Aviation and the Environment: Impact of Aviation Noise on	 
Communities Presents Challenges for Airport Operations and Future
Growth of the National Airspace System (24-OCT-07, GAO-08-216T). 
                                                                 
To address projected increases in air traffic and current	 
problems with aviation congestion and delays, the Joint Planning 
and Development Office (JPDO), an interagency organization within
the Federal Aviation Administration (FAA), is working to plan and
implement a new air traffic management system, known as the Next 
Generation Air Transportation System (NextGen). This effort	 
involves implementing new technologies and air traffic control	 
procedures, airspace redesign, and infrastructure developments,  
including new or expanded runways and airports. Community	 
opposition is, however, a major challenge, largely because of	 
concerns about aviation noise. As a result, according to JPDO,	 
aviation noise will be a primary constraint on NextGen unless its
effects can be managed and mitigated. GAO's requested testimony  
addresses (1) the key factors that affect communities' level of  
exposure to aviation noise, (2) the status of efforts to address 
the impact of aviation noise, and (3) major challenges and next  
steps for reducing and mitigating the effects of aviation noise. 
The testimony is based on prior GAO work (including a 2000 survey
of the nation's 50 largest airports), updated with reviews of	 
recent literature, FAA data and forecasts, and interviews with	 
officials from FAA and the National Aeronautics and Space	 
Administration (NASA), industry and community representatives,	 
and aviation experts.						 
-------------------------Indexing Terms------------------------- 
REPORTNUM:   GAO-08-216T					        
    ACCNO:   A77549						        
  TITLE:     Aviation and the Environment: Impact of Aviation Noise on
Communities Presents Challenges for Airport Operations and Future
Growth of the National Airspace System				 
     DATE:   10/24/2007 
  SUBJECT:   Air traffic control systems			 
	     Aircraft						 
	     Aircraft engines					 
	     Aircraft industry					 
	     Aircraft research					 
	     Airports						 
	     Aviation						 
	     Commercial aviation				 
	     Federal funds					 
	     International airspace law 			 
	     Land use						 
	     Program management 				 
	     Regulatory agencies				 
	     Research and development				 
	     Standards						 
	     Next Generation Air Transportation 		 
	     System						 
                                                                 

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GAO-08-216T

   

     * [1]Summary
     * [2]Jet Aircraft Operations, Land Uses, and Aircraft Flight Path

          * [3]Aircraft Operations Are the Major Source of Aviation Noise
          * [4]Incompatible Land Use Exposes Communities to Aviation Noise
          * [5]Airspace Redesign Initiatives May Change Some Communities' E

     * [6]A Number of Efforts Are Underway or Planned to Reduce the Im

          * [7]Implementation of More Stringent Noise Standards May Not Not
          * [8]Noise Mitigation Programs Have Reduced Adverse Noise Effects
          * [9]Past Research Has Significantly Advanced Noise Reduction Tec

               * [10]Collaboration with Industry and Others Has Advanced
                 Research
               * [11]Federal Funding for Aviation Noise Research Has Declined
               * [12]Legislative Proposals Would Increase Funding for Noise
                 Reduc

          * [13]Planning for NextGen Includes an Environmental Focus, and Te
          * [14]Airport Restrictions on Aircraft Operations Offer Limited Re
          * [15]Airports Are Using Additional Studies, Supplemental Noise Me

     * [16]Reducing the Impact of Aviation Noise Poses Challenges Invol

          * [17]Technological Advances through Research and Development Are
          * [18]Providing Funding for Research and Development and for Equip
          * [19]Managing Land Use for Compatibility with the Airport Environ

     * [20]Contact and Acknowledgments
     * [21]GAO's Mission
     * [22]Obtaining Copies of GAO Reports and Testimony

          * [23]Order by Mail or Phone

     * [24]To Report Fraud, Waste, and Abuse in Federal Programs
     * [25]Congressional Relations
     * [26]Public Affairs

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 11:00 a.m. EDT
Wednesday, October 24, 2007

AVIATION AND THE ENVIRONMENT

Impact of Aviation Noise on Communities Presents Challenges for Airport
Operations and Future Growth of the National Airspace System

Statement of Gerald L. Dillingham, Ph.D.

Director, Physical Infrastructure Issues

GAO-08-216T

Mr. Chairman and Members of the Subcommittee:

I appreciate the opportunity to testify before you today on the issue of
aviation noise. As you know, air traffic has grown steadily over the past
5 years and is expected to continue growing, from 740 million air
passengers in fiscal year 2006 to nearly 1 billion in 2015. With this
growth has come a host of benefits and costs, from greater productivity
and mobility for the nation as a whole to increased air traffic
congestion, flight delays, and environmental issues, including aviation
noise. To handle the forecasted growth, the Joint Planning and Development
Office (JPDO), an interagency organization within the Department of
Transportation's Federal Aviation Administration (FAA), is working to plan
and implement a new air traffic management system, the Next Generation Air
Transportation System (NextGen). Critical objectives for NextGen are to
improve the overall safety and increase the efficiency of the National
Airpspace System. Achieving these objectives for airports will involve the
implementation of new technologies and air traffic control procedures,
airspace redesigns, and infrastructure developments, including new or
expanded runways and airports. Community opposition to these developments
is, however, a major challenge, largely because of concerns about aviation
noise. According to JPDO's 2007 Concept of Operations document, "current
operational trends show that environmental impacts . . . will be the
primary constraint on the capacity and flexibility of the NextGen unless
these impacts are managed and mitigated." JDPO further states that noise
has been and will continue to be a primary area of concern. Legislative
proposals to reauthorize FAA^1 include a number of provisions designed to
address aviation noise issues.

My testimony today addresses the following questions: (1) What are the key
factors that affect the level of aviation noise exposure for communities?
(2) What is the status of efforts to address the impact of aviation noise
on communities? (3) What are the major challenges and next steps for
reducing and mitigating the effects of aviation noise? My statement is
based on our previous reports on aviation and the environment, one of
which included a survey of the nation's 50 largest airports;^2 a synthesis
of recent empirical literature; current FAA data and forecasts; published
reports of selected airports' noise abatement initiatives and
community-based aviation noise groups' efforts; and interviews with
officials from FAA and the National Aeronautics and Space Administration
(NASA), representatives of aviation industry groups and aircraft
manufacturers, and selected aviation noise experts. We conducted our work
from September to October 2007 in accordance with generally accepted
government auditing standards.

^1H.R. 2881 and S. 1300.

Summary

Key factors affecting the level of aviation noise that communities are
exposed to include jet aircraft operations, land uses around airports, and
aircraft flight paths. Jet aircraft operations are the primary source of
aviation noise, particularly during takeoffs and landings, and people's
perceptions of aviation noise, which vary from one individual to another,
can also influence communities' views on aviation noise. As a result, even
comparatively low levels of noise exposure can create concerns in
communities surrounding airports. More stringent standards for aviation
noise--imposed through legislation and regulation and enabled by advances
in technology--have, together with the airlines' response to the economic
downturn following the terrorist attacks of September 11, 2001, led to the
retirement or modification of older, noisier jet aircraft and their
replacement with new, quieter jet aircraft. According to FAA, this change
in the composition of the U.S. commercial fleet has been the most
important factor in decreasing noise around airports. Local government
decisions that allow communities to expand near airports may, however,
erode the reductions in noise achieved through the introduction of quieter
aircraft. FAA has issued guidance that discourages incompatible land uses,
such as residences, schools, and hospitals, in areas with significant
aviation noise, but communities face strong development pressures, and
research suggests that federal land-use guidelines have had mixed results
in deterring residential development in these areas. Finally, aircraft
flight paths expose communities to aviation noise near airports, and
changes in those flight paths may reduce or eliminate noise exposure in
some communities and introduce or increase it in others. To date, FAA's
airspace redesign projects, which are intended to improve safety and
efficiency while reducing congestion and delays, have generally involved
changes in flight paths above 10,000 feet and have not greatly affected
community noise levels. A planned project in the New York/New
Jersey/Philadelphia area would, however, involve changes to flight paths
at lower levels and has led to expressions of concern from communities
that could experience higher noise levels.

^2See GAO, Aviation and the Environment: Airport Operations and Future
Growth Present Environmental Challenges, [27]GAO/RCED-00-153 (Washington,
D.C.; Aug. 30, 2000). For this report GAO surveyed officials from the
nation's 50 busiest commercial service airports to obtain their views on
the key environmental concerns and challenges affecting airports'
operations and future growth and to identify the efforts under way to
address these concerns.

A number of efforts are underway or planned to address the impact of
aviation noise on communities. First, more stringent noise standards,
which are significantly lower than the prior standards, are being
implemented as new aircraft are being designed, built, and integrated into
the U.S. commercial fleet. However, the implementation of these new
standards may not have a significant impact on aviation noise levels
because many aircraft in the current fleet met the new standards before
they were required, the new aircraft will be integrated into the fleet
over time, and increases in air traffic are likely to offset the
reductions in noise levels attributable to quieter aircraft. Second, noise
mitigation measures can reduce the impact of aviation noise on
communities. These measures, which are typically carried out by airports
and funded primarily through FAA's voluntary Part 150 Noise Compatibility
program, include soundproofing buildings, acquiring noise-sensitive
properties, and relocating people. Nearly 300 airports have participated
in the Part 150 program and have both received and raised billions of
dollars for mitigation measures. New FAA guidance, which is scheduled for
release at the end of 2007, and the proposed FAA reauthorization
legislation would respectively facilitate and expand airports' noise
mitigation options. Third, research has led to the development of
technologies that have reduced aviation noise, and this research is
continuing, although declines in federal funding may have slowed the pace
of government efforts. Both the National Aeronautics and Space
Administration (NASA) and FAA have sponsored aviation noise research,
often in collaboration with industry or academia. Such collaboration, for
example, has contributed to the development of a Boeing aircraft that is
expected to produce 60 percent less noise than its predecessor. Fourth,
the planning for NextGen includes an environmental focus because concerns
about aviation noise and emissions, which will grow with the expected
increase in air traffic, will constrain efforts to expand system capacity.
New technologies are being designed to control aircraft more precisely
during approach and descent, thereby enabling the use of procedures that
will reduce communities' exposure to aviation noise and emissions. Fifth,
at an airport's request, FAA can impose restrictions on the operation of
certain types of aircraft to reduce the impact of noise in surrounding
communities. Generally, however, airports and airlines negotiate such
restrictions without involving FAA. Finally, airports are using additional
studies of aviation activity, supplemental measures of the effects of
exposure to aviation noise, and community outreach and education to
respond to community concerns about aviation noise and gain support for
projects to increase airports' safety and efficiency.

Major challenges and next steps for reducing or mitigating the effects of
aviation noise include technological advances, substantial funding from
government and the aviation industry, and cooperation on land-use issues.
In the future, as in the past, technological advances through research and
development will be the key to reducing aviation noise, but the timing of
future advances is uncertain. Furthermore, additional federal funding for
noise reduction research and development programs may be difficult to
obtain without shifting funds from other federal noise reduction efforts,
such as the Part 150 program. For the airlines, equipping new and existing
aircraft with the NextGen technologies that will reduce communities'
exposure to aviation noise will also be challenging. FAA estimates that
the costs of equipping the fleet to take full advantage of NextGen will be
about $14 billion. Yet even with quieter aircraft and quieter and more
efficient NextGen procedures, aviation noise will persist around airports,
and incompatible land uses will pose challenges for airports and FAA.
State and local officials can help to address these challenges through
land-use planning and regulations that limit incompatible development, and
FAA can complete and issue proposed guidance that will clarify the options
available for airports to dispose of adjacent land previously purchased
with federal grants to buffer surrounding communities from aviation noise.
The options, which would require passage of the pending FAA
reauthorization legislation, include selling the land and using the sale
proceeds for environmental projects. Cooperation on land-use issues among
officials at all levels of government and aviation stakeholders will also
be necessary to reduce or mitigate aviation noise sufficiently to obtain
public buy-in for the capacity enhancement projects that are critical to a
safe and efficient national air transportation system.

We provided a draft of this testimony to FAA and NASA for review and
comment. The agencies generally agreed with the information presented and
provided technical clarifications that we incorporated as appropriate.

Jet Aircraft Operations, Land Uses, and Aircraft Flight Paths Are Key Factors
That Affect Communities' Level of Noise Exposure

Noise is one of the most significant environmental impacts of aviation.
Although noise is present around virtually every airport in the country,
the problem is greatest near busy commercial airports served by large jet
aircraft. According to FAA, the retirement of older, louder aircraft and
ground-based noise-mitigation efforts over the past 35 years have reduced
by over 90 percent the number of people affected by significant aviation
noise levels--defined as a 65-decibel^3 day night level (DNL 65 dB) or
greater^4--despite nationwide increases in population and air traffic.
FAA's estimates indicate that from 2000 to 2006 alone, the number of
people affected by these noise levels dropped by more than a third, from
about 780,000 to about 500,000. ^5 Nevertheless, these half million people
are still exposed to significant aviation noise levels, and as communities
expand near airports just outside the highly exposed areas and as air
traffic increases, millions more are affected by lower levels of aviation
noise. Changes in aircraft flight paths can also affect communities'
exposure to aviation noise, redirecting air traffic over some communities
that were not previously exposed and diverting it from others.

Aircraft Operations Are the Major Source of Aviation Noise

Both jet aircraft engines and jet airframes produce aviation noise during
aircraft operations, particularly during takeoffs and landings. Moreover,
certain types of aircraft contribute disproportionately to the level of
noise around airports. In our 2000 report on environmental concerns and
challenges for airports, we reported that the primary issue of concern
identified by officials of the nation's 50 busiest airports was the noise
generated by older jet aircraft. With the implementation of technologies
to reduce aircraft engine noise, efforts to reduce noise from airframes
will become more important.

^3A decibel is a unit for expressing the relative intensity of sounds on a
scale from zero for the average least perceptible sound to 130 for the
average pain level.

^4The impact of aviation noise is usually analyzed in terms of the extent
to which this noise annoys people by interfering with their normal
activities, such as sleep, relaxation, speech, television viewing, and
school and business operations. The generally accepted model for assessing
the effects of long-term noise exposure assigns additional weight to
sounds occurring at night (between 10:00 p.m. and 7:00 a.m.), and when
those sound levels exceed 65 decibels, individuals report a noticeable
increase in annoyance.

^5These estimates reflect a revision in FAA's method of estimating the
number of people exposed to significant aircraft noise. FAA previously
estimated that the number of people exposed to significant noise in 2000
was about 500,000.

As technologies for reducing aviation noise have advanced (see our
discussion of some of these advances in the next section of this
testimony), regulatory standards for jet aircraft noise have become more
stringent. The Airport Noise and Capacity Act of 1990 authorized the
Secretary of Transportation to reduce aviation noise through a program to
phase out older, noisier aircraft - known as Stage 2 aircraft-- by
December 31, 1999. Aircraft owners could either retire Stage 2 aircraft
weighing over 75,000 pounds or modify them with hushkits to sufficiently
muffle the noise they generated to meet Stage 3 standards. FAA had adopted
the Stage 3 standards in 1977, the year they were established by the
International Civil Aviation Organization (ICAO), and all aircraft
designed after that time were required to meet the Stage 3 standards, but
previously certified aircraft designs were grandfathered until the 1990
act required that they be retired or modified.^6 However, the act exempted
aircraft weighing less than 75,000 pounds, a category that includes older
business class jets. Stage 2 aircraft that weigh less than 75,000 pounds
and Stage 3 aircraft that have been recertified as such after being
modified with hushkits are in compliance with current standards, although
these aircraft tend to be louder than new aircraft in the same weight
range.^7 Bills pending in both the House and the Senate^8 would require,
with certain exceptions, that all existing aircraft meet Stage 3
standards, including those aircraft under 75,000 pounds that are currently
exempted. In addition, in July 2005, FAA issued a Federal Aviation
Regulation^9 requiring that all new jet aircraft designs be subject to the
current, more stringent ICAO noise standards, known as Stage 4.
Specifically, any new aircraft whose design was submitted to FAA for
approval on or after January 1, 2006, must meet these standards, which are
based on the Chapter 4 standards adopted by ICAO in 2001. The Stage 4
standards are 10 decibels lower on a cumulative basis^10 than the Stage 3
standards and represent a significant reduction in noise.

^6ICAO is an advisory organization affiliated with the United Nations that
aims to promote the establishment of international civil aviation
standards and recommended practices and procedures. FAA is the U.S.
representative to ICAO.

^7Some older business class jets that do not meet Stage 3 standards are
still in service. According to the Airports Council International-North
America, these louder business jets pose a noise problem at some smaller
airports.

^8H.R. 2881 and S. 1300.

^914 CFR Parts 36 and 91.

Since 2001, substantial progress has been made in retiring older, noisier
aircraft. According to FAA, there has been a reduction of about 70 percent
in the number of registered aircraft that have been modified with
hushkits--mainly Boeing 727s and DC-9s. Today, there are 498 registered
hushkitted aircraft, which make up about 8 percent of the U.S. commercial
aircraft fleet. The replacement of these older aircraft with new, quieter
aircraft has been the most important factor in decreasing noise around
airports since the significant noise reductions achieved through the
phaseout of Stage 2 commercial aircraft, according to FAA. Figure 1
indicates that the number of people exposed to significant noise levels
has decreased even as the number of people flying has increased.

^10Under the Stage 4 standards, none of an aircraft's maximum noise levels
at takeoff, flyover, and approach can exceed Stage 3 noise levels.
Compliance with the standards is determined by subtracting an aircraft's
maximum takeoff, flyover, and approach levels from the maximum permitted
noise levels. The differences obtained are the noise limit margins, which
are added together to determine what is termed the effective perceived
noise (EPN). When the three margins are added together, the total must be
10 EPN dB or greater; and when any two of the margins are added together,
the sum must be 2 EPN dB or greater.

Figure 1: Trends in Aviation Noise Exposure and Enplanements

Incompatible Land Use Exposes Communities to Aviation Noise and Erodes Gains in
Noise Control Achieved through More Stringent Standards and Advances in
Technology

Decisions that allow communities to expand near airports may expose
residences, schools, hospitals, and other uses to aviation noise. Such
decisions are made primarily by local governments, but airports, which
cannot control development in the communities that surround them, may
nevertheless be held accountable by these communities for the effects of
aviation noise. Although the areas around airports exposed to significant
noise levels (DNL 65 dB or greater), known as noise contours (see fig. 2),
have shrunk with the retirement of older aircraft, the incompatible use of
land around airports remains a problem in dealing with the effects of
aviation noise. Some stakeholders have said that the gains that have been
made in noise attenuation through regulation and technology are being
eroded or threatened by incompatible land use.

Figure 2: Aerial Photo Overlaid with Color-shaded DNL Contours

FAA set the DNL 65 dB standard that is used to measure noise contours.
This standard reflects the level of noise exposure over time that FAA has
determined annoys people by interfering with normal activities such as
sleep, relaxation, school, and business operations. FAA has also issued
guidelines that identify land uses that would not be compatible with the
noise generated by a nearby airport's operations, as well as land uses
that could successfully be located close to an airport without interfering
with their activity. Despite this guidance, however, strong pressure
exists to develop residential areas around heavily used airports, and
despite the steady decline in the number of people exposed to significant
noise levels (DNL 65 dB and above), large numbers of people are still
exposed to at least some noise around airports. And for FAA, population
increases in areas around airports that are exposed to even moderate
amounts of aviation noise pose a challenge because, given individuals'
varying sensitivity to noise, even comparatively low levels of exposure
can generate community concerns. Population growth near airports also
creates challenges for airports when planning expansion projects to meet
the growing demand for air travel.

Any efforts to limit development have implications for the tax base of
local communities. As a result, as FAA noted in a 2004 report to Congress
on aviation and the environment,^11 there is a disconnect between federal
aviation policy and local land-use decision-making. Until recently,
evidence about trends in land use incompatible with airport activity was
mostly anecdotal, but some empirical research is now available. For
example research sponsored by FAA and NASA shows that for 92 commercial
airports, between 1990 and 2000, "the effectiveness of existing federal
land-use guidelines on reducing total noise exposure and deterring
residential development inside the DNL 65 dB contours is mixed." Moreover,
according to the research, "land-use planning has done little to address
the increasing population aggregation on lands near existing noise
footprints."^12

Furthermore, according to FAA, incompatible land use is emerging as a
problem around reliever airports, which predominantly service general
aviation traffic that would otherwise go to nearby busy airports. These
airports are located in quieter suburban and rural areas where aviation
noise is more noticeable. Local governments with jurisdiction over
land-use planning and development continue to permit building near
airports, where developable land is comparatively plentiful. As a result,
communities that did not exist when some airports were built are now
opposing increases in aircraft operations and expansion at these airports.

^11FAA, Aviation and the Environment: A National Vision Statement,
Framework for Goals and Recommended Actions (Washington, D.C.: December
2004).

^12Timothy F. LeDoux, Airports and Their Cities: The Effectiveness of
Mitigating Noise Exposure through Land Use Planning, 1990-2000, Wyle
Research Report WR 07-23, October 2007.

Airspace Redesign Initiatives May Change Some Communities' Exposure to Aviation
Noise

The air traffic environment for the nation's airspace was designed and
implemented in the 1960s and has undergone only minor changes over the
years. However, the use of the airspace has changed significantly, with
higher overall air traffic volumes and greater use of smaller and regional
jet aircraft. As discussed later in this statement, FAA's airspace
redesign initiatives have the potential to improve safety and efficiency
by allowing the use of new arrival and departure procedures that can
reduce the impact of noise and emissions on nearby communities. At the
same time, though, they have led to concerns about aviation noise in some
communities that were not previously exposed to it.

Airspace redesign projects usually involve changes in aircraft arrival and
departure routes from airports. These changes may result in exposing some
communities to less noise and others to more noise. FAA has completed over
30 airspace redesign projects, including projects around major airports
such as those serving Las Vegas, Dallas-Fort Worth, Minneapolis, and
Boston. According to FAA, between 2002 and 2007, airspace redesign
projects have produced almost $700 million in customer benefits from
reduced delays, more efficient routing, and reduced restrictions
attributable to a more balanced air traffic control workload.

Until recently, most airspace redesign projects have involved changes in
flight paths above 10,000 feet and have therefore not had a significant
impact on noise levels in communities near airports. However, FAA has
approved the most ambitious airspace redesign project to date, which
involves flight path changes in the New York/New Jersey/Philadelphia
airspace, including changes at levels below 10,000 feet. According to FAA,
this airspace is some of the most complex and congested anywhere in the
world, with about one third of the nation's commercial air traffic passing
through it. Delays and congestion in this airspace or at area airports
tend to ripple throughout the system. Airspace redesign projects have the
potential to alleviate some of these problems at this critical chokepoint
in the national airspace system.

Because the airspace redesign for the New York/New Jersey/Philadelphia
area will make changes to arrival and departure routes, the noise contours
in the area will also change, exposing some communities to less noise and
others to more. According to FAA's analysis of the effect of the redesign,
fewer people would be exposed to moderate to significant noise levels than
is currently the case, but some people who live under the new flight paths
would be exposed to higher though moderate levels of noise. On the basis
of this analysis, the environmental impact statement prepared for the
redesign project concludes that the project will not have a significant
environmental impact with respect to noise. However, the possible shift in
noise contours has led to significant expressions of concern, including
litigation in many of the communities that could experience higher though
moderate levels of aviation noise. One of these communities, which has a
large minority population, contends that the redesign would
disproportionately affect minority neighborhoods. This contention could
raise concerns about environmental justice.^13 We are currently reviewing
the New York/New Jersey/Philadelphia airspace redesign at the request of
this Subcommittee.

A Number of Efforts Are Underway or Planned to Reduce the Impact of Aviation
Noise

To reduce the impact of aviation noise, FAA, in conjunction with NASA,
aircraft and aircraft engine manufacturers, airlines, airports, and
communities, follows what the International Civil Aviation Organization
refers to as its "balanced approach." This approach recognizes that
short-term opportunities to mitigate the impact of aviation noise on
communities should be combined with longer-term efforts to reduce aviation
noise. Efforts include reducing noise at the source through more stringent
standards; implementing noise abatement programs in communities near
airports; supporting research and development programs for new
technologies to make aircraft quieter, developing and implementing NextGen
technologies and procedures, and restricting aircraft operations . In
addition, many airports address aviation noise issues through studies,
supplemental analyses, and community outreach.

Implementation of More Stringent Noise Standards May Not Noticeably Reduce
Current Noise Levels

As aircraft whose design was approved on or after January 1, 2006, are
integrated into the fleet, the new Stage 4 noise standards will be
implemented. While these standards are more stringent than the prior Stage
3 standards and have been adopted internationally as well as domestically,
their implementation may not have a significant impact on aviation noise
levels. According to the Airports Council International-North America,
which represents many of the nation's airports and other stakeholders, the
Stage 4 standards were already being met by a significant proportion of
the aircraft in production when ICAO adopted its identical Chapter 4
standards in 2001. Additionally, aircraft manufacturers' sales forecasts
indicate that most of the new aircraft coming into service in the near
future will be for the international market rather than for the U.S.
market.

^13Environmental justice generally refers to efforts to identify and
address the disproportionately high and adverse human health and
environmental impacts on minority and low income populations. In 1994,
President Clinton issued an executive order requiring all federal agencies
to make environmental justice a priority. In accordance with the executive
order, the U.S. Department of Transportation issued an Order on
Environmental Justice upholding principles laid out in the National
Environmental Policy Act and other federal statutes that ensure the
social, economic and environmental welfare of low-income and minority
communities, as well as their involvement in the environmental and
transportation decision-making processes.

During the discussions leading up to the adoption of the ICAO Chapter 4
standards, the European Union argued that more stringent noise limits
would push technology toward quieter aircraft. However, under the current
ICAO system, a key criterion for the adoption of new standards is that
they must be found to be "technologically feasible"--that is, demonstrably
capable of being introduced across a sufficient range of the fleet, as
shown by the commercial deployment or deployability of technologies that
can meet the specified noise reductions.^14 Aviation industry
representatives indicated that they considered the ICAO process rational
for several reasons, including "not pushing the technology envelope,"
which could lead to a potential trade-off with aircraft performance.
Additionally, industry representatives have stated that new product
development programs are already complex and pose many business and
schedule risks. As a result, they believe it is inadvisable to force more
aggressive standards because they could lead to delays in new programs.
More recently, ICAO has formed independent review committees under its
Long Term Technology Goals initiatives to begin discussions with
stakeholders on technologies that might be available 10 to 20 years from
now. These committees are not charged with developing standards, but
rather with involving stakeholders in these early discussions and
preparing a report based on these efforts that is designed to stimulate
further development of the most promising technologies and better inform
ICAO when new standards may need to be considered.

^14The other criteria for adopting new standards are that they must
provide environmental benefits, be economically reasonable, and take the
potential interrelationships between noise and emissions into account.

Noise Mitigation Programs Have Reduced Adverse Noise Effects, and Proposed
Guidance and Proposed Legislation Would Support Further Noise Mitigation Efforts

Most airports are owned and operated by state governments and local
municipalities. Therefore, the primary responsibility for addressing
community concerns about noise resides with these entities. Nevertheless,
airports can reduce the impact of noise on surrounding communities by
undertaking measures to mitigate incompatible land use, such as acquiring
noise-sensitive properties, relocating people, modifying structures to
reduce noise, encouraging compatible zoning, and assisting in the sale of
affected properties.

FAA supports airports' efforts to mitigate aviation noise through its
voluntary noise compatibility program, known as the Part 150 Noise
Compatibility Program, which provides guidance to airports on the types of
land uses that are incompatible with certain levels of airport noise and
encourages them to develop a noise compatibility program to reduce and
prevent such uses. As part of the process, airports map the area affected
by the noise and estimate the affected population. According to FAA,
mitigation measures, such as soundproofing homes, have brought relief to
tens of thousands of people in neighborhoods near long-established
airports since the early 1980s.

Airports that participate in the Part 150 program can receive noise
set-aside funds from the Airport Improvement Program (AIP),^15 which they
must match to varying degrees, depending on their size.^16 According to
FAA, nearly 300 airports have participated in the program. These funds can
be used to, among other things, soundproof buildings and support
relocation by acquiring homes in areas with significant noise. Thirty five
percent of AIP discretionary funds are reserved for planning and
implementing noise compatibility programs. In fiscal year 2006, FAA issued
90 noise-related AIP grants totaling $305 million.

Since the early 1980s, the federal government has issued grants or allowed
airports to impose charges to mitigate noise around many airports.
According to FAA, it has provided about $5 billion in AIP grants and
airports have used about $2.8 billion in passenger facilities charges
(PFC)^17 for Part 150 noise mitigation studies and projects. In total,
this funding amounts to nearly $8 billion (see table 1). FAA officials
further noted that while the vast majority of airport noise mitigation
projects use some AIP or PFC funding, airports may undertake projects with
other financing.^18

^15The AIP program provides federal funds for development projects at the
entire range of the nation's 3,400 airports - from small general aviation
airports to the very largest airports that handle several million
passengers per year.

^16According to FAA, noise projects are eligible for 80 percent funding
under AIP for large- and medium-hub airports and 95 percent funding at
small, nonhub, general aviation, and reliever airports.

Table 1: AIP and PFC Investments for Noise-Related Purposes through Fiscal
Year 2007

Dollars in millions                      
AIP funds, fiscal years 1982-2007        Funding 
Mitigation measures for residences        $1,903 
Land acquisition                          $2,170 
Noise monitoring system                     $170 
Mitigation measures for public buildings    $703 
Noise compatibility plan                     $87 
Total AIP funds                           $5,033 
PFC funds, fiscal years 1992-2007                
Multiphase                                $1,283 
Land acquisition                            $481 
Soundproofing                             $1,018 
Monitoring                                   $31 
Planning                                     $15 
Total PFC funds                           $2,828 
Grand total                               $7,861 

Source: FAA.

Although all airports are eligible to participate in the Part 150 program,
some of the busiest commercial airports do not. Among these are New York's
JFK International and La Guardia, Newark International, Houston's George
Bush Intercontinental, Dallas-Fort Worth International, Boston-Logan
International, Dulles International, O'Hare International, and Miami
International (see app. I for a list of those airports among the 50
busiest that do not participate in the Part 150 program). According to
FAA, some airports have chosen not to participate in the Part 150 program
for a variety of reasons. Some airport operators view the program as too
complicated, costly, and difficult to implement. FAA officials note that
some larger airports that have chosen not to participate in the program
may have such a significant number of incompatible land uses that it would
be financially prohibitive to implement mitigation measures in all areas
significantly affected by noise and that the projects that were undertaken
could take decades to complete. In addition, in some cases, neighborhoods
are so clustered together that mitigation measures would have to be
applied to a substantial number of homes outside significant noise
contours in order to establish equitable neighborhood boundaries. FAA
officials further note that an airport's nonparticipation in the Part 150
program does not mean that the airport does not have an airport noise
mitigation program. For example, Boston Logan Airport has a noise program
that predates the Part 150 program and qualifies for federal noise
mitigation funding under the program through a grandfathering provision.
Airports can also use AIP discretionary grant and PFC funds for noise
mitigation without joining the Part 150 program. In addition, some
soundproofing of schools and healthcare facilities is eligible for federal
funding even if an airport does not participate in the Part 150
program.^19

^17Passenger facility charges are fees airports can charge passengers to
fund FAA-approved projects. Not all airports charge these fees.

^18 According to FAA, noise projects are 100 percent eligible under PFC
and airports can use PFC funds for the required match for AIP funding.

Besides providing funding for airports' noise mitigation efforts through
the Part 150 program, FAA published draft guidance in June 2007 on the
acquisition, management and disposal under AIP of noise land--that is,
land that is exposed to significant noise levels. The guidance initiative
was in part a response to the findings of an audit by the Department of
Transportation Inspector General of 11 airports that disposed of land
acquired for noise mitigation purposes.^20 The audit found that each of
the 11 airports had noise land acquired with AIP funds, ranging from
nominal acreage at several airports to hundreds of acres at others, that
either was no longer required for noise compatibility purposes or did not
have a documented need for airport development. The Inspector General
concluded that with improved oversight of noise land and its disposal, FAA
could recover an estimated $242 million for the Airport and Airways Trust
Fund, which provides most of the funding for aviation programs, or for
other airport noise mitigation projects.^21 This finding was particularly
important in light of the constrained resources that are available for all
aviation programs. The final FAA guidance, which is scheduled for issuance
by the end of calendar year 2007, explains the current options for
reinvesting or transferring the proceeds from the sale of noise land
acquired under AIP, giving preference to investment in airport noise
compatibility projects. Provisions in the House^22 and Senate^23
reauthorization proposals would authorize these options. These provisions
have the potential to help airports further mitigate the adverse effects
of the incompatible land uses around airports and could provide additional
resources for noise mitigation and other AIP-eligible investments.

^1949 U.S.C. 47504 c (2) (D).

^20 U.S. Department of Transportation, Office of the Inspector General,
Audit of the Management of Land under Airport Noise Compatibility Programs
(Washington, D.C.: Sept. 30, 2005).

The House reauthorization bill (H.R. 2881) also contains other provisions
that, if enacted, could enhance FAA's and airports' efforts to mitigate
the impact of noise on communities. Section 503 would allow FAA to accept
funds from airport sponsors^24 to conduct special environmental studies to
support approved noise compatibility measures for federally funded airport
projects. In addition, Section 504 would allow FAA to accept funds,
including AIP grants and PFC funds, from a sponsor in order to hire staff
or obtain services to provide environmental reviews for new flight
procedures that have been approved for airport noise compatibility
purposes. Finally, Section 507 would authorize a new pilot program to
allow FAA to fund six environmental mitigation demonstration projects at
public-use airports to take previously laboratory-tested environmental
research concepts into the airport environment in order to determine if
they can measurably reduce or mitigate the environmental impacts of
aviation noise or emissions.

^21Under current law, an airport that disposes of noise land acquired with
AIP grant funds is required either to return a proportional amount of the
sale proceeds to the Trust Fund or to reinvest that amount in a noise
compatibility project at the airport.

^22FAA Reauthorization Act of 2007, House of Representatives Report
110-331, 110th Congress 1st Session, Section 132, pg. 9, September 17,
2007.

^23Aviation Investment and Modernization Act of 2007, U.S. Senate, 110th
Congress 1st Session, Section 203, pg. 30, May, 2007.

^24An airport sponsor is the entity that owns the airport. For example,
the City of Los Angeles is the sponsor for Los Angeles International
Airport.

Past Research Has Significantly Advanced Noise Reduction Technologies, and
Efforts Are Continuing, though Federal Funding Has Declined

Research and development of technologies for reducing aviation noise has
led to advancements that have significantly reduced the amount of noise
produced by aircraft, and this research continues, although further
advancements will be challenging. NASA, FAA, academic institutions, and
the aircraft and manufacturing industry are all involved in research and
development projects aimed at reducing aviation noise and its impacts.

  Collaboration with Industry and Others Has Advanced Research on Aviation Noise

NASA, in partnership with the aircraft and aircraft engine manufacturing
industry, has contributed to a number of advancements in aircraft engine
and airframe technology that have substantially reduced the amount of
noise produced by aircraft and may lead to further reductions in the
future, depending on the extent to which current research leads to
noise-reducing aircraft engine and airframe designs. For example, through
partnerships with industry, NASA has conducted research on engine noise
reduction technologies that have significantly reduced aviation noise.
Research on the use of composites has also enabled reductions in the
weight of aircraft, which affects the amount of noise the airframe
produces. As a result of these and other advancements, the newest aircraft
currently in production will produce substantially less noise than the
models they will replace. For example, Boeing estimates that the 787
aircraft will produce 60 percent less noise than the 767 and the noise
from the 747-800 will be 30 percent less than the 747-400 it is replacing.
Similarly, Airbus says that its new A-380 jumbo jet will produce 46
percent less noise than the 747-400. However, industry representatives
have indicated that returns are diminishing from these types of
improvements.

FAA conducts a significant amount of its research on aviation noise
issues, much of it through the Partnership for Air Transportation Noise
and Emission Reduction (PARTNER), the Department of Transportation's Volpe
National Transportation Systems Center, and other entities. PARTNER is a
Center of Excellence that brings together experts from government,
academia, and industry.^25 Sponsored by FAA, NASA and Transport Canada,^26
PARTNER includes 11 collaborating universities and approximately 50
advisory board members who represent aerospace manufacturers, airlines,
airports, state and local governments, and professional and community
groups. The collaborating universities and organizations represented on
the advisory board provide equal matches for federal funds for research
and other activities. PARTNER projects related to aviation noise involve
testing alternative descent patterns; identifying a means to reduce
aircraft landing noise, fuel consumption, and emissions; assessing the
human health and welfare risks of aviation noise; and developing online
resources to better inform the public about aviation noise issues.
According to FAA, in the last 10 years, it has spent about $42 million on
research to characterize noise and improve prediction methods, including
developing a capability to determine the trade-offs between noise and
emissions and quantifying the costs and benefits of various mitigation
strategies.

^25FAA 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 emissions, and airworthiness.

^26Transport Canada is the department within the government of Canada that
is responsible for developing policies, regulations and services for the
Canadian transportation system.

  Federal Funding for Aviation Noise Research Has Declined

Federal funding for aviation noise research has declined over the past
decade, particularly for NASA, which provides most of the federal funding
for aeronautics research. NASA's budget for aeronautics research has
dropped by about half over the past decade and is about $717 million for
fiscal year 2007.^27 Partly to address this overall funding reduction,
NASA has reorganized its aeronautical research portfolio to focus on what
it calls "fundamental" research--a relatively early stage in the research
and development process that is less costly than the later stages.^28
According to FAA, the combination of a dramatic decrease in NASA's funding
and the reorganization of its aeronautical research portfolio to focus on
fundamental research has left a gap in the near- and mid-term applied
research and development that could produce technological solutions within
the NextGen time frame.

^27According to NASA, about $58 million this budget goes toward
noise-related research for subsonic fixed-wing aircraft.

^28According to NASA. fundamental research includes(1) foundational
research, which is the lowest level of the research pyramid on which
advanced noise reduction technologies can be built; (2) discipline-level
fundamental research, which includes the development of noise prediction
methods that can be used to understand the potential for noise reduction
of various concepts; (3) multidiscipline-level fundamental research, which
includes studying the trade-offs between noise, emissions, and performance
that must be understood in order the determine the performance
characteristics of a new aircraft; and (4) system-level fundamental
research, which includes explaining research issues when noise reduction
technologies are integrated into a new aircraft and can include major wind
tunnel tests.

According to FAA, most of the federal funding available for mitigating
aviation noise is targeted to sound insulation projects for buildings
around airports and relocation or acquisition programs. In a 2002 report
on reducing the environmental impacts of aviation, the National Research
Council's Committee on Aeronautics Research and Technology for
Environmental Compatibility noted that the vast majority of federal
expenditures on aviation noise are allocated to noise abatement at
individual airports rather than to research on quieter aircraft and
engines, which would ultimately reduce aviation noise nationally and
internationally. The report concluded that the funding for federal
research programs was too low to remove noise as an impediment to the
growth of aviation--a conclusion that FAA reiterated in its 2004 report to
Congress on aviation and the environment. An analysis prepared by the
Aerospace Industries Association^29 indicates that NASA's aeronautics
budget, which includes funding for noise reduction research, has been
declining in constant dollars since the mid-1990s (see fig. 3).

^29The Aerospace Industries Association represents the nation's leading
manufacturers and suppliers of civil, military, and business aircraft,
helicopters, unmanned aerial vehicles, space systems, aircraft engines,
missiles, material, and related components, equipment, services, and
information technology.

Figure 3: NASA Aeronautics Funding, Fiscal Years 1994-2007

  Legislative Proposals Would Increase Funding for Noise Reduction Technologies,
  and More Efficient Targeting Can Maximize Research Resources

FAA officials told us that both the Senate and the House reauthorization
proposals for FAA include several provisions for funding programs that the
authorizers believe will be critical to address the research gap. For
example, the CLEEN^30 Engine and Airframe Technology Partnership would
create a program for the development, maturation, and certification of
engine and airframe technologies for aircraft over the next 10 years to
reduce aviation noise and emissions. FAA said that the program is intended
to provide some short-term advancement while NASA focuses on longer-term
research on noise and emissions.

NASA officials told us the agency has become more effective in targeting
its research resources to areas that have the most potential for success.
In particular, these officials cited work on significant noise-reducing
technologies that could be implemented in aircraft and engine designs as
early as 2015, depending on whether manufacturers take over responsibility
for integrating the new technologies into production-ready aircraft. NASA
has set goals for developing technologies that could reduce what is known
as effective perceived noise (EPN) by 42 EPN dB^31 below Stage 3 standards
and that could be implemented in the next generation of aircraft,^32 which
NASA refers to as N+1, by 2015 (N is the current generation of advanced
twin-engine aircraft). For the longer term (2020), NASA is focusing on the
development of tools and technologies that can be used in the design of
advanced hybrid wing body aircraft (N+2) and that would achieve even
greater noise reductions, in the range of 52 EPN dB below Stage 3
standards.^33 According to NASA, both of these research efforts are also
aimed at reducing emissions and fuel burn, which in combination with noise
reductions would help mitigate the environmental effects of future
increases in air traffic. NASA officials stress that because NASA's
research ends at a relatively early stage of development, aircraft and
engine manufacturers would need to take over responsibility for
integrating the noise reduction improvements into aircraft and engine
designs, and their assumption of this responsibility is not guaranteed.
NASA and others in the aeronautics research community are working on
similar advanced designs, such as the "silent aircraft" concept that
involves researchers from Cambridge University in Great Britain and the
Massachusetts Institute of Technology (see fig. 4).

^30CLEEN stands for continuous lower energy, emissions and noise.

^31See footnote 10.

^32The reductions would occur in aircraft that would replace such current
aircraft as the Boeing 737 and Airbus A320. Reductions would be different
for larger aircraft and regional jets.

^33The noise reductions NASA predicts would be achieved through the
technologies it is researching would be achieved if noise reduction is the
only goal. However, when other factors are considered, such as the need to
reduce pollutants like nitrogen oxides, the noise reductions may be lower.

Figure 4: Concept Design for the Silent Aircraft

Planning for NextGen Includes an Environmental Focus, and Technologies and
Procedures Are Being Developed to Reduce Noise as well as Improve Efficiency

Part of the planning for NextGen includes reducing the environmental
impact of aviation because concerns about aviation noise and emissions,
which will increase with the expected growth in air traffic, are strong
constraints on system capacity. A preliminary JPDO^34 analysis shows that
noise and emissions could increase between 140 and 200 percent over the
next 20 years as a result of increased flights, which would become a
significant constraint on planned capacity improvements.

Technologies and procedures that are being developed as part of NextGen to
improve the efficiency of flight operations are also expected to help
reduce the impact of noise. One such technology, considered a centerpiece
of the NextGen system, is the Automatic Dependent Surveillance-Broadcast
(ADS-B) satellite aircraft navigational system. ADS-B is designed, along
with other navigation technologies, to provide for more precise control of
aircraft during approach and descent. This improved control will
facilitate the use of various air traffic control procedures that will
reduce communities' exposure to aviation noise and emissions. For example,
the Continuous Descent Arrivals (CDA) procedure (see fig. 5) is expected
to allow aircraft to remain at cruise altitudes longer as they approach
destination airports, use lower power levels, and thereby lower noise and
emissions during landings. Under current landing procedures, aircraft make
step-down approaches that alternate short descents and forward thrusts,
which produce more noise than a continuous descent. The PARTNER Center of
Excellence has designed and flight-tested a nighttime CDA procedure for
the Louisville International Airport, which United Parcel Service plans to
begin using for its hub operations in the near future. ^35

^34As noted, JPDO is the interagency office housed within FAA that is
responsible for planning NextGen and coordinating the transition to this
new system. A JPDO task team is responsible for researching, developing,
implementing, and maintaining an environmental protection strategy for
NextGen.

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

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

^35See John-Paul Clarke, et al., Partnership for Air Transportation and
Emissions Reduction Development, Design, and Flight Test Evaluation of a
Continuous Descent Approach Procedure for Nighttime Operation at
Louisville International Airport (Cambridge, MA: Jan. 9, 2006).

Similarly, Area Navigation/Required Navigation Performance (RNP)
procedures^36 will permit aircraft to descend on a precise route that will
allow them to avoid populated areas. FAA notes, however, that the new
procedures will not always be usable when traffic is heavy at busy
airports (see fig. 6).

Figure 6: Comparison of RNP and Current Step-down Approach

Note: An RNP approach 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.

^36Area Navigation/Required Navigation Performance procedures provide
enhanced navigational capability to the pilot. Area Navigation equipment
can compute the airplane's position, actual track, and ground speed, and
then provide meaningful information relative to the route of flight
selected by the pilot. A critical component of Required Navigation
Performance is the ability of the navigation system to monitor the
aircraft 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.

Airport Restrictions on Aircraft Operations Offer Limited Relief from Aviation
Noise

Airports can seek restrictions on the operations of certain types of
aircraft to reduce the impact of noise on surrounding communities. FAA
implements a national program for reviewing airport noise and access
restrictions, known as Part 161. Through this program, FAA reviews
airports' requests to limit the operations of louder aircraft. According
to FAA, the Part 161 process has rarely been used since 2000. Only a few
airports have drafted Part 161 studies to support requests for
restrictions, and only one--Naples Airport in Florida--has fully completed
the Part 161 process. Los Angeles International Airport and Bob Hope
Airport in Burbank, California, have indicated to FAA that they will be
submitting Part 161 studies to FAA to restrict the operations of certain
aircraft that meet the Stage 3 noise standards. FAA's approval will be
required for the restrictions these airports are seeking. Because the Part
161 process demands that airports submit studies showing, among other
things, the benefits of restricting aircraft operations, airport operators
generally choose to negotiate informal agreements with airlines rather
than seek mandatory restrictions. Airports have also imposed curfews on
aircraft operations in order to reduce the impact of noise in the early
morning and late evening. For example, at Reagan National Airport and San
Diego International Airport, louder aircraft are not allowed to land or
take off in the late evening and early morning.

Airports Are Using Additional Studies, Supplemental Noise Metrics, and Community
Outreach to Address Community Concerns about Aviation Noise

According to FAA, communities are increasingly aware of efforts to plan
for and mitigate aviation noise, and complaints about noise are coming
increasingly from outside the DNL contours, along with demands for action
to address noise in areas outside significant noise contours. Some
community groups and the Environmental Protection Agency (EPA) have
questioned whether the DNL standard adequately captures the impact of
noise on people. FAA officials note that the Federal Interagency Committee
on Aviation Noise^37 supports the use of the DNL measure and that the use
of the metric to measure noise near airports has been upheld in court
decisions. However, a number of airports have undertaken additional
measures, such as special noise studies, to respond to community concerns
about aviation noise.

^37The Federal Interagency Committee on Aviation Noise serves as a forum
for debate over future research needs to better understand, predict, and
control the effects of aviation noise, and to encourage new technical
developments in these areas. Federal agencies represented on the committee
include the Departments of Defense, Housing and Urban Development, the
Interior, and Transportation; the U.S. Environmental Protection Agency;
and NASA.

According to some noise experts, the typical airport noise study presents
results only in terms of DNL contours on a background map, but very rarely
quantifies noise exposure with DNL or any other metric at specified
geographic locations in the study area. While DNL contours are used
effectively to establish land-use guidelines and define noise mitigation
program boundaries, they do not provide residents with practical
information about the aviation noise they will experience in their homes.
By contrast, the special noise studies not only enable residents to locate
their homes on a map that is overlaid with DNL contours, but they also
indicate how often airplanes fly overhead, at what time of day flights
occur, or how those flights may interfere with activities such as
sleeping, speaking, or watching television. According to the experts we
spoke with, the public has responded very positively to receiving this
detailed information about noise exposure.

With growing complaints about noise from outside the DNL contours,
airports are also contracting for analyses based on alternative noise
metrics to supplement the DNL noise analysis. Although the Federal
Interagency Committee on Noise^38 in 1992 recommended continuing the use
of the DNL noise metric as the principal means of describing airport noise
exposure, it also recommended supplementing this description with noise
analyses based on alternative metrics. According to a leading engineering
firm that specializes in performing noise analyses, two supplemental
metrics are thought to define exposure in ways that the general public can
understand more readily than the DNL metric. One of these metrics, the
Number Above--which counts how many times noise exceeds a selected
threshold level in a given time period--has emerged as the most useful
supplemental metric, while another metric, Time Above--the total time that
noise exceeds the threshold during the time period--is also being used
with increasing frequency. According to FAA officials, FAA supports the
use of supplemental metrics, noting that they may be useful in evaluating
some specific noise impacts, such as interference with speech, sleep, and
learning (see fig. 7).

^38 The Federal Interagency Committee on Noise was the predecessor of the
Federal Interagency Committee on Aviation Noise.

Figure 7: Levels of Noise Associated with Various Activities

Besides additional studies and supplemental noise metrics, airports are
using community outreach and education to address some of the impacts of
aviation noise. Representatives of airports and local governments we spoke
with emphasized that effective community outreach programs are essential
for addressing noise issues that arise when airports are planning to
expand or change their operations. One of these representatives noted that
early and continuous open communication between the airport, local
governments, and the affected communities is a key to gaining support for
projects to increase airport capacity. They pointed out that airports
should have ongoing efforts to seek stakeholder involvement on
airport-related issues and not wait until potential noise problems arise,
such as when airport expansion projects are being planned. For example,
the San Francisco International Airport has been bringing community
representatives and aviation officials together since 1981 to discuss and
attempt to resolve airport-related issues through the San Francisco
Roundtable--a voluntary body created by the airport that includes
representatives from 45 Bay Area jurisdictions, FAA officials, airline
advisers, air traffic managers, and the airport director. In addition,
according to a San Francisco International Airport official, the airport
reaches out to the community through its Managed Noise Mitigation program,
which encourages communities affected by airport noise to determine their
noise mitigation priorities and manage their distribution of noise
mitigation funds in accordance with their priorities. Other airports have
also made community outreach an important component of their efforts to
deal with the impacts of aviation noise. For instance, Chicago established
the O'Hare Noise Compatibility Commission in 1996 to begin constructive
dialogue on aircraft noise issues with the 40 communities surrounding
O'Hare International Airport. The commission's community outreach efforts
include a Web site on aircraft noise issues; a community outreach vehicle
that travels to schools, libraries, and community events and provides
aircraft noise and noise-monitoring demonstrations; and a quarterly
newsletter that highlights the work of the commission and its work to
reduce noise at O'Hare.

To support airports' community outreach efforts, the Transportation
Research Board (TRB) is undertaking a project that is intended to result
in guidance for airports on best practices in community outreach.
According to TRB, the project will identify the jurisdictions with
authority over various aspects of aviation noise and the obstacles to
airport operations and development that can occur because of surrounding
communities' negative perceptions about local aviation noise. The study
will result in a guidebook about local aviation noise that will allow
airport decision makers to manage expectations related to aviation noise
within the community. The study also includes alternative ways to
communicate noise issues and suggests other improvements that can help
ease concerns about aviation noise issues.

Reducing the Impact of Aviation Noise Poses Challenges Involving Technology,
Funding, and Cooperation on Land-use Issues

Reducing aviation noise requires technological advances, substantial
funding from government and the aviation industry, and cooperation among
stakeholders and communities on land-use issues. Fulfilling these
requirements will be challenging because the pace of improvement in
existing technologies may have slowed, government and industry resources
are constrained, and land use involves strong competing interests. While
most of these challenges will take years to fully address, steps can be
taken now to help mitigate the impact of noise on communities and reduce
the constraints that noise can have on transforming the air traffic
system.

Technological Advances through Research and Development Are Key to Future
Aviation Noise Reduction

The first challenge will be to continue reducing the amount of noise from
aircraft engines and airframes. NASA's, FAA's, and manufacturers' past
research and development efforts have led to advances that have
significantly lowered aviation noise, but the timing of the next leaps in
technologies is uncertain. While NASA is conducting work on technologies
that it believes could, with industry support, lead to significant noise
reductions by 2015, FAA and aircraft industry representatives maintain
that, for some time, reductions in aircraft noise are likely to be
incremental. In addition, it may be technologically challenging to improve
the environment by reducing aviation noise without adversely affecting the
environment in other ways. As we reported in 2003,^39 designing aircraft
engines to minimize noise could increase fuel burn, which would release
more carbon dioxide and other greenhouse gases into the atmosphere.

Providing Funding for Research and Development and for Equipping the Fleet with
NextGen Technologies Poses Challenges for Government and Industry

Funding noise reduction research and development programs poses a
challenge for federal agencies. Given the federal government's long-term
structural fiscal imbalance, additional funding for such programs may not
be available without shifting funds from other aviation noise reduction
efforts, such as programs to mitigate the impact of noise on communities.
Currently, most of the federal funding for reducing aviation noise goes to
soundproofing programs. Although funding for noise mitigation programs may
not generate the highest return on investments, reducing such funding
could make it more difficult to obtain community approval of airport
expansion projects necessary to increase system safety and efficiency.
Provisions in the Senate and House reauthorizations bills such as the
CLEEN proposal could help to address the challenges in this area, and
industry funding will continue to play an important role.

^39See GAO, Aviation and the Environment: Strategic Framework Needed to
Address Challenges Posed by Aircraft Emissions, [28]GAO-03-252
(Washington, D.C.: Feb. 28, 2003)

Implementing new noise reduction technologies, whether by integrating new,
quieter aircraft into the fleet or by retrofitting aircraft, poses
financial challenges for the aviation industry. Aircraft have an average
lifespan of about 30 years, and it can take almost that entire period for
airlines 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 is therefore expected to be in operation for
many years to come. Additionally, the financial pressures facing many
airlines make it difficult for them to upgrade their fleets with new,
quieter aircraft. Currently, for example, U.S. carriers have placed a
small proportion of the over 700 orders (40, or less than 6 percent) that
Boeing officials say the company has received for its new state-of-the-art
787. These financial pressures also have implications for airlines'
ability to equip new and existing aircraft with NextGen technologies such
as ADS-B that can enable more efficient, quieter approaches and descents.
FAA estimates that it will cost the industry about $14 billion to equip
aircraft to take full advantage of NextGen. Congress and FAA may want to
consider how to incentivize the airlines to train their pilots and to
equip and retrofit the fleet with the technologies necessary to operate in
NextGen as soon as possible.

Managing Land Use for Compatibility with the Airport Environment Requires
Cooperation among Stakeholders and Communities

Even with the introduction of quieter aircraft and the implementation of
NextGen technologies and procedures that will enable quieter aircraft
approaches and landings, there will still be some noise around airports.
Additionally, these reductions in aviation noise are likely to be eroded
by the public's increasing awareness of and sensitivity to even moderate
amounts of aviation noise and to predicted increases in the number of
aircraft flying overhead. Hence, incompatible land use will continue to
present obstacles to airport expansion projects. However, since most
airports are owned and managed by state or local authorities, it is
incumbent upon those authorities to work in good faith with FAA to
minimize incompatible land use in their jurisdictions (see fig. 8).

Figure 8: Residential Exposure to Aviation Noise

State and local authorities can take action, through land-use planning and
development, zoning, and housing regulation, to limit the use of land near
airports to purposes compatible with airport operations. State and local
governments could require, for example, that appropriate notice of airport
noise exposure be provided to purchasers of real estate and to prospective
residents near airports to ensure awareness of aviation noise issues. In
addition, FAA can make it easier for airports to dispose of AIP noise land
by completing and issuing its draft guidance on this process. Passing the
related provisions in the Senate and House FAA reauthorization bills will
also be important steps.

Thank you, Mr. Chairman and Members of the Subcommittee, this concludes my
prepared statement. I will be glad to answer any questions that you may
have at this time.

Contact and Acknowledgments

For further information on this testimony, please contact Dr. Gerald L.
Dillingham at (202) 512-2834 or [29][email protected] . Individuals
making key contributions to this testimony include Ed Laughlin, Lauren
Calhoun, Bess Eisenstadt, Jim Geibel, David Hooper, Rosa Leung, Maureen
Luna-Long, Josh Ormond, Jena Sinkfield, and Larry Thomas.

Appendix I: U.S. Airports That Are among the Nation's 50 Busiest and Do
Not Have a Part 150 Noise Mitigation Program

Airport                                      
Boston-Logan International                   
Chicago-O'Hare International                 
Dallas-Fort Worth International              
Dallas Love Field                            
Denver International                         
Gillespie Field (San Diego, CA)              
Houston-David Wayne Hooks                    
Houston-George Bush Intercontinental         
John F. Kennedy International (New York, NY) 
John Wayne-Orange County                     
Miami International                          
Newark International                         
New York La Guardia                          
Phoenix Deer Valley                          
Phoenix Mesa Gateway                         
Van Nuys (Van Nuys, CA)                      
Washington Dulles International              

Source: FAA.

Related GAO Products

Airport Finance: Observations on Planned Airport Development Costs and
Funding Levels and the Administration's Proposed Changes in the Airport
Improvement Program. [30]GAO-07-885 . Washington, D.C.: June 29, 2007.

Reagan National Airport: Update on Capacity to Handle Additional Flights
and Impact on Other Area Airports. [31]GAO-07-352 . Washington, D.C.:
February 28, 2007.

Aviation and the Environment: Strategic Framework Needed to Address
Challenges Posed by Aircraft Emissions. [32]GAO-03-252 . Washington, D.C.:
February, 28, 2003.

Aviation Infrastructure: Challenges Related to Building Runways and
Actions to Address Them. [33]GAO-03-164 . Washington, D.C.: January 30,
2003.

Aviation and the Environment: Airport Operations and Future Growth Present
Environmental Challenges. [34]GAO/RCED-00-153 , Washington, D.C.: August
30, 2000.

Aviation and the Environment: Results from a Survey of the Nation's 50
Busiest Commercial Service Airports. [35]GAO/RCED-00-222 . Washington,
D.C.: August 30, 2000.

Aviation and the Environment: FAA's Role in Major Airport Noise Programs.
[36]GAO/RCED-00-98 . Washington, D.C.: April 28, 2000.

Reagan National Airport: Limited Opportunities to Improve Airlines'
Compliance with Noise Abatement Procedures. [37]GAO/RCED-00-74 .
Washington, D.C.: June 29, 2000.

(540162)

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Highlights of [45]GAO-08-216T , a testimony before the Subcommittee on
Aviation, Committee on Transportation and Infrastructure, House of
Representatives

October 24, 2007

AVIATION AND THE ENVIRONMENT

Impact of Aviation Noise on Communities Presents Challenges for Airport
Operations and Future Growth of the National Airspace System

To address projected increases in air traffic and current problems with
aviation congestion and delays, the Joint Planning and Development Office
(JPDO), an interagency organization within the Federal Aviation
Administration (FAA), is working to plan and implement a new air traffic
management system, known as the Next Generation Air Transportation System
(NextGen). This effort involves implementing new technologies and air
traffic control procedures, airspace redesign, and infrastructure
developments, including new or expanded runways and airports. Community
opposition is, however, a major challenge, largely because of concerns
about aviation noise. As a result, according to JPDO, aviation noise will
be a primary constraint on NextGen unless its effects can be managed and
mitigated.

GAO's requested testimony addresses (1) the key factors that affect
communities' level of exposure to aviation noise, (2) the status of
efforts to address the impact of aviation noise, and (3) major challenges
and next steps for reducing and mitigating the effects of aviation noise.
The testimony is based on prior GAO work (including a 2000 survey of the
nation's 50 largest airports), updated with reviews of recent literature,
FAA data and forecasts, and interviews with officials from FAA and the
National Aeronautics and Space Administration (NASA), industry and
community representatives, and aviation experts.

Key factors affecting the level of aviation noise that communities are
exposed to include jet aircraft operations, land uses around airports, and
aircraft flight paths. With more stringent regulatory standards for
aviation noise, enabled by advances in technology, aircraft operations
have become quieter, but aviation noise is still a problem when
communities allow incompatible land uses, such as residences, schools, and
hospitals, near airports. Aircraft flight paths also expose communities to
aviation noise, and airspace redesign efforts, which are intended to
improve aviation system safety and efficiency, may expose some previously
unaffected communities to noise, raising concerns in those communities
about higher noise levels.

A number of efforts are underway or planned to address the impact of
aviation noise on communities. More stringent noise standards for aircraft
have been implemented, billions of federal dollars have been spent to
soundproof buildings around airports, federal and private funding for
research and development has advanced technologies to reduce aviation
noise, NextGen technologies and procedures are being planned and will
contribute to reducing communities' exposure to noise, some airports have
imposed restrictions on the operation of certain aircraft, and airports
are reaching out to communities to address their concerns about aviation
noise and gain support for projects to increase airports' safety and
efficiency.

Major challenges for reducing or mitigating the effects of aviation noise
include continuing to make technological advances; obtaining substantial
funding--from the federal government for NextGen in particular and from
industry for equipping aircraft with new technologies--and cooperating on
land-use issues. Next steps could include state and local actions to limit
incompatible development, FAA's issuance of guidance related to the
disposal of land acquired with federal funding for noise mitigation
purposes, and the passage of legislative proposals that would address
environmental issues, including the reduction of aviation noise.

FAA and NASA officials generally agreed with the information presented in
this testimony and provided technical clarifications that GAO
incorporated.

Concept Design for the Silent Aircraft

References

Visible links
  27. http://www.gao.gov/cgi-bin/getrpt?GAO/RCED-00-153
  28. http://www.gao.gov/cgi-bin/getrpt?GAO-03-252
  29. mailto:[email protected]
  30. http://www.gao.gov/cgi-bin/getrpt?GAO-07-885
  31. http://www.gao.gov/cgi-bin/getrpt?GAO-07-352
  32. http://www.gao.gov/cgi-bin/getrpt?GAO-03-252
  33. http://www.gao.gov/cgi-bin/getrpt?GAO-03-164
  34. http://www.gao.gov/cgi-bin/getrpt?GAO/RCED-00-153
  35. http://www.gao.gov/cgi-bin/getrpt?GAO/RCED-00-222
  36. http://www.gao.gov/cgi-bin/getrpt?GAO/RCED-00-98
  37. http://www.gao.gov/cgi-bin/getrpt?GAO/RCED-00-74
  38. http://www.gao.gov/
  39. http://www.gao.gov/
  40. http://www.gao.gov/fraudnet/fraudnet.htm
  41. mailto:[email protected]
  42. mailto:[email protected]
  43. mailto:[email protected]
  44. http://www.gao.gov/cgi-bin/getrpt?GAO-08-216T
  45. http://www.gao.gov/cgi-bin/getrpt?GAO-08-216T
*** End of document. ***