rI IiI

Eligibility of Noise

0Abatement Proposals foruSD, Grants-in-aid under theFO-,,d M*3*MAirport Improvement

Program

0

DTICELECTEFEB 2 719EUs~;D

DOT/FAA/PP-89-2 January 1989 Report of the Administratorof the Federal AviationAdministration to the UnitedStates Congress pursuant to

DISTRIBUiTIt N StA I ENTA Section 301 (e) of PublicApprov r tt public recxs Law 100-223

IIIrbuto III I II

Technical Report Documentetion Poge

1. Reort No. 2. Gevotmenf Access.on No. 3. Rocsev n'.s Catia g N.

DOT/FAA/PP- 09- 2

4. Title en" S.61,04 5. Rep.rt Dee.

January 198'Eligibility of Noise Abatement Proposals 6. P.,fo-.ng DO.se .een Coefor Grants-in-aid under the Airport APP-510Improvement Program is. Perfem,- OgOni, to Report, No.

7. Auteo' a?Ellis Ohnstad pp-89-2

9. Poief,ming Orgaeiation Name end Address 10. Work Un-t No (TRAIS}

Federal Aviation AdministrationOffice of Airport Planning and Programming 11. Contracte, GraetNo.800 Independence Avenue, 8. W.Washington, DC 20591 13. Type of Report end Peried Coeored

12. 5priOsoaing Agency Name nd Address Report to Congress - Coversairport noise compatibilityproject eligibility for grants

14. Spn.rr.ng Agency Code

15. SePoletmetery Notes

16. Abetract

This report is in response to the requirement in section 301(e)of the Airport and Airway Safety and Capacity Expansion Act of1987 (Public Law 100-223). The Federal Aviation Administrationwas directed to study noise abatement proposals by airport oper-ators and local governments, to identify those proposals whichare ineligible for grant-in-aid assistance under existing laws oradministrative policies, and to recommend whether such laws andpolicies should be modified to make such proposals eligible forFederal assistance.

, 4> This report summarizes the provisions of existing Federal laws,

regulations, administrative policies and grant program procedureswhich relate to funding of noise abatement projects. The reportalso presents historical data on Federally assisted noise compat-

ibility projects and funding levels in fiscal years 1982 - 1987.A literature search was conducted and parties involved with air-port noise compatibility planning and project implementation wereconsulted to identify proposals which are currently not eligiblefor grant assistance and the reasons for their ineligibility.The report concludes with recommendations to make eligibilitycriteria more flexible and to provide clearer guidance to partiesinvolved vith noise compatibility project formulation, evaluationand implementation.

17. Key Weids 1s. Distibtlon Stesement

Airports,?Airport Noise, Land Use Availability unlimited. Document

Compatibility, Airport Noise Com- may be released to the Nationalpatibility Programs, Noise Abate- Technical Information Service,ment, and Airport Improvement Springfield, VA 21151, for sale

program Grants to the public.i*,- -,-,,.I.-,N..---' Pug,Unclassified IUnclassified 1 25

Form DOT F 1700.7 0-72) Iterdvat" of completed page owherled

TABLE OF CONTENTS

Page

I. EXECUTIVE SUMMARY ....... .............. 1

II. EXISTING STATUTORY AUTHORITY AND

ADMINISTRATIVE POLICIES ..... .......... 2

- Aviation Safety and Noise Abatement Act . 2

- Title 14, Code of Federal Regulations,Part 150 . . . .................. 4

- Airport and Airway Improvement Act . . .. 6

- Federal Aviation AdministrationOrder 5100.38 ........ ............... 7

III. NOISE COMPATIBILITY PROJECTS FUNDEDUNDER THE AAIA ....... .............. 9

IV. NOISE ABATEMENT PROPOSALS UNDER CONSIDERATIONBY AIRPORT OPERATORS AND LOCAL GOVERNMENTSWHICH ARE NOT CURRENTLY ELIGIBLE FORFEDERAL ASSISTANCE ... ............ 11

- Specific Noise Abatement Proposals . . . . 12

- Noise Abatement Proposals Groupedby origin or Type ... ......... ... . . 17

- Proposals to Revise the Noise LevelCriteria used to Determine Eligibilityfor Certain Noise Abatement Measures . . . 22

- Proposal to Expand and ClarifyExisting Guidance .... ............. . 24

V. RECOMMENDATIONS ..... .............. 24

FEDERAL AVIATION ADMINISTRATION

REPORT TO CONGRESS

ELIGIBILITY OF NOISE ABATEMENT PROPOSALSFOR GRANTS-IN-AID UNDER

THE AIRPORT IMPROVEMENT PROGRAM

I. EXECUTIVE SUMMARY.

Section 301(e) of the Airport and Airway Safety and CapacityExpansion Act of 1987 (1987 Act) directs the Federal AviationAdministration (FAA) to conduct a study of noise abatement pro-posals under consideration by airport operators and local govern-ments. The purpose of the study is to identify those proposalswhich are not currently eligible for Federal assistance becauseof existing law or administrative policy and to determine whetheror not such proposals should be made eligible for funding. TheFAA is further directed to report to Congress on the results ofthe study and to recommend whether existing law and administra-tive policy should be modified to make additional noise abatementproposals eligible for Federal assistance.

Eligibility determinations related to noise compatibilityprojects are based on Federal laws, regulations, administrativepolicies and procedures, and technical criteria. These providesufficient authority and flexibility to provide financial supportto a broad variety of noise abatement proposals. Nearly $425million was issued in grants to implement noise compatibilityprojects in fiscal years 1982 through 1987. About 90 percent ofthose funds were used for acquisition of noise impacted propertyor for sound insulation of residences and public buildings. Theremaining $38.6 million was granted for other projects rangingfrom construction of noise abatement runways to revision ofbuilding codes.. An additional $17 million was used to assistairport operators in conducting noise compatibility planning.

Noise abatement proposals evaluated in this report wereidentified by reviewing House of Representatives Report 100-123,by reviewing noise compatibility programs prepared by airportopeLators, and by consulting with parties active in airport noisecompatibility planning and project implementation. Such propos-als may have been disapproved in conjunction with formal noisecompatibility programs or in connection with other initiatives toreduce adverse noise impacts, or they may never have been submit-ted for any formal FAA review.

This study found that many noise abatement proposals wereineligible for Federal assistance because: they involved nocapital costs, they could not be implemented by an eligible grant

2

recipient, or they were not approved noise abatement measures ina noise compatibility program prepared by an airport operator.

This study recommends that, for the benefit of airportoperators and residents around airports,the FAA should revisecertain administrative policies and technical criteria used toevaluate noise abatement project eligibility. In addition,better guidance should be developed to assist all parties in-volved in formulating and evaluating noise abatement proposals.The study makes the following specific recommendations:

- sound insulation projects may include the installation ofair conditioning, subject to a limitation on allowable costsequivalent to that for a positive ventilation system;

- allow limited exceptions to the noise exposure criterionused to determine eligibility for noise insulation projects;

- revise guidance on the interior noise level criterion usedto determine eligibility for noise insulation;

- adopt the findings of a concurrent FAA study regarding amore comprehensive review of noise compatibility planning todetermine whether an alternative interior noise measurementsystem should be used to determine the eligibility and scopeof noise insulation proposals, and revise eligibilitycriteria accordingly; and

- revise, expand, and clarify guidance to FAA field offices oneligibility criteria to facilitate evaluation of noiseabatement proposals.

All of these recommendations can be implemented by the FAAunder the authority of existing laws and regulations.

II. EXISTING STATUTORY AUTHORITY AND ADMINISTRATIVE POLICIES.

The authority, policies, criteria and procedures governingFAA determinations and actions related to noise compatibilityprograms and project implementation are found in Federal laws andregulations, and in FAA directives. The relevant provisions ofthese documents are discussed briefly below.

Aviation Safety and Noise Abatement Act.

The Aviation Safety and Noise Abatement (ASNA) Act of 1979is the principal law supporting Federal efforts to identify andreduce noncompatible land uses around civil airports in theUnited States. It established, or cause" to bc cstablished,standardized terms and measurement systems to describe aviationnoise and to identify compatible land uses around airports. In

3

addition, it is the principal catalyst for airport noise compat-ibility planning and for implementation of noise abatement pro-posals recommended in those plans.

Section 102 of the ASNA Act required the FAA to establish,by regulation, standard terms and definitions related to certaincivil airport noise and land use compatibility issues. Specifi-cally, the FAA was directed to:

(1) establish a single system of measuring noise at airportswhich reliably relates various noise levels with thereactions of people to noise;

(2) establish a single measurement system to determine theexposure of individuals to noise resulting from airportoperations which incorporates noise intensity, duration,frequency and time of occurrence; and

(3) identify land uses which are normally compatible withvarious noise exposure levels.

One of the main features of the ASNA Act is that it permitsan airport operator to prepare noise exposure maps which describethe existing and forecast noise exposure levels and which iden-tify noncompatible land uses around the airport. An airportoperator who has submitted a noise exposure map and related in-formation to the Secretary of Transportation may also submit anoise compatibility program (NCP). The NCP sets forth the meas-ures which the airport operator has taken or proposes to take toreduce existing noncompatible land uses and to prevent the intro-duction of additional noncompatible land uses within the areacovered by the noise exposure map. The ASNA Act notes that suchmeasures may include, but are not limited to:

- preferential runway systems;

- airport use restrictions;

- noise barriers and acoustical shielding, includingsoundproofing;

- noise abatement flight procedures; and

- acquisition of land and interests therein.

The ASNA Act also directs the Secretary to approve any such C3NCP (other than those measures related to flight procedures fornoise abatement) if the measures to be undertaken meet certainstatutory criteria. The Administrator is authorized by the ASNAAct to approve or disapprove noise abatement flight procedures,and the Secretary has delegated authority to the Administrator toapprove other measures in the NCP.

.i.. .,t I I I I I I I

4

In addition, the ASNA Act authorizes the issuance of grantsto prepare noise exposure maps and NCP's and for any project tocarry out approved noise compatibility program measures. Noisecompatibility planning grants may be made only to eligible air-port operators. Grants to carry out noise compatibility projectsmay be made to airport operators and to units of local governmentin areas surrounding such airports if the FAA determines thatthey have the capability to carry out those projects.

Grant authority was also extended to projects in an NCPwhich was prepared prior to the enactment of the ASNA Act or thepromulgation of its implementing regulations. Such a prior pro-gram must be determined to be substantially consistent with thegoal of reducing noncompatible land uses and to further thepurposes of the Act. The 1987 Act also authorized the FAA toissue grants for noise insulation projects in public buildingsused primarily for educational or medical purposes without thepreparation of a noise compatibility program if they aredetermined to be adversely affected by airport noise.

Title 14. Code cf Federal Regulations Part 150.

Designations of noise measurement systems, compatible landuses, and policies and procedures for evaluating noise exposuremaps and noise compatibility programs are contained in Title 14,Code of Federal Regulations, Part 150. The regulation designatesthe systems to be used for measuring noise and for calculatingnoise exposure, and it establishes a uniform methodology for thepreparation of airport noise exposure maps which includes use ofthose systems. Part 150 also provides for the use of computermodels to develop standardized noise contour maps depicting noiseexposure levels around an airport, and it designates which ofseveral land uses are compatible and noncompatible with variousnoise exposure levels.

After thorough study and interagency and intergovernmentalconsultation, the FAA designated the standard system for airportnoise measurement to be the A-weighted sound pressure level indecibels (dBA). The dBA measurement system has generally beenaccepted as one which has a highly reliable relationship betweenprojected noise exposure and the surveyed reactions of people tonoise. In addition, it has long been an established term in thenoise measurement field, is commonly used by experts in describ-ing the intensity of individual noise events, and is easilyunderstood by the general public.

Similar study and consultation preceded the selection of anoise measurement system for determining the exposure of indi-viduals to airport noise. It was concluded that the long rangeeffects of exposure to airport noise correlate well with severalcumulative noise exposure measures. Each of these provides asingle number which is equivalent to the cumulative acoustical

u u l u n l l l l l l I I

5

energy associated with fluctuating sound levels over a specifiedtime period.

The unit selected to represent the time and energy compo-nents of cumulative noise exposure is the day-night sound level(Ldn). Ldn is the 24-hour average sound level, in A-weighteddecibels, obtained after the addition of ten decibels to soundlevels occurring between 10 P.M. and 7 A.M. The purpose of theten decibel penalty is to account for increased annoyance tonoise during late night and early morning hours. Yearly Ldn, theaverage day-night sound level over 365 consecutive days, is thestandard measurement system used to describe noise exposure ofindividuals around airports and to designate compatible andnoncompatible land uses around the airport.

Designation of the noise systems described above dependedlargely on easily quantifiable acoustical factors such asmeasurable sound energy, duration, and the sound attenuationvalues that various construction materials provide for buildingoccupants. Identifying land uses which are compatible with vari-ous noise exposure levels, however, is less precise because thereare several qualitative nonacoustical factors which must be con-sidered. These include the type of human activity associatedwith specific land uses, the differing responses of individualsto the same noise environment, individual attitudes about thenoise source, the extent to which an activity is disturbed ordisrupted by various noise levels, the cost of achieving loweraverage sound levels, and other factors.

The adverse impacts of aviation noise on land use have beenstudied extensively by several Federal agencies, foreign govern-ments and independent researchers. The specific impacts studiedinclude the effects of noise on speech intelligibility, annoyanceand interruption of human activities, including sleep disturb-ance. Following exhaustive review of the existing research andthorough intergovernmental and interagency consultation, the FAAdeveloped generalized land use categories and designated which ofthose land uses are normally compatible with various noise expo-sure levels. These land use designations incorporate the resultsof numerous statistical surveys involving the reactions of largegroups of people to noise. They may not, however, accuratelyrepresent the reaction of a particular individual to an actualnoise environment.

Under Federal land use guidelines contained in Part 150, allland uses are considered to be compatible with noise levels lessthan 65 Ldn. Residential land uses and places of public assembly(hospitals, schools, churches, etc.) are generally considered in-compatible with noise levels of 65 Ldn or more. (As a frame ofreference, noise exposure in an urban residential environmentwith no recurring disruptive noise events is approximately 60Ldn; the noise exposure level adjacent to a very busy commercial

6

airport may exceed 85 Ldn.) Commercial, recreational and indus-trial land uses are considered less noise sensitive, i.e., theyare compatible with higher noise exposure levels. These desig-nations, however, do not constitute a Federal determination thatany particular land use is acceptable under Federal, state orlocal law. Final land use determinations rest with localofficials.

In addition, Part 150 incorporates the statutory criteriaset forth in the ASNA Act and used by the FAA to evaluate NCP'sprepared and submitted by airport operators. The Administratorapproves noise compatibility programs, or portions of programs,if they are consistent with the following criteria:

- the program measures are reasonably consistent withachieving the goals of reducing existing noncompatible landuses around the airport and of preventing the introductionof additional noncompatible land uses;

- the program measures would not reduce the level of aviationsafety, would not derogate the requisite level of protectionfor aircraft, their occupants and persons and property onthe ground, would not adversely affect the efficient use andmanagement of the national airspace;

- the program measures, if implemented, would not create anundue burden on interstate or foreign commerce;

- the program measures are not unjustly discriminatory;

- the program measures, to the extent practicable, meet bothlocal needs and needs of the national air transportationsystem, considering tradeoffs between economic benefitsderived from the airport and the noise impact;

- the program provides for its revision if made necessary by arevision of the noise exposure map; and,

- the program measures would not adversely affect any otheipowers and responsibilities of the Administrator prescribedby law or any other program, standard or requirementestablished in accordance with law.

Airport and Airway Improvement Act.

While the ASNA Act authorizes the issuance of grants fornoise compatibility projects, the enabling legislation for allsuch grants, in addition to airport planning and developmentgrants, is the Airport and Airway Improvement Act of 1982 (AAIA).The AAIA originally required that at least eight percent of thefunds made available in any fiscal year for airport planning anddevelopment be obligated during such fiscal year for airport

7

noise compatibility planning and projects. The 1987 amendmentraised this provision to ten percent. From 1982 through 1987,the total amount required to be set aside for noise compatibilityplanning and projects was slightly more than $371 million. Infiscal years 1988 and 1989, those amounts are $127 million and$140 million, respectively.

Federal financial assistance for airport planning, airportdevelopment, and noise compatibility projects is available toairport operators and units of local government as authorizedunder the AAIA. The Federal share of allowable costs for noisecompatibility planning is the same as allowed for an airportdevelopment project at that airport under the AAIA. The Federalshare for noise compatibility projects was originally set by theASNA Act at 80 percent. That provision was modified by the 1987Act to be either 80 percent or the Federal share which would beapplicable to a development project at that airport, whichever isgreater.

Eligible noise compatibility projects include elements of anFAA-approved noise compatibility program or prior program underthe ASNA Act. Funds granted for such projects are creditedagainst the ten percent "set-aside" noted above for noise com-patibility planning and projects. As noted above, the 1987 Actalso authorizes the FAA to provide funds to soundproof schoolsand hospitals which are determined to be adversely affected byairport noise. These specific soundproofing projects are notrequired to be included in a Part 150 or prior noise compati-bility program. (Projects to mitigate the environmental impactsof airport development are also eligible for assistance under theAIP when they are included as mitigation commitments in an envi-ronmental impact statement or a finding of no significant impact.Grant funds issued for such projects, however, are not creditedto the ten percent set-aside specified for noise compatibilityprojects.)

Federal Aviation Administration Order 510C.38.

Formal guidance on the eligibility of prospective granteesand all projects under the AAIA, including those for noise com-patibility, is contained in FAA Order 5100.38, Airport Improve-ment Program (AIP) Handbook. The AIP Handbook borrows languagefrom the ASNA Act which states that all provisions applicable togrants for airport development projects under the AIP are alsoapplicable to grants for noise compatibility projects, unlessthey are determined to be unnecessary or inconsistent with thepurposes of that Act. Such provisions are based on policies andregulations applicable to all Federal departments and agencies,and on legislation addressed specifically to aviation and othertransportation programs. Provisions applicable to projecteligibility and allowable costs for all projects under the AAIAinclude, but are not limited to, the following requirements:

M' , l I I I

8

- the project is reasonably consistent with plans of planningagencies for development in the area;

- the project will be completed without undue delay;

the project does not involve construction, alteration orrepair of public parking facilities for passenger auto-mobiles, aircraft hangers, or any part of an airportbuilding unless specifically identified as eligible;

- completion of the appropriate environmental process for thescope and nature of anticipated environmental impacts;

- costs must be necessary for accomplishment of the projectand they must be in conformity with plans and specificationsand other grant documents and conditions;

- costs must be determined to be reasonable;

- costs must be incurred after the date of execution of thegrant agreement, except project formulation costs;

allowable project costs may include costs attributable tomaster planning and noise compatibility planning, relatedconsultant studies, purchase of certain equipment andfacilities, construction, and similar one-time capitalinvestments; and

- costs related to personnel training or to operation andmaintenance of airport or noise compatibility facilities arenot allowable costs for grants under the AAIA.

The AIP Handbook also contains more detailed eligibilitycriteria for noise compatibility projects. For example, a pri-mary requirement applicable to such projects is that they be lo-cated in areas where the noise exposure attributable to airportoperations is 65 Ldn or more, consistent with Federal guidelineson compatible and noncompatible land uses. In addition, projectsin higher noise exposure areas (i.e., 75 Ldn or greater) areaccorded higher priority than those where noise exposure is less(i.e., 65 to 75 Ldn).

Current eligibility criteria for noise insulation projectsare based in part on research which indicates that, where outdoornoise levels are 65 Ldn or more, residential structures shouldprovide 20 decibels or more noise level reduction for residents.Normal residential construction techniques provide about 20 deci-bels of reduction from outside to inside, so, in areas where theexterior noise exposure levels are less than 65 Ldn, residentialuses are generally considered compatible without additional noiseattenuation. Research has also demonstrated that most people donot perceive a change in the noise environment that is less than

9

five decibels. Consequently, the interior noise level thresholdfor residential noise insulation projects has been set at 50 Ldn,and the project should be designed to reduce that level by atleast 5 decibels.

Noise insulation proposals for noncompatible schools andsimilar public use buildings where noise exposure is 65 Ldn ormore are evaluated on the basis of the interior single eventnoise levels because such buildings are generally not used duringnighttime hours, and because oral communication is essential toachieving the purpose for which the buildings are intended. Anaverage sound level of 45 dBA, with a single event maximum of 55dBA, is the nominal design objective, and, as with residences, anadditional 5 decibels is added to establish the thresholdcriterion for eligibility.

III. NOISE COMPATIBILITY PROJECTS FUNDED UNDER THE AAIA.

Prior to 1980, the FAA was authorized to issue grants fornoise projects only for land acquisition and noise compatibilityprojects located on the airport. Consequently, although approxi-mately $99.26 million was issued in grants to implement noisecompatibility projects from fiscal year 1976 through 1981, allbut $1.03 million was for land acquisition. The ASNA Act expand-ed that eligibility dramatically by authorizing the issuance ofgrants to implement any noise abatement measure in an NCP pre-pared by an airport operator and approved by the FAA under Part150.

As a result of the expanded grant authority and the emphasison comprehensive study under the ASNA Act, noise abatement propo-sals have become much more innovative and diverse. Most NCP'sprepared by airport operators now include actions to reduce noiseat the source (the aircraft), actions to change the design oroperation of the airport, and construction or land use changesoff the airport to eliminate noise sensitive land uses or tomitigate adverse noise impacts. Specific noise compatibilitymeasures may be implemented by regulatory or administrativeaction (noise-based landing fees, revised flight tracks, etc.),through construction (a new runway or structural sound insula-tion), or by purchase of equipment or property.

It should be emphasized that prior to the ASNA Act, localgovernment units which were not airport operators were not eli-gible to receive grants for noise compatibility projects underthe AAIA. Under the ASNA Act, however, entities such as publicschool districts, hospital districts, municipalities and countieswhich do not operate airports may sponsor and implement approvednoise compatibility projects with Federal assistance. Over $10million has been issued in grants to such local government unitssince this innovative provision was adopted.

10

During fiscal years 1982 through 1987, 320 grants wereissued under the AAIA for projects to carry out approved measuresin noise compatibility programs or prior programs. Funding forthese projects was in excess of $424.6 million. This is in addi-tion to approximately $17 million for noise compatibility plan-ning at 136 airports. Total Federal funds issued for noisecompatibility planning and projects during that period were$441.6 million. That is approximately 9.15 percent of theaggregate amount available for obligation under the AAIA, andabout $70 million more than the statutory requirement. Generalproject categories and total funding in each category are asfollows:

Project CateQory Funding (million)

Acquisition of land or interests $327.64in land and associated relocation

Sound insulation of dwellings and 58.38public buildings

Runway and taxiway construction, including 30.22associated land acquisition, lighting andnavigational aids

Noise monitoring systems and equipment 4.89

Noise barriers 2.26

Miscellaneous 1.23

Total $424.62

Acquisition of noise impacted properties allows the airportoperator or another local government agency to eliminate resi-dential and other noncompatible land uses from areas of signifi-cant noise exposure. Subsequent disposal of those properties,while retaining an avigation easement or a similar land interestwhich allows overflights and their related noise, can ensure con-tinued compatibility without limiting activity at the airport.More than three-quarters of the AIP funds used for noise compa-tibility projects in the 1982-1937 period were for acquisition ofland or interests in land and relocation assistance to residentsand businesses. The Inspector General, Department of Transporta-tion, has raised issues concerning the effectiveness of landacquisitions in reducing noncompatible use of noise impactedareas. Recommendations in that report are under review.

An alternative that has been recommended frequently in areaswhere local officials and residents determine that noise levelsare significantly high, but that land use patterns should notchange, is the insulation of structures to reduce interior noise

11

levels. Residences, schools, hospitals, and some other publicuse buildings may be eligible for grants under the AAIA for suchnoise insulation projects. About 14 percent of all funding fornoise compatibility projects from 1982 through 1987 was for soundinsulation of dwellings and other structures.

The third major project category, runway and taxiway con-struction, accounted for an additional seven percent of the noisecompatibility project funds during the 1982-1987 period. (Theseprojects also include associated work, such as land acquisitionneeded for construction, lighting, and connecting taxiways.)Implementation of these projects results in shifting noise awayfrom sensitive land uses toward more compatible areas.

Approximately two percent of the noise compatibility projectgrant funds issued during this period was for projects other thanthose described above. These include noise monitoring equipment,noise barriers, and a variety of innovative projects such asground marker lights to help aircrews follow an approved visualnoise abatement track at night, area-specific planning studies,development of a noise attenuation section of local buildingcodes, and transaction assistance.

Transaction assistance involves noncompatible residentialland use in areas where local government officials have deter-mined, through consultation with all affected parties, that theresidential use will be continued. That local land use determi-nation is coupled with a program to help existing occupants selltheir homes and move out of the area. The assistance may takeseveral forms, but most often involves payment of sales costs forthe seller. The end results are that the existing occupant isable to sell and move from a noise impacted area, the new owneracquires the property with full disclosure of the noise environ-ment, and the airport operator retains an avigation easement overthe property to permit continued overflights and their attendantnoise. In most cases, sound insulation is installed in thehouses prior to reoccupancy.

IV. NOISE ABATEMENT PROPOSALS UNDER CONSIDERATION BY AIRPORTOPERATORS AND LOCAL GOVERNMENTS WHICH ARE NOT CURRENTLY ELIGIBLEFOR FEDERAL ASSISTANCE.

Information about noise abatement proposals which arecurrently not eligible for Federal assistance was obtained fromseveral sources. First, those measures specifically cited inHouse of Representatives Report 100-123 were evaluated to deter-mine whether they are eligible, and if not, whether they shouldbe. In addition, officials at several airports, including eachof those named in the House Report, were contacted to invitetheir suggestions on innovative noise abatement concepts whichshould be eligible for Federal assistance.

12

Next, all Part 150 noise compatibility programs submitted tothe FAA were screened to identify those measures proposed byairport operators and subsequently disapproved by the FAA. Asdiscussed above, approval of a noise abatement proposal in an NCPis normally a prerequisite for eligibility.

Finally, all FAA regional offices were surveyed to identifyas many noise abatement proposals as possible which may have beenconsidered either individually, on an ad hoc basis, or during thecourse of a noise compatibility planning study but not includedin an NCP submitted by the airport operator. Of primary interestwere those measures which were dropped from consideration as aresult of FAA advice to the effect that they either would not beapproved in a noise compatibility study, or would not be eligiblefor Federal assistance.

The noise abatement proposals and suggestions which emergedduring this study have been categorized as specific measureswhich can be evaluated on the basis of their noise abatementmerits, measures which are grouped collectively by origin ortype, and proposals to change the criteria and thresholds used todetermine eligibility.

Specific Noise Abatement Proposals.

The specific noise abatement proposals identified in thisstudy and discussed here include only those projects involvingcapital investments. Several of these are similar to projectswhich have previously been implemented with Federal assistance.Additional specific measures which are not eligible for grantassistance because they are not approved measures in an NCP, orbecause they do not involve capital outlays, are discussed belowas generic noise abatement proposals.

Voluntary acquisition of Properties and relocation ofresidents. Airport operators have developed a wide variety ofland acquisition proposals to alleviate adverse noise impactsnear airports. These include conventional land acquisition andrelocation, voluntary acquisition by the airport operator orlocal government upon the request of a property owner, and finan-cial assistance to homeowners during a conventional private partysale transaction. The first two are discussed in this section.The third, often called transaction assistance, was noted insection III, above, and is discussed further in a later section.

Land acquisition and relocation are frequently proposed inareas around an airport where noise exposure is 75 Ldn or more,and where local communities have agreed that the land should beredeveloped into other uses which are compatible with noiselevels in the area. The details of each program are developedlocally, but generally involve acquisition of all noncompatible

13

properties in designated areas by the airport operator or anotherlocal government unit.

Acquisition usually proceeds according to a local implemen-tation plan based on redevelopment potential, severity of noiseimpact, homeowner applications, the availability of Federal andlocal funds, and other considerations. Although such programsare generally voluntary, in that property owners may offer theirproperty for sale at any time, local officials may establish pur-chase priorities within the acquisition area. Also, in certaincircumstances, local officials may determine that the use ofeminent domain is necessary or locally advantageous.

If Federal funds are sought in conjunction with any landacquisition and relocation program, the details of the trans-actions are governed by the provisions of Title 49, Code ofFederal Regulations, Part 24. This interim rule was recentlypromulgated to implement the Uniform Relocation and Real Proper-ties Acquisition Policies Act, and is applicable to all Federalagencies. Under Part 24, the purchase price is established by anappraisal of the fair market value, subject to appeal, and therelocated residents are authorized to receive relocation benefitsand other assistance if:

- the acquisition is carried out under the threat of eminentdomain, including amicable agreements under the threat ofsuch power, or

- where there is an intended, planned, or designated projectarea, and all or substantially all of the property withinthat area is eventually intended to be acquired.

Land acquisition and relocation proposals have been approvedin numerous noise compatibility programs, both under Part 150 andas prior programs under the ASNA Act. Funding for these propos-als is discussed in section III, above. No change in existinglaws or regulations is necessary to continue implementing theseproposals.

A somewhat different voluntary acquisition program is one inwhich the airport operator or local government agrees to acquirethe property of residents who wish to relocate out of a noiseimpacted area. These are often called purchase assurance pro-grams, and are distinguished from conventional land acquisitionand relocation programs by the following factors:

- under purchase assurance, no specific site or property needsto be acquired;

- the property to be acquired is not in an area where all orsubstantially all of the properties will be acquired; and

14

- the airport operator will not acquire the property ifnegotiations fail to result in an amicable agreement.

Purchase assurance is most often proposed in areas where thenoise exposure level is between 65 Ldn and 75 Ldn and where resi-dential land use is planned to continue without major rezoning orredevelopment. It generally involves an agreement by an airportoperator or other local government unit to purchase the homes ofresidents living in designated noncompatible areas around theairport at the residents' request. The residents are then freeto relocate to any area of their choice and the property is re-sold for continued residential use with the reservation of anavigation easement on behalf of the airport operator. Theproposal may also include installation of structural noiseinsulation prior to reoccupancy.

As with conventional acquisition and relocation, describedabove, the provisions of Part 24 govern the procedures and bene-fits related to purchase assurance projects. Under Part 24,however, the airport operator may determine that acquisitionunder a purchase assurance program is a "voluntary transaction."In that case, homeowners who request that the airport operatoracquire their property under a purchase assurance program wouldnot receive relocation payments. Most airport operators favorthis approach in areas where noise exposure is less than 75 Ldnbecause the lower implementation costs are seen as appropriatefor the strongly voluntary nature of the program. Additionally,because costs and administrative requirements are less, purchaseassurance programs can be implemented to reach a larger number ofresidents more quickly.

Several airport operators have included purchase assuranceproposals in their noise compatibility programs and all that weredescribed in sufficient detail have been approved by the FAA.Although these proposals have included only voluntary trans-actions as described above, it should be noted that an airportoperator may submit a noise compatibility program which includesfull benefits under Part 24 in conjunction with a purchase assur-ance measure. If properly justified and approved under Part 150by the FAA, costs associated with such benefits are eligibleunder the AAIA.

Part 24 appears to offer enough flexibility to permit air-port operators and local communities to develop noise compati-bility programs best suited to their needs. For areas whereacquisition and redevelopment of all noncompatible properties isconsidered best, all benefits under Part 24 are required to bemade available to persons displaced by the acquisition.Conversely, in areas where only some of the properties will beacquired, the airport operator and the community can design theprogram to the mutual benefit of all parties. Consequently, nochanges in existing laws, regulations or administrative policies

15

are recommended in connection with the purchase assuranceconcept.

Air conditioning in conjunction with noise insulation. Airconditioning is by far the most frequently suggested work itemwhich respondents feel should be made eligible for grant funding.FAA administrative policy has held that a properly designedpositive ventilation system provides adequate air movement andexchange for a comfort level equivalent to that obtained withopen windows. The cost of such a positive ventilation system isallowable in conjunction with the installation of acousticalinsulation. Air conditioning, however, has not been consideredeligible because, although it provides additional comfort, it isunnecessary to achieve the noise reduction benefits of theproject.

The rationale for including air conditioning is that venti-lation alone is not adequate in a sealed structure during warmweather. It is assumed that school staff and residents will tendto open windows for fresh air, thereby negating the benefits ofnoise attenuating materials which have been installed. In addi-tion, it is argued that airport operators need to build as muchcommunity support as possible to allow the airport to continue tooperate and grow. Air conditioning provides an extra measure ofbenefit, thereby reducing community opposition to the airport.

The FAA has reviewed arguments both opposing and favoringthe eligibility of air conditioning costs, and has concluded thatits current administrative policy should be modified. The revis-ed policy permits the installation of air conditioning in lieu ofa continuous positive ventilation system if requested by the re-cipient. Allowable costs for air conditioning are limited to theequivalent cost for an adequate ventilating system. Additionalcosts attributable to acquisition and installation of air condi-tioning equipment may be shared in any way that is acceptable toproject sponsors and recipients. Sponsors should also presentrecipients with information about operating and maintenance costsfor the additional equipment, as well as reduced noise attenua-tion benefits, if any, during periods when air conditioning isnot used. This guidance has been disseminated to FAA fieldfacilities.

Other noise insulation methodologies. Two proposals comeunder this heading. One involves residential sound insulation toestablish a "quiet room" in a home rather than the more commonpractice of installing whole-house insulation. The otheremphasizes the application of new materials or techniques toaccomplish noise reduction goals.

In proposing the quiet room concept, residents express apreference for greater noise reduction in a specific room wherefamily activities are concentrated, while other parts of the home

16

are provided with less noise attenuation. This concept has notas yet been included in any airport operator's proposed noisecompatibility program, although informal inquiries have been madeabout its eligibility. At least one airport operator has agreedto test such a program to evaluate resident reaction and cost,and it is expected that the results will determine whether itbecomes a recommendation in the airport operator's NCP. NoFederal assistance was sought for this demonstration program.

Other insulation methodologies may also mean the use of newmaterials or techniques to achieve lower interior noise levels.New structural components and mechanical equipment, for example,periodically replace earlier materials because they performbetter or cost less. Because Federally-assisted noise insulationprograms are relatively new, it is expected that there will besignificant advances in both noise attenuation materials andtechniques in the future.

These noise insulation methodologies are currently eligiblefor noise compatibility funds under the AAIA, subject to certaincriteria. One prerequisite is that such measures be approved inan airport operator's NCP, as is true for all noise compatibilityprojects. Another is that interior and exterior noise levels beat or above the thresholds established by the AIP Handbook. Inaddition, the materials and procedures should conform to acceptedstandards and practices. (See the discussions below on eligibil-ity without an approved NCP, on revised noise level thresholds,and on demonstration projects.) No change in existing legalauthority or administrative policy is necessary to continue theeligibility of these specific proposals.

Programs intended to assure receipt of full fair marketvalue upon the sale of residential proDerties for those desiringto relocate out of a noise zone (generally termed "transactionassistance" Drotrams). Transaction assistance, described brieflyin section III, is an eligible noise abatement measure if it isan approved measure in an airport operator's NCP. It is similarto other acquisition programs in that it permits a homeowner tosell property in a noise impacted area with some financial assis-tance from the airport operator. The assistance usually providesthat the airport operator or other local government unit payscosts associated with the transaction, such as the real estatesales commission, so that the seller receives the full saleprice. A primary difference between transaction assistance andother acquisition programs is that neither the airport operatornor any unit of local government acquires title to the propertyduring the course of the transaction.

The provisions of Part 24 are not applicable to transactionassistance programs because the transactions are between privateparties and no Federal agency or Federally-assisted local agencyacquires the property. If, however, such a program does not

17

satisfy local noise compatibility objectives, the airport opera-tor should formulate other proposals, including conventional landacquisition and purchase assurance, to achieve those objectives.An airport operator's noise compatibility program may, in fact,include a variety of measures involving a various forms of acqui-sition and assistance. Because this flexibility already allowsairport operators the ability to tailor their NCP's to fit localneeds, the FAA does not recommend any changes to Federal laws,regulations or administrative policies in connection with suchproposals.

Development of noise abatement flight procedures. Onesuggestion called for the use of grant funds to assist in thedevelopment of noise abatement flight procedures. Civil flightprocedures, for any purpose, are developed, tested and approvedfor use by the FAA, and costs associated with their developmentare essentially FAA operational costs. The FAA has consistentlymaintained the policy that funds authorized and appropriated forthe Airport Improvement Program not be used to pay such opera-tional ccsts. No change in this policy is recommended.

Noise Abatement Proposals Grouped by Origin or Type.

Several noise abatement proposals which were identified inthis study are ineligible for grant-in-aid assistance for reasonsunrelated to their specific noise abatement potential. In somecases, they are nearly identical to measures which have beenimplemented with Federal assistance at other locations.

Noise abatement proposals submitted and disapproved by theFAA in conjunction with Part 150 noise compatibility Droarams.An airport operator's proposed noise compatibility program maycontain as many as 50 individual measures to reduce or mitigatenoise around the airport. The FAA evaluates and approves ordisapproves each measure in accordance with the standards andcriteria set forth in Part 150. A measure which is disapprovedunder Part 150 is subsequently ineligible for a grant as a noisecompatibility project under the AAIA.

A measure in a noise compatibility program will be disap-proved if the FAA determines that it would adversely affectaviation safety and efficiency, if it is ineffective as a noisecontrol or mitigation action, or if it is unduly burdensome orunjustly discriminatory. A proposed measure may also be disap-proved if the airport operator does not provide enough informa-tion on which the FAA can base a reasonable determination thatthe measure meets the criteria in the ASNA Act and Part 150.

As of May 1, 1988, the FAA had reviewed and approved 34 air-port noise compatibility programs and one revised program. (Anadditional 86 noise studies are under FAA review or have complet-ed one stage of FAA evaluation.) Although each of the 34 NCP's

18

gained overall approval, there weie in each case some measureswhich were disapproved. In all, 63 proposed noise mitigationmeasures have been disapproved under Part 150.

Two-thirds of the measures disapproved under Part 150 arenot at issue in this study because they would have involved theimplementation of flight procedures, airport use restrictions orpricing mechanisms, or airport tenant lease provisions. Thequestion of eligibility is immaterial with respect to these pro-posals because they do not involve capital outlays on the part ofthe airport operator or local government, the only possibleexception being minor administrative costs.

Twenty-one noise mitigation measures which were disapprovedby the FAA under Part 150 would have been eligible for fundinghad they been approved. Each of these would have involved somecapital or construction cost and could have been sponsored by aneligible airport operator or unit of local government. In 16instances FAA disapproved a proposal because it was not describedin sufficient detail to determine the noise abatement benefitsassociated with its implementation. The remaining five measurescould not be justified on the basis of noise abatement benefits,although each did have merit for capacity enhancement or improvedairport efficiency. (Some of these have since been funded asairport development projects.)

Section III described projects in various noise mitigationcategories which have been funded under the AAIA. Each of the 21measures just discussed can be placed in one of those projectcategories. Consequently, had these measures been submitted withmore detail, or had they been shown to reduce noncompatible landuses, it is likely that they would have been approved in the air-port operators' noise compatibility programs and would have beeneligible for Federal funding. Furthermore, any such proposalwhich was originally determined to lack sufficient detail onwhich to base approval may be resubmitted with additional infor-mation for reconsideration by the FAA. In either case, approvalin the context of an airport operator's NCP would then satisfy aprerequisite for funding eligibility under the AAIA.

Noise compatibility measures proposed in an NCP for whichFAA aproval is Dendin. and proposals not in an airport opera-tor's NCP. These proposals, measures awaiting NCP approval andmeasures not in an NCP, initially appear to be attractive candi-dates for more liberal eligibility rules. Measures not in an NCPmay have been considered during program development, may havebeen overlooked during NCP preparation, or may be Ad hoc propos-als by an airport operator who has not engaged in comprehensivenoise compatibility planning.

A proposal considered but not included in an airport oper-ator's NCP may have been eliminated because of FAA advice,

19

projected high costs, marginal benefits, or other local consid-erations. Later, however, the same measure may seem to haveattractive benefits and the airport operator or the community maywish to implement it. Such proposals may be similar to projectsfunded at other locations and usually considered eligible, orthey may be for measures which are usually determined to beineligible.

A noise abatement proposal may also appear spontaneously,without prior study. Noise insulation or minor land acquisition,for example, have been shown to be effective and eligible meas-ures in several locations. It can be argued that, under certaincircumstances, these measures should be eligible immediatelywithout protracted study. Similarly, some respondents suggestedthat if a measure has been studied and recommended in the airportoperator's NCP, it should be eligible immediately without havingto wait for FAA to approve the NCP.

The FAA does not agree that noise compatibility proposalsshould be made eligible without comprehensive study and FAAapproval for several reasons. First, the FAA has consistentlyinterpreted the language in both the ASNA Act and the AAIA tomean that, except for certain specified exceptions, grant fundsfor noise mitigation projects are authorized only to implementapproved NCP's.

Second, most airport operators that complete a detailednoise study develop better programs than those that quicklyaccept the first apparent solution. They benefit by incorpora-ting a broad array of noise mitigation proposals which do morethan focus on a single aspect of the problem. Such studiespresent a clearer picture of how future actions may proscribefuture operations or growth at the airport, of tradeoffs betweenairport capacity and land use compatibility, and of the benefitsattributable to a variety of noise compatibility alternatives.In addition, airport neighbors and airport users generallydevelop an increased tolerance for, and understanding of, eachother's problems during the course of a comprehensive study.

Another reason that proposals should be included in approvedprograms is that all airport operators should be subject to thesame rules in order to qualify for Federal assistance. Sponsorswho have conducted detailed noise studies and produced NCP'sapproved by the FAA should not have to compete for limited grantfunds with others seeking to implement similar projects withoutcomparable study.

In addition, Congress has recently authorized the issuanceof grants to insulate public schools and hospitals in high noiseareas around airports without an approved NCP. Although thisprovision appears to provide a timely solution for a limitednumber of buildings, it is too early to judge the ultimate level

20

of interest in this provision. Therefore, the FAA does notrecommend expanded eligibility of projects without the study andconsultation originally contemplated by the ASNA Act at thistime.

Demonstration projects. Demonstration projects have tradi-tionally been considered not eligible for grants under airportgrant-in-aid programs. This is because such projects, as inter-preted by the FAA, are intended to test or demonstrate the effi-cacy of a novel design, a new product or an unproven technique.Projects funded under the AAIA are instead required to use provenmethods and materials to achieve specified objectives. The FAAdoes not recommend that the policy regarding such demonstrationprojects be changed.

Airport operators and other local agencies, however, maypropose a demonstration project for a different purpose. Theyoften wish to demonstrate the effectiveness of a noise mitigationmeasure, such as noise insulation, on a small scale to buildsupport for a large scale neighborhood program. That type ofproject, described as phase one of a neighborhood noise insula-tion program, for example, avoids the conflicting definition, iscurrently approvable under Part 150, and would, in most cases, beeligible for Federal funding. The FAA will advise its fieldoffices which administer the grant-in-aid program to be aware ofthis distinction and to advise airport operators accordingly.

Proposals involyin no construction or capital outlays.Some respondents suggested that the costs associated with publi-cation of community newsletters, rental of avigation easements,and the operation and maintenance of noise abatement navigationalaids installed with grant funds be eligible for Federal grants.The FAA views these as administrative and ongoing operationalcosts which are prohibited under the AAIA, just as they are forairport development items. The FAA proposes no change in thisprovision.

Proposals to implement noise abatement measures in areaswhere noise exposure is less than 65 Ldn. Several respondentssuggested that certain projects, such as land acquisition andnoise insulation, should be eligible, even in areas where noiseexposure is less than 65 Ldn. Current guidance generally limitseligibility for noise insulation and land acquisition to areaswhere existing or future noise exposure is 65 Ldn or more. Asubstantial number of airport operators, however, indicated thatthey receive noise complaints from those who live and work inareas normally considered compatible.

The FAA has studied this matter and has concluded that theexisting 65 Ldn exterior noise level criterion is appropriate forland acquisition and most residential noise insulation proposals.In most cases cited by airport operators and FAA staff, a rela-

21

tively small proportion of the residential population exposed tonoise levels less than 65 Ldn has registered noise complaints,even when questioned in surveys. This is consistent with thestatistical data from earlier research on the reactions of peopleto various noise exposure levels.

In addition, the land area and resident population increaseexponentially as one moves outward from an airport into areas oflower noise exposure. Extending grant eligibility in this direc-tion would substantially increase the number of potential noiseinsulation and land acquisition candidates in areas of low noiseexposure and tend to divert funds from more seriously impactedareas.

Another reason to continue using 65 Ldn as the noise expo-sure level criterion for eligible land acquisition is that thereare other effective measures which can be implemented locally toprevent development of potentially sensitive land uses. Newzoning regulations and building codes, for example, have beendrafted in some communities as a result of noise compatibilityprogram recommendations. The FAA encourages local officials andcommunity representatives to consider such measures when prepar-ing an NCP, and will continue to do so.

Under Part 150, however, airport operators may substitutelocal determinations of land use compatibility for the Federalguidelines in Part 150. Several airport operators have alreadysubmitted noise exposure maps to FAA under Part 150 which includenoise contours and noncompatible land use designations in areaswhere noise exposure is less than 65 Ldn. These designations arebased on explicitly documented locally determined land use com-patibility values. The noise compatibility programs accompanyingthese noise exposure maps have, in some cases, recommendedremedial noise mitigation projects outside the 65 Ldn. Suchprojects have been approved by FAA under Part 150. FAA fundingeligibility has, however, to date been based on consistency withFederal guidelines, i.e., noncompatible areas within a 65 Ldn.

The FAA believes, upon further consideration, that fundingguidelines should allow eligibility for those occasional projectsoutside a 65 Ldn contour to achieve local land use compatibility.Such projects may be specifically justified in an airport opera-tor's Part 150 NCP or on an ad hoc basis with respect to thesoundproofing of schools and hospitals which are eligible withoutan approved Part 150 program. Two examples have come to light inconnection with the potential eligibility of noise compatibilitymeasures which may be recommended in an NCP.

One exception to Federal land use compatibility guidelinesmay be applicable in tropical areas where local building prac-tices produce structures in which the exterior to interior noiselevel reduction is much less than 20 decibels. Similarly, for a

22

noise abatement project in a public school located where noiseexposure is less than 65 Ldn, airport operator's documentationshould determine that the average sound level during normalschool hours is 45 dBA or more and single event noise levelsattributable to airport operations exceed 55 dBA.

Proposals to Revise the Noise Level Criteria used to DetermineEliQibility for certain Noise Abatement Measures.

Several airport operators noted that a large proportion ofthe residential structures in high noise areas around their air-ports are ineligible for noise insulation because measurementshave shown that interior noise levels are below the criterionlevel of 50 Ldn. The measurements also show that those residentsare subjected to a large number of noise events daily which dis-rupt conversation and other activities in their homes. Theseconditions have been documented at locations where the outsidenoise exposure level is as high as 75 Ldn.

Proposal to revise the interior noise exposure levelcriterion for noise insulation projects. One problem, as viewedby airport operators and local residents, is that the interiornoise exposure level criterion (50 Ldn) established in the AIPHandbook is too stringent. They argue that, in light of past FAAstudies which concluded that residential interior noise levelsshould be 45 Ldn or less, the FAA should not require an addi-tional 5 Ldn penalty in order to qualify for noise insulation.Rather, the criterion should be revised downward to 45 Ldn tomake all dwelling units eligible for Federal assistance if theirinterior noise levels reach or exceed that threshold ofcompatibility.

During the course of this study, it was learned that a tech-nical change should be made in the criterion used to determinethe eligibility and proper scope of a proposed noise insulationproject. The Ldn measurement system was devised to describegeneral land use compatibility over a range of outdoor noiseexposure levels, but was not intended to determine the compati-bility or noncompatibility of interior noise environments. Forexample, the table of land use compatibility in Part 150 listsresidential land use as noncompatible in areas where noise expo-sure is 65 Ldn to 70 Ldn. It is further noted, however, thatresidential use may be compatible if residential structures inthat zone achieve a noise level reduction (NLR) of 25 decibelsfrom outdoors to indoors.

Based on the above information, the FAA will make a techni-cal revision to the AIP Handbook stating that eligibility fornoise insulation will be based on outdoor Ldn and the noise levelreduction achieved by the structure without the addition of afive decibel penalty factor. That portion of the guidance whichrequires a project to produce at least five decibel improvement

23

will be retained, however. This revision is expected to resultin a substantial increase in the number of residences eligiblefor sound insulation. For example, in a residential arearecently screened for eligibility, the proportion of eligibledwellings increased from 54 percent to 98 percent under therevised criteria.

PrOposal to allow an alternative noise level measurement todetermine eligibility for noise insulation. Another point ofconcern expressed by airport operators is that the Ldn measure-ment system does not adequately address adverse noise impactsunder certain circumstances, and that single event noise levelsshould also be considered. It was noted, for example, that insome areas where the noise exposure is more than 75 Ldn, theapplication of local thermal insulation standards have alreadyreduced interior noise exposure levels to 45 Ldn or less. Never-theless, reactions of residents in such areas are similar tothose of residents in much noisier dwelling environments.

In an earlier FAA publication (Advisory Circular 150/5020-1,Noise Control and Compatibility Planning for Airports), it wasnoted that, although the "cumulative noise metric (Ldn) is usefulas an indicator that soundproofing may be required in a particu-lar area .... it is recommended that additional analysis viasingle event maximum sound level ... be used to determine thenecessity (and/or eligibility) for soundproofing." Otherresearch has suggested various measurement systems to more fullydescribe the adverse effects of aviation noise on the indoorenvironment. These systems generally emphasize a specific noisecharacteristic which is particularly disruptive to a given humanactivity.

Examples of other noise measurement systems are:

- speech interference level, frequently used to evaluate noiseproblems in classrooms by measuring the acoustical energywithin the frequency range encountered in normal speech;

- sound exposure level, which incorporates both the energy andduration of a noise event, but does not include additional

* weight for noise events which occur at night;

- sound equivalent level, a measure used to describecumulative noise energy over a given length of time, e.g.,one hour, six hours, or any other time period of interest;and

- time above, a measure of the aggregate length of time that agiven noise level, usually specified in dBA, is exceeded.

It is considered beyond the scope of this study to selectone or more of these alternative noise measurement systems as a

24

replacement for, or alternative to, the noise level reductioncriterion discussed above. However, the FAA is currently con-ducting another study at the direction of Congress to determinewhether the noise compatibility planning and program developmentprocedures under Part 150 should be revised to take into accountspecial circumstances at certain airports. It is expected thatthis study will also address the use of single event noisemeasurement systems. The findings of that study, to be completedJune 30, 1989, will be incorporated in a subsequent revision ofthe AIP Handbook, if appropriate.

Proposal to Expand and Clarify Existing Guidance.

Although it was not mentioned specifically in any of thedata gathered for this report, it is clear that FAA field officesneed better and more thorough guidance on the eligibility ofspecific noise compatibility proposals. Several projects whichwere assumed by FAA field personnel and airport operators to beineligible, such as construction of a new runway for noise abate-ment, have, in fact, been funded at other locations. The FAAintends to promptly revise, expand and clarify the AIP Handbookso that such inconsistencies are avoided in the future.

V. RECOMMENDATIONS.

The results of this study indicate that existing legislationprovides the FAA with adequate authority to make eligible thosenoise abatement proposals which have merit and are recommended inan airport operator's noise compatibility program. Therefore,the FAA recommends no changes to existing law for that purpose.

The study also indicated that the FAA should reconsider itsadministrative policies on several criteria for evaluating noiseabatement proposals. Recommendations to address those issues andthe actions FAA has taken to implement them are set forth below.

* Recommendation: Allow installation of air conditioning withnoise insulation proiects. FAA action: Revised guidance onthe eligibility of air conditioning in conjunction withnoise insulation projects has been developed and distributedto FAA offices. Air conditioning equipment may be installedin connection with a positive ventilation system at therecipient's request. The allowable cost under the AAIA islimited to the cost of an adequate ventilation system. Thisguidance applies to projects under an approved Part 150program or publicly owned educational and medical facilitiesas authorized under the 1988 amendments.

* Recommendation: Allow funding for certain projects outsidethe 65 Ldn. FAA action: The AIP Handbook will be revisedto explain the circumstances under which noise abatement

6 25

proposals are eligible in areas where noise exposure is lessthan 65 Ldn. Specifically, noise abatement proposals in anairport operator's noise compatibility program which areapproved by the FAA under Part 150 and which are outside the65 Ldn are eligible if the airport operator, in consultationwith local officials, has determined that such land use isnot compatible with noise levels resulting from operation ofthe airport. Proposals to provide soundproofing for medicaland educational facilities which are not included in a noisecompatibility program, and which are located in areas wherenoise exposure is less than 65 Ldn, will be eligible whenaccompanied by documentation sufficient to allow the FAA todetermine that the facility is adversely affected by airportnoise.

* Recommendation: Revise the interior noise level criterionused to establish eligibility for residential and schoolnoise insulation. FAA action: Guidance on the evaluationof noise insulation proposals will be revised to specify thedesign objective as a given amount of noise level reduction(NLR) to be achieved in a structure. In addition, the NLRthreshold of 20 dBA where noise exposure is 65 Ldn will beestablished as the basic eligibility criterion. The effectof this revision will be to increase substantially thenumber of structures qualifying for Federal assistance underthe AAIA.

* Recommendation: Conduct further study. including the FAAstudy of Part 150 currently underway, to determine whetherand to what extent an alternative noise measurement systemshould be used to evaluate noise insulation proposals. FAAaction: Based on the results of the FAA's current study ofnoise compatibility planning under Part 150, the FAA willdetermine whether to revise existing guidance to permit theuse of alternative noise measurement systems to evaluate theeligibility and proper scope of noise insulation proposals.Should such a revision be made, it is expected that thenumber of structures eligible for Federal assistance willincrease substantially.

* Recommendation: Provide more comprehensive guidance on theeligibility of noise compatibility projects. FAA action:The FAA will promptly revise, expand, clarify and distributeto its field offices that portion of the Airport ImprovementProgram Handbook which provides guidance related to theeligibility of noise compatibility proposals, including theappropriate description of "demonstration projects" andchanges due to the recommendations described above.

The revisions to eligibility criteria described above willbe published as changes to the AIP Handbook, and will not requirelegislative or rulemaking action.