    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]dillinghamg@gao.gov . 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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    Congressional Relations

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    For more information, contact Gerald L. Dillingham at (202) 512-2834 or
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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:dillinghamg@gao.gov
      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:fraudnet@gao.gov
      42. mailto:jarmong@gao.gov
      43. mailto:beckers@gao.gov
      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. ***