Aircraft Noise: A Toolkit for Managing Community Expectations (2009)

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Noise frequently first becomes an issue for the airport manager through complaints about the loudness, proximity or frequency of overflights near an airport. Managers become involved because the public who present these complaints assume that the airport administration has con- trol of the aircraft flight patterns and operations in use at the airport. The public has a difficult time understanding that the many entities present at the airport are distinctly different from one another, with different authorities and levels of influence over conditions. Instead, the public views the airport as one organization that has the authority to manage all activities that take place within its boundaries and within the airspace around it. This misunderstanding often leads to frustration, not only on the part of the public who want to make conditions they complain about better, but also for the airport manager who must deal with multiple entities to see if anything can (or should) be done to respond to the public concerns. Most public airports in the United States are owned and operated by public governmental bodies—city or county departments, independent airport authorities, or agencies of state or national government. The others are operated by private companies or individuals. As such, airport manage- ment personnel generally view themselves as public servants and their role as one that is customer- oriented, with the mission to provide for the safe, smooth, and efficient operation of the airport facility. Often, they are also public employees, with responsibilities to the elected officials and departmental managers responsible to the public at large. Political influences occasionally demand that airport management be responsive to public noise complaints or other concerns and seek to resolve the issues raised by them through restrictions of, or negotiated modifications to, the flight activities that generate the complaints. To do so, the manager will be faced with political demands on one side and a host of restrictions on his ability to act on the other. There will be regulatory lim- itations on the manager’s ability to act independently in any way that has been preempted by the federal government, the manager will have little or no control on how the property beyond the air- port’s boundaries is developed, and the manager will have to deal with his client base – the users of the airport that provide the aviation-supported services demanded by the community. Several principles may be brought into play by the airport managers in their effort to manage their relationships with the public and users, politicians and regulators, land owners and envi- ronmental advocates and still meet the needs of the community for safe and efficient aviation services. Although some airports may be equipped and staffed to address the issues on a daily basis, planning for the compatibility between the airport and its neighbors is an infrequent activity for most airports, usually happening only once every five to 10 years in a comprehensive analysis. The elements of noise compatibility planning include the definition of existing and pro- jected aircraft noise levels around the airport, the identification of land use patterns and their relationship to the noise exposure levels, and the development of operational or land use man- agement measures to enhance the compatibility between aircraft noise levels and underlying land uses. Throughout the planning process, the well-designed planning program incorporates a 87 C H A P T E R 6 Noise Management and Public Response

comprehensive set of public communication techniques to allow the public to understand the foundation of the measures developed and their anticipated effect on future conditions. Noise abatement planning in the United States is largely conducted under the provisions of 14 CFR Part 150 Airport Noise Compatibility Planning or as a part of the mitigation planning process as Environmental Assessments or Environmental Impact Statements are prepared for the development of airport facilities or other significant federal actions on the airport. Flow charts of the planning process for each type of study are similar and require consultation with the public and agencies as a significant element of their study design. Flow Chart Examples: • 14 CFR Part 150 Exposure Map (NEP) and Noise Compatibility Study (NCP) (126) • EA and EIS NEPA Process (127) Legislative Control of Aviation Over the years since the public first became concerned about the intrusion of aircraft noise into their lives, governments have been asked to implement measures that control the amount, location, and time of noise exposure that people living around the nations airports experience. A series of legislative measures have been approved by Congress and state legislatures, which have subsequently been implemented by various regulations and guidance circulated by the FAA and state agencies to control noise exposure patterns. The primary measures among these are dis- cussed briefly below. For additional information, the reader may access substantial information about any of them through internet search engines. Congressional and Federal Regulatory Actions • Federal Aviation Act of 1958 (128) (PL 85-726) – The Act established federal responsibility for safety and the development of civil aeronautics within the borders of the United States. It fur- ther established precedence of federal regulation and control over local authority on aircraft in flight mode (landing, takeoff, and in-flight). • Aircraft Noise Abatement Act of 1968 (ANAA) (129) (PL 90-411) – This Act added aircraft noise to the areas under the jurisdiction of the Federal Aviation Administration. It resulted in the promulgation of 14 CFR Part 36 to establish noise level standards at the aircraft source, as well as the technologies to determine the levels associated with each aircraft type. • 14 CFR Part 36 – Noise Standards: Aircraft Type and Airworthiness Certification (3)– Regulation published in 1969 to implement provisions of the ANAA to establish noise level limits for each aircraft type as measured under approach and takeoff paths and sideline to takeoffs. • National Environmental Policy Act of 1969 (NEPA) (2) (PL 91-109) – The environmental consequences associated with federal development actions are required by the Act to be eval- uated. This Act gave birth to the Environmental Protection Agency (EPA), which developed guidelines to consider environmental policy during development of federal projects or proj- ects funded with federal monies. As applied to aircraft noise conditions, assessments required by NEPA are regulated by the Federal Aviation Administration through FAA Order 1050.1E and Order 5050.4B. • Airport and Airway Development Act of 1970 – (AADA) (130) (PL 91-258) – This Act provided for the funding of airport development programs under the Airports Improvement Program (AIP) by providing federal funding assistance to local sponsors of airport capital or planning projects. The Act did not include funding for noise abatement planning. 6-2 6-1 88 Aircraft Noise: A Toolkit for Managing Community Expectations

• Noise Control Act of 1972 (131) (PL 92-574) – This Act amended the Federal Aviation Act to include “public health and welfare” as a consideration for noise abatement planning. It expanded 14 CFR Part 36 to add Stage 3 aircraft and added EPA to the rulemaking process to consider aircraft noise impacts in airport planning. • Aviation Noise Abatement Policy of 1976 (132) (ANAP) – FAA policy statement to establish a gradual phase out of older, louder Stage 1 aircraft from the operating fleet by the end of 1988. • 14 CFR Part 91 – General Operating and Flight Rules (4) – Regulation published in 1976 to require the gradual phase out of Part 36, Stage 1 aircraft over 75,000 pounds from the operating fleet by the end of 1988. The measure gave birth to the engine retrofit industry as owners of Stage 1 aircraft sought methods to modify their aircraft to continue their use under the new regula- tion. The measure was subsequently expanded by later legislation to require the phase out of Part 36, Stage 2 aircraft weighing more than 75,000 pounds not later than December 31, 1999. • Airline Deregulation Act of 1978 (133) (PL 95-504) – This Act eliminated federal control of route structures and pricing for commercial aviation and placed the industry on a competitive basis. The Act gave rise to a proliferation of low-fare and start-up carriers as routes became available to any user. The Act prohibited the regulation of noise levels through price controls, or charges based on route or aircraft type. • Quiet Communities Act of 1978 (134) (PL 95-609) – This Act provided for collaboration between the FAA and the EPA in the development of aviation noise abatement plans and actions, and provided funding for noise abatement and mitigation actions. The EPA’s noise office was defunded in 1982, but the authorization has remained in place should the office be refunded at some future time. • Aviation Safety and Noise Abatement Act of 1979 (6) (ASNA) (PL 96-193) – This Act extended funding for planning for noise mitigation and abatement actions for an additional time. It also brought foreign carriers under the provisions of 14 CFR Part 91 for the phase out of the loudest aircraft, effective in 1980. The extension of funding resulted in the promulgation of 14 CFR Part 150, Airport Noise Compatibility Planning, in 1981 to guide the development of airport noise abatement programs. • 14 CFR Part 150, Airport Noise Compatibility Planning (135) – This regulation establishing the airport noise compatibility planning program and its guiding criteria was promulgated by the FAA in 1981, subsequent to its authorization under ASNA. The regulation sets forth the requirements that program sponsors must first identify the current and anticipated noise exposure patterns at the airport, based on annual average conditions, using tools and methodologies prescribed by the regulation. Secondly, the sponsor may prepare a Noise Compatibility Program for review and approval by the FAA to make noise mitigation projects eligible for federal funding. These may include acquisition in areas of significant noise exposure, modification of flight paths and runway use programs, structures and facilities to mitigate noise, sound insulation programs, or any num- ber of other project categories. This program has become the primary vehicle for airports to become eligible for AIP and PFC funding for noise abatement and mitigation projects. • Airport and Airway Improvement Act of 1982 (136) (AAIA) (PL 97-248) – This action re- authorized the AADA and added coordination between multiple modes of transportation, as well as setting aside a portion of the AIP funds for noise abatement planning projects. • National Parks Overflights Act of 1987 (137) (PL 100-91) – This Act forms the basis of require- ments for detailed assessment of supplemental noise metrics in national parks environs, and the development of a Flight Management Plan for the Grand Canyon National Park. The cri- teria of the Act have been extended to all national parks, as well as other scenic national prop- erties including monuments and wilderness areas. Many airports in the West now need to consider the effects of their development actions relative to their potential impacts on these national properties. • Airport Noise and Capacity Act of 1990 (ANCA) (5) (49 USC 47521) – This Act forms the basis of the FAA’s criteria for review and approval of actions that restrict access to any airport Noise Management and Public Response 89

that receives federal funding. In exchange for a scheduled phase out of Stage 2 aircraft by the end of 1999, airports were prohibited from implementing new access restrictions on Stage 3 aircraft unless an application is prepared and approved under 14 CFR Part 161, Notice and Approval of Airport Noise and Access Restrictions. • 14 CFR Part 161, Notice and Approval of Airport Noise and Access Restrictions (138) – The regulation restricts the ability of an airport that is or has received federal funding for airport improvement projects from implementing any restrictions on access to its facility under local police powers. The regulation requires that any airport desiring to implement a restric- tive measure (curfew, aircraft type prohibition, noise cap, etc.) must first complete a rigor- ous application that evaluates the benefits and costs of each such action. The sponsor must consider not only the effects of the action in the local environment, but also on the national transportation system. For Stage 2 aircraft, the required evaluations are less extensive than for restrictions proposed for Stage 3 aircraft, but in practice, the FAA reviewers have set a high bar for approval of restrictions on both aircraft groups. In late 2008, no airport had received approval for any new restriction on Stage 3 aircraft, and only Naples Municipal Airport (Florida) had achieved a restriction on Stage 2 operations, but even then after years of litigation. • Federal Aviation Reauthorization Act of 1996 (139) (PL 104-264) – This act restructured the Air Traffic Organization (air traffic control), modified the funding program, provided for environmental streamlining to speed project review, and established a research program for aviation initiatives. • Vision 100 Century of Aviation Reauthorization Act of 2003 (140) (PL 108-176) – This Act con- tinued funding of airport grant programs and addressed airline and airport safety issues, as well as continuing the research component of the planning analyses. During the period since 2003, Congress has passed continuing resolutions to fund the several reauthorizations of Vision 100 to continue program funding without interruption. FAA Orders and Guidance on Environmental Planning In addition to the regulation of aircraft noise assessment set forth under 14 CFR Parts 36, 91, 150, and 161 described in the previous section, the Federal Aviation Administration has estab- lished Environmental Orders and supplemental guidance for the evaluation of aircraft noise within the larger context of the assessment of all environmental consequences of an airport- related development or planning action. These orders are: • FAA Order 1050.1E, CHANGE 1 – Environmental Impacts: Policies and Procedures (2006) (141) – This Order provides specific guidance and instructions to the preparers of Envi- ronmental Impact Statements, Assessments, Categorical Exclusions, and other findings. It delineates specific detailed requirements for information that must be incorporated into envi- ronmental documents and provides standards of significance to be addressed for each envi- ronmental category. For noise, the standard of significance has been determined to be a change of 1.5 dB of DNL resulting in an annual average DNL of 65 dB or more, when compared to an established baseline condition for the same period of time. • FAA Order 5050.4B – NEPA Implementing Instructions for Airport Actions (2006) (142) – This Order provides FAA organizations with Agency policies and procedures to comply with NEPA and CEQ implementing regulations. It is intended primarily as guidance to the pro- cessing of environmental evaluations for the FAA reviewer and planning professional to assure consistent and accurate processing of all environmental evaluations for airport-related projects. 6-4 6-3 90 Aircraft Noise: A Toolkit for Managing Community Expectations

• Environmental Desk Reference (2007) (143) – The FAA released a reference document late during 2007 that was intended to provide applicable special purpose laws relating to envi- ronmental evaluations in a single location for FAA staff, airports, and preparers of environ- mental documentation. It presents the information based on the 23 environmental categories typically included in an Environmental Impact Statement by providing information in each of the following sections: – Introduction and Definitions – Applicable Statutes and Implementing Laws or Regulations – Applicability to Airport Development Actions – Permits, Certifications, and Approvals – Environmental Compliance Procedures – Environmental Analysis – Determining Impacts – Determining Impact Significance – Environmental Impact Statement Content • The Part 150, Airport Noise Compatibility Planning process, has evolved over the years since its initiation, but the guidance document (FAA Advisory Circular 150-5020-1) (144) is outdated. An update is in preparation, with completion and release expected during 2008. The reader may find the documentation provided in the current Part 150 planning guidance of use. • The 14 CFR Part 161, Notice and Approval of Airport Noise and Access Restrictions (138), requirements are often cited by the public as a mechanism for airports to implement curfews, noise level limitations, runway use requirements and similar actions as a means of abating noise in communities. The regulation is provided on the accompanying Toolkit. State and Local Action Several states and communities have established environmental regulations similar to those enacted by the NEPA, for environmental review, or for land use management. For airports, these regulations are frequently focused on reporting the effects of current environmental conse- quences on surrounding communities. There may be differences between the standards adopted by the FAA in its Order 5040.4B regarding levels of significance, or there may be additional reporting required for airports within the state. Frequently, the anticipated future consequences of airport development projects must be reported against current conditions (under NEPA, future consequences are reported against future baseline conditions). Owing to the great diver- sity between state and local programs, the airport manager should establish contact with local legal advice and assistance of State aviation organizations to assure that state and local require- ments are met for the evaluation of aircraft noise. In general, courts have established federal preemption over state and local actions to restrict noise associated with aircraft in flight. The U.S. Supreme Court (City of Burbank v. Lockheed Air Terminal (1973) (441 U.S. 624, 93 S.Ct. 1854, 36 L.Ed.2d 547) (145) opened the door to the theory that communities cannot use police powers to control aircraft noise if the community is not the owner or operator of the airport. Further, the U.S. Court of Appeals found in Leudtke v. County of Milwaukee (1975) (7th Cir.; 521 F.2d 387) (146) that the airport and the airlines could not be held liable for violation of a state law if operations were con- ducted in compliance with federal laws and regulations (subsequently, the preemption of state-law relief was expressly overruled). Extensive additional information on these and similar cases, with an emphasis on federal and California litigation, may be found at http:// airportnoiselaw.org. 6-7 6-6 6-5 Noise Management and Public Response 91

Mandatory and Voluntary Noise Abatement Actions Mandatory noise abatement actions are those measures that are required of all, or a category of, operators at the airport. If new, they fall under the requirements of 14 CFR Part 161 to be fully evaluated for their benefits and costs prior to approval by the FAA and implementation. In the United States, there has been a strong resistance among aviation operators to noise abate- ment actions which prohibitively restrict their use of an airport, while neighbors have often sought such prohibitions to assure a consistent and predictable level of quiet in their commu- nities. The FAA, courts and regulators have typically sided with the airport or the user against mandatory restrictions on operations. Even so, the typical airport manager or owner continues to face public complaints and opposition to airport activity and its perceived impacts on those who live nearby. Both the airport operator and the public should be aware that restrictive actions may have an impact on airport efficiency and may result in increased delay or cancelled operations. In many cases, airport sponsors have sought abatement of aircraft noise through the develop- ment of voluntary actions that seek to implement the intent of mandatory actions without fac- ing regulatory opposition to restrictions. The aircraft operating programs of many Part 150 studies or EIS mitigation plans use voluntary actions to achieve a portion of the desired noise reduction. For example, rather than implementing a mandatory “formal” runway use program which specifies for given conditions or times of day the runways to be used for landing and take- off, a voluntary program may be negotiated with the users to seek their participation in an “infor- mal” runway use program that may be approved under Part 150 or an EIS to result in much of the noise reduction sought with a formal program. The use of the informal program would be at the discretion of the user, however at busy towered airports, if the FAA and the users are party to the development of the informal program, it is likely that it becomes the normal mode of oper- ation and deviations from it become difficult to accommodate because they must be worked safely into the arrival or departure traffic flows. Similarly, airport operators may seek coopera- tion with users to use quieter aircraft types, to fly preferred routes, or to reduce ground level noise through various voluntary agreements. It is important to remember that voluntary agreements are exactly that – voluntary, and that some operators may choose not to participate in the pro- gram. Of equal importance, however is that the establishment of any program will likely lead to the improvement of the noise conditions that the manager is seeking to alleviate, so long as it is safe and conducted in a controlled environment. Airport Role in Comprehensive Planning The compatibility between the noise generated at or near an airport and the usage of land in the airport vicinity is based on both the amount of noise generated and the locations of sensitive land uses. For many years noise abatement planning focused on the modification of flight paths, run- way use patterns, and aircraft activity, but with the completion of the phase-out of older, louder Stage 2 aircraft at the end of 1999, much of the achievable noise exposure reduction available under current technology and regulations had been accomplished. Although research is continuing into additional noise reduction technologies at the aircraft source, the regulatory agencies, airports and users have begun to increase the pressure to attain balance between actions that had been taken at the source and focus more control of incompatibility on the receiver. Consequently, the manage- ment of land use development has taken a greater role in the noise compatibility programs of the new century. During the period of the 1970s, 80s and 90s, noise exposure patterns gradually shrank as qui- eter Stage 3 aircraft became greater and greater portions of the operating fleet. The shrinkage of 92 Aircraft Noise: A Toolkit for Managing Community Expectations

the contours of significant noise exposure, within which development of incompatible land use had been constrained by early program actions, resulted in more and more land becoming avail- able for development into noise-sensitive uses. In many cases, local authorities yielded to resi- dential development pressures to allow construction adjacent to or within the 65 DNL contour on land that updated contours now showed as being compatible. The result was the creation of a smaller envelope of area within which significant noise levels could remain compatible with under- lying uses. Growing operations or changing missions of airports may now lead to an increase in the noise contour sizes for the first time in many years. Many airports how have smaller contours than in the past and more operations. The airport surveys conducted for this study have shown that many noise complaints are made about the frequency of operation, rather than the overall noise level. Consequently, as the contours shrink and numbers of operations increase, land is opened for more noise-sensitive development to be located closer and closer to the routes of flight and the runway ends. This will likely lead to an increase in noise complaints as operations increase and residences are allowed to develop near the airport in previously incompatible areas. Some airports, like Dallas Fort Worth International Airport and Los Angeles International Airport have maintained contours from many years ago as the control for land use management and mitigation planning, even though more current contours might indicate less area within them. The FAA has established a policy to not fund mitigation of residential properties that have been constructed within the published area of incompatibility at an airport. Air carrier and other user groups are demanding that communities do their share to control the introduction of new noise-sensitive uses into areas exposed to high noise levels. To respond to these demands, air- ports may take a role in the comprehensive planning process to work closely with community planners to develop risk adverse plans for the airport environs. The flight patterns for airports are well established, the noise contours are easily projected, and the land uses already present are known. Airports in many communities are working to review planning proposals and make known the potential for elevated noise exposure over areas before they enter the development phase. These actions may occur in collaboration with planning staff, with community zoning and subdivision regulators, or with developers themselves to seek the greatest level of compatibil- ity between the airport and its surrounding uses. To be fully successful, the political powers within the community must be on board with the decision to limit the risks to the economic engine for the community that resides in the airport. Stakeholder Involvement and Jurisdictional Coordination Interviews and surveys conducted in support of this study indicate that communications about noise and the efforts to manage it are critical to efficiently accomplishing abatement goals. Clear descriptions of the roles and expectations of each participant in the noise management process—the producers of aircraft noise, the recipients of aircraft noise and the controllers of the location and intensity of that noise—are all essential to the success of any program. Honesty and clarity in communication with airport neighbors has been cited by many airport noise man- agers as the most important element in assuring that changes to noise patterns are understood and the public is aware of what to expect. A clear communication and discussion with aircraft operators about their capability and will- ingness to actively participate in noise abatement actions leads to a more effective program by limiting expectations to achievable results. This is also true of interactions with air traffic man- agement personnel regarding their ability to efficiently move traffic through the airport and over areas of greatest compatibility. Noise Management and Public Response 93

Implementation Responsibilities and Constraints The management of noise and its effects at an airport is the responsibility of several parties. While the public may see the airport as a single entity, the airport manager is faced with the need to coordinate activities across regulators, users, local governments, and neighbors to address the issues of noise. Table 6-1 provides an overview of the responsibilities of the U.S. Congress, the FAA, state and local governments, the airport operator, aircraft users and manufacturers, and air- port neighbors in the management of a number of different topics that often arise in discussions of how to control aircraft noise. Interestingly, the Airport has direct control only over the noise produced by aircraft that are not in flight mode (i.e., during maintenance run-up activity), con- struction of noise abatement facilities, and management of the use of land which it owns or oper- ates. It may advise, request or negotiate for modifications in actions controlled by others. The federal government sets policy regulating allowable noise levels, controls airspace and airport operating patterns, and provides a major part of the funding for noise abatement actions con- ducted by the airport. It also reviews and may approve or deny any proposed restrictions on aircraft flight activity at an airport. Local governments control the use of land around the air- port through zoning, subdivision control, and comprehensive planning actions. Aircraft opera- tors/pilots have ultimate responsibility for all phases of the flight of the aircraft, but operate within the environment set by air traffic control direction or rules; they are also responsible for their selection of aircraft type and, implicitly, its noise level. Aircraft manufacturers are responsible for producing aircraft that meet federally specified noise levels. Airport neighbors are responsible for reviewing and commenting on airport environmental actions, as well as taking due diligence in the acquisition of property; property owners may have additional responsibilities if property is part of a mitigation program such as sound insulation or acquisition by the airport. Information to Respond to Typical Public Concerns About Noise When dealing with the public, the airport manager will often be confronted with comments about issues with which he has limited experience. Such issues include: • The difference between cumulative and single-event noise levels and when each is useful; • The thresholds of significant noise level and how it’s used; • The difference between noise impact (within 65 DNL contour) and noise effect (outside 65 DNL contour); • The difference between compatible and incompatible land use; • The differences between thresholds of evaluation for different FAA divisions; • The precedence of federal and state standards and when they are applicable; • The difference between noise measurements and computer modeling of noise levels, and why one may be preferable to the other in given cases; • Aircraft contribution to vibration and rattle; • Sound insulation programs and how do they work; • The difference between interior and exterior sound levels and the abatement of each; and • Contour and impact area change over time and the differences between federal and local response to change. The following sections discuss each of these issues. Cumulative versus Single Event Noise Levels Observers frequently complain that cumulative noise measures such as DNL or CNEL or LEQ do not adequately reflect the noise levels heard. When they compare the significant DNL level of 94 Aircraft Noise: A Toolkit for Managing Community Expectations

65 decibels to a single event of 65 Lmax they often consider the two to be equivalent. Most people fail to understand the integration of all noise events into the calculation of the cumulative noise levels. The misunderstanding is even more aggravated by calling the cumulative noise level the “average aircraft noise level”, when in truth, it is the total aircraft noise energy distributed over 86,400 seconds during a day, and includes the many seconds during the day when aircraft noise is not present. The components of the cumulative noise measure must be clearly understood to be a deriva- tive of the sum of the noise energy of every event that occurs during the period under consider- ation, divided by the number of seconds during that period. These factors are further complicated by the logarithmic nature of noise energy computation. Consider the example of a rain barrel that has a capacity of 10 billion rain drops to help explain the DNL. Assume an empty rain barrel that will be filled with drops of water proportionate to the amount of noise energy generated during each second of a single aircraft event, using a base of 1 decibel. Based on the accompanying chart (Table 6-2), an event lasts 10 seconds and the aver- age energy per second is 30 decibels, resulting in a total of 10,000 units. Assume one drop of water represents a unit. Therefore, 10,000 drops of rain are poured into the barrel and the level rises imperceptibly. The next 100 events last 10 seconds each and the average energy per second is 60 decibels, resulting in 1 billion drops of rain dropping into the barrel, raising the level of water to less than 10% percent of the height of the barrel. The third event lasts for 50 seconds and aver- ages 70 decibels, resulting in 500 million drops of water falling into the barrel and raising the level of water to over 15% of its capacity. The next three events all last 10 seconds and average 80 decibels, and one of those events is at night. The first two events add 2 billion drops of water to the barrel, and raises its water level to over 35% of the height of the barrel. The nighttime event adds as many drops as the capacity of the barrel and everything that is already in the barrel flows out. This example is designed to demonstrate the relative effect on cumulative average noise levels of operations of varying loudness and at different times of the day. Each increase of decibel level by 10 dB equates to 10 times as much noise energy. Therefore it would take 10 events of the lower level to provide as much energy as one event of the higher level. Every event that occurs at night (10 p.m. to 7 a.m.) is considered to have 10 times the amount of energy as the same event that occurs during the daytime (7 a.m. to 10 p.m.) hours. Thresholds of Significant Noise A threshold of significance, in terms of aircraft noise, may be described as the noise level at which aircraft noise creates a significant impact on noise sensitive uses and persons exposed to it or higher levels. The FAA has selected 65 dBA of DNL to be the default threshold of significance for aircraft noise. Any such uses exposed to 65 DNL for the average annual condition are described to be significantly impacted. On federally funded aviation projects, any uses that are exposed to less than 65 DNL for the average annual condition are described as not being signifi- cantly impacted. With few exceptions, the FAA does not participate in funding actions to miti- gate parcels of land exposed to less than 65 DNL. In addition to the exceedance of 65 DNL, properties may be exposed to another threshold of sig- nificance when the noise level over them increases by 1.5 dBA of DNL or more from a no-action condition and the resultant with-project average annual DNL exceeds 65 dBA. Other jurisdictions, including state and local governments, may define different thresholds of significance for their own communities. Such thresholds may be tools to control the loudness of aircraft using their airports, or may be used to control the development of noise-sensitive land uses in areas exposed to noise greater than the threshold. For example, at Naples, Florida, the Noise Management and Public Response 95

96 Aircraft Noise: A Toolkit for Managing Community Expectations Authorities and Responsibilities of Parties Noise Abatement Opportunity United States Congress FAA - All divisions except Air Traffic FAA - Air Traffic Control Authority to establish noise abatement actions through operational change Establish environmental policy in accordance with national priorities. May legislate to specific goals for noise abatement Must prepare environmental guidance, regulations and standards to meet Congressional policy. Prepares environmental reviews on federal development actions at airports Must manage for the safe and expeditious flow of air traffic. Prepares environmental reviews on airspace and flight procedure modifications May establish state requirements to monitor noise levels or evaluate a change of environmental noise associated with proposed action Loudness of individual aircraft airframe and engine design Set general policy for aircraft noise levels and compatibility Sets standards by size and number of engines for landing and takeoff noise None None Location of takeoff routes None Establishes and manages routes in accordance with requirements for safety and efficiency of flow Usually none. Some states may require assessment of environmental consequences of changes Location of arrival routes None Establishes and manages routes in accordance with requirements for safety and efficiency of flow Usually none. Some states may require assessment of environmental consequences of changes Steepness of climb or descent None Assure proper separation between climbing and descending traffic and with surface structures and topography None N oi se A ba te m en t A ct io ns Reduction of power or thrust settings during takeoff or landing (including reverse thrust and cutbacks) None Assure proper separation between climbing and descending traffic and with surface structures and topography NoneFlight standards and certification may have a role in approval of procedures Flight standards and certification may have a role in approval of procedures Advise on environmental and operational consequences of route revisions Advise on environmental and operational consequences of route revisions State Government Selection of runway Assign runways in accordance with wind and operating standards None None None Time of activity (curfew) Establish criteria for implementation of access restrictions Review and/or approve or deny restrictions on activity times None Limits on flight operations (number of flights or noise budget or aircraft type restrictions) Establish criteria for implementation of access restrictions Review and/or approve or deny restrictions on activity times proposed by airport None Ground run-up location and timing None None Construction of new on-Airport facilities for noise mitigation May provide funding authorizations through the AIP process or through line-item funding in legislation Must review and approve modifications to Airport Layout Plan through the environmental review process prior to construction. May participate in funding effort if eligible under Airport Improvement Program Review to assure the proposed action does not degrade safety. Modify operating plan to incorporate new facilities, if applicable May participate in funding. May require completion of state environmental documentation prior to construction Advise on environmental and operational consequences of route revisions None Assign aircraft to preferred run-up location None Table 6-1. Authorities and responsibilities of parties.

Noise Management and Public Response 97 Authorities and Responsibilities of Parties Airport Owner or Operator Aircraft Manufacturers Local Government Jurisdictions May request change of FAA Air Traffic management procedures, through Part 150 or other action. May control noise of aircraft not in flight or on runway Operate aircraft safely and in accordance with federal flight standards. Must manufacture aircraft to meet established guidelines for weight and number of engines Communities may establish controls on ground activity, but are preempted from jurisdiction over aircraft in flight or during landing or takeoff None None None None None None None Design and construct aircraft to achieve certification standards set by federal regulation None May advise and request modifications to routes for noise abatement IFR – fly routes assigned by ATC. VFR – fly where desired assuring separation from other traffic None May advise and request modifications to routes for noise abatement. May add number of routes through improved instrumentation for landing IFR – fly routes assigned by ATC. VFR – fly where desired assuring separation from other traffic None for noise abatement Fly to procedures set by FAA and within capabilities of aircraft None for noise abatement Develop and train on standardized procedures within capabilities published by manufacturers Publish information about aircraft capability for use by operators None None None None Maintain aircraft to continue to meet standards May request changes May request changes Aircraft Operators Airport Neighbors Operate in accordance with assigned runway from FAA-ATCT. Pilot may request a different runway. None None None None None None None None None None None Operate in accordance with established rules None None Propose, design, and construct as approved by FAA. Provide local funding required. Maintain on completion. Use operational facilities as assigned by FAA ATCT upon completion. None Review, comment on, and discuss proposed development plans during environmental review process. Consider resulting noise levels in home purchase deliberations May request from FAA-ATCT a preferential runway use program for noise abatement. May propose limits on time (curfews) of operation to FAA May propose limits on numbers of operations or restrictions on aircraft types to FAA for review and approval/denial Authorized to establish run-up rules and criteria, to include times, bearings and thrust Communities may establish “at the fence” noise standards for ground activity, but must apply the standards to non-aviation activity as well. Review and modify if appropriate land use policies in areas that may become impacted by newly introduced or increased aircraft noise levels (continued on next page)

98 Aircraft Noise: A Toolkit for Managing Community Expectations Authorities and Responsibilities of Parties Noise Abatement Opportunity United States Congress FAA - All divisions except Air Traffic FAA - Air Traffic Control State Government Mitigation actions within various noise levels Establish funding priorities to designated levels of Day-Night Average Sound Level (DNL) Interpret Congressional action to prioritize proposed mitigation actions requiring funding. Reviews and denies or approves EIS, Part 150 and Part 161 program actions requiring federal participation Review proposed actions requiring modification of flight procedures or runway use to assure safety and continued efficiency of operation Within the state, establishes priorities for noise abatement activities and sets bounds for statewide standards of noise sensitivity N oi se M et ric S el ec tio n Noise metric used Established DNL as the acceptable metric to describe aircraft noise, based on annoyance. Reviews on a case-by-case basis the acceptability of supplemental metrics for planning Follows FAA policy on suitable metrics Within the state, may select additional metrics that are required for airport assessments Land use planning None La nd U se M an ag em en t A ct io ns Land acquisition for noise abatement None None Authorized FAA to select suitable metric for the description of aircraft noise Within the state, may establish goals for land use compatibility and require efforts to achieve mitigation through planning, acquisition or remedial treatment. May require periodic reporting of achievements or changes in noise exposure levels Recommends appropriate land uses compatible with airport operations and noise based on DNL noise levels None May require completion of state environmental documentation prior to acquisition May fund part of the acquisition cost if included in an approved Part 150 Noise Compatibility Program or as mitigation in an approved EIS Zoning for compatible land use None None None Residential density control through subdivision design None None None Modify building codes to improve sound insulation on construction None Sound insulation of existing structures None None Noise level disclosure None None None May provide statewide guidance for compatibility, and methodology for zoning coordination Typically, none None None Typically, none Typically, none May fund part of the program cost if included in an approved Part 150 Noise Compatibility Program or as mitigation in an approved EIS May require notifications within given noise levels or distances from airport Table 6-1. (Continued).

Noise Management and Public Response 99 Authorities and Responsibilities of Parties Airport Owner or Operator Aircraft Manufacturers Local Government Jurisdictions Aircraft Operators Airport Neighbors Develops program of noise abatement and land use management actions for review and approval by FAA or local jurisdictions. Manages mitigation and implementation actions for which it is the funding source or agent None None Where applicable, comment on proposed program actions under Part 150, Part 161 or EIS mitigation actions as part of public involvement process Selects supplemental metrics most useful to provide information to those interested in noise patterns at airport. Uses DNL for all required documentation None None None Work with land use management to seek controls on the development of incompatible uses within noise exposure pattern, based on local determination of noise level target None None Review and comment on proposed Noise Compatibility Program or EIS mitigation actions during public involvement process. Exercise due diligence in selection of residential property prior to acquisition May acquire land for noise mitigation as deemed appropriate to airport need None None Unless the owner of the property under consideration, none. If the owner, active participation, usually voluntary is required Communities may determine compatibility standards within their own jurisdictions, but to obtain FAA concurrence, they must manage development to control the introduction of incompatible uses to those standards Provides certification data to FAA using EPNdB and EPNL metrics. Provides SEL data to FAA for application in Integrated Noise Model Jurisdictions establish and enforce land use management policies, including usage and density of development. May express preferences, but unless the jurisdiction is the airport owner, will not have an active authority in process None, unless the airport has jurisdiction over land uses in the airport environs None None May review and comment through any hearing process associated with zoning or building codes None None May review and comment through any hearing process associated with zoning or building codes None None May review and comment through any hearing process associated with zoning or building codes None None None, unless an affected property owner None, unless the airport has jurisdiction over land uses in the airport environs None None May be obligated to disclose noise levels in any property transfer Sets zoning policy and establishes code within jurisdiction. Hears zoning change cases. Approves or denies applications for change Sets subdivision design requirements through development code. Hears and approves or denies requests for new subdivision or modification None, unless the airport has jurisdiction over land uses in the airport environs None, unless the airport has jurisdiction over land uses in the airport environs Adopts a standard building code or modifies to local need. Hears applications for variances May establish standards for sound insulation within noise impacted areas for new or rehabilitated structures May fund and manage sound insulation programs for mitigation of existing structures. If eligible, partial funding is required May require noise level disclosure in transfer or advertisements for sale of properties within noise impacted areas - usually based on noise level, but may be based on distance from airport (continued on next page)

100 Aircraft Noise: A Toolkit for Managing Community Expectations Authorities and Responsibilities of Parties Noise Abatement Opportunity United States Congress FAA - All divisions except Air Traffic FAA - Air Traffic Control State Government La nd U se M an ag em en t A ct io ns Acquire noise/overflight easements None None None Institute development rights transfer program None None Institute purchase assurance program None None NoneReview development proposals for noise compatibility None None Typically, none Typically, none Typically, none Typically, none May fund part of the easement cost if included in an approved Part 150 Noise Compatibility Program or as mitigation in an approved EIS May fund part of the acquisition assurance cost if included in an approved Part 150 Noise Compatibility Program or as mitigation in an approved EIS, and ultimately purchased by the airport Table 6-1. (Continued). Airport Authority established a ban on Stage 2 business jets after fulfilling the requirements of a 14 CFR Part 161 process. The measure was twice challenged in court by the FAA and user groups, and ultimately won by the city after several years delay. Conversely, several airports have estab- lished thresholds of significance for land management that restrict the development of residen- tial development and noise-sensitive uses within lesser noise contours than 65 DNL, thus providing a greater envelope of protection against the risks of future conflicts between the airport and neighbors, through increased operations or upgrades of service. The specific noise levels of local thresholds are best defined through a thorough evaluation of local need. Difference Between Noise Impact and Noise Effect In simple terms, noise impact is limited to an area within a defined threshold of significance. For example, persons residing within the 65 DNL contour typically are considered to be adversely impacted by aircraft noise, if the 65 DNL contour has been determined to be the threshold of significant noise exposure. Conversely, persons residing beyond the 65 DNL con- tour are not considered to be adversely impacted by noise to a significant degree, but rather may be affected by aircraft noise. Persons may be affected by aircraft noise at any level or under a vari- ety of different measurement techniques, but are not considered to be impacted by aircraft noise unless they are exposed to noise greater than the threshold of significance. See also“Differences within the FAA Divisions Regarding Thresholds of Noise Level Evaluation (60/65 DNL in Air- ports vs. 45/60/65 DNL in Air Traffic)”on the next page for additional clarification. Difference Between Compatible and Incompatible (Noise-Sensitive) Land Uses In practice, compatible land uses are those activities which may coexist with aircraft noise with- out being adversely impacted by them. Incompatible land uses are more specifically described as

residences, schools, churches, nursing homes, hospitals, outdoor amphitheaters, etc. where air- craft fly over activity may substantially impact the conduct of normal activity within those uses. 14 CFR Part 150 provides a detailed matrix of land use compatibility descriptions (147, Appen- dix A, Table 1) used by the FAA to assess how various land uses are affected by aircraft noise. See Table 6-3. Differences within the FAA Divisions Regarding Thresholds of Noise Level Evaluation (60/65 DNL in Airports vs. 45/60/65 DNL in Air Traffic) The FAA, Office of Environment and Energy, has established specific thresholds that are con- sidered acceptable and supported by a preponderance of available scientific evidence. The FAA’s Office of Planning and Environment has advised that these levels must be reported in 14 CFR Part 150 and Part 161 reporting, as well as in Environmental Impact Statements. The thresholds state that, for there to be a significant noise impact, there must be noise-sensitive public uses or persons residing within the 65 DNL contour of the annual average condition. When a change in the noise pattern is being environmentally assessed, an increase of 1.5 dB of DNL with a resul- tant DNL of 65 decibels or more constitutes a significant change. Should this situation be pres- ent, any areas exposed to a change of 3.0 dB of DNL or more, resulting in an annual average DNL of 60 dB or more are disclosed as having slight to moderate impacts. The FAA’s Air Traffic Organization has accepted these levels and added another for evalua- tions of modifications to flight routes. Should the changes previously cited be present, then any areas exposed to a change of 5.0 dB of DNL, resulting in an average annual DNL of 45 dB or more also is disclosed as having slight to moderate impacts. This reporting criteria is not recognized for application to environmental statements disclosing the effects of changes imposed by airport facility development, but only to modifications of aircraft flight paths. (141) Noise Management and Public Response 101 Authorities and Responsibilities of Parties Airport Owner or Operator Aircraft Manufacturers Local Government Jurisdictions Aircraft Operators Airport Neighbors None None None, unless an affected property owner None None None, unless an affected property owner. If an owner, may negotiate terms after being contacted by the initiating party None None None None None May review and comment through any hearing process associated with zoning or building codes May require easements as a condition of zoning change or subdivision approval in areas of elevated noise, or within a designated distance from the airport May fund and manage easement acquisition programs for mitigation of existing uses and lands that are at risk for incompatible development. If eligible, partial funding is required If a change of zoning is required, must hear and approve or deny proposed transfer of development rights from one parcel to another May be an active participant in a swap of development rights or facilitator of transfers among others None, unless an affected property owner. If an owner, and unable to sell after a designated period of time, may contact airport to negotiate sale May fund and manage purchase assurance programs for mitigation of existing structures. If resold, the funds must be returned to the FAA or used for fundable programs. If eligible, partial funding is required Collaborates with airport owner in review of development proposals or applications for modification of zoning to incompatible uses within a designated airport environs area May participate in review of proposals provided by development approval agencies

The standards used by the Office of Planning and Environment are used by all divisions of the FAA, with the exception of the additional criteria described by the Air Traffic Organization use earlier. NO DIVISION OF THE FAA HAS ADOPTED SPECIFIC THRESHOLD CRITERIA TO DESCRIBE A SIGNIFICANT IMPACT FOR ANY SINGLE EVENT METRIC, WHETHER BY NOISE LEVEL, DURATION OR NUMBER OF OPERATIONS. Precedence of Federal and State/Local Standards and When Applicable The federal government and its aviation regulatory agency, the FAA, holds precedent over local or state regulation of aircraft noise conditions, or numbers or time of operations when the aircraft is in the air, on the runway, or actively taxiing to and from a terminal area (including general aviation, cargo, or maintenance parking aprons) from a runway or taxiway. Several law- suits have established the precedence of federal regulation over local control – the most notable of these was the case of City of Burbank vs. Lockheed Air Terminal, in 1973. In that case, the United States Supreme Court found that local communities may not use their police powers to control noise at airports that are owned by others. (145) 102 Aircraft Noise: A Toolkit for Managing Community Expectations Decibel Level Duration - Seconds Energy Units – Day Energy Units – Night 1 1 1 10 10 10 100 50 50 500 10 1 10 100 10 100 1000 50 500 5000 20 1 100 1000 10 1000 10000 50 5000 50000 30 1 1000 10000 10 10000 100000 50 50000 500000 40 1 10000 100000 10 100000 1000000 50 500000 5000000 50 1 100000 1 x 106 10 1000000 1 x 107 50 5000000 5 x 107 60 1 1 x 106 1 x 107 10 1 x 107 1 x 108 50 5 x 107 5 x 108 70 1 1 x 107 1 x 108 10 1 x 108 1 x 109 50 5 x 108 5 x 109 80 1 1 x 108 1 x 109 10 1 x 109 1 x 1010 50 5 x 109 5 x 1010 90 1 1 x 109 1 x 1010 10 1 x 1010 1 x 1011 50 5 x 1010 5 x 1011 100 1 1 x 1010 1 x 1011 10 1 x 1011 1 x 1012 50 5 x 1011 5 x 1012 110 1 1 x 1011 1 x 1012 Table 6-2. Relative effect.

Noise Management and Public Response 103 YEARLY DAY-NIGHT AVERAGE SOUND LEVEL (DNL) IN DECIBELS BELOW OVER LAND USE 65 65-70 70-75 75-80 80-85 85 RESIDENTIAL Residential, other than mobile homes Y N1 N1 N N N and transient lodgings Mobile home parks Y N N N N N Transient lodgings Y N1 N1 N1 N N PUBLIC USE Schools, hospitals, nursing homes Y 25 30 N N N Churches, auditoriums, and concert halls Y 25 30 N N N Governmental services Y Y 25 30 N N Transportation Y Y Y2 Y3 Y4 N4 Parking Y Y Y2 Y3 Y4 N COMMERCIAL USE Offices, business and professional Y Y 25 30 N N Wholesale and retail -- building materials, hardware, and farm equipment Y Y Y2 Y3 YS N Retail trade, general Y Y 25 30 N N Utilities Y Y Y2 Y3 Y4 N Communication Y Y 25 30 N N MANUFACTURING AND PRODUCTION Manufacturing, general Y Y Y2 Y3 Y4 N Photographic and optical Y Y 25 30 N N Agriculture (except livestock) and forestry Y Y6 Y7 Y8 Y8 Y8 Livestock farming and breeding Y Y6 Y7 N N N Mining and fishing, resource production Y Y Y Y Y Y and extraction RECREATIONAL Outdoor sports arenas and spectator sports Y Y Y5 N5 N N Outdoor music shells, amphitheaters Y N N N N N Nature exhibits and zoos Y Y N N N N Amusements, parks, resorts, and camps Y Y Y N N N Golf courses, riding stables, and water recreation Y Y 25 30 N N The designations contained in this table do not constitute a federal determination that any use of land covered by the program is acceptable under federal, state, or local law. The responsibility for determining the acceptable and permissible land uses and the relationship between specific properties and specific noise contours rests with the local authorities. FAA determinations under Part 150 are not intended to substitute federally determined land uses for those determined to be appropriate by local authorities in response to locally determined needs and values in achieving noise compatible land uses. Key To Table 1, Appendix A, 14 CFR Part 150 Y (Yes) Land use and related structures compatible without restrictions. N (No) Land use and related structures are not compatible and should be prohibited. NLR Noise Level Reduction (outdoor to indoor) to be achieved through incorporation of noise attenuation into the design and construction of the structure. 25, 30, 35 Land use and related structures generally compatible; measures to achieve a NLR of 25, 30, or 35 dB must be incorporated into design and construction of structure. Notes for Table 1, Appendix A, 14 CFR Part 150 1. Where the community determines that residential or school uses must be allowed, measures to achieve outdoor-to- indoor Noise Level Reduction (NLR) of at least 25 dB and 30 dB should be incorporated into building codes and be considered in individual approvals. Normal residential construction can be expected to provide a NLR of 20 dB, thus, the reduction requirements are often stated as five, ten, or 15 dB over standard construction and normally assume mechanical ventilation and closed windows year round. However, the use of NLR criteria will not eliminate outdoor noise problems. 2. Measures to achieve NLR of 25 dB must be incorporated into the design and construction of portions of these buildings where the public is received, office areas, noise-sensitive areas, or where the normal noise level is low. 3. Measures to achieve NLR of 30 dB must be incorporated into the design and construction of portions of these buildings where the public is received, office areas, noise-sensitive areas, or where the normal noise level is low. 4. Measures to achieve NLR of 35 dB must be incorporated into the design and construction of portions of these buildings where the public is received, office areas, noise-sensitive areas, or where the normal noise level is low. 5. Land use compatible provided special sound reinforcement systems are installed. 6. Residential buildings require a NLR of 25 dB. 7. Residential buildings require a NLR of 30 dB. 8. Residential buildings not permitted. Source: FAR Part 150 Airport Noise Compatibility Planning, Appendix A, Table 1. Table 6-3. Land use compatibility guidelines – 14 CFR PART 150 (Table 1, Appendix A).

Local government may establish criteria for the regulation of aircraft noise when the aircraft is parked on an apron or ramp, or is under maintenance in an active run-up configuration. This finding was confirmed by the U.S. District Court in its finding in National Aviation et al. vs. City of Hayward (1976) which decided that local noise control restrictions may be implemented by a community as an airport owner or operator, but not through its police powers. (148) The United States Congress passed the Airport Noise and Capacity Act (49 USC 47521) in 1990, which among other things included a National Aviation Noise Policy prohibiting locally based restrictions on Stage 3 aircraft without federal approval, while requiring phase out of Stage 2 air- craft weighing more than 75,000 pounds by 2000. It also authorized Passenger Facility Charge (PFC) funding for airport development. Although the FAA has published guidance to the compatibility of various land uses with dif- fering levels of aircraft noise (as described by DNL) through its 14 CFR Part 150 guidance, the agency does not have the authority to manage or control land uses on property beyond the boundaries of federal ownership off the airport. Further, the airport sponsor is responsible for the usage of land within the boundaries of the airport, but must comply with federal guidelines to assure the safe operation of any aircraft using the airport (i.e., to avoid the introduction of obstructions on the airport). Local communities or states may regulate the use of land in areas off the airport, including zoning and subdivision, review of development propositions, and the regu- lation of the heights of structures. Frequently the federal and local agencies work together to develop plans for the compatible development of lands surrounding the aviation facility within the framework of community- wide planning needs and airport need. Measured versus Computer-Modeled Noise Levels The airport manager will frequently be asked to explain the difference between noise levels that have been measured in the field and noise levels for the same location that have been mod- eled by computer software. Frequently there will be differences of several decibels between two numbers for the same place. Modeled Noise At most airports, noise levels are described by either a series of contour lines representing points of equal noise exposure or by projected single event or cumulative noise levels at selected locations. Because it would require extensive sets of noise measurement equipment placed over a wide area for long periods of time to develop contours from measured data – at costs well beyond the means of all but the most affluent airports – computer models have been developed to simulate the noise patterns created by aircraft. Two models are accepted by the FAA’s Office of Environment and Energy (AEE) for use on federally funded airport noise studies – these are the Integrated Noise Model (INM) and the Helicopter Noise Model (HNM). Under the provisions of FAA Order 1050.1E, Change 1, Appendix A, Section 14.4d, noise contours required for various environmen- tal analyses conducted with federal funding assistance must be developed using the INM or HMH. In studies of flight track relocations above 3,000 feet above the ground level, the Noise In Route System (NIRS) model is also acceptable, but generally applied only to work sponsored by the Air Traffic Organization. Other models may be used if prior approval is sought from and certified by the AEE as having results equivalent to those produced by the INM or HNM. For planning evaluations and assessments of environmental effect conducted under federal grant or for federally funded development, the modeling of noise levels is considered more acceptable than the use of measurements for several reasons. Measurements cannot reflect con- ditions that do not exist, i.e., they cannot provide projected noise levels for future years or for 104 Aircraft Noise: A Toolkit for Managing Community Expectations

alternative operating configurations. Furthermore, except for the most sophisticated systems, measurements do not reflect the complete annual condition usually required by planning doc- uments. Modeled noise levels can capture hypothetical cases and alternative conditions that are impractical to measure over any length of time. Computer models can also interpolate the noise patterns across any area, based upon the input provided to the model. Consequently, great care must be taken to the preparation and verification of input data, including flight track locations, types and numbers of aircraft, their distribution through the day, their use of various runways, and the rates at which they climb or descend from the airport. Once these variables are coded and processed, the projected noise levels of individual aircraft may be compared to measured noise levels of similar aircraft flying comparable flight paths to verify the validity of the modeling effort. If not comparable, the input data may be adjusted to provide a better fit with the measured data for individual aircraft. Measured Noise Measurements of single aircraft events, collected with a properly calibrated scientific noise mea- surement instrument in the field, are nearly always more accurate than the computer-modeled noise level—for that same operation, and if the portion of the measured noise attributable to non- aircraft sources is filtered out. Further, Section 14.4f of FAA Order 1050.1E, Change 1, Appendix A, provides that noise measurements are not required in federally funded environmental documents, nor should they be used to calibrate the computer model. To be fully acceptable for inclusion in federally sponsored environmental evaluations, measure- ments should be conducted in accordance with the programmatic guidelines presented in 14 CFR Part 150 guidelines (FAA Advisory Circular 150/5020-1, Noise Control and Compatibility Planning for Airports, FAA, 1983). Notably, measured data is required by state law to be reported in some locations. For example, in California, measurements are required to be reported quarterly to the State Division of Aeronautics under the California Airport Noise Standards (149) Under Section 5032 of the Code; the mea- sured data recorded by sets of permanent noise monitors serves as the basis for noise contour mapping at each airport designated as a “noise problem airport”. Currently, nine large California air carrier airports and Van Nuys Airport are designated to be “noise problem airports”. Aircraft Noise-Based Vibration and Rattle Persons who reside near airports will occasionally comment about vibration or rattle, which they associate with aircraft noise events. When related to aircraft, these phenomena are normally caused by low frequency noise generated during takeoff roll or the application of reverse thrust that is often limited in area to locations near the airport. A recent assessment of the available literature regarding this relationship (150) indicated that there is no generally accepted relationship between low frequency and annoyance. Neither have any studies indicated a causal relationship between low-frequency noise generated by aircraft and structural damage to any buildings off of an airport, although the rattle generated by the low-frequency vibrations may be considered annoying by some persons. Low-frequency noise and rattle was the subject of a recent PARTNER project, the results of which may be found at http://web.mit.edu/aeroastro/partner/projects/index.html. (151) Sound Insulation Programs for Noise Abatement Since early recorded history, the Egyptians and Romans have used cork as a renewable source of thermal insulation for pipes and roofs. What they didn’t realize was that they were also the first 6-8 Noise Management and Public Response 105

humans actually providing sound insulation to their homes. Even back in 1937, The Washington Post published an article stating how insulating materials were being used for thermal and sound insulation. However, it really wasn’t until the 1960s when large jet aircraft became common at commer- cial airports that aircraft noise began to be recognized as a real issue in residential areas around airports. LAX started one of the first airport-sponsored sound insulation programs in 1967. However it really was not until The Aviation Safety and Noise Abatement Act (ASNA) of 1979 that sound insulation programs really started to take off. ASNA permitted the FAA to provide funding noise mitigation projects at airports. One of the first projects in the early 1980s was the treatment of homes near Boston’s Logan International Airport (BOS). FAA funds are provided once an airport has an approved Noise Compatibility Program (NCP), but the FAA will also provide funds for buildings used for educational or medical pur- poses without an approved NCP. A sound insulation program is comprised of several phases including the following: • Startup activities; • Design and implementation phase; • Bid and award phase; • Construction phase; and • Program evaluation. The startup activities include the review of existing program documents, development of a pol- icy and procedures manual, determining the community outreach requirements, reviewing acoustical treatment options, and coordinating with the local jurisdictional agencies and the FAA. The design and implementation phase includes undertaking homeowner outreach, schedul- ing and conducting initial assessment visits, performing pre-construction acoustical testing, eval- uating the mechanical and electrical systems, performing a structural and hazardous materials evaluation, and preparing final bid documents. During the bid and award phase, a pre-bid con- ference is held, along with a pre-bid walk through, followed by a review of bids, and the contract award. In the construction phase a pre-construction conference and walk through is held followed by pre-construction review. Construction begins and work includes construction administra- tion and inspections, followed by contract closeout. The final program evaluation would include post-construction acoustical testing, undertaking homeowner satisfaction surveys, preparation of a final program report, and preparation of the documentation to close-out the FAA Grant. One of the biggest issues facing airports today, with regards to their sound insulation program, is changing DNL/CNEL contours. Many airports have large ongoing programs with the limits defined as part of an approved NCP, some going back to the 1990s. Since that time the airline industry has changed dramatically. Overcapacity and the 9/11 attacks, among other reasons, have caused carriers to cutback and phase out the noisier hush-kitted aircraft. Quieter regional jets became more common and many carriers either went bankrupt or restructured and down- sized due to financial considerations. More recently the high cost of fuel has resulted in sched- ule reductions, further airline bankruptcies, and mergers. The result is that many contours around airports have shrunk dramatically. They are much smaller than the contours upon which the sound insulation program was based in the original NCP. In many cases the FAA is requiring airports to update the noise contours, resulting in smaller sound insulation programs. Where residents were initially in the program, they now fall outside the program limits and the airports have to deal with the public relations fallout as a result of these diminished contours. 106 Aircraft Noise: A Toolkit for Managing Community Expectations

Difference between Interior and Exterior Sound Levels and Methods to Abate Each The abatement of noise inside a structure is largely based on structural modifications to the receiving building, while abatement of noise outside a structure is focused on its source. As a rule of thumb, aviation noise levels are reduced by approximately 15-20 decibels between exterior and interior measurements for well-constructed buildings in the middle latitudes. When windows remain closed year-round or the structure is in higher latitudes and well-insulated to retain heat, the difference between levels may average somewhat higher, while in the tropics or sub-tropics where windows remain open for much of the year, the difference between outdoor and indoor noise levels from an aircraft overflight may be less. Interior Noise Abatement The purpose of a sound insulation program is to reduce the adverse impacts of aircraft noise on residents near an airport. In general, sound insulation programs help to preserve neighbor- hoods and communities, improves homes and neighborhoods, and makes the interior of homes more inhabitable. The major paths for noise transmission into a house in order of importance are: gaps and cracks, windows and doors, and walls and roof. Therefore, the generalized acoustical approach for treat- ment protocols would be to: • eliminate all openings and flanking; • improve all windows and doors; • improve walls and ceilings; • add mechanical ventilation or central air conditioning; and • treat attic spaces and/or roof structures. Windows treatments would include replacing existing windows with single- or double-pane acoustical windows that may include monolithic or laminated glass and also may include a storm window depending upon the noise reduction requirements. Specialty windows such as bay, bow, stained glass, or garden windows are evaluated on a case-by-case basis for treatment requirements. Windows in unfinished attics, attached garages, and unfinished basements are typically not treated, although the windows may be replaced with a nonacoustical window to maintain the similar look on the outside of the house. Door treatments are likely to include replacing existing doors with acoustically rated or solid wood doors making sure the door and frame have good seals and gaskets. Storm doors are added depending upon noise reduction requirements. Specialty doors such as sliding patio doors and French doors also are treated. Doors to basement areas, attached garages and finished attic spaces are usually not treated, while a door to an unfinished attic may be treated. Roof treatments are usually not required in homes with normal attic space although additional batting or blown-in insulation may be added. Hatches to attic spaces may be covered with batt insu- lation and the opening resealed and regasketed. For homes with vaulted or cathedral ceilings, acoustical treatment is evaluated on a case-by-case basis. Additional gypsum board may be added to the interior ceiling in some cases to build up the noise reduction capabilities of the ceiling. Wall treatments are rarely required, except in extremely high noise areas. In those cases, addi- tional gypsum board may be added to the interior walls to build up the noise reduction capabilities of the exterior walls. The HVAC system of each home is also evaluated and treated. Installation may include either a central air conditioning or whole house ventilation system. For homes with a forced air system, a central air conditioning system will be installed as required. Existing furnaces may be upgraded Noise Management and Public Response 107

to accommodate the system if the cost is less than furnace replacement. For homes with a hot water system, the existing boiler system will not be replaced, but a separate condensing system would be installed. Electrical systems will be upgraded as necessary to accommodate the new systems. Kitchen and bathroom vents will be treated as necessary. This may include replacing with a non- recirculating fan, baffling the fan exhaust, or rerouting the ductwork thru a ceiling or attic space. In most cases, roof, gable, soffit, and ridge vents are baffled per standard details to reduce noise infiltration into the house. Exterior Noise Abatement The abatement of noise outside a structure may be accomplished through quieting the source or making it less frequent. These actions may be accomplished through modifications of flight tracks, runway usage programs, changes in aircraft run-up locations or hours, or changes in flight procedures. Of comparable value are noise mitigation actions that manage the develop- ment of noise-sensitive properties in areas exposed to significant levels of aircraft noise. The land itself may be designated for uses that are deemed compatible with aviation noise sources (indus- trial, commercial, agricultural, and open space uses are often selected as the most suitable to accomplish this end). Chapters 7 and 8 of this report discuss a number of opportunities for noise abatement through aircraft operation or land use management. Contour and Impact Area Change Over Time and the Differences Between Federal and Local Response to Change During the years since the introduction of noise contours, the area within the contours of sig- nificant noise exposure (65 DNL) have generally shrunk around airports where its mission and character of its operations have remained unchanged through time. In 2007 the FAA reported that the requirement of increasingly more restrictive 14 CFR Part 36 noise level requirements during the last quarter of the 20th century resulted in a reduction of the number of persons within the 65 DNL contour around the nation’s airports by 90 percent between 1975 and 2000. When the last of the Stage 2 jets were retired from the United States continental fleet at the end of 1999, the population within the 65 DNL pattern at U.S. airports was estimated to have been reduced from over 7 million to less than 700,000. Subsequent information suggests an additional reduction of approximately 27 percent from year 2000 levels, or to less than 500,000 today. (More is available at: http://www.faa.gov/about/plans_reports/Performance/quarter_scorecard/media/ Noise%20Exposure%20Detail.pdf) Even though the number of large aircraft operating today is much greater than was present more than 30 years ago, the patterns of significant noise levels have been reduced through a combina- tion of improvement in aircraft design, engine design, flying techniques, and air traffic actions. The reductions are being maintained through the management of land uses in areas exposed to high noise levels to assure that the risks to the continued operation of the nation’s airports remains low. Federal Response With the gradual shrinking of the noise exposure patterns of 65 DNL or more has been the reduction of the area in which the FAA will fund land mitigation programs. The FAA has made it a practice to limit its funding of acquisition and sound insulation programs to areas within the 65 DNL contour, often prioritizing such programs to mitigate the most severely (loudest) affected areas first. Consequently, some programs implemented in areas around large airports find that by the time the schedule of improvements has reached the outlying program areas, the noise levels are no longer sufficiently high to justify the mitigation action because the contours have shrunk. 108 Aircraft Noise: A Toolkit for Managing Community Expectations

More recently, the FAA has become more rigid in its evaluation of noise abatement proce- dures for the ability to mitigate noise impacts within the 65 DNL contour. For example, a mea- sure may have the substantial benefit of removing low level overflights from a residential area just beyond the 65 DNL contour if the traffic that created those overflights were turned 15 degrees away from the runway heading. Although many might benefit at a level just below 65 DNL and experience many fewer direct overflights, the measure may not be justified if one addi- tional person is exposed to 65 DNL or more as a result of the turn. This situation has been the crux of the evaluation arguments on a number of Part 161 study cases that have been presented to the FAA for review. Local Response The reduction of the size of the 65 DNL contour has led communities into a dilemma of land management and compatibility controls. Two principal ways this has occurred have been through 1) the modification of public expectations for sound insulation programs for those who were within the contour of definition at some time in the past and have come to believe they are entitled to sound insulation that will “fix up” their homes; and 2) the release of areas of vacant and undeveloped land from within the controlled contour area that becomes either eligible for development of, or much more difficult to justify the prevention of, noise-sensitive uses. In the first case, and depending upon the number of units that remain to be sound insulated, airports may choose to continue a preexisting program at their own expense or abandon the pro- gram for those areas that no longer are eligible for federal reimbursement. When programs are abandoned, there is usually a public relations crisis and hard feelings develop that may continue for years. It is usually a better practice to publish only the programmatic boundaries of sound insulation programs that are actively underway and to emphasize in every news release about the program that additional areas may be added as federal funding becomes available. Should the airport sponsor choose to continue a program beyond the 65 DNL contour, only limited federal funding for immediately contiguous areas may be available and the bulk of the excess cost will fall on the sponsor. In the second case, land that has been prevented from incompatible development, but is sub- sequently removed from within the 65 DNL contour by area shrinkage, will often become the focus of new opportunities for the development of noise-sensitive uses. Around many airports, residential developers build up to the contour line. When the contour line retracts, proposals often soon follow to develop additional new residential lands to the new contour line, and so forth. Then, if the character of the airport changes, or if only a couple of new nighttime opera- tions by loud aircraft are introduced, the contour may expand and the new residential develop- ment is again within the contour and the airport often faces a public relations crisis of increasing noise over residential areas and public demand for abatement. Two widely used controls avail- able to the airport to manage this situation are either outright ownership of all the land within the larger 65 DNL contour, or public land use jurisdictional control for non-noise sensitive uses within an area surrounding the 65 contour for the expected worst case condition. Self Assessment Tools for Noise Management Programs As airport managers face the question of whether or not to implement a noise management program, or if one is in place, what its status may be, it is helpful to have an organized way to think through the issues. The preceding sections have provided an overview of the rules, the roles, the responsibilities, and the issues involved in noise abatement and land use mitigation planning efforts, and have discussed the involvement of the public in those efforts. This section Noise Management and Public Response 109

provides two checklists that airport managers may use in 1) assessing the usefulness of establish- ing such a program if one does not exist, or 2) evaluating the status of an existing program. Evaluation Checklist for Airports without Noise Programs Those airport managers that have not previously had the need to engage with the public regard- ing aircraft or airport noise issues may not have a clear understanding of the issues. New noise management programs are often the result of pressure generated by the local political process at the urging of outspoken members of the public. Although their governance structures differ, both public and private airports must be sensitive to public pressure manifested through the political process. The tool included in this section provides an overview to the manager of an airport with- out a noise program in 1) is a program advisable; and 2) what information is needed to consider the approach to initiating a program? Evaluation Checklist for Airports with Established Noise Programs Airports with well-established noise programs are usually aware of their level of success in see- ing its components implemented. Airports with permanent noise officers or staff address public inquiries on a daily basis, provide status reports on the success or failure of their programs, and act as a conduit between higher management and the surrounding community. However, the level of commitment to noise program management, its funding, and its responsibilities varies widely among those airports that have addressed aircraft noise issues. The checklist tool provided in this section allows the airport noise officer or airport manager to evaluate the status of the existing program and changes that may have occurred since the program was initiated to determine if modifications or updates are warranted. 6-10 6-9 110 Aircraft Noise: A Toolkit for Managing Community Expectations