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OCR for page 95
Noise Management and Public Response 95 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

OCR for page 95
96 Aircraft Noise: A Toolkit for Managing Community Expectations Table 6-1. Authorities and responsibilities of parties. Authorities and Responsibilities of Parties Noise Abatement FAA - All divisions Opportunity United States Congress except Air Traffic FAA - Air Traffic Control State Government Authority to establish Establish environmental Must prepare environmental Must manage for the safe and May establish state noise abatement actions policy in accordance with guidance, regulations and expeditious flow of air traffic. requirements to monitor through operational national priorities. May standards to meet Prepares environmental noise levels or evaluate a change legislate to specific goals Congressional policy. reviews on airspace and change of environmental for noise abatement Prepares environmental flight procedure modifications noise associated with reviews on federal proposed action development actions at airports Loudness of individual Set general policy for aircraft Sets standards by size and None None aircraft airframe and noise levels and compatibility number of engines for landing engine design and takeoff noise Location of takeoff routes None Advise on environmental and Establishes and manages Usually none. Some states operational consequences of routes in accordance with may require assessment route revisions requirements for safety and of environmental efficiency of flow consequences of changes Location of arrival routes None Advise on environmental and Establishes and manages Usually none. Some states operational consequences routes in accordance with may require assessment of route revisions requirements for safety of environmental and efficiency of flow consequences of changes Steepness of climb None Flight standards and Assure proper separation None Noise Abatement Actions or descent certification may have a role between climbing and in approval of procedures descending traffic and with surface structures and topography Reduction of power or None Flight standards and Assure proper separation None thrust settings during certification may have a role between climbing and takeoff or landing in approval of procedures descending traffic and with (including reverse thrust surface structures and and cutbacks) topography Selection of runway None Advise on environmental and Assign runways in accordance None operational consequences of with wind and operating route revisions standards Time of activity (curfew) Establish criteria for Review and/or approve or None None implementation of deny restrictions on activity access restrictions times Limits on flight operations Establish criteria for Review and/or approve or deny None None (number of flights or noise implementation of access restrictions on activity times budget or aircraft type restrictions proposed by airport restrictions) Ground run-up None None Assign aircraft to preferred None location and timing run-up location Construction of new May provide funding Must review and approve Review to assure the May participate in funding. on-Airport facilities authorizations through modifications to Airport proposed action does May require completion of for noise mitigation the AIP process or through Layout Plan through the not degrade safety. state environmental line-item funding in environmental review Modify operating plan to documentation prior to legislation process prior to construction. incorporate new facilities, construction May participate in funding if applicable effort if eligible under Airport Improvement Program

OCR for page 95
Noise Management and Public Response 97 Authorities and Responsibilities of Parties Local Government Airport Owner or Operator Aircraft Operators Aircraft Manufacturers Jurisdictions Airport Neighbors May request change of FAA Operate aircraft safely and in Must manufacture aircraft to Communities may establish None Air Traffic management accordance with federal flight meet established guidelines controls on ground activity, procedures, through Part 150 standards. for weight and number of but are preempted from or other action. May control engines jurisdiction over aircraft in flight noise of aircraft not in flight or during landing or takeoff or on runway None Maintain aircraft to continue Design and construct aircraft None None to meet standards to achieve certification standards set by federal regulation May advise and request IFR fly routes assigned by None None None modifications to routes for ATC. VFR fly where desired noise abatement assuring separation from other traffic May advise and request IFR fly routes assigned by None None None modifications to routes for ATC. VFR fly where desired noise abatement. May add assuring separation from number of routes through other traffic improved instrumentation for landing May request changes Fly to procedures set by FAA None None None for noise abatement and within capabilities of aircraft May request changes Develop and train on Publish information about None None for noise abatement standardized procedures aircraft capability for use within capabilities published by operators by manufacturers May request from FAA-ATCT Operate in accordance with None None None a preferential runway use assigned runway from program for noise abatement. FAA-ATCT. Pilot may request a different runway. May propose limits on time None None None None (curfews) of operation to FAA May propose limits on numbers None None None None of operations or restrictions on aircraft types to FAA for review and approval/denial Authorized to establish run-up Operate in accordance with None Communities may establish None rules and criteria, to include established rules "at the fence" noise standards times, bearings and thrust for ground activity, but must apply the standards to non-aviation activity as well. Propose, design, and construct Use operational facilities as None Review and modify if Review, comment on, as approved by FAA. assigned by FAA ATCT appropriate land use policies and discuss proposed Provide local funding required. upon completion. in areas that may become development plans Maintain on completion. impacted by newly introduced during environmental or increased aircraft review process. noise levels Consider resulting noise levels in home purchase deliberations (continued on next page)

OCR for page 95
98 Aircraft Noise: A Toolkit for Managing Community Expectations Table 6-1. (Continued). Authorities and Responsibilities of Parties Noise Abatement FAA - All divisions Opportunity United States Congress except Air Traffic FAA - Air Traffic Control State Government Mitigation actions within Establish funding priorities Interpret Congressional action Review proposed actions Within the state, establishes various noise levels to designated levels of to prioritize proposed mitigation requiring modification of flight priorities for noise abatement Day-Night Average Sound actions requiring funding. procedures or runway use to activities and sets bounds Level (DNL) Reviews and denies or assure safety and continued for statewide standards of Noise Metric Selection approves EIS, Part 150 and efficiency of operation noise sensitivity Part 161 program actions requiring federal participation Noise metric used Authorized FAA to select Established DNL as the Follows FAA policy on suitable Within the state, may select suitable metric for the acceptable metric to describe metrics additional metrics that are description of aircraft noise aircraft noise, based on required for airport annoyance. Reviews on a assessments case-by-case basis the acceptability of supplemental metrics for planning Land use planning None Recommends appropriate land None Within the state, may uses compatible with airport establish goals for land use operations and noise based on compatibility and require DNL noise levels efforts to achieve mitigation through planning, acquisition or remedial treatment. May require periodic reporting of achievements or changes in noise exposure levels Land acquisition for None May fund part of the acquisition None May require completion of noise abatement cost if included in an approved state environmental Part 150 Noise Compatibility documentation prior to Program or as mitigation in an acquisition Land Use Management Actions approved EIS Zoning for compatible None None None May provide statewide land use guidance for compatibility, and methodology for zoning coordination Residential density control None None None Typically, none through subdivision design Modify building codes to None None None Typically, none improve sound insulation on construction Sound insulation of None May fund part of the program None Typically, none existing structures cost if included in an approved Part 150 Noise Compatibility Program or as mitigation in an approved EIS Noise level disclosure None None None May require notifications within given noise levels or distances from airport

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