and R&D over the 
longer term to fully enable NextGen and reduce aircraft emissions. Some 
NextGen technologies and procedures, such as satellite-based navigation 
systems, should allow for more direct routing, which could improve fuel 
efficiency and reduce carbon dioxide emissions. According to FAA, the 
full implementation of NextGen could reduce greenhouse gas emissions 
from aircraft by up to 12 percent by 2025. Federal R&D efforts--led 
primarily by FAA and NASA and often conducted in collaboration with 
industry and academia--have achieved significant reductions in aircraft 
emissions over the last 30 years, and FAA and NASA officials and 
aviation experts agree that such efforts are the most effective means 
of achieving further reductions in the longer term. As part of the a 
national plan for aeronautics R&D, issued by the White House Office of 
Science and Technology Policy, the federal government supports a 
comprehensive approach to R&D on aviation emissions involving FAA, 
NASA, and other federal agencies that is intended both to improve 
scientific understanding of the impact of aviation emissions and to 
develop new technologies, fuels, and air traffic management approaches. 
Better understanding of the nature and impact of aviation emissions can 
inform the development of lower-emitting alternative fuels, more 
efficient air traffic management technologies and procedures, and more 
fuel-efficient aircraft engines. 

Reducing aviation emissions includes steps that FAA and others can take 
to move the implementation of NextGen forward and to support R&D on 
NextGen and emissions-reduction technologies, as well as technical, 
financial, and regulatory challenges facing the federal government, the 
aviation industry, and Congress. One step for FAA is to ensure the 
efficiency of NextGen's management by, for example, addressing 
congressional leaders' and stakeholders' concerns about the program's 
management structure and authority. Another step for FAA is to further 
deploy, as soon as practicable, NextGen technologies and procedures, 
such as the more efficient takeoff and landing procedures now in use at 
a few airports, to realize their benefits and lower emissions levels. A 
third step, for FAA and NASA, is managing a decline in federal funding 
for aeronautics research, the research category that includes work on 
aviation emissions, new aircraft and engine technologies, and 
alternative fuels. As a result of this decline, NASA is now sometimes 
developing technologies to a lower maturity level than in the past, and 
the technologies are less ready for manufacturers to adopt them. The 
administration's reauthorization bill for FAA seeks some additional 
funding for an initiative that could lead to the earlier maturation of 
certain emissions-reduction technologies, but according to some 
experts, increased funding of the initiative could increase the 
probability of success and decrease the time needed to achieve that 
success. Challenges in reducing aviation emissions for the federal 
government, the aviation industry, and Congress include designing 
aircraft that can simultaneously reduce noise and emissions of air 
pollutants and greenhouse gases; encouraging financially stressed 
airlines to purchase more fuel-efficient aircraft and emissions- 
reduction technologies; addressing the impact on airport expansion of 
more stringent EPA air quality standards and growing public concerns 
about effects of aviation emissions; and responding to proposed 
domestic and international measures for reducing greenhouse gases that 
could affect the financial solvency and competitiveness of U.S. 
airlines. 

Aviation's Small but Growing Proportion of Total Emissions Contributes 
to Health and Environmental Effects: 

Aviation-related activities contribute to local air pollution and 
produce greenhouse gases that cause climate change. Aircraft account 
for about 70 to 80 percent of aviation emissions, producing emissions 
that mainly affect air quality below 3,000 feet and increase greenhouse 
gases at higher altitudes. At ground level, airport operations, 
including those of motor vehicles[Footnote 11] traveling to and from 
the airport, ground service equipment,[Footnote 12] and stationary 
sources such as incinerators and boilers, also produce emissions. 
Together, aircraft operations in the vicinity of the airport and other 
airport sources produce emissions such as carbon monoxide, sulfur 
oxides, particulate matter, nitrogen oxides, unburned hydrocarbons, 
hazardous air pollutants,[Footnote 13] and ozone[Footnote 14] that 
contribute to air pollution. In addition, these sources emit carbon 
dioxide and other greenhouse gases that contribute to climate change, 
but aircraft operations in the upper atmosphere are the primary source 
of aviation-related greenhouse gases. Carbon dioxide is both the 
primary aircraft emission and the primary contributor to climate 
change. It survives in the atmosphere for over 100 years. Furthermore, 
other gases and particles emitted by aircraft--including water vapor, 
nitrogen oxides, soot, contrails,[Footnote 15] and sulfate--can also 
have an impact on climate, but the magnitude of this impact is unknown, 
according to FAA. Figure 1 illustrates aviation's impact on air quality 
and climate. 

Figure 1: Environmental Effects of Aviation Emissions and Noise: 

[See PDF for image] 

This figure is an illustration of environmental effects of aviation 
emissions and noise. The following information is depicted: 

Ground level to 3,000 feet: Airports produce:
Nitrogen oxides, O3, particulates and noise; effect local air quality 
and noise pollution. 

Troposphere (3,000 to 40,000 feet): Aircraft produce: 
CO2, NOx, H2O, and particulates; effect on climate change. 

Stratosphere (above 40,000 feet): Aircraft produce: 
NOx, halogens; effect on ozone layer change. 

Source: GAO. 

[End of figure] 

Currently, aviation accounts for a small portion of air pollutants and 
greenhouse gas emissions. Specifically, aviation emissions represent 
less than 1 percent of air pollution nationwide, but their impact on 
air quality could be higher in the vicinity of airports. In addition, 
aviation accounts for about 2.7 percent of the total U.S. contribution 
of greenhouse gas emissions, according to the Department of 
Transportation's Center for Climate Change and Environment. A 1999 
study by the United Nations' Intergovernmental Panel on Climate Change 
(IPCC) estimated that global aircraft emissions generally accounted for 
approximately 3.5 percent of the warming generated by human 
activity.[Footnote 16] 

As air traffic increases, aviation's contribution to air pollution and 
climate change could also grow, despite ongoing improvements in fuel 
efficiency, particularly if other sectors achieve significant 
reductions. In addition, aviation's impact on air quality is changing 
as more fuel-efficient, quieter aircraft engines are placed in service. 
While new aircraft engine technologies have reduced fuel consumption, 
noise, and emissions of most pollutants, they have not achieved the 
same level of reductions in nitrogen oxide emissions, which contribute 
to ozone formation. According to FAA, nitrogen oxide emissions from 
aviation will increase by over 90 percent by 2025 without improvements 
in aircraft emissions technologies and air traffic management, and 
emissions of other air pollutants will also increase, as shown in 
figure 2. Additionally, aviation's greenhouse gas emissions and 
potential contribution to climate change is expected to increase. IPCC 
has estimated that aircraft emissions are likely to grow by 3 percent 
per year, outpacing the emissions reductions achieved through 
technological improvements. Furthermore, as emissions from other 
sources decline, aviation's contribution to climate change may become 
proportionally larger, according to FAA. Alternative fuels are not yet 
available in sufficient quantities for jet aircraft, as they are for 
some other uses, and therefore aviation cannot yet adopt this approach 
to reduce its greenhouse gas emissions (see discussion below on U.S. 
efforts to develop alternative fuels for aviation). 

Figure 2: FAA Analysis of Growth in Aviation Related Pollutants by 
2025: 

[See PDF for image] 

This figure is a vertical bar graph depicting the following data: 

FAA Analysis of Growth in Aviation Related Pollutants by 2025: 

Pollutant: Hydrocarbons; 
Percent increase: 75%. 

Pollutant: Carbon monoxide; 
Percent increase: 70%; 

Pollutant: Nitrogen oxides; 
Percent increase: 90%. 

Pollutant: Sulfur oxides; 
Percent increase: 85%. 

Source: FAA. 

Note: According to FAA, the increases in aviation-related pollutants 
are baseline forecasts that do not account for potential improvements 
in aircraft technology and air traffic management. 

[End of figure] 

Aviation emissions, like other combustible emissions, include 
pollutants that affect health. While it is difficult to determine the 
health effects of pollution from any one source, the nitrogen oxides 
produced by aircraft engines contribute to the formation of ozone, the 
air pollutant of most concern in the United States and other 
industrialized countries. Ozone has been shown to aggravate respiratory 
ailments. A National Research Council panel recently concluded that 
there is strong evidence that even short-term exposure to ozone is 
likely to contribute to premature deaths of people with asthma, heart 
disease, and other preexisting conditions. With improvements in 
aircraft fuel efficiency and the expected resulting increases in 
nitrogen oxide emissions, aviation's contribution to ozone formation 
may increase. In addition, aviation is associated with other air 
pollutants, such as hazardous air pollutants, including benzene and 
formaldehyde, and particulate matter, all of which can adversely affect 
health. Data on emissions of hazardous air pollutants in the vicinity 
of airports are limited, but EPA estimates that aviation's production 
of these pollutants is small relative to other sources, such as on-road 
vehicles. Nevertheless, according to EPA, there is growing public 
concern about the health effects of the hazardous air pollutants and 
particulate matter associated with aviation emissions. See appendix I 
for more detailed information on the health and environmental effects 
of aviation emissions. 

Carbon dioxide and other greenhouse gas emissions from aircraft 
operations in the atmosphere, together with ground-level aviation 
emissions that gradually rise into the atmosphere, contribute to global 
warming and climate change. IPCC's most recent report[Footnote 17] 
documents mounting evidence of global warming and projects the 
potential catastrophic effects of climate change. As figure 6 shows, 
climate change affects precipitation, sea levels, and winds as well as 
temperature, and these changes in turn will increasingly affect 
economies and infrastructure around the world. 

Figure 3: Concerns about the Effects of Climate Change: 

[See PDF for image] 

This figure is an illustration of concerns about the effects of climate 
change. The following information is depicted: 

Climate Change: 
* Temperature; 
* Precipitation and severe weather; 
* Rising sea levels; 
* Winds. 

Possible effects: 
* Health Impacts; 
* Agricultural impacts; 
* Forest impacts; 
* Water resource impacts; 
* Coastal area impacts; 
* Ecosystem impacts; 
* Economic and infrastructure impacts. 

Source: EPA and FAA. 

[End of figure] 

Key Federal Efforts to Address Aviation Emissions Include Near-Term 
Operational Changes and Longer-Term R&D Initiatives: 

Two key federal efforts, if implemented effectively, can help to reduce 
aviation emissions--near-term NextGen initiatives and an array of R&D 
programs over the longer term to fully enable NextGen and to reduce 
aircraft emissions. The NextGen initiatives are primarily intended to 
improve the efficiency of the aviation system so that it can handle 
expected increases in air traffic, but these initiatives can also help 
reduce aviation emissions. In addition, the federal government, led by 
FAA and NASA, has longer-term R&D programs in place to improve the 
scientific understanding of the impact of aviation emissions in order 
to inform decisions about emissions-reduction strategies, explore 
potential emissions-reducing alternative fuels, and develop NextGen and 
aircraft emissions-reduction technologies. 

NextGen Initiatives Have the Potential to Help Reduce Emissions: 

Technologies and procedures that are being developed as part of NextGen 
to improve the efficiency of flight operations can also reduce aircraft 
emissions. According to FAA, the implementation of NextGen could reduce 
greenhouse gas emissions from aircraft by up to 12 percent. One NextGen 
technology, considered a centerpiece of NextGen, is the Automatic 
Dependent Surveillance-Broadcast (ADS-B) satellite aircraft navigation 
system. ADS-B is designed, along with other navigation technologies, to 
enable more precise control of aircraft during en route flight, 
approach, and descent. ADS-B will allow for closer and safer 
separations between aircraft and more direct routing, which will 
improve fuel efficiency and reduce carbon dioxide emissions. This 
improved control will also facilitate the use of air traffic control 
procedures that will reduce communities' exposure to aviation emissions 
and noise. One such procedure, Continuous Descent Arrivals (CDA), 
allows aircraft to remain at cruise altitudes longer as they approach 
destination airports, use lower power levels, and thereby lower 
emissions and noise during landings. Figure 3 shows how CDA compares 
with the current step-down approach to landing, in which aircraft make 
alternate short descents and forward thrusts, which produce more 
emissions and noise than continuous descents. A limited number of 
airports have already incorporated CDA into their operations. For 
example, according to officials from Los Angeles International Airport, 
nearly 25 percent of landings at their airport use CDA procedures in 
one of the airport's standard terminal approaches. In addition, United 
Parcel Service plans to begin using a nighttime CDA procedure, designed 
and tested at the Louisville International Airport, for its hub 
operations. 

Figure 4: Comparison of CDA and Current Step-Down Approach: 

[See PDF for image] 

This figure is an illustration of the comparison of CDA and current 
step-down approach. The illustration shows the relative position of the 
aircraft to the runway using the two techniques. 

Source: Naverus and AVTECH. 

Note: Continuous Descent Arrivals keep aircraft higher for longer and 
have them descend at near-idle power to touchdown. Optimal profiles are 
not always possible, especially at busy airports. 

[End of figure] 

Two closely associated NextGen initiatives, Area Navigation (RNAV) and 
Required Navigation Performance (RNP), have the potential to modify the 
environmental impact of aviation by providing enhanced navigational 
capability to the pilot. RNAV equipment can compute an airplane's 
position, actual track, and ground speed, and then provide meaningful 
information on the route of flight selected by the pilot. RNP will 
permit the airplane to descend on a precise route that will allow it to 
avoid populated areas, reduce its consumption of fuel, and lower its 
emissions of carbon dioxide and nitrogen oxides.[Footnote 18] See 
figure 4. Currently, over 350 RNAV/RNP procedures are available at 54 
airports, including Dallas/Fort Worth, Miami International, Washington 
Dulles, and Atlanta Hartsfield. 

Figure 5: Comparison of RNP and Current Step-Down Approach: 

[See PDF for image] 

This figure is an illustration of the comparison of RNP and current 
step-down approach. The illustration shows the relative position of the 
aircraft to the runway using the two techniques. In RNP, the idle 
thrust descent produces less emissions, less fuel used and less noise. 

Source: Naverus and AVTECH. 

Note: An RNP approach and path allows for idle-thrust, continuous 
descent instead of today's step-down approaches with vectors. RNP 
precision and curved-approach flexibility can shift flight paths to 
avoid populated areas. 

[End of figure] 

Still another NextGen initiative, High-Density Terminal and Airport 
Operations, is intended to improve the efficiency of aircraft 
operations at busy airports, and, in the process, reduce emissions. At 
high-density airports, the demand for access to runways is high, and 
arrivals and departures take place on multiple runways. The combination 
of arrivals, departures, and taxiing operations may result in 
congestion, which in turn produces delays, emissions, and noise as 
aircraft wait to take off and land. Under the High-Density Terminal and 
Airport Operations initiative, which FAA has just begun to implement, 
aircraft arriving and departing from different directions would be 
assigned to multiple runways and safely merged into continuous flows 
despite bad weather and low visibility. To guarantee safe separation, 
these airports would need enhanced navigation capabilities and 
controllers with access to increased automation. Under this initiative, 
aircraft would also move more efficiently on the ground, using 
procedures that are under development to reduce spacing and separation 
requirements and improve the flow of air traffic into and out of busy 
metropolitan airspace. More efficient aircraft movement would increase 
fuel efficiency and reduce emissions and noise. Although the 
implementation of this initiative is in the early stages, FAA has 
identified the R&D needed to move it forward. 

Technologies and procedures planned for NextGen should also help 
improve the efficiency of flights between the United States and other 
nations, further reducing emissions, particularly of greenhouse gases. 
A test program scheduled to begin in the fall of 2008, known as the 
Atlantic Interoperability Initiative to Reduce Emissions (AIRE), 
sponsored by FAA and the European Commission, Boeing, and Airbus, will 
involve gate-to-gate testing of improved procedures on the airport 
surface, during departures and arrivals, and while cruising over the 
ocean. Some of the procedures to be tested will use technologies such 
as ADS-B. A similar effort--the Asia and South Pacific Initiative to 
Reduce Emissions (ASPIRE)--was launched earlier this year, involving 
the United States, Australia, and New Zealand. 

Federal R&D Focuses on Long-Term Approaches to Addressing Aviation 
Emissions: 

We have previously reported[Footnote 19] that the federal government 
and industry have achieved significant reductions in some aircraft 
emissions, such as carbon dioxide, through past R&D efforts, and 
federal officials and aviation experts agree that such efforts are the 
most effective means of achieving further reductions in the longer 
term[Footnote 20]. As part of the a national plan for aeronautics R&D, 
issued by the White House Office of Science and Technology Policy, the 
federal government supports a comprehensive approach to R&D on aviation 
emissions that involves FAA, NASA, and other federal agencies. 
According to FAA, this approach includes efforts to improve the 
scientific understanding of the nature and impact of aviation emissions 
and thereby inform the development of more fuel-efficient aircraft, of 
alternative fuels that can reduce aircraft emissions, and of air 
traffic management technologies that further improve the efficiency of 
aviation operations. NASA, industry, and academia are important 
partners in these efforts. Notably, however, the development of 
breakthrough technologies, such as highly fuel-efficient aircraft 
engines that emit fewer greenhouse gases and air pollutants, is 
expensive and can take a long time, both to conduct the research and to 
implement the new technologies in new aircraft designs and introduce 
these new aircraft into the fleet. Successfully developing these 
technologies also requires the support and cooperation of stakeholders 
throughout the aviation industry. 

FAA Supports Research on Improving the Scientific Understanding of 
Aviation Emissions and on Alternative Fuels: 

Improving the scientific understanding of aviation emissions can help 
guide the development of approaches to reducing emissions by improving 
aircraft manufacturers' and operators' and policy makers' ability to 
assess the environmental benefits and costs of alternative policy 
measures. Such an assessment can then lead to the selection of the 
alternative that will achieve the greatest net environmental benefits. 
For example, one technology might greatly increase fuel efficiency, but 
produce higher nitrogen oxide emissions than another, somewhat less 
fuel-efficient technology. Overall, a cost benefit analysis might 
indicate that the less fuel-efficient technology would produce greater 
net benefits for the environment. 

FAA currently supports several recent federal efforts to better 
quantify aviation emissions and their impact through improvements in 
emissions measurement techniques and modeling capability. One of these 
efforts is FAA's Partnership for Air Transportation and Emissions 
Reduction (PARTNER) Center of Excellence.[Footnote 21] Created in 2003, 
PARTNER carries on what representatives of airlines, aircraft and 
engine manufacturers, and experts in aviation environmental research 
have described as a robust research portfolio. This portfolio includes 
efforts to measure aircraft emissions and to assess the human health 
and welfare risks of aviation emissions and noise. For example, 
researchers are developing an integrated suite of three analytical 
tools--the Environmental Design Space, the Aviation Environmental 
Design Tool, and the Aviation Environmental Portfolio Management Tool - 
that can be used to identify interrelationships between noise and 
emissions. Data from these three tools, together with the Aviation 
Environmental Design tool being developed by the Volpe National 
Transportation Systems Center and others, will allow for assessing the 
benefits and costs of aviation environmental policy options. Another 
R&D initiative, the Airport Cooperative Research Program 
(ACRP),[Footnote 22] conducts applied research on aviation emissions 
and other environmental issues facing airports. The program is managed 
by the National Academies of Science through its Transportation 
Research Board under a contract with FAA, which provided $10 million 
for the program in both 2007 and 2008 and is seeking to increase these 
investments through its reauthorization to specifically focus on 
aviation environmental issues. Several of the emissions-related 
projects undertaken through ACRP have concentrated on developing 
methods to measure particulate matter and hazardous air pollutants at 
airports in order to identify the sources of these pollutants and 
determine whether their levels could have adverse health effects. FAA 
has also developed an Aviation Emissions Characterization roadmap to 
provide a systematic process to enhance understanding of aviation's air 
quality emissions, most notably particulate matter and hazardous air 
pollutants. In addition, FAA, in conjunction with NASA and the National 
Oceanic and Atmospheric Administration, launched the Aviation Climate 
Change Research Initiative to develop the scientific understanding 
necessary for informing efforts to limit or reduce aviation greenhouse 
gas emissions. 

Another effort, the Commercial Aviation Alternative Fuels Initiative 
(CAAFI),[Footnote 23] led by FAA, together with airlines, airports, and 
manufacturers, is intended to identify and eventually develop 
alternative fuels for aviation that could lower emissions of greenhouse 
gases, and other pollutants; increase fuel efficiency; and reduce U.S. 
dependence on foreign oil. CAAFI supports research on low-carbon fuel 
from sources such as plant oils, algae, and biomass that are as safe as 
petroleum-based fuel and compare favorably in terms of environmental 
impact. Part of the research will involve assessing the environmental 
impact of alternative fuels to determine whether their use could reduce 
emissions of pollutants that affect climate and air quality. The 
research will also assess the impact of producing these fuels on the 
overall carbon footprint. The CAAFI sponsors have set goals for 
certifying a 50 percent synthetic fuel for aviation use in 2008, a 100 
percent synthetic fuel for use by 2010, and a biofuel made from 
renewable resources such as palm, soy, or algae oils. As part of CAAFI, 
Virgin Atlantic Airlines, together with Boeing, has tested a blend of 
kerosene (normal jet fuel) and biofuels in a flight from London to 
Amsterdam, and Continental, in association with Boeing and jet engine 
manufacturer General Electric, is planning a similar test in 2009. 

NASA Conducts Fundamental Aeronautics R&D in Support of NextGen, 
Including Efforts That Can Help Lower Emissions: 

NASA has devoted a substantial portion of its aeronautical R&D program 
to the development of technologies critical to the implementation of 
NextGen, as well as new aircraft and engine technologies, both of which 
can help reduce aviation emissions. 

NASA has three main aeronautics research programs - Fundamental 
Aeronautics, Aviation Safety, and Airspace Systems - each of which 
contributes directly and substantially to NextGen. For example, the 
Airspace Systems program supports research on air traffic management 
technologies for NextGen, and the Fundamental Aeronautics program 
focuses on removing environmental and performance barriers, such as 
noise and emissions, that could constrain the capacity enhancements 
needed to accommodate projected air traffic increases. Appendix II 
describes in more detail how NASA's aeronautics R&D programs support 
the implementation of NextGen. 

NASA also works with aircraft and aircraft engine manufacturers to 
increase fuel efficiency and reduce emissions. Their efforts have 
contributed to a number of advancements in aircraft engine and airframe 
technology, and NASA's R&D on emissions-reduction technologies 
continues. NASA has set technology-level goals for reducing greenhouse 
gases, nitrogen oxides, and noise, which have become part of the U.S. 
National Aeronautics Plan. For example, the plan includes a goal for 
developing technologies that could reduce nitrogen oxide emissions 
during landings and takeoffs by 70 percent[Footnote 24] below the ICAO 
current standard. The plan also sets a goal of increasing fuel 
efficiency (and thereby decreasing greenhouse gases emissions) by 33 
percent. These technologies would be incorporated in the next 
generation of aircraft, which NASA refers to as N+1,[Footnote 25] by 
2015. However, as NASA officials note, these goals must be viewed 
within the context that each of the goals can be fully met only if it 
is the only goal. For example, the goal for reducing nitrogen oxides 
can be fully achieved only at the expense of the goals for lowering 
greenhouse gas emissions and noise, because it is technologically 
challenging to design aircraft that can simultaneously reduce all of 
these environmental impacts. 

For the longer term (2020), NASA is focusing on developing tools and 
technologies for use in the design of advanced hybrid-wing body 
aircraft, the following generation of aircraft, or N+2. Emissions from 
these aircraft would be in the range of 80 percent below the ICAO 
standard for nitrogen oxide emissions during landings and takeoffs, and 
fuel consumption would be 40 percent less than for current aircraft. 
The U.S. aircraft and engine manufacturing industry has also set goals 
for reducing aircraft emissions in the engines the industry plans to 
produce. According to the Aerospace Industries Association, which 
represents this industry, its members have set a goal of reducing 
carbon dioxide emissions by 15 percent in the next generation of 
aircraft while continuing to significantly reduce nitrogen oxide 
emissions and noise. 

The development of aircraft technologies such as those that NASA is 
currently working on to reduce emissions can take a long time, and it 
may be years before the technologies are ready to be incorporated into 
new aircraft designs. According to FAA, the development process 
generally takes 12 to 20 years. For example, the latest Pratt and 
Whitney engine, the geared turbofan, which is expected to achieve 
significant emissions and noise reductions, took 20 years to develop. 

Several Steps Can Be Taken to Help Reduce Aviation Emissions, but 
Challenges Remain to Be Addressed: 

Reducing aviation emissions includes steps that FAA and others can take 
to move the implementation of NextGen forward and support R&D on 
NextGen and emissions-reduction technologies, as well as technical, 
financial, regulatory challenges facing the federal government, the 
aviation industry, and Congress. 

Expediting the Implementation of NextGen Can Help Reduce Aviation 
Emissions: 

Implementing NextGen expeditiously is essential to handle the projected 
growth in air traffic efficiently and safely, and in so doing, help to 
reduce aircraft emissions. Steps to advance NextGen's implementation 
include management improvements and the deployment of available NextGen 
components. 

Management Improvements Can Move NextGen Forward More Efficiently: 

Several management actions are important to advance the implementation 
of NextGen. One such action is to establish a governance structure 
within FAA that will move NextGen initiatives forward efficiently and 
effectively. FAA has begun to establish a governance structure for 
NextGen, but it may not be designed to give NextGen initiatives 
sufficient priority to ensure the system's full implementation by 2025. 
Specifically, FAA's implementation plan for NextGen is called the 
Operational Evolution Partnership (OEP). The manager responsible for 
OEP is one of nine Vice Presidents who report to the Chief Operating 
Officer (COO) of FAA's Air Traffic Organization (ATO), who reports 
directly to the FAA Administrator. While the manager responsible for 
OEP is primarily responsible for implementing NextGen, other Vice 
Presidents are responsible for NextGen-related activities in their 
designated areas. In addition, the FAA managers responsible for 
airports and aviation safety issues are Associate Administrators who 
report through the Deputy FAA Administrator to the FAA Administrator. 
Some of the activities for which these Associate Administrators are 
responsible are critical to NextGen's implementation, yet there is no 
direct line of authority between the OEP manager and these activities. 

Some congressional leaders and other stakeholders, including aviation 
industry representatives and aviation experts, view FAA's management 
structure for NextGen as too diffuse. Some of the stakeholders have 
called for the establishment of a position or NextGen program office 
that reports directly to the FAA Administrator to ensure accountability 
for NextGen results. These stakeholders have expressed frustration that 
a program as large and important as NextGen does not follow the 
industry practice of having one person with the authority to make key 
decisions. They point out that although the COO is nominally in charge 
of NextGen, the COO must also manage FAA's day-to-day air traffic 
operations and may therefore not be able to devote enough time and 
attention to managing NextGen. In addition, these stakeholders note 
that many of NextGen's capabilities span FAA operational units whose 
heads are on the same organizational level as the head of OEP or are 
outside ATO, and they believe that an office above OEP and these 
operational units is needed. In prior work, we have found that programs 
can be implemented most efficiently when managers are empowered to make 
critical decisions and are held accountable for results.[Footnote 26] 

Another management action is needed to help ensure that FAA acquires 
the skills required for implementation, such as contract management and 
systems integration skills. Because of the scope and complexity of the 
NextGen implementation effort, FAA may not have the in-house expertise 
to manage it without assistance. In November 2006, we recommended that 
FAA examine its strengths and weaknesses and determine whether it has 
the technical expertise and contract management expertise that will be 
needed to define, implement, and integrate the numerous complex 
programs inherent in the transition to NextGen.[Footnote 27] In 
response to our recommendation, FAA has contracted with the National 
Academy of Public Administration (NAPA) to determine the mix of skills 
and number of skilled persons, such as technical personnel and program 
managers, needed to implement the new OEP and to compare those 
requirements with FAA's current staff resources. In December 2007, NAPA 
provided FAA with its report on the types of skills FAA will require to 
implement NextGen, and it has undertaken a second part of the study 
that focuses on identifying any skill gaps between FAA's current staff 
and the staff that would be required to implement NextGen.[Footnote 28] 
NAPA officials told us that they expect to publish the findings of the 
second part of the study in the summer of 2008. We believe this is a 
reasonable approach that should help FAA begin to address this 
challenge as soon as possible. It may take considerable time to select, 
hire, train, and integrate into the NextGen initiative what could be a 
large number of staff. 

We have also identified potential approaches for supplementing FAA's 
capabilities, such as having FAA contract with a lead systems 
integrator (LSI)-that is, a prime contractor who would help to ensure 
that the discrete systems used in NextGen will operate together and 
whose responsibilities may include designing system solutions, 
developing requirements, and selecting major system and subsystem 
contractors.[Footnote 29] However, this approach would require careful 
oversight to ensure that the government's interests are protected and 
could pose significant project management and oversight challenges for 
the Joint Planning and Development Office (JPDO), the organization 
within FAA responsible for planning NextGen, and for FAA. 

Deploying Available NextGen Components Can Demonstrate Their Ability to 
Operate Together and Achieve Anticipated Efficiencies: 

Moving from planning to implementing some components of NextGen can 
begin to demonstrate the potential of the system as well as reduce 
congestion in some areas of the country, thereby also reducing 
emissions. Many of the technologies and procedures planned for NextGen 
are already available, and a few have been implemented individually, 
such as the CDA procedures in use in Los Angeles and Louisville and ADS-
B in Alaska. However, the available technologies and procedures have 
not yet been deployed simultaneously to demonstrate that they can be 
operated safely as an integrated suite of technologies and procedures 
in the national airspace system. Several stakeholders have suggested 
that FAA consider a gradual rollout of NextGen technologies and 
procedures in a particular area. For example ADS-B technologies, CDA 
and RNAV/RNP procedures, and high-density airport operations could be 
deployed in a defined area of the current system, possibly in sequence 
over time, to test their combined use and demonstrate the safety of an 
integrated suite of NextGen advancements. Such a graduated rollout is 
sometimes referred to as "NextGen Lite." FAA is currently considering a 
demonstration project in Florida and Georgia, in which it, together 
with aviation equipment manufacturers and municipalities, would use the 
NextGen capabilities of ADS-B, RNAV, and RNP for on-demand air taxi 
fleet[Footnote 30] operations. As other NextGen capabilities, such as 
System-Wide Information Management (SWIM),[Footnote 31] are deployed 
and as air taxi fleet operations move to other airports and regions, 
the demonstration will be expanded to include those new capabilities 
and other airports and regions. According to the airlines and other 
stakeholders we interviewed, a demonstration of the successful 
integration of NextGen capabilities and of efficiencies resulting from 
their use would give the airlines an incentive to equip their aircraft 
with NextGen technologies. They could then lower their costs by 
reducing their fuel consumption and decrease the impact of their 
operations on the environment. The findings from our research indicate 
that such regional or targeted demonstrations could accelerate the 
delivery of NextGen benefits while helping to ensure safe operations 
within the current system. In addition, demonstrations can increase 
stakeholders' confidence in the overall NextGen initiative. 

Resolving Aeronautics R&D Funding Issues Is a Further Step in 
Addressing Aviation Emissions: 

Federal funding for aeronautics research, the category that includes 
work on aviation emissions, has declined over the past decade, 
particularly for NASA, which historically provided most of the funding 
for this type of research. NASA's current aeronautics research budget 
is about half of what it was in the mid-1990s. Moreover, the budget 
request for aeronautics R&D for fiscal year 2009 is $447 million, or 
about 25 percent less than the $594 million provided in fiscal year 
2007. (See table 1.) According to NASA, about $280 million of the 
proposed $447 million would contribute to NextGen. In addition, 
according to NASA officials, a significant portion of the funding for 
subsonic fixed-wing aircraft is directed toward emissions-related 
research, and many other research efforts contribute directly or 
indirectly to potential emissions-reduction technologies. 

Table 1: The President's Budget for NASA's Aeronautics Programs for 
Fiscal Years 2007 and 2008 and Budget Projections for Fiscal Years 2009 
through 2013 (Dollars in millions): 

Program: Aviation Safety: Integrated Vehicle Health Management; 
Enacted: FY 2007: 30.7; 
Enacted: FY 2008: 222.2; 
Requested: FY 2009: 19.7; 
Proposed: FY 2010: 19.9; 
Proposed: FY 2011: 18.8; 
Proposed: FY 2012: 18.6; 
Proposed: FY 2013: 19.2. 

Program: Aviation Safety: Aging Aircraft; 
Enacted: FY 2007: 14.9; 
Enacted: FY 2008: 10.0; 
Requested: FY 2009: 10.6; 
Proposed: FY 2010: 11.3; 
Proposed: FY 2011: 11.2; 
Proposed: FY 2012: 12.0; 
Proposed: FY 2013: 12.4. 

Program: Aviation Safety: Integrated Resilient Aircraft Control; 
Enacted: FY 2007: 22.2; 
Enacted: FY 2008: 15.3; 
Requested: FY 2009: 17.1; 
Proposed: FY 2010: 18.5; 
Proposed: FY 2011: 19.0; 
Proposed: FY 2012: 18.2; 
Proposed: FY 2013: 18.8. 

Program: Aviation Safety: Integrated Intelligent Flight Deck 
Technologies; 
Enacted: FY 2007: 19.5; 
Enacted: FY 2008: 19.3; 
Requested: FY 2009: 15.2; 
Proposed: FY 2010: 16.3; 
Proposed: FY 2011: 16.0; 
Proposed: FY 2012: 15.7; 
Proposed: FY 2013: 16.1. 

Program: Aviation Safety: Subtotal; 
Enacted: FY 2007: 87.3; 
Enacted: FY 2008: 66.5; 
Requested: FY 2009: 62.6; 
Proposed: FY 2010: 65.9; 
Proposed: FY 2011: 65.0; 
Proposed: FY 2012: 64.5; 
Proposed: FY 2013: 66.5. 

Program: Airspace Systems: NextGen - Airspace; 
Enacted: FY 2007: 85.1; 
Enacted: FY 2008: 83.3; 
Requested: FY 2009: 61.3; 
Proposed: FY 2010: 56.0; 
Proposed: FY 2011: 57.3; 
Proposed: FY 2012: 58.5; 
Proposed: FY 2013: 60.8. 

Program: Airspace Systems: NextGen - Airportal; 
Enacted: FY 2007: 17.4; 
Enacted: FY 2008: 16.8; 
Requested: FY 2009: 13.3; 
Proposed: FY 2010: 16.7; 
Proposed: FY 2011: 16.9; 
Proposed: FY 2012: 16.9; 
Proposed: FY 2013: 17.5. 

Program: Airspace Systems: Subtotal; 
Enacted: FY 2007: 102.5; 
Enacted: FY 2008: 100.1; 
Requested: FY 2009: 74.6; 
Proposed: FY 2010: 72.7; 
Proposed: FY 2011: 74.2; 
Proposed: FY 2012: 75.4; 
Proposed: FY 2013:78.4. 

Program: Fundamental Aeronautics: Subsonic - Rotary Wing; 
Enacted: FY 2007: 36.1; 
Enacted: FY 2008: 30.8; 
Requested: FY 2009: 25.8; 
Proposed: FY 2010: 26.6; 
Proposed: FY 2011: 26.7; 
Proposed: FY 2012: 26.9; 
Proposed: FY 2013: 28.0. 

Program: Fundamental Aeronautics: Subsonic - Fixed Wing; 
Enacted: FY 2007: 133.9; 
Enacted: FY 2008: 119.9; 
Requested: FY 2009: 108.4; 
Proposed: FY 2010: 105.3; 
Proposed: FY 2011: 107.6; 
Proposed: FY 2012: 109.1; 
Proposed: FY 2013: 111.5. 

Program: Fundamental Aeronautics: Supersonics; 
Enacted: FY 2007: 67.7; 
Enacted: FY 2008: 53.0; 
Requested: FY 2009: 44.0; 
Proposed: FY 2010: 44.9; 
Proposed: FY 2011: 44.3; 
Proposed: FY 2012: 45.2; 
Proposed: FY 2013: 46.6. 

Program: Fundamental Aeronautics: Hypersonics; 
Enacted: FY 2007: 92.8; 
Enacted: FY 2008: 66.2; 
Requested: FY 2009: 57.3; 
Proposed: FY 2010: 56.4; 
Proposed: FY 2011: 56.5; 
Proposed: FY 2012: 57.4; 
Proposed: FY 2013: 58.4. 

Program: Fundamental Aeronautics: Subtotal; 
Enacted: FY 2007: 330.4; 
Enacted: FY 2008: 269.9; 
Requested: FY 2009: 235.4; 
Proposed: FY 2010: 233.2; 
Proposed: FY 2011: 235.2; 
Proposed: FY 2012: 238.6; 
Proposed: FY 2013: 244.6. 

Program: Aeronautics Test Program: Aero Ground Test Facilities; 
Enacted: FY 2007: 48.5; 
Enacted: FY 2008: 50.0; 
Requested: FY 2009: 48.2; 
Proposed: FY 2010: 49.4; 
Proposed: FY 2011: 50.8; 
Proposed: FY 2012: 51.0; 
Proposed: FY 2013: 51.0. 

Program: Aeronautics Test Program: Flight Operations and Test 
Infrastructure; 
Enacted: FY 2007: 25.0; 
Enacted: FY 2008: 25.1; 
Requested: FY 2009: 25.6; 
Proposed: FY 2010: 26.4; 
Proposed: FY 2011: 27.2; 
Proposed: FY 2012: 27.2; 
Proposed: FY 2013: 27.2. 

Program: Aeronautics Test Program: Subtotal; 
Enacted: FY 2007: 73.5; 
Enacted: FY 2008: 75.1; 
Requested: FY 2009: 73.9; 
Proposed: FY 2010: 75.8; 
Proposed: FY 2011: 78.0; 
Proposed: FY 2012: 78.2; 
Proposed: FY 2013: 78.2. 

Program: Total; 
Enacted: FY 2007: 593.8; 
Enacted: FY 2008: 511.7; 
Requested: FY 2009: 446.5; 
Proposed: FY 2010: 447.5; 
Proposed: FY 2011: 452.4; 
Proposed: FY 2012: 456.7; 
Proposed: FY 2013: 467.7. 

Source: NASA. 

Note: Most of the research on aircraft emissions reductions that NASA 
performs is funded through the Fundamental Aeronautics - Fixed Wing 
program. 

[End of table] 

As its funding for aeronautics R&D has declined, NASA has emphasized 
fundamental research, which serves as the basis for developing 
technologies and tools that can later be integrated into aviation 
systems, and has focused less on developmental and demonstration work. 
As a result, NASA is now sometimes developing technologies to a lower 
maturity level than in the past, and the technologies are less ready 
for manufacturers to adopt them, resulting in a gap in the research 
needed to bring technologies to a level where they can be transferred 
to industry for further development. Failure to address this gap could 
postpone the development of emissions-reduction technologies. 

As a partial response to the gap, the administration has proposed some 
additional funding for FAA that could be used to further develop NASA's 
and others' emissions-and noise reduction technologies. Specifically, 
FAA's reauthorization proposal seeks $111 million through fiscal year 
2011 for the CLEEN Engine and Airframe Technology Partnership,[Footnote 
32] which FAA officials said is intended to provide for earlier 
maturation of emissions and noise technologies while NASA focuses on 
longer-term fundamental research on noise and emissions. The CLEEN 
partnership, which is also contained in the House's FAA reauthorization 
bill,[Footnote 33] would create a program for the development and 
maturation of certifiable engine and airframe technologies for aircraft 
over the next 10 years which would reduce aviation noise and emissions. 
The legislation would require the FAA Administrator, in coordination 
with the NASA Administrator, to establish objectives for developing 
aircraft technology outlined in the legislation. The technology 
requested to be developed would increase aircraft fuel efficiency 
enough to reduce greenhouse gas emissions by 25 percent relative to 
1997 subsonic jet aircraft technology, and, without increasing other 
gaseous or particle emissions, reduce takeoff-cycle nitrogen oxide 
emissions by 50 percent relative to ICAO's standard. Although FAA's 
reauthorization bill has not yet been enacted, the administration's 
proposed fiscal year 2009 budget includes $10 million for the CLEEN 
program. 

The CLEEN program would be a first step toward further maturing 
emissions and noise reduction technologies, but experts agree that the 
proposed funding is insufficient to achieve needed emissions 
reductions. While acknowledging that CLEEN would help bridge the gap 
between NASA's R&D and manufacturers' eventual incorporation of 
technologies into aircraft designs, aeronautics industry 
representatives and experts we consulted said that the program's 
funding levels may not be sufficient to attain the goals specified in 
the proposal. According to these experts, the proposed funding levels 
would allow for the further development of one or possibly two 
projects. Moreover, in one expert's view, the funding for these 
projects may be sufficient only to develop the technology to the level 
that achieves an emissions-reduction goal in testing, not to the level 
required for the technology to be incorporated into a new engine 
design. Nevertheless, according to FAA and some experts we consulted, 
the CLEEN program amounts to a pilot project, and if it results in the 
development of emissions-reduction technologies that can be introduced 
into aircraft in the near future, it could lead to additional funding 
from the government or industry for such efforts. 

FAA and NASA have identified the R&D that is needed for NextGen, but 
have not determined what needs to be done first, at what cost, to 
demonstrate and integrate NextGen technologies into the national 
airspace system. Completing this prioritization is critical to avoid 
spending limited funds on lower-priority efforts or conducting work out 
of sequence. Once the identified R&D has been prioritized and 
scheduled, cost estimates can be developed and funds budgeted. 
Prioritizing research needs is an essential step in identifying the 
resources required to undertake the research. 

The European Union is investing substantially in R&D that can lead to 
fuel-efficient, environmentally friendly aircraft. In February 2008, 
the European Union announced the launch of the Clean Sky Joint 
Technology Initiative, with total funding of $2.4 billion over 7 years-
-the European Union's largest-ever research program. The initiative 
establishes a Europe-wide partnership between industry, universities, 
and research centers and aims to reduce aircraft emissions of carbon 
dioxide and nitrogen oxides by up to 40 percent and aircraft noise 
levels by 20 decibels. According to FAA, it is difficult to compare 
funding levels for U.S. and European R&D efforts because of differences 
in program structures and funding mechanisms, Nevertheless, foreign 
government investments of such magnitude in R &D on environmentally 
beneficial technologies could reduce the competitiveness of the U.S. 
aircraft manufacturing industry, since greater investments are likely 
to lead to greater improvements in fuel efficiency and keep U.S. 
aircraft manufacturers competitive in the global economy as well as 
reducing aviation's impact on the environment. 

Reducing the Impact of Aviation Emissions Poses Technical, Financial, 
and Regulatory Challenges: 

Reducing aviation emissions will require technological advances, the 
integration of lower-emitting aircraft and NextGen technologies into 
airline fleets, and strengthened or possibly new regulations to improve 
air quality and limit greenhouse gas emissions. Fulfilling these 
requirements will pose challenges to aviation because of the technical 
difficulties involved in developing technologies that can 
simultaneously address air pollutants, greenhouse gases, and noise; 
constraints on the airline industry's resources to invest in new 
aircraft and technologies needed to reduce emissions and remain 
competitive; and the impact that emissions regulations can have on the 
aviation system's expansion and the financial health of the aviation 
industry. 

Simultaneously Addressing Air Pollutants, Greenhouse Gases, and Noise 
from Aircraft Presents Technical Challenges: 

Although the aviation industry has made strides in lowering emissions, 
more reductions are needed to keep pace with the projected growth in 
aviation, and achieving these reductions will be technically 
challenging. NASA's efforts to improve jet engine designs illustrate 
this challenge: While new designs have increased fuel efficiency, 
reduced most emissions, and lowered noise, they have not achieved 
comparable reductions in nitrogen oxide emissions. Nitrogen oxide 
emissions have increased because new aircraft engines operate at higher 
temperatures, producing more power with less fuel and lower carbon 
dioxide and carbon monoxide emissions, but also producing higher 
nitrogen oxide emissions, particularly during landings and takeoffs, 
when engine power settings are at their highest. It is during the 
landing/takeoff cycle that nitrogen oxide emissions also have the 
greatest impact on air quality. As discussed, nitrogen oxides 
contribute to ground-level ozone formation. Similarly, as we noted in a 
report on NASA's and FAA's aviation noise research earlier this 
year,[Footnote 34] it is technologically challenging to design aircraft 
engines that simultaneously produce less noise and fewer greenhouse gas 
and other emissions. Although it is possible to design such engines, 
the reductions in greenhouse gases could be limited in engines that 
produce substantially less noise. NASA and industry are working on 
technologies to address these environmental trade-offs. For example, 
the Pratt & Whitney geared turbo fan engine that we mentioned earlier 
is expected to cut nitrogen oxide emissions in half while also 
improving fuel efficiency and thereby lowering carbon dioxide 
emissions. Nevertheless, it remains technologically challenging to 
design aircraft that can reduce one environmental concern without 
increasing another. 

In a 2004 report to Congress on aviation and the environment,[Footnote 
35] FAA noted that the interdependencies between various policy, 
technological, and operational options for addressing the environmental 
impacts of aviation and the full economic consequences of these options 
had not been appropriately assessed. However, in recent years, FAA has 
made progress in this area, including its sponsorship of the previously 
mentioned PARTNER study on the interrelationships between noise and 
emissions. This study can be used to assess the costs and benefits of 
aviation environmental policy options. 

The Financial Condition of the Airline Industry Creates a Challenge to 
Implementing Emissions-Reduction Technologies: 

Most U.S. airlines have stated that they plan to invest in aircraft and 
technologies that can increase fuel efficiency and lower emissions, but 
in the near term, integrating new aircraft into the fleet, or 
retrofitting aircraft with technologies that can improve their 
operational efficiency, poses financial challenges to the airline 
industry. Aircraft have an average lifespan of about 30 years, and the 
airlines can take almost that entire period to pay for an aircraft. The 
current fleet is, on average, about half as many years old--11 years 
for wide-body aircraft, and 14 years for narrow-body aircraft--and 
therefore is expected to be in operation for many years to come. In 
addition, the financial pressures facing many airlines make it 
difficult for them to upgrade their fleets with new, state-of-the-art 
aircraft, such as the Boeing 787 and Airbus A380, which are quieter and 
more fuel efficient, emitting lower levels of greenhouse gases. 
[Footnote 36] Currently, U.S. carriers have placed a small proportion 
(40, or less than 6 percent) of the over 700 orders that Boeing 
officials say the company has received for its 787 model. Furthermore, 
no U.S. carriers have placed orders for the new Airbus 380. These 
financial pressures also limit the airlines' ability to equip new and 
existing aircraft with NextGen technologies such as ADS-B that can 
enable more efficient approaches and descents, resulting in lower 
emissions levels. FAA estimates that it will cost the industry about 
$14 billion to equip aircraft to take full advantage of NextGen. 

Delays by airlines in introducing more fuel-efficient, lower-emitting 
aircraft into the U.S. fleet and in equipping or retrofitting the fleet 
with the technologies necessary to operate NextGen could limit FAA's 
ability to efficiently manage the forecasted growth in air traffic. 
Without significant reductions in emissions and noise around the 
nation's airports, efforts to expand their capacity could be stalled 
and the implementation of NextGen delayed because of concerns about the 
impact of aviation emissions. As we previously reported,[Footnote 37] 
offering operational advantages, such as preferred takeoff and landing 
slots, to fuel-efficient, lower-emitting aircraft or aircraft equipped 
with ADS-B could create incentives for the airlines to invest in the 
necessary technologies. Similarly, as noted, deploying an integrated 
suite of NextGen technologies and procedures in a particular region 
could create incentives for carriers to equip their aircraft with 
NextGen technologies. 

More Stringent Regulatory Standards Pose Challenges for Airport 
Expansion Projects: 

Concerns about the health effects of air pollutants have led to more 
stringent air quality standards that could increase the costs or delay 
the implementation of airport expansion projects. In recent years, EPA 
has been implementing a more stringent standard for ozone emissions to 
better protect the health of people exposed to it, and this standard 
could require more airports to tighten controls on nitrogen oxides and 
some types of volatile organic compounds that also contribute to ozone 
formation. Under the current standard,[Footnote 38] 122 airports are 
located in areas that are designated as nonattainment areas. This 
number includes 43 of the 50 busiest U.S. commercial service airports. 
In March 2008, EPA further revised the ozone standard, because new 
evidence demonstrated that exposure to ozone at levels below the level 
of the current standard are associated with a broad array of adverse 
health effects.[Footnote 39] This recent revision to the ozone standard 
will increase the number of U.S. counties, and hence airports, that 
will be in nonattainment. EPA estimated that the number of affected 
counties could potentially grow from 104 to 345 nationwide. While the 
exact number of airports that will be affected has not been officially 
determined at this time, FAA estimates that a modest number of 
commercial service airports in California, Arizona, Utah, Texas, 
Oklahoma, Arkansas, and along the gulf coast to Florida will be in 
nonattainment areas for the revised 8-hour ozone standard. According to 
EPA, any development project beginning in 2011 at these airports would 
have to conform to the state implementation plan. 

As communities gain more awareness of the health and environmental 
effects of aviation emissions, opposition to airport expansion 
projects, which has thus far focused primarily on aviation noise, could 
broaden to include emissions. According to a California air quality 
official, many of the same communities that have interacted with 
airports over aviation noise have more recently recognized that they 
could also be affected by emissions from airport sources. In Europe, 
concerns about the impact of aviation on air quality and climate change 
have led to public demands for tighter control over aircraft emissions, 
and these demands have hindered efforts to expand airports in 
Birmingham, and London (Heathrow). Moreover, a plan to expand London's 
Stansted Airport was rejected because of concerns about climate change 
that could result from additional emissions. 

To minimize constraints on the future expansion of airport capacity 
stemming from concerns about the health and environmental effects of 
aviation emissions, it will be important for airports; the federal and 
state governments; and the airline industry to work together to 
accurately characterize and address these concerns and to take early 
action to mitigate emissions. As noted, constraints on efforts to 
expand airports or aviation operations could affect the future of 
aviation because the national airspace system cannot expand as planned 
without a significant increase in airport capacity. The doubling or 
tripling of air traffic that FAA expects in the coming decades cannot 
occur without additional airports and runways. 

Market-Based Initiatives to Reduce Aviation Emissions of Greenhouse 
Gases Could Pose Challenges for U.S. Airlines by Increasing Their 
Costs: 

Concerns about the environmental effects of greenhouse gas emissions 
have grown steadily over the years, leading to national and 
international efforts to limit them. In the: 

In the United States, EPA has not regulated greenhouse gas emissions; 
[Footnote 40] however, Congress is taking steps to deal with climate 
change, some of which could include market-based measures that would 
affect the aviation industry. For example, several bills were 
introduced in the 110th Congress to initiate cap and trade[Footnote 41] 
programs for greenhouse gas emissions[Footnote 42] None of these bills 
would include aviation directly in a cap and trade program. However, 
some could have indirect consequences for the aviation industry by, for 
example, requiring fuel producers to purchase allowances through the 
system to cover the greenhouse gas content of the fuel they sell to the 
aviation sector. The cost of purchasing these allowances could be 
passed on to fuel consumers, including airlines, raising the cost of 
jet fuel. Fuel is already the airline industry's largest cost. 
According to the Air Transport Association, cap and trade programs that 
significantly increase airline fuel costs could have significant 
consequences for the industry and such programs could make it more 
difficult for carriers to pay for aircraft or technologies that would 
reduce greenhouse gas emissions. As we have previously noted,[Footnote 
43] cap and trade programs can cost-effectively reduce emissions of 
greenhouse gases such as carbon dioxide, especially when compared with 
other regulatory programs. However, it is important that the impact of 
such measures on various sectors of the economy, such as the aviation 
industry, be thoroughly considered. 

Internationally, ICAO has not set standards for aircraft carbon dioxide 
emissions,[Footnote 44] but it has been working, with the support of 
FAA, other government aviation authorities, and the aviation industry, 
to develop a strategy for addressing the impact of aviation on climate 
change, among several efforts to address climate change. For example, 
ICAO published a manual for countries, Operational Opportunities to 
Minimize Fuel Use and Reduce Emissions. In 2004, ICAO endorsed the 
development of an open emissions trading system as one option countries 
might use and endorsed draft guidance for member states on establishing 
the structural and legal basis for aviation's participation in a 
voluntary open trading system. The guidance includes information on key 
elements of a trading system, such as reporting, monitoring, and 
compliance, while encouraging flexibility to the maximum extent 
possible. In adopting the guidance last fall at the ICAO Assembly, all 
190 Contracting States--with the exception of those in the European 
Union--agreed that the inclusion of one country's airlines in another 
country's emissions trading system should be based on mutual consent 
between governments. 

Consistent with the requirement to pursue reductions of greenhouse gas 
emissions from international aviation through ICAO, some countries that 
have included the aviation sector in their emissions trading systems or 
other emissions-reduction efforts have, excluded international flights. 
Consequently, these countries' efforts will not affect U.S. airlines 
that fly into their airports. The European Union (EU), however, is 
developing legislation, which has not been finalized, that would 
include both domestic and international aviation in an emissions 
trading scheme.[Footnote 45] As proposed, the EU's scheme would apply 
to air carriers flying within the EU and to carriers, including U.S. 
carriers, flying into and out of EU airports in 2012. For example, 
under the EU proposal, a U.S. airline's emissions in domestic airspace 
as well as over the high seas would require permits if a flight landed 
or departed from an EU airport. Airlines whose aircraft emit carbon 
dioxide at levels exceeding prescribed allowances would be required to 
reduce their emissions or to purchase additional allowances. Although 
the legislation seeks to include U.S. airlines within the emissions 
trading scheme, FAA and industry stakeholders have argued that U.S. 
carriers would not legally be subject to the legislation. 

While the EU's proposal to include international aviation in its 
emissions trading system is intended to help forestall the potential 
catastrophic effects of climate change, according to FAA and airlines, 
it will also affect the aviation industry's financial health. In 
particular, according to FAA and airline and aircraft and engine 
manufacturing industry representatives, the EU's proposal could 
disadvantage U.S. airlines, which have older, less fuel-efficient 
fleets than their European competitors. Paying for emissions credits 
could, according to U.S. airlines, also leave them with less money for 
other purposes, including investing in newer, more fuel-efficient 
aircraft and technologies to improve flight efficiency and reduce fuel 
usage. Furthermore, according to U.S. carriers, the proposed trading 
scheme unfairly penalizes the aviation sector because it lacks a 
readily available non-carbon-based alternative fuel, whereas other 
sectors can use alternative fuels to reduce their emissions. 

The governments of many nations, including the United States, oppose 
the European Union's proposal to unilaterally include international 
aviation in its emissions trading system because the proposed approach 
is not consistent with ICAO guidance. Furthermore, such an approach 
could be inconsistent with international aviation agreements and may 
not be enforceable. According to FAA, the EU's inclusion of aviation in 
its emissions trading scheme violates the Chicago Convention on 
International Civil Aviation[Footnote 46] and other international 
agreements. FAA further notes that the EU proposal ignores differences 
in the U.S. and EU aviation systems[Footnote 47] and ignores a 
performance-based approach in which countries decide which measures are 
most appropriate for goals on emissions. We are currently undertaking 
for this Subcommittee a study of the EU emissions trading system and 
its potential impact on U.S. airlines, and other issues relating to 
aviation and climate change.[Footnote 48] 

Mr. Chairman, this concludes my prepared statement. I would be pleased 
to respond to any questions that you or other Members of the 
Subcommittee may have. 

Contacts and Acknowledgments: 

For further information on this testimony, please contact Dr. Gerald L. 
Dillingham at (202) 512-2834 or by email at [email protected]. 
Individuals making key contributions to this testimony include Ed 
Laughlin, Lauren Calhoun, Bess Eisenstadt, Jim Geibel, Rosa Leung, Josh 
Ormond, Richard Scott, and Larry Thomas. 

[End of section] 

Appendix I: Federal Agency Views on Health and Environmental Effects of 
Air Pollution: 

Pollutant: Ozone; 
Heath effects: Lung function impairment, effects on exercise 
performance, increased airway responsiveness, increased susceptibility 
to respiratory infection, increased hospital admissions and emergency 
room visits, pulmonary inflammation, and lung structure damage (long 
term); 
Environmental effects: Results from animal studies indicate that 
repeated exposure to high levels of ozone for several months or more 
can produce permanent structural damage in the lungs. Ozone is also 
responsible for several billion dollars of agricultural crop yield loss 
in the United States each year. 

Pollutant: Carbon monoxide; 
Heath effects: Most serious for those who suffer from cardiovascular 
disease. Healthy individuals are also affected, but only at higher 
levels of exposure. Exposure to elevated carbon monoxide levels is 
associated with visual impairment, reduced work capacity, reduced 
manual dexterity, poor learning ability, and difficulty in performing 
complex tasks; 
Environmental effects: Adverse health effects on animals similar to 
effects on humans. 

Pollutant: Nitrogen oxides; 
Heath effects: Lung irritation and lower resistance to respiratory 
infections; 
Environmental effects: Acid rain, visibility degradation, particle 
formation. Contributes toward ozone formation, and acts as a greenhouse 
gas in the atmosphere and, therefore, may contribute to climate change. 

Pollutant: Particulate matter; 
Heath effects: Effects on breathing and respiratory systems, damage to 
lung tissue, cancer, and premature death. The elderly, children, and 
people with chronic lung disease, influenza, or asthma, tend to be 
especially sensitive to the effects of particulate matter; 
Environmental effects: Visibility degradation, damage to monuments and 
buildings, safety concerns for aircraft from reduced visibility. 

Pollutant: Volatile organic compounds; 
Heath effects: Eye and respiratory tract irritation, headaches, 
dizziness, visual disorders, and memory impairment; 
Environmental effects: Contribute to ozone formation, odors, and have 
some damaging effect on buildings and plants. 

Pollutant: Carbon dioxide, water vapor, and contrails; 
Heath effects: None; 
Environmental effects: Act as greenhouse gases in the atmosphere and, 
therefore, may contribute to climate change. Contrails and contrail-
induced clouds produce warming effect regionally where aircraft fly. 

Pollutant: Sulfur dioxide; 
Heath effects: Breathing, respiratory illness, alterations in pulmonary 
defenses, and aggravation of existing cardiovascular disease; 
Environmental effects: Together, sulfur dioxide and nitrogen oxides are 
the major precursors to acid rain, which is associated with the 
acidification of lakes and streams, accelerated corrosion of buildings 
and monuments, and reduced visibility. 

Sources: EPA and FAA. 

[End of table] 

[End of section] 

Appendix II: Examples of the National Aeronautics and Space 
Administration's Research and Development Programs Supporting NextGen: 

NextGen research and development (R&D) needs: 
* Safety management procedures that can predict, rather than respond 
to, safety risks, in a high density, complex operating environment; 
research to support safety analysis, development of advanced materials 
for continued airworthiness of aircraft, aircraft system and equipage 
management; and adaptive aircraft control systems to allow the crew and 
aircraft to recover from unsafe conditions; 
NextGen capabilities from the National Aeronautics and Space 
Administration's (NASA) R&D programs: 
* Under its Aviation Safety program, NASA research supports development 
of Safety Management Systems to provide a systematic approach to manage 
safety risks; integrates prediction and mitigation of risks prior to 
aircraft accidents or incidents; and shares safety-related information 
through programs such as the Aviation Safety Analysis and Information 
Sharing program. 

NextGen research and development (R&D) needs: 
* Improved air traffic management technologies to manage airspace 
configuration, support increases in volume and complexity of traffic 
demands, mitigate weather impacts, and maintain safe and efficient 
operations at airports, decrease runway incursions, and address wake 
vortex issues; 
NextGen capabilities from the National Aeronautics and Space 
Administration's (NASA) R&D programs: 
* Under its Airspace Systems program, NASA research supports 
development of variable separation standards based on aircraft 
performance levels in the en route environment; trajectory-based 
operations, traffic spacing, merging, metering, flexible terminal 
airspace, and expanded airport access; technologies and procedures for 
safe runway procedures in low-visibility conditions; coordinated 
arrival/departure management; and mitigation of weather and wake vortex 
issues. 

NextGen research and development (R&D) needs: 
* Management of aviation growth to meet the complexity of operations 
within the NextGen environment, regulation and certification of new 
manned and unmanned aircraft, and management of operations in an 
environmentally sound manner; 
NextGen capabilities from the National Aeronautics and Space 
Administration's (NASA) R&D programs: 
* Under its Fundamental Aeronautics program, NASA research supports 
development of improved performance for the next generation of 
conventional subsonic aircraft, rotorcraft and supersonic aircraft and 
develops methods for environmental management system to measure and 
assess reductions in air quality impact, noise, and emissions. 

Source: GAO analysis of Joint Planning and Development Office and NASA 
information. 

[End of table] 

[End of section] 

Related GAO Products: 

Aviation and the Environment: FAA's and NASA's Research and Development 
Plans for Noise Reduction Are Aligned, but the Prospects of Achieving 
Noise Reduction Goals Are Uncertain. [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO-08-384]. Washington, D.C.: February 15, 2008. 

Aviation and the Environment: Impact of Aviation Noise on Communities 
Presents Challenges for Airport Operations and Future Growth of the 
National Airspace System. [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO-08-216T]. Washington, D.C.: October 24, 2007. 

Climate Change: Agencies Should Develop Guidance for Addressing the 
Effects on Federal Land and Water Resources. [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-07-863]. Washington, D.C.: August 
7, 2007. 

Responses to Questions for the Record; Hearing on the Future of Air 
Traffic Control Modernization. [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO-07-928R]. Washington, D.C.: May 30, 2007. 

Responses to Questions for the Record; Hearing on JPDO and the Next 
Generation Air Transportation System: Status and Issues. [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-07-918R]. Washington, D.C.: May 
29, 2007. 

Next Generation Air Transportation System: Status of the Transition to 
the Future Air Traffic Control System. [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-07-748T]. Washington, D.C.: May 
9, 2007. 

Joint Planning and Development Office: Progress and Key Issues in 
Planning the Transition to the Next Generation Air Transportation 
System. [hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-07-693T]. 
Washington, D.C.: March 29, 2007. 

Next Generation Air Transportation System: Progress and Challenges in 
Planning and Implementing the Transformation of the National Airspace 
System. [hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-07-649T]. 
Washington, D.C.: March 22, 2007. 

Next Generation Air Transportation System: Progress and Challenges 
Associated with the Transformation of the National Airspace System. 
[hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-07-25]. Washington, 
D.C.: November 13, 2006. 

Aviation and the Environment: Strategic Framework Needed to Address 
Challenges Posed by Aircraft Emissions. [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-03-252]. Washington, D.C.: 
February 28, 2003. 

Aviation and the Environment: Transition to Quieter Aircraft Occurred 
as Planned, but Concerns about Noise Persist. [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-01-1053]. Washington, D.C.: 
September 28, 2001. 

Aviation and the Environment: Aviation's Effects on the Global 
Atmosphere Are Potentially Significant and Expected to Grow. 
[hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO/RCED-00-57]. 
Washington, D.C.: February 18, 2000. 

Aviation and the Environment: Results from a Survey of the Nation's 50 
Busiest Airports. [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO/RCED-00-222]. Washington, D.C.: August 30, 2000. 

Aviation and the Environment: Airport Operations and Future Growth 
Present Environmental Challenges. [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO/RCED-00-153]. Washington, D.C.: August 30, 2000. 

[End of section] 

Footnotes: 

[1] These emissions include airborne pollutants, which affect air 
quality, and greenhouse gases, primarily carbon dioxide, which are 
produced by the combustion of fossil fuel, and contribute to climate 
change. 

[2] These figures are based on a long-range FAA forecast using 2006 as 
the baseline. 

[3] See the list of related products at the end of this statement, 
especially GAO, Next Generation Air Transportation System: Progress and 
Challenges in Planning and Implementing the Transformation of the 
National Airspace System, [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO-07-649T] (Washington, D.C.: Mar. 22, 2007.) 

[4] As we noted in our recent testimony before this Subcommittee, 
aviation noise has been a greater constraint on airport expansion 
efforts than aviation emissions, but we are limiting our discussion in 
this testimony to aviation emissions. 

[5] 42 U.S.C. ï¿½4332(2)(C). 

[6] States are required to submit implementation plans to EPA for 
reducing emissions in areas that fail to meet the National Ambient Air 
Quality Standards set by EPA under the Clean Air Act for common air 
pollutants with health and environmental effects (known as criteria 
pollutants). Geographic areas that have levels of a criteria pollutant 
above those allowed by the standard are called nonattainment areas. 

[7] 42 U.S.C. ï¿½7506(c)(1) (The Conformity Provision). 

[8] ICAO is an organization affiliated with the United Nations that 
aims to promote the establishment of international civilian aviation 
standards and recommended practices and procedures. FAA, as the U.S. 
representative to ICAO, in consultation with EPA, works with 
representatives from other countries to formulate aircraft emissions 
standards. 

[9] See the list of related GAO products at the end of this statement, 
especially GAO, Aviation and the Environment: Strategic Framework 
Needed to Address Challenges Posed by Aircraft Emissions, [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-03-252] (Washington, D.C.; Feb. 
28, 2003). 

[10] We are currently undertaking a study on aviation environmental 
trends, efforts, and challenges for this Subcommittee and the 
Subcommittee on Space and Aeronautics, Committee on Science and 
Technology, House of Representatives. 

[11] Motor vehicles include cars and buses for airport operations and 
passenger, employee, and rental agency vehicles. 

[12] Ground service equipment includes aircraft tugs, baggage and belt 
loaders, generators, lawn mowers, snow plows, loaders, tractors, air- 
conditioning units, and cargo moving equipment. 

[13] Hazardous air pollutants from aviation activities include benzene 
and formaldehyde. 

[14] Ground-level ozone is formed when nitrogen oxides and volatile 
organic compounds as well as other gases and substances are mixed and 
heated in the atmosphere. 

[15] Contrails are clouds and condensation trails that form when water 
vapor condenses and freezes around small particles (aerosols) in 
aircraft exhaust. 

[16] Intergovernmental Panel on Climate Change, Aviation and the Global 
Atmosphere (1999). 

[17] Intergovernmental Panel on Climate Change, Fourth Assessment 
Report, Summary for Policy Makers, Cambridge University Press, 
Cambridge, UK, November 2007. 

[18] A critical component of RNP is the ability of the navigation 
system to monitor its achieved navigation performance and to identify 
for the pilot if an operational requirement is or is not being met 
during an operation. 

[19] [hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-03-252]. 

[20] Alternatively, some scientists studying options for addressing 
climate change believe that a price on emissions would represent the 
most effective means of achieving reductions overall. 

[21] FAA Centers of Excellence are FAA partnerships with universities 
and affiliated industry associations and businesses throughout the 
country that conduct aviation research in a number of areas, including 
advanced materials, aircraft noise, and aircraft emissions. PARTNER is 
a cooperative research organization that includes 10 collaborating 
universities and approximately 50 advisory board members who represent 
aerospace manufacturers, airlines, airports, state and local 
governments, and professional and community groups. NASA, FAA, and 
Transport Canada are sponsors of PARTNER. The collaborating 
universities and organizations represented on the advisory board 
provide equal matches for federal funds for research and other 
activities. 

[22] ACRP was authorized in 2003 as part of Vision 100--Century of 
Aviation Reauthorization Act, Pub. L. 108-176, Section 712 (Dec 12, 
2003). 

[23] CAAFI, established in October 2006, is sponsored by the Air 
Transport Association, the Aerospace Industries Association, and the 
Airports Council International-North America under the direction of 
FAA, and involves stakeholders from industry, universities, and other 
federal agencies, including NASA. 

[24] This goal is at a pressure ratio of 30, over the ICAO standard 
adopted at the Committee on Aviation Environmental Protectionï¿½s sixth 
meeting (CAEP 6), with commensurate reductions over the full pressure 
ratio range. 

[25] "N" refers to the current generation of tube-and-wing aircraft 
entering service in 2008, such as the Boeing 787. 

[26] See GAO, Best Practices: Better Support of Weapon System Program 
Managers Needed to Improve Outcomes, [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO-06-110] (Washington, D.C.: Nov. 30, 2005). In this study 
of private-sector best practices that could be applied to federal 
programs, we found that program managers at highly successful companies 
were empowered to decide whether programs were ready to move forward 
and to resolve problems and implement solutions. In addition, program 
managers were held accountable for their choices. 

[27] GAO, Next Generation Air Transportation System: Progress and 
Challenges Associated with the Transformation of the National Airspace 
System, [hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-07-25] 
(Washington, D.C.: Nov. 13, 2006). 

[28] NAPA, Workforce Needs Analysis for the Next Generation Air 
Transportation System (NEXTGEN): Preliminary Findings and Observations 
(Washington, D.C.: December 2007). 

[29] [hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-07-25]. 

[30] Air taxis are small aircraft that can be hired to carry passengers 
or cargo and are regulated under Part 135 of the Federal Aviation 
Regulations. 

[31] SWIM is information-management architecture for the national 
airspace system, acting as its "World-Wide Web." SWIM will manage 
surveillance, weather, and flight data, as well as aeronautical and 
system status information and will provide the information securely to 
users. 

[32] CLEEN stands for continuous lower energy emissions and noise. 

[33] H.R. 2881. 

[34] GAO, Aviation and the Environment: Impact of Aviation Noise on 
Communities Presents Challenges for Airport Operations and Future 
Growth of the National Airspace System, [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-08-216T] (Washington, D.C.: Oct. 
24, 2007). 

[35] FAA, Aviation and the Environment: A National Vision Statement, 
Framework for Goals and Recommended Actions (Washington, D.C.: December 
2004). 

[36] We are currently undertaking a study for this Subcommittee and the 
House Committee on Transportation and Infrastructure that, among other 
things, will assess the financial condition of the airlines. 

[37] GAO, Aviation and the Environment: FAA'S and NASA's Research and 
Development Plan's for Noise Reduction Are Aligned, but the Prospects 
of Achieving Noise Reduction Goals Are Uncertain, [hyperlink, 
http://www.gao.gov/cgi-bin/getrpt?GAO-08-384] (Washington, D.C.: Feb. 
15, 2008). 

[38] In 2003, EPA began implementing a new standard that called for 
concentrations of ozone not to exceed 0.08 parts per million over an 8- 
hour period. The former standard required concentrations not to exceed 
0.12 parts per million over a 1-hour period. The more stringent 
standard resulted in the designation of more nonattainment areas for 
ozone. These areas contained 12 airports. 

[39] 73 Fed. Reg. 16436 (Mar. 27, 2008). The new standard would lower 
the allowed concentrations of ozone from 0.08 parts per million in an 8-
hour period to 0.075 parts per million during that period. 

[40] Recently, however, the Supreme Court ruled that greenhouse gases 
meet the Clean Air Act's definition of an air pollutant and that EPA 
has the statutory authority to regulate greenhouse gas emissions from 
new motor vehicles under the Clean Air Act. Massachusetts v. 
Environmental Protection Agency, 127 S.Ct. 1438, 1459-62 (2008). As a 
result of this opinion, EPA must take one of three actions: (1) issue a 
finding that greenhouse gas emissions cause or contribute to air 
pollution that may endanger public heath or welfare; (2) issue a 
finding that greenhouse gases do not endanger public health or welfare; 
or (3) provide a reasonable explanation as to why it cannot or will not 
exercise its discretion to issue a finding. If EPA makes an 
endangerment finding, the Clean Air Act requires EPA to regulate 
greenhouse gas emissions from new motor vehicles. In response to this 
case, EPA has announced that it will issue an Advance Notice of 
Proposed Rulemaking on "specific effects of climate change and 
potential regulation of greenhouse gas emissions from stationary and 
mobile sources under the Clean Air Act. 

[41] Cap and trade programs combine a regulatory limit or cap on the 
amount of a substance--in this case a greenhouse gas such as carbon 
dioxide--that can be emitted into the atmosphere with market elements 
like credit trading to give industries flexibility in meeting this cap. 
A current example is the cap and trade program for sulfur dioxide under 
the Clean Air Act. This program includes electric utilities, which are 
the primary emitters of sulfur dioxide, and established a cap on the 
utilities' emissions. Sulfur dioxide allowances were primarily given 
(rather than auctioned) to companies. 

[42] S. 28, S, 309, S. 317, S. 485, S. 1168, S. 1177, S. 1201, S. 1554, 
S. 1766, S. 2191,H.R. 620, H.R. 1590, H.R. 3989, H.R. 4226. 

[43] GAO, Vehicle fuel Economy: Reforming Fuel Economy Standards Could 
Help Reduce Oil Consumption by Cars and Light Trucks, and Other Options 
Could Complement These Standards, [hyperlink, http://www.gao.gov/cgi-
bin/getrpt?GAO-07-921] (Washington, D.C.: Aug. 2, 2007). 

[44] According to FAA, the last extensive discussion within ICAO on 
carbon dioxide emissions from aircraft occurred several years ago. At 
that time, ICAO's experts agreed that the cost of fuel provided 
sufficient incentive to minimize fuel consumption - hence carbon 
dioxide emissions. There was some technical work around 2001 on the 
development of an aircraft efficiency parameter, which might have been 
used to target carbon dioxide reductions. However, it failed to 
identify a parameter that would be able to assess aircraft fleets in 
their multiple operational environments in an equitable manner. 

[45] The emissions trading scheme involves a cap and trade system that 
sets allowances for greenhouse gas emission for industries and other 
sources. Parties that pollute below their allowance receive emissions 
credits, which they can trade in a market to other parties that have 
exceeded their allowance. 

[46] The Chicago Convention on International Civil Aviation of 1944 
organized global aviation. According to the Convention, no state may 
condition the right of transit over or entry into or exit from its 
territory of any aircraft of another state on their operator's payment 
of fees, dues, or other charges. 

[47] For example, FAA notes that there are considerable differences in 
the air traffic system efficiencies across the Atlantic, that the 
United States has a domestic fuel tax while nearly all EU states have 
none, and that the cost of fuel is about 50 percent more expensive for 
U.S. airlines because of the dollar's weakness in recent years. 

[48] This ongoing work was jointly requested by the Committee on 
Transportation and Infrastructure, House of Representatives, and the 
Committee on Science and Technology, House of Representatives. 

[End of section] 

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