	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. 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. 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. 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. 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.”
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. This contention could  raise concerns about environmental justice. 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 . 3). 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. FAA  implements a national program for reviewing airport noise and access  restrictions, known as Part 161. 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. 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. 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. 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. Currently, most of the federal funding for reducing aviation noise goes to  soundproofing programs. Aviation Infrastructure: Challenges Related to Building Runways and  Actions to Address Them. Aviation and the Environment: Results from a Survey of the Nation’s 50  Busiest Commercial Service Airports.
Why GAO Did This Study

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.

What GAO Found

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.