Research into the improvement of the management …usir.salford.ac.uk/30805/1/nanr235-project-report.pdf1 DEFRA NANR235: Project report Executive Summary Introduction This report describes

Research into the improvement of the management of helicopter noise

Waddington, DC and Kendrick, P

Title Research into the improvement of the management of helicopter noise

Authors Waddington, DC and Kendrick, P

Type Monograph

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Published Date 2008

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Research into the Improvement of the Management of Helicopter Noise June 2008

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Department for Environment, Food and Rural Affairs Nobel House 17 Smith Square London SW1P 3JR Tel: 020 7238 6000 Website: www.defra.gov.uk © Queen's Printer and Controller of HMSO 2007 This publication is value added. If you wish to re-use this material, please apply for a Click-Use Licence for value added material at http://www.opsi.gov.uk/click-use/value-added-licence-information/index.htm. Alternatively applications can be sent to Office of Public Sector Information, Information Policy Team, St Clements House, 2-16 Colegate, Norwich NR3 1BQ; Fax: +44 (0)1603 723000; email: [email protected] Information about this publication and further copies are available from: Local Environment Protection Defra Nobel House Area 2A 17 Smith Square London SW1P 3JR Email: [email protected] This document is also available on the Defra website and has been prepared by Salford University. Published by the Department for Environment, Food and Rural Affairs

Research into the Improvement of the Management of Helicopter Noise(NANR235)

Performed onbehalf of Defra

1

DEFRA NANR235: Project report

Executive Summary

IntroductionThis report describes research undertakento investigate the improvement of themanagement of helicopter noise in theUK. This work was carried out on behalfof the Department for Environment, Foodand Rural Affairs (Defra) by the Universityof Salford and QinetiQ (Farnborough) Ltd.The aims of this study were to determinethe issues and the extent of the reportedproblem of noise from helicopteroperations in the UK, and to developpractical guidance on the management ofhelicopter noise, including improvementsin the handling of complaints.

MethodologyThe methodology used to achieve theseaims included a worldwide literaturesearch, a survey of stakeholders, and aOne-day Meeting carried out under theauspices of the Institute of Acoustics.

ConclusionsNature and extent of the concernabout helicopters noise in the UK1) Problems due to helicopter noise are

centred on helicopter infrastructuresuch as holding areas, heliports andaerodromes. However, unlike fixed-wing aircraft noise, helicopter noise isoften not directly attributable to aspecific heliport or airfield.

2) Compared with fixed-wing aircraft, theratio of movements to the number ofcomplaints received is generally smallfor most helicopter operations.

3) The consensus among stakeholders isthat there is increasing opposition tothe development of heliports on thegrounds of noise disturbance.

4) There is no comprehensive databaseof helicopter movements in the UK.Consequently, it is impossible todetermine the extent to which noisenuisance is a growing concern.

5) Precise determination of the scale ofpublic concern about helicopter noisewould require a careful social study.

Procedures in place for handlinghelicopter noise complaints1) The CAA acts as a focal point for

receiving and responding to aircraft-related environmental complaintsfrom the public1. The CAAencourages noise complaints to bemade directly to the airport operator.

2) Complaints regarding military flightsshould be addressed to the base'scommunity liaison officer.

3) Problems related to noise generatedon the ground at aerodromes shouldbe referred to the Local Authority.

4) Consultative committees to enabledialogue between residents, councilsand heliport operators have beenshown to improve understanding andacceptance by the public.

5) The failure to act on complaints is oneof the largest causes of dissatisfactionand resentment amongst thepublic.

Rules and regulations governinghelicopter operations1) BHAB codes of practice aim to

persuade helicopter pilots andoperators to take more notice ofenvironmental noise issues.

2) Helicopter noise certification does notaddress community annoyance causedby helicopter noise. A gradualreduction in the certification levels willnot address public acceptability.

3) In England, the current land useplanning guidance (PPG24) states thatnoisy and noise sensitive land usesshould be kept apart. PPG24 providesadvice to assist with the considerationof new residential development nearexisting sources of aircraft noise, butthe guidance states that it should beused with caution where there isexisting helicopter noise. PPG24contains limited planning guidance onthe noise impact of new heliports.

Dose response relationships1) Helicopters can be up to 15dB more

annoying than fixed-winged aircraft.However, helicopter noise levels alonedo not account for annoyance trendsin communities.

2) There is no single satisfactory noiseindex for the measurement orprediction of the impact of noise onthe community.

3) Noise maps displaying Lden are notsuitable to be used for the predictionof subjective response of communitiesto helicopter noise.

Opportunities for improvements 1) The UK has world-leading expertise in

the sound insulation of residencesfrom helicopter noise. This expertisecould be exploited by designers andplanners with regard to futurebuilding developments in the vicinityof helicopter operations.

2) The UK has world-class expertiseregarding community response tosoundscapes. This expertise could beexploited in future research, and toimprove dose-response relationshipsfor helicopter noise.

3) The UK has world-class expertise inhelicopter noise propagation predictionand in the measurement of sourcenoise from helicopters. This expertise,currently only available within MODprogrammes, could be exploited infuture civil noise mapping.

Recommendations1) Academic research is required to

better understand the humanresponse to helicopter noise. Indefining new approaches, the lowincidence rate of most helicopteroperations and the non-acousticfactors, also known as ‘virtual noise’,which encompasses communityattitudes and fears towards theoperations, should be considered.

2) Complaints should be collected andlogged in a central database. Thisshould embrace all sources includingthe CAA, the MOD, local authorities,operators and airfield managers.Attention should be paid to methodsutilised in Australia where monthlyreports on complaint statistics areprovided to stakeholders.

3) Pilots should be made more aware ofhelicopter noise, perhaps duringtraining for the Private Pilots Licence(PPL) or Basic Flying Training for themilitary pilot. Such a scheme, the HAI’s‘Fly neighbourly’ program, issuccessfully operated in the US,Germany and other countries. This canbe part of the best practical means ofminimising noise complaints.

4) Applied research is required so thatland use planning guidance, such asPPG24 in England, can be revised.Specific land use planning guidanceneeds to be developed for theassessment of noise from helicopteroperations.

5) Developers need to be encouraged toenhance sound insulation in new /change-of-use builds near helicopterbases.

6) For accurate prediction ofenvironmental noise from helicopteroperations, and for noise maps, dataon the source noise of civil helicoptersneeds to be obtained.

1CAP 724 Airspace Charter, November 2007(Directorate of Airspace Policy, CAA).

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Summary

I) Objectives 1) To investigate the reported adverse

impacts of helicopter noise and toprovide information on the nature andextent of the concern about helicoptersnoise in the UK.

2) Compile a summary of procedures inplace for handling helicopter noisecomplaints and the roles, responsibilitiesand powers of the related authoritiesand organisations.

3) Compile a summary of the current rulesand regulations governing helicopteroperations, any current relevant industrycodes of practice, and any existingreported dose response relationships.

4) Identify opportunities for improvementand make recommendations on howimprovements could be implemented.

II) Methodology The methodology used to complete theseaims and objectives consisted of aworldwide literature search, a survey ofstakeholders and a One-day meeting carriedout under the auspices of the Institute ofAcoustics. Key literature was identified bysearching technical journals, conferenceproceedings, the internet, libraries, andthrough stakeholder contact. Atelephone/email survey of stakeholders wasconducted to investigate the extent of theconcern about helicopter noise in the UK.Additionally stakeholders were asked aboutprocedures for handling complaints, currentrules and regulations, and industry codes ofpractice governing helicopter operations.Stakeholders were identified through theDefra technical working group, contact withthe BHAB, contact with the MOD, contactsin local government and as a result of theliterature review. Stakeholders identified andcontacted included; helicopter operators;helicopter pilots, airport management,environmental health officers, publicpressure groups, helicopter manufacturers,private consultants and emergency servicesamongst others. A One-day Meeting washeld on the 6th February and all contactedstakeholders were invited. The IoApublicised the meeting and a goodattendance was achieved. Speakers at themeeting included representatives fromDefra, CAA, AgustaWestland, MOD, BHAB,QinetiQ and Wandsworth council. Thisprovided opportunity for debate betweenkey stakeholders.

III) Results – nature of the concernabout helicopter noise

Social surveys indicate that helicopters canbe up to 15dBA more annoying than fixed-

wing aircraft for the same or lowermeasured sound level. Studies attemptingto relate dose-response with annoyance dueto helicopter operations have producedpoor correlation and have been broadlycriticised. There is no straightforwardrelationship between objective noise andsubjective annoyance. No good correlationwith complaints has been found with LAeq,LCeq, LAmax, L10 and LAmax-L90. Studiesaddressing the noise from light aircraft andmicrolights reveal similar issues; that noiselevel may be a secondary issue and differentindices may be required for low volumeoperations.

Reaction to helicopter noise is determinedby acoustic and non-acoustic 'virtual' noise.Non-acoustic factors are thought to be ofequal or greater importance and may betriggered by impulsive/tonal noise generatedby the rotors. This means that addressingacoustic noise limits may be unlikely tosignificantly improve public acceptance ofhelicopter noise. 'Virtual' noise by factorsother than noise including flight safety,privacy, soundscape, locus of control andmental health. Perceived effect on houseprice has also been shown to be asignificant factor. Highest annoyance hasbeen correlated with uncommon orexceptional helicopter events andcomplaints have been found to be morelikely if the resident has a negative attitudetowards the helicopter operator. It issuggested that the term annoyance doesnot fully describe the subjective response tohelicopter noise and perhaps a multifactorapproach similar to the approach ofclassifying work-related stress may beadopted. The following classifications,amongst others, may be important;intrusion, distress, startle, disturbance, locusof control.

IV) Results – extent of the concernabout helicopter noise

The Chartered Institute for EnvironmentalHealth (CIEH) conducts an annual survey ofenvironmental health departments but hasonly in the past two years started to recordhelicopter noise complaints. On average, forthose two years, helicopter complaintsmake up about 5% percent of the overallnumber of noise complaints received fromall transport, in 2005-2006 there were 45individual complaints and in 2006-2007there were 37. The CAA reports that therewere 370 noise complaints resulting fromhelicopter operations in the UK in 2007, 80of which were regarding helicopter

operations over London. RAF Shawburyreports receiving 313 noise complaints in2007.

As a result of debate at the One-daymeeting it was revealed that the ratio ofhelicopter movements to number ofcomplaints received is generally very smallfor most operations. The consensusamongst stakeholders is that there is not asignificant helicopter noise problem in theUK. However, problems do exist and theseare centred on helicopter infrastructure suchas specific heliports and aerodromes.However, this may simply be becausecomplainers near to an airfield/heliportknow who to complain to, whereas thosethat live further away do not.

V) Results – procedures for handlingcomplaints, roles andresponsibilities and noise reduction

The CAA acts as a focal point for receivingand responding to aircraft-relatedenvironmental complaints from the generalpublic. However, the CAA does not havethe legal power to prevent aviation activityon solely environmental grounds, exceptwhen considering changes to the structureof controlled airspace. An independentreview is considering greater powers for theCAA over environmental matters.

The CAA encourages noise complaints tobe made directly to the airport operator.However, this only works if the complainantknows where the helicopter is operatingfrom/to. Problems related to noisegenerated on the ground at aerodromes,other than in association with the normaloperation of aircraft, should be referred tothe Local Authority. MOD complaints shouldbe addressed to the base's communityliaison officer or via the MOD complaintstelephone line.

Consultative committees to enable dialoguebetween residents, councils and heliportoperators have been shown to improveunderstanding and acceptance by thepublic. When operated successfully, thepublic appreciate that their concerns arebeing taken seriously. This is because theyrepresent a neutral position from which toinfluence operators to change operationalprocedures. Consultation with the public ina number of instances has encouragedoperators to make operational changeswith a positive outcome for thecomplainants, examples include;establishment of voluntary avoid areas,circuit rotation for training flights andimproved pilot awareness.

3


BHAB codes of practice aim to persuade thehelicopter pilots and operators to take morenotice of environmental noise issues.Although pilots are aware of noise issues,factors such as safety are considered moreimportant. Pilots should be made moreaware of helicopter noise. This could formpart of the training for the Private PilotsLicence (PPL) or Basic Flying Training formilitary pilots. This can be part of the bestpractical means of minimising noisecomplaints.

Helicopter noise certification does not takeinto account all aspects of noise from urbanoperations and the subjective problemscaused by helicopter noise are notrepresented by the certification parameters.Manufacturers are concerned that a gradualreduction in the certification levels willcompromise helicopter performance (oreven refusal of type certification) while notaddressing the public acceptability.

Two significant European projects addressnoise from helicopters, FRIENDCOPTER andthe "Clean Sky" JTI. Both aim to produce asignificant reduction in the noise generatedby helicopters using new technology.

VI) Results – planning and predictionThe Planning Policy Guidance document(PPG24) lists a series of four ExposureCategories to help indicate whetherplanning permission should be granted fornew housing near an existing source ofaircraft noise. A residential planningapplication close to an operating heliport,when evaluated in accordance with PPG24solely on the grounds of Leq, is unlikely tobe rejected because of excess noise. This isbecause PPG24 Exposure Categories arebased on Leq levels, which are notappropriate for intermittent noise eventssuch as helicopter operations. The land useplanning system offers an opportunity forthe control of the noise impact of heliportsbut the current guidance is rather limited.PPG24 recommends Leq levels not be usedto assess small operations (<30movements/day), although an alternativemethod is not specified.

Noise maps and action plans are required bythe Environmental Noise Directive on a five-year cycle. Helicopters are not excluded,though rudimentary noise mapping ofhelicopter noise is currently restricted tomajor airports. However, the accuracy ofthese strategic noise maps relating tohelicopter noise is limited by the lack ofsufficient metrological source data andvalidation of noise prediction models in thiscontext.

The Lden is not an informative parameterfor the depiction of helicopter noise, sincehelicopter noise arises from individual flightsas opposed to the average of a largenumber of flights. Noise maps displayingLden are therefore unlikely to be suitable forthe prediction of community response tohelicopter noise.

VII) Conclusions – nature of the concernabout helicopter noise

Academic research is required to betterunderstand the human response tohelicopter noise. It is suggested that new ormodified measurement indices need to bedefined that address the unique subjectivereaction to helicopter noise. In defining newapproaches the low incidence rate of mosthelicopter operations and the non-acousticfactors or ‘virtual noise’ that encompassescommunity attitudes and fears towards theoperations should also be considered.

VIII) Conclusions – extent of theconcern about helicopter noise

Determination of the scale of publicconcern about helicopter noise wouldrequire a social survey. However,determination of a dose-responserelationship for the prediction of communityresponse to helicopter noise would needcareful design and an extensive study. Thestudy would need to take into accountsocio-economic and cultural factors, andthe type of helicopter activity.

A repeated view expressed amongststakeholders was that the scale of theproblem of helicopter noise could not beestimated without the central logging ofcomplaints. It was suggested that there is aneed for a more “holistic” approach, andnational statistics for helicopter noisecomplaints are required before an“informed debate”.

There is consensus amongst stakeholdersthat there may not be a helicopter noiseproblem now but it has the potential tobecome one. Others suggested thatperhaps the question should not be ‘is therea serious noise problem in the UK?’ butrather ‘Are we facing increased oppositionto the development of helicopter bases andoperations, and if so, what are we going todo about it?’

IX) Conclusions – procedures forhandling complaints / roles andresponsibilities / noise reduction

Helicopter noise certification is not directedat urban operations and certification doesnot guarantee public acceptance.

Consultative committees can be effective inmanaging the public’s concern abouthelicopter noise and help lobby operators tochange operational procedures.

To ensure there is accountability related toenvironmental noise problems caused byhelicopter operations, it is suggested thatcomplaints are collected and logged in acentral database from all sources includingMOD, CAA, local authorities, operators andairfield managers. Attention should be paidto methods utilised in Australia wheremonthly reports on complaint statistics areprovided to stakeholders.

A fast and sincere response is important inkeeping complainants from becomingrepeat complainers. The failure to act oncomplaints is one of the largest causes ofdissatisfaction and resentment amongst thepublic.

X) Conclusions – planning andprediction

Developers need to be encouraged toenhance sound insulation in new /change-of-use builds near helicopterbases. Extending consultation to includedevelopers may help to make developersmore aware of the problem.

In England, the current land use planningguidance (PPG24) states that noisy andnoise sensitive land uses should be keptapart. PPG24 provides advice to assistwith the consideration of new residentialdevelopment near existing sources ofaircraft noise, but the guidance states thatit should be used with caution wherethere is existing helicopter noise. PPG24contains limited planning guidance on thenoise impact of new heliports.

Applied research is required so that landuse planning guidance, such as PPG24 inEngland, can be revised and specificassessment methods suggested for noisefrom helicopter operations.

Appropriate data on the source noise ofcivil helicopters, except where they overlapwith military platforms, is not available,and needs to be collected and/orestimated through source prediction codeas a matter of priority. The UK has world-leading expertise in helicopter noiseprediction and in the measurement ofsource noise from helicopters due toinvolvement in military programmes. Thisexpertise, currently only available withinMOD programmes, could be exploited infuture civil noise mapping.

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This report presents work performed onbehalf of Defra by the University ofSalford and QinetiQ Ltd. However, wewould like to thank the large number ofpeople that assisted in this research and inthe preparation of this report.

The work was performed with theassistance of the following technical groupon behalf of Defra:

Ian SherlockRichard PerkinsAntonio AcunaWendy HartnellStephen TurnerColin GrimwoodPaul FreebornDarren RhodesJames DeeleySteve MaynerColin StanburyChristopher ForrestRoy StrappFrank Evans

The work was performed at theUniversity of Salford by:

Paul KendrickDavid WaddingtonGeoff KerryMags AdamsThurai RahulanYui Wai Lam

The work was performed atQinetiQ Ltd by:

Matthew MuirheadRay Browne

A One-day Institute of Acoustics meetingwas held to inform this research. Thefollowing presenters contributed to thiswork:

Parminder DhillonRodger MuntKath SixsmithSteven MaynerBob McLoughlinTim OwensJim WalkerPaul FreebornTony Pike

In addition, the following peoplecommented on the draft of this report:

John LevertonTony PikeRodger MuntLee Copley

Preface

5


EXECUTIVE SUMMARY 1Introduction 1Methodology 1Conclusions 1Recommendations 1

SUMMARY 2I) Objectives 2II) Methodology 2III) Results – Nature of the Concern

About Helicopter Noise 2IV) Results – Extent of the Concern

About Helicopter Noise 2V Results – Procedures for Handling

Complaints, Roles andResponsibilites and NoiseReduction 2

VI) Results – Planning and Prediction 3VII) Conclusions – Nature of the

Concern About Helicopter Noise 3VIII) Conclusions – Extent of the

Concern About Helicopter Noise 3IX Conclusions – Procedures for

Handling Complaints / Roles andResponsibilities / NoiseReduction 3

X) Conclusions – Planning andPrediction 3

PREFACE 4

CONTENTS 5

1. INTRODUCTION 61.1. Background to the Research

Project 61.2. Policy Context 61.3. Aims and Objectives 61.4. DEFRA Technical Working Group 6

2. THE PROBLEM OF NOISE FROMHELICOPTER OPERATIONS INTHE UK 72.1. Nature of the Concern About

Helicopter Noise in the UK 72.2. Extent of the Concern About

Helicopter Noise in the UK 72.3. Noise Indices and Measurement

Methods 72.4. Existing Dose Response

Relationships 82.5. Subjective Responses to

Helicopter Noise 92.6. Means of Redress for any

Perceived Disturbance Caused 9

2.7. London Assembly Environment Committee Report, “LondonIn A Spin" 9

2.8. Estimating the Scale of the Problemof Helicopter Noise 9

2.9. Summary of Chapter 2 10

3. HELICOPTER OPERATIONS INTHE UK 113.1. Helicopter Noise Generation and

Reduction Methods 113.2. Emergency Services 113.3. Military Helicopter Operations 123.4. Civilian Helicopter Operations 133.5. Helicopter Infrastucture 143.6. Helicopter Airspace Restrictions 153.7. Helicopter Routes 153.8. Helicopter Noise Certification 153.9. Summary of Chapter 3 15

4. RULES AND REGULATIONS RELATING TO HELICOPTER OPERATIONS 164.1. Rules of the Air Regulations 164.2. Rules and Regulations Governing

Low-Flying Helicopter Operations(ANO) 16

4.3. Relevant Sections of PlanningLaw 16

4.4. Nuisance Law 174.5. Helicopter Operations: ‘Codes of

Practice’ 184.6. Guidance Provided by the British

Helicopter Advisory Board(BHAB). 18

4.7. Helicopter Civil NoiseCertification 18

4.8. Rules and Regulations inAustralia 19

4.9. Rules and Regulations in Europe 194.10. Rules and Regulations in the

USA 194.11. Summary of Chapter 4 19

5. SUBJECTIVE RESPONSES TOHELICOPTER NOISE 205.1. Social Effects 205.2. Health Effects 205.3. Community Attitudes 215.4. Non-Acoustic Factors 225.5. Comparison with Light

Aircraft/Microlights 235.6. Summary of Chapter 5 23

6. MANAGEMENT OF ENVIRONMENTAL NOISE FROM HELICOPTERS 246.1. Existing Procedures for

Handling Noise Complaintsfrom Helicopters 24

6.2. Means of Redress for anyPerceived Disturbance Caused 24

6.3. Roles, Responsibilities andPowers of the Various Authoritiesand Regulating Organisations. 25

6.4. The Effectiveness of Dealingwith Helicopter Noise in the UKUsing Current Methods 25

6.5. Comparisons with otherEuropean Countries 26

6.6. Comparisons with Australia 266.7. Comparisons with the USA 276.8. Options for the Improvement

of the Management ofHelicopter Noise 27

6.9. Noise Prediction and Modelling 286.10. Options for the Improvement

of Prediction for Noise Mapping 286.11. Summary of Chapter 6 29

7. CONCLUSIONS 307.1. Exent of the Reported Problem

of Noise from Helicopter Operationsin the UK 30

7.2. Guidance on the Managementof Helicopter Noise 30

7.3. Improving the Handling ofComplaints - ConsultativeCommittees 30

7.4. Opportunities for ImprovingDose-Response Relationships 30

7.5. Recommendations for Plannersand Developers 30

7.6. Improvement of Predictions 30

8. LIST OF ABBREVIATIONS 31

9. RECOMMENDATIONS OFLONDON IN SPIN 32

10. INSTITUTE OF ACOUSTICSONE-DAY MEETING TIMETABLE 34

11. REFERENCES 35

Contents

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1.1 Background to the research project1.1.1. Helicopter noise can have anegative impact on the quality of life forsome people. Affected populations arenot just those living close to heliports, butinclude those exposed to noise fromhelicopters used by emergency services,the military, commercial companies andprivate individuals. One problem identifiedis that it is often difficult to complainabout helicopter noise since it is unclearwhich organisation is responsible fordealing with the complaint.

1.1.2. This research project was proposedby Defra with the objective of improvingthe management of noise from helicopteroperations. This was due to a perceivedlack of information in connection withhelicopter noise, and in particular, withregard to whom complaints should beaddressed. Clarification was also requiredon remediation and mitigation.

1.1.3. Current perceptions were supportedby the recent London AssemblyEnvironment Committee report, “Londonin a Spin – a review of helicopter noiseOctober 2006”. That report states thatthere is anecdotal evidence of a growingconcern amongst members of the publicabout helicopter noise. The Departmentfor Transport (DfT) is currently workingwith the Civil Aviation Authority (CAA)and National Air Traffic Services (NATS) inresponse to the key recommendations.This report for Defra, which also looks atprocedures abroad, addresses many of thequestions raised in the London Assemblyreport although the scope of this study isUK wide.

1.2. Policy context1.2.1. The Environmental Noise Directive(END) 2002/49/EC [1] was published in theOfficial Journal on 18 July 2002. The aimof END is to provide a high level of healthand environmental protection againstnoise.

1.2.2. The END requires Member States tomake Strategic Noise Maps for majoragglomerations (defined as areas of urbandevelopment with a population of at least250,000, a population density of 500person per square kilometre and acontinuous urban area of at least 20hectares) major roads, major railways andmajor airports within their territories.

1.2.3. As part of the END, Action plansdesigned to manage noise issues andeffects including noise reduction ifpossible will have to be drawn up by 18July 2008 and submitted to theCommission by January 2009. The airportauthorities are responsible for drawing upaction plans, which must be approved bythe SoS. Action plans for other sourcesincluding agglomerations will be drawnup by the SoS. Public and stakeholderswill be consulted.

1.2.4. Helicopters are not excluded fromthe Environmental Noise Directive but areonly accounted for at major airports.

1.3. Aims and objectivesThe aims of the project were:1) To determine the issues and the extent

of the reported problem of noise fromhelicopter operations in the UK.

2) To develop practical guidance on themanagement of helicopter noise,including improvements in thehandling of complaints.

The objectives of the study were:1) To investigate the reported adverse

impacts of helicopter noise and toprovide information on the nature andextent of the concern about helicopternoise in the UK.

2) To compile a summary of the existingprocedures in place for handlingcomplaints relating to noise fromhelicopters together with the roles,responsibilities and powers of thevarious authorities and regulatingorganisations.

3) To compile a summary of the currentrules and regulations governinghelicopter operations, any currentrelevant industry codes of practice andany existing reported dose-responserelationships. Opportunities forimprovement will also be reported andrecommendations made on how thesecould be implemented.

1.4. Defra Technical Working Group1.4.1. Defra formed an ad-hoc technicalworking group of key stakeholders toparticipate in and oversee this project.Their role was to advise Defra oninformation sources, current problems andpossible solutions, and to peer review theproject deliverables. The members of thistechnical working group are summarised

in the table below.

1. Introduction

Table 1: Defra Technical Working Group - Helicopter noise

Role Name Affiliation

Nominated Officer Antonio Acuna Defra

Chairman: Richard Perkins Defra

Project Manager Ian Sherlock Defra

Policy Officer: Wendy Hartnell Defra

Policy Adviser: Stephen Turner Bureau Veritas

Member Colin Grimwood Bureau Veritas (PPG24)

Member Paul Freeborn Bureau Veritas (BHAB)

Member Darren Rhodes ERCD / CAA

Member James Deeley ERCD / CAA

Member Steve Mayner Wandsworth Council

Member Colin Stanbury Wandsworth Council

Member Christopher Forrest PremiAir [BHAB]

Member Roy Strapp DfT (Aviation Environmental Division)

Member Frank Evans DfT (Aviation Environmental Division)

7


This section introduces the issues and theextent of the reported problem of noisefrom helicopter operations in the UK. Thenature and the extent of concern abouthelicopter noise in the UK is presented.Objective measures and dose-responserelationships are briefly described tofacilitate a short overview of subjectiveresponses. Current means of redress forany perceived disturbance caused arelisted before an overview of the London ina Spin report. A short summary of theviews elicited from stakeholders at anInstitute of Acoustics meeting on thistopic is presented as part of an estimationof the problem of helicopter noise. Theseissues are addressed in detail later in thisreport.

2.1. Nature of the concern abouthelicopter noise in the UK2.1.1. Surveys suggest some people tendto be concerned about helicopteroperations and the noise they create for anumber of reasons. The main issuesidentified in this report are summarised asfollows:1) The subjective response to aircraft

noise is often described in terms ofcommunity ‘annoyance’ and studieshave indicated that helicopters can beup to 15dB 'more annoying' thanother aircraft [3].

2) Sound levels alone do not account forannoyance trends in communities.People are also concerned about otheraspects of the operations and thenoise acts as a trigger for theseconcerns. Examples include concernsabout safety, perceived intrusion ofthe helicopter into one's personalliving space, and negative opinionstowards the purpose of the flight [3].

3) Research (primarily concerned withfixed wing aircraft) has shown thatnoise adversely affects classroomlearning. It has been shown that lowachieving students are the mostadversely affected [4].

4) High aircraft (fixed wing) noise levelscan awaken people, but the likelihoodof the average person having theirsleep noticeably disturbed due to anindividual aircraft noise event isrelatively low [4]. However, sleepdisturbance from helicopter operationsmay differ considerably due to itsunique modes of flight such ashovering and low flying.

5) A recent study has shown that forevery 10dB increase in night-timenoise level for fixed-wing aircraft (Lnight

2300 – 0700), the risk of hypertensionis increased by about 14% [5].

2.2. Extent of the concern abouthelicopter noise in the UK2.2.1. The CAA reports that there were370 noise complaints resulting fromhelicopter operations in the UK in 2007,80 of which were regarding helicopteroperations over London [6]. However, thisis not a complete list as complaints aboutmilitary helicopter use and complaintsdirected at operators and local authoritiesare not included.

2.2.2. The London Assembly EnvironmentCommittee ‘London in a Spin’ reportstates that ”anecdotal evidence from thepublic has indicated a growing concernwith helicopter noise” [7]. The authorscomment “there is no comprehensivedatabase of helicopter movements acrossLondon, so it is impossible to tell theextent to which this noise nuisance hasincreased”.

2.2.3. Anecdotal evidence reveals'pockets' of complaints arising aroundareas such as busy heliports, aerodromesand some RAF bases. RAF Shawburyreports receiving 313 noise complaints in2007.

2.2.4. The Chartered Institute forEnvironmental Health (CIEH) conducts anannual survey of environmental healthdepartments but has only recently (in thepast two years) started to recordhelicopter noise complaints. On average,for those two years, helicopter complaintsmake up about 5% of the overall numberof noise complaints received from alltransport; all transport being fixed-wingaircraft, motorbikes, cars and commercialvehicles (e.g. lorries, vans buses etc) [8].

2.3. Noise indices and measurementmethods2.3.1. In assessing the environmentalimpact of noise on individuals andcommunities, an objective descriptor with awell-defined relationship with communityannoyance is required. Annoyance iscomplex and different individuals andcommunities react differently to differentnoise sources. A large number of indiceshave been developed for variousapplications. As this may lead to confusionand misinterpretation of data, a number ofresearchers have tried to move towards astandardised method of assessing aircraftnoise [9] but have met with little success“because of the variability and unpre-dictability of reaction the impact of noisehas always been difficult to quantify. As aresult there is no single measure of theimpact on the community of noise” [10].

2.3.2. Noise level is measured as soundpressure level in decibels (dB), a measuredescribing a sound level relative to thethreshold of human hearing (in the midfrequency range). Sound level is oftenaveraged over a period of time, and oftenfrequency weighting scales are applied tosounds to take into account the humanauditory response systems’ uneven nature.The most commonly used frequencyweighting system is A-weighting which isdesigned to model the human auditoryfrequency response at relatively low levels(<55dB). A-weighting was also found tocorrelate well with the human responseover a wider range of sound pressurelevels. There are also B, C and Dweightings. B and C weightings weredesigned to account for the change infrequency response at different soundpressure levels of the human auditorysystem. The D weighting was introducedto account for the spectral characteristicsof turbo-jet powered aircraft as anapproximation to Perceived Noise Level(PNL) but is now obsolete.

2. The Problem of Noise from HelicopterOperations in the UK

2005-2006 2006-2007

Number of Complaints 56 40

Number of Noise Incidents complained of 45 37

Nuisance Ceased and Not Likely to Recur 0 1

Referred to Other Services 6 1

Resolved Informally 11 1

No Action Possible 13 4

Table 2: Helicopter noise complaints received 2005-2007 (survey of EnvironmentalHealth departments) [8].

8


2.3.3. A wide variety of noise indices havebeen developed for use in aircraft noiseand community response studies:● Perceived Noise Level (PNL)● Effective Perceived Noise Level (EPNL)● Noise and Number Index (NNI)● Australian Annoyance Index (AI)● Disturbance Index (Q)● Equivalent Continuous Noise Level (Leq)● Equivalent Sound Level with Threshold● Single Event Noise Exposure Level (SEL)● Exposure Forecast● Psophic Index● Weighted Equivalent Continuous

Perceived Noise Level (WECPNL)● Day-Night Level (DNL)● The 16h A-weighted Equivalent

Continuous Noise Level (LAeq, 16h)● Day Equivalent Continuous Noise Level

(Lday)● Evening Equivalent Continuous Noise

Level (Levening)● Night Equivalent Continuous Noise

Level (Lnight)● Day, Evening, Night Equivalent

Continuous Noise Level (Lden)

2.3.4. In the UK, NNI was used from thegovernment’s Wilson committee reportfrom 1963 until 1990, when the 1984Aircraft Noise Index Study (ANIS) led tothe LAeq being adopted as the UK aircraftnoise index. However, just as the NNI hasbeen dropped in the UK, so too has thePsophic index, the Dutch are about todrop the Kosten Index, and the Japaneseare about to drop WECPNL. All aremoving towards the use of Lden.

2.3.5. The 16-hour LAeq and night-timeLAeq are used in planning legislation todetermine whether planning applicationcan be granted. Often noise levels arepredicted to determine whether planningapplications will be granted. As a result ofthe Environmental Noise Directive (END)(2002/49/EC), noise maps have beenproduced to identify noise climate andhelp develop action plans to managenoise levels. These maps show noisecontours where each contour representsan average noise level. Lden is the 24-hrLeq calculated for an annual period, butwith a 5 dB weighting for evening and a10 dB weighting for night. Directive2002/49/EC requires EU Member States toproduce noise maps using the Lden noisemetric, although helicopters are notcurrently included. The Lden is not aninformative parameter for the depiction ofhelicopter noise, since helicopter noisearises from individual flights as opposed to

the average of a large number of flights.The situation is illustrated by figure 1.

2.3.6. Civilian helicopters must undergo anoise certification test for each type ofcraft. Heavy (>3175 kg) and light (≤3175kg) helicopters have separately definedtests, although light helicopters may usethe scheme for heavier helicopters. Forheavy helicopters, noise levels aremeasured at three points on the groundduring three prescribed flight conditions –take-off, level flight and approach tolanding. The Effective Perceived NoiseLevel (EPNL) is used as a descriptor of thenoise level. For light helicopters,certification is based on the flyovercondition only and the sound exposurelevel is used to categorise the noise level.Both SEL and EPNL utilise only the highest10dB of the noise event, however, soundoutside this upper 10dB region can stillcause annoyance, especially where highlevels of impulse noise are present [3].Since there is a discrepancy between noisetarget limits and public acceptance, theuse of certification levels by manufacturersas design targets for acceptable noiseperformance may be problematic. Itshould be noted that although militaryhelicopters are expressly excluded fromnoise certification, civil and militaryvariants of newly designed aircraft areusually based on common rotor, engineand transmission systems so that the noisecharacteristics are virtually identical. Itfollows that military helicopters aredesigned to the same noise standards ascivil aircraft. Chapters 4.7 and 3.8 refer inmore detail to noise certification.

2.4. Existing dose responserelationships2.4.1. A dose-response relationship is afunction that is designed to predict therelationship between an objective physicalmeasure such as sound level, to asubjective response such as annoyance.The Aircraft Noise Index Study (ANIS),published by the CAA in 1984, aimed toaccurately measure human responses toaircraft noise, and to find the dose-response relationship that best describesthis subjective response. The result ofANIS was a dose-response relationshipwhere the percentage of people whofound the aircraft noise unacceptableincreases from around 15% at 57dB LAeqroughly in a straight line to around 75%at 69dB LAeq. No equivalent study hasbeen performed specifically for helicopters[11].

2.4.2. DORA published DR Report 8304:1982 Helicopter Disturbance Study [112],although inconclusive, found thatannoyance was greater from helicopternoise than for fixed-wing aircraft for agiven noise exposure level. Anotherlimited social survey was undertaken aspart of the 1990s London Heliport Study[113] and is mentioned in that report. Asa result of that work, helicopter noisecontours were plotted down to 51dBLAeq 16hr (6dB lower), acknowledginggreater annoyance from helicopter traffic.A separate helicopter social survey reportwas referenced to be published shortlyafter, but ultimately never appeared.

Figure 1: Simulated time history (SPL) of sporadic helicopter flyovers comparedwith 16hr Leq.

9


2.5. Subjective responses to helicopternoise2.5.1. Most community responsemeasures to acoustic stimuli are based onA-weighted sound pressure levelsaveraged over a long period of time.However, when dealing with only a smallnumber of acoustic events, e.g. sevenhelicopter flights over a sixteen-hourperiod (see figure 1), the acoustic eventshave little bearing on the resultingmeasure. The United States FAA report [4]states the current measures are deficientfor helicopters in terms of not only thenumber of events, but also in how thesubjective effect is measured. In particular,low frequencies and the impulsive natureof sound are not accounted for in currentmetrics. The FAA acknowledges thisproblem in its 2004 report to the UnitedStates Congress but continues to use theDay-Night sound level (DNL) as there is noverified alternative.

2.5.2. In addition to these problems withmeasurement indices, studies have foundthat current objective metrics are notrepresentative of annoyance, and thatattitudes to the helicopter operations area contributing factor. The term ‘virtualnoise’ is used to describe non-acousticfactors such as fear of crashes and othernegative views of the helicopteroperations [3].

2.6. Means of redress for anyperceived disturbance caused2.6.1. The CAA acts as a focal point forreceiving environmental complaints aboutaircraft. However, the CAA has no legalpower to prevent aviation solely onenvironmental grounds. Unless there isclear evidence of a breach of the AirNavigation Order, the CAA will advise thecomplainant to contact the operatordirectly.

2.6.2. Often establishing communicationand dialogue with helicopter operatorscan produce a positive outcome and anexplanation of the purpose and nature ofthe operation that caused the disturbancecan be satisfactory. Consultativecommittees have been found to beparticularly helpful in raising issues withoperators and ensuring operators areaware of their environmental impact. Inaddition, making the operator aware ofproblems caused can often result inchanges to operational procedures to helpalleviate the public disturbance.

2.7. London Assembly EnvironmentCommittee report, “London in a Spin" 2.7.1. In 2006, the Greater LondonAuthority published a review of helicopternoise in London. The report highlights“concern among a number of groups ofresidents as to the impact of helicopternoise on their quality of life”. The reportcomments that “helicopter movementshave been growing over the past fewyears” and are a distinctive feature ofurban living. The report makes a numberof short-term practical recommendationsto the Government and the Civil AviationAuthority (see chapter 9).1) Develop a database to allow the

public to monitor helicoptermovements.

2) Develop robust complaints proceduresto ensure the public’s concerns aretaken seriously.

3) Establish a consultative committee atthe London heliport.

4) Changes to the way London’s airspaceare managed.

5) The possibility of a user charge foroperators.

6) More effective write-down incentivesfor older, noisier helicopters.

7) Consideration should be given tomoving the heliport to anotherlocation.

2.7.2. Use of the findings from the‘London in a Spin’ report to highlight the“growing concern over helicopter noise”has been criticised as anecdotal evidence.This is because data was received fromonly 132 London residents. This is a smallproportion of those currently subjected tonoise from helicopter movements [2].Since the report, and at least in part as aresult of the recommendations, thefollowing steps have been taken:1) A consultative committee has been

established at the London Heliport.2) A complaints telephone line has been

established at the London Heliport.3) The CAA has initiated changes to

airspace classification and designatedhelicopter routes to prevent helicopterholding.

4) The CAA has agreed a mechanismwith NATS to provide helicoptermovement data for the public on itswebsite.

2.8. Estimating the scale of theproblem of helicopter noise2.8.1. On the 6th Feb 2008 an Institute ofAcoustics meeting was held at theUniversity of Salford entitled “Theimprovement of the management ofhelicopter noise”. One of the aims of themeeting was to try to collect informationby engaging major stakeholders instructured discussion. One of the resultsof the debate was that it appears the ratioof helicopter movements to number ofcomplaints received is generally very smallfor most operations. A repeated view wasthat the scale of the problem of helicopternoise could not be estimated without thecentral logging of complaints. It wassuggested that there is a need for a more“holistic” approach, and national statisticsfor helicopter noise complaints arerequired before an “informed debate”.

2.8.2. An important point raised was theneed to be cautious in using complaintstatistics as a measure of the problem.While many complaints are from repeatcomplainers, not everyone that isdisturbed complains. Furthermore, withrelatively few numbers of complaintsreceived about helicopter noise, astatistically meaningful result is difficult toderive.

2.8.3. Another suggestion to estimate thescale of the problem involved carrying outa national public survey. A point raisedwas that “canvassing opinion may raisethe profile of the problem and aggravateit”. However, social survey techniquesexist to avoid this problem.

2.8.4. A generally common view fromdelegates was that the question ofwhether or not helicopter noise is a“problem” still needs to be determined;there does not seem to be enoughevidence at present to answer thisquestion. Recorded views included:“Although there is an argument that itmay not be (a problem) now, I feel itcertainly has the potential to becomeone” and “perhaps the question shouldnot be ‘is there a serious noise problem inthe UK?’ but rather ‘Are we facingincreased opposition to the developmentof helicopter bases and operations, and ifso, what are we going to do about it?’


2.8.5. General consensus amongstakeholders is that there is not asignificant helicopter noise problemthroughout the UK. However, problemsdo exist and these are centred onhelicopter infrastructure such as heliportsand aerodromes.

2.9. Summary of Chapter 22.9.1. Problems due to helicopter noiseare centred on helicopter infrastructuresuch as heliport and aerodromes. Theratio of helicopter movements to numberof complaints received is generally smallfor most operations. The CharteredInstitute for Environmental Health (CIEH)reports that helicopter complaints makeup around five per cent of the noisecomplaints received from alltransportation. The CAA reports thatthere were 370 noise complaints resultingfrom helicopter operations in the UK in2007. However, there is no comprehensivedatabase of helicopter movements in theUK. Consequently, it is impossible todetermine the extent to which noisenuisance is a growing concern.

2.9.2. Helicopters can be up to 15dBmore annoying than fixed-winged aircraft.However, sound levels alone do notaccount for annoyance trends incommunities from helicopter noise. Thereis no single satisfactory noise index for themeasurement or prediction of the impactof noise on the community. The use ofcertified levels as design targets foracceptable noise performance is likely tobe problematic, since there is adiscrepancy between noise target limitsand public acceptance.

2.9.3. The Lden is not an informativeparameter for the depiction of helicopternoise, since helicopter noise arises fromindividual flights as opposed to theaverage of a large number of flights.Noise maps displaying Lden are thereforeunlikely to be suitable for the predictionof community response to helicopternoise. It is widely recognised that whileLeq or Lden are not ideal, currently thereis not a better option. Further research isrequired to develop a dose-responserelationship to accurately measure humanresponse to helicopter noise.

10

11


This section considers helicopteroperations in the UK. An introduction tohelicopter noise generation mechanisms isgiven, together with noise reductionmethods relating to these mechanisms.The helicopter operations of theemergency services, including the police,air ambulance and search and rescue areoutlined, followed by military and civilianoperators. Finally, explanations ofhelicopter infrastructure, helicopter routesand noise certification are presented,together with comparisons as appropriateto those of fixed wing aircraft.

3.1. Helicopter noise generation andreduction methods3.1.1. Helicopter noise generation differsfrom fixed wing propeller driven aircraftbecause the main rotor and tail rotoroperate close to the horizontal plane andvertical plane, respectively, with axes ofrotation normal to the flight direction.Whilst for propeller driven aircraft the axisof the propeller is aligned to the directionof travel, and the noise from eachpropeller generally has symmetry aboutthis axis. Such axial symmetry does notexist for helicopter rotor blade noisesources. For this reason very few of thehelicopter noise sources are similar to thatof its fixed wing counterparts [12].

3.1.2. Helicopter noise is generated froma number of main sources: engine noise,rotor noise and transmission noise. Apartfrom piston engine powered craft, themain noise sources are from the rotors [3].Spectral analysis of helicopter noise revealsa series of tones generated by the mainand tail rotors. The main rotor generates aseries of tones whose fundamental is inthe range 10 to 40Hz. The tail rotorgenerates a higher frequency tone serieswhose fundamental is usually in the range100 to 200Hz [13]. Although the tonalnoise dominates, broadband noise fromboth the tail and the main rotors ispresent at a lower level. There also existinteractive effects between tail and mainrotors and the fuselage, the formerinteraction leads to combination tonalfrequencies known as ‘Burble’[14].Impulsive sounds also result from theblade tips intercepting the vortex from apreceding blade (Blade Vortex Interaction -BVI) or the vortices from the main rotorbeing intercepted by the tail rotor (TailRotor Interaction - TRI). In addition thereexists high speed impulsive (HSI) noise

generated by transonic flow on advancingblades [13]. It is because of the highspeed of the advancing rotor tips incomparison with the speed of sound inthe medium (air) that the noise output isoften directed ahead of the helicopterrather than behind it [13].

3.1.3. Helicopters differ from fixed wingaircraft since the primary noise generationmechanisms are also the primary lift andcontrol mechanisms. For this reason, therealisation of a quiet helicopter must befully integrated within the design process.Reduction in noise level is generally at theexpense of performance factors such aspayload, range and speed. Therelationship between the helicopter designparameters is very close. For example,reducing the rotor tip speed will reducethe noise level however to maintainperformance the blade area/number/shapewould have to be altered [3]. Thisprocedure was adopted in thedevelopment of the EH101/Merlinhelicopter [15] the exceptionaladvancement in performance of theBritish Experimental Rotor Program (BERP)blade was partly traded for noise, byreducing tip speed, to produce thequietest helicopter in its weight class.Blade tips can be used to control BVI, seefor example the vane tip programme [3].Reducing tip speed can be effective butusually for a loss of performance and careis needed to prevent retreating blade stallfor the lower speed.

3.1.4. Currently practical designimprovements aim to reduce BVI and tailrotor noise. These are perhaps the biggestsource of complaints regarding helicopternoise and the main trigger for non-acoustic factors or ‘virtual noise’. Currentlyactive and passive methods are beingtested, and results have indicated varyingdegrees of success. Given sufficientdevelopment, a reduction of 6dB(A) in thisarea is foreseeable. Modifications toreduce BVI noise would not impact duringnoise abatement procedures and levelflight [3] but tail rotor noise is present inall flight conditions and is a significanttrigger of ‘virtual noise’.

3.1.5. Tail rotor noise, because of itshigher frequency content than main rotornoise, has a significant effect on thesubjective perception of helicopter noise.A number of manufacturers have

embarked on design initiatives addressingthis, including the Westland Helicopter’squiet tail rotor (Q.T/R), the McDonnellDouglas NOTAR, and the Eurocopter’sfenestron fan-in-fin approach [3].

3.1.6. Following a study conducted byLeverton for Bell Helicopter Textron [3] itwas recommended that the Mach numberof the advancing blade tips should notexceed 0.875, and should generally bekept at less than 0.85 to prevent theimpulsive sound becoming unacceptable.

3.1.7. As the temperature decreases, thespeed of sound decreases, and thereforethe Mach number increases. This results ina dramatic increase in the perceivedmagnitude and impulsiveness of the mainrotor thickness noise close to the rotordisk plane. Helicopter manufacturers oftenprovide noise data at the ICAOcertification specified temperature of25

oC. The possible significant variation in

level and subjective character of thehelicopter noise due to temperaturedifferences is not taken into account, andas such, some noise abatementoperational procedures are not achievingthe noise levels predicted. This is aparticular problem for helicopters withhigh tip speeds and unsophisticated rotordesigns. One manufacturer has recentlyintroduced flyover speed limits wheretemperature is taken into account, andanother two have indicated that theyintend to follow suit. [3]

3.1.8. Operational procedures can helpreduce the environmental impact ofhelicopters. Type specific Aircraft FlightManuals (helicopter) contain aperformance graph that details flyingprocedures to produce the least amountof noise although the flight envelope isdifficult to follow due to the variety ofpower and airspeed configurations. Areduction in speed of just 10 knots canhave a significant noise reduction effect[16].

3.2. Emergency services3.2.1. Police: The UK police service fundtheir own helicopter operations [17]. Thedifferent forces will either buy or lease thehelicopter, and use either their own staffor pay a third party, such as PremiAir orSterling Helicopters Ltd, to operate thehelicopter. Many police forces haverecently upgraded their fleets with quieter

3. Helicopter operations in the UK

12


helicopters such as the McDonnellDouglas NOTAR equipped MD902, andthe Eurocopter EC135 with its fenestrontail rotor. Currently the EC135 is the mostpopular police helicopter, followed by theMD902. These helicopters are some of thequietest available [16]. The proportion ofdifferent helicopter models in the policeforce in the UK is indicated in Figure 2.Police helicopters operate from a range oflocations including RAF airfields, privategeneral aviation aerodromes, majorairports and bespoke landing sites.

3.2.2. Air ambulance: Air AmbulanceServices operate as charities and rely onthe public for funding. A survey byMorepace revealed that only 40% of theUK public is aware of this fact [19]. 16regional charities support 26 airambulances in the UK. In Scotland,however, the Scottish executive funds airambulances, whilst in London airambulance receives partial NHS funding.Figure 3 describes the break down of thedifferent helicopter models operating asair ambulances in the UK. The Associationof Air Ambulance Charities (AAAC)supports the work of the UK’sindependent air ambulance charities. Theair ambulances undertake 17,500 missionsin a year of which 40% involve roadtraffic collisions, 24% are other medicalemergencies and 3% are hospitaltransfers[20].

3.2.3. Search and rescue (SAR): Searchand rescue in the UK (on land and at sea)is covered by six RAF Search and Rescueteams, four civilian coastguard teamsoperated by the Maritime and CoastguardAgency (MCA), while the Royal Navyoperates two SAR teams[21]. BeforeDecember 2005 the Maritime andCoastguard Agency contracted Bristow'sHelicopters Ltd to operate 3 Sikorsky S61Nhelicopters and bases of operations areSumburgh Airport (Shetland), Stornoway(Isle of Lewis) and Lee-on-Solent. All arecapable of the full range of airbornesearch and rescue tasks. A fourth S61Nhelicopter stationed at Portland (nearWeymouth) can operate in daylightonly[22]. Announced in December 2005CHC is now contracted to operate two S-92s at Stornoway and two S-92s atSumburgh, plus two AB139s based at Lee-on-Solent and an additional AB139 atPortland [23].

3.3. Military helicopter operations3.3.1. Almost all complaints generated byMOD helicopters will arise from low-flyingoperations. MOD low flying operations arecomprehensively summarised in annualreports [24]. Low flying timetables forupcoming months are also published onthe MOD’s website.

3.3.2. The MOD divides the country into20 Low Flying Areas (LFAs) as shown inFigure 4. Statistics on the distribution ofmilitary helicopter flights across the UKare then divided according to these areas.

Four of these areas are referred to asDedicated User Areas (DUAs) where mostof the helicopter pilot training takes place.These are areas 1, 3, 9 and 10 on themap. LFA1 contains RAF Odiham, home toChinook and Lynx, and RAF Benson, hometo Merlin and Puma. LFA3 contains RNASCuldrose, home to Merlin and Sea King.LFA9 contains the Defence Flying TrainingSchool at RAF Shawbury, which runs pilottraining on Gazelles, Griffins and Squirrels.LFA10 contains the Army Air Corps. atWattisham, home to Apache andLynx.

Figure 2: Breakdown of Police helicopter types[18]

Figure 3: Breakdown of Air Ambulance helicopter types[18]

13


3.3.3. It should be noted that militaryhelicopters do not have to meet the civilnoise certification standard unless they arealso used for civilian purposes. However,variants are often used for civilianapplications in which case civil certificationis required and as mentioned in 2.3.6,military and civil aircraft are usually basedon common rotor, engine andtransmission systems so that the noisecharacteristics are virtually identical.

3.3.4. Helicopters outside of DedicatedUser Areas (DUAs) are considered to below flying below 500ft, but in DUAs(because of the increased number offlights) any flight below 2000ft has to berecorded as a low flying activity. In2006/2007 there were 16,164 hours offlying recorded outside of the DUAs, and26,041 hours of flying recorded in thefour specified DUAs.

3.3.5. There are 14 major areas in thecountry that the MOD cannot use for lowflying. These predominantly lie aroundairports and large built up areas. Inaddition, towns with more than 10,000inhabitants are avoided and anyone iseligible to apply to the MOD for anadditional avoidance area.

3.4. Civilian helicopter operations3.4.1. Figure 7 indicates a steady increasein the number of civilian helicoptersoperating in the UK from 2002. Thesecurrently number 1,393[19]. There hasbeen a particular increase in the numberof smaller piston engine craft and thisincrease appears to be due to the recentpopularity of the Robinson R22 and R44helicopter.

Figure 4: Low flying areas for military aircraft. (LFA1 highlighted)

Figure 5: Break down of civilian helicopter types [19] Data from BHAB handbookCopyright 2007 Computair Consultants : email [email protected].

14


Types of operations include:1) Flights that take place during major

sporting events (e.g. GoodwoodRevival, British Grand Prix, RoyalAscot) and other major events such asthe Farnborough air show.

2) Traffic surveillance.3) Transporting heavy loads into

inaccessible places (e.g. NationalParks).

4) Pleasure flights.5) Charter.6) Transfers between airports /

commercial premises.7) Private owners.8) Pipe line / power line surveying.9) Scheduled services (e.g. Penzance to

Isles of Scilly).10) Servicing oil fields (e.g. Aberdeen).12) Corporate flights.13) Press / Aerial photography.

3.5. Helicopter infrastructure3.5.1. When compared with fixed wingaircraft with a similar personnel capacity,the fixed wing aircraft is faster andcheaper in terms of capital and operatingcosts. The advantage of the helicopter isthat it does not require a large amount ofspace from which to take off and land.This means that helicopters do not requirethe extensive infrastructure needed byfixed wing craft, and this enables thehelicopter to offer virtually door-to-doortransportation [25].

3.5.2. Helicopter landing / take-off sites:For ground level sites it is not possible tospecify general requirements as allhelicopters have different performancecharacteristics. A flat area around 24x16mshould be sufficient for smaller types.Additionally, there should be noimmediate obstructions after take-off andif possible, helicopters should be able totake off into the prevailing wind. It is thepilot’s responsibility to ensure that thelanding site meets the craft’sspecifications. When operated fromelevated sites, such as rooftops,helicopters must meet more stringentsafety requirements. For a craft to be ableto operate from an elevated site, it mustbe certified Group A/ Class 1 by the CAA.This means that even if one engine fails,the craft is able to land or fly away safelyusing the remaining engine thus onlytwin-engine craft can operate fromelevated sites [25].

3.5.3. Helicopters can operate frompermanent landing sites such as heliportsor aerodromes, and temporary landingsites such as fields, gardens andcommercial premises. Refer to section 4.3for details on planning permission for thedifferent types of landing sites.

Figure 6: Break down multi-turbine civilian helicopter types [19]Data from BHAB handbook Copyright 2007 Computair Consultants:email [email protected].

Figure 7: Recent trends in helicopter types [19]Data from BHAB handbook Copyright 2007 Computair Consultants: email [email protected].

15


3.6. Helicopter airspace restrictions3.6.1. UK air space can be categorised as‘Controlled Airspace’ (CAS) or ‘UncontrolledAirspace’ (UCAS). Within controlled airspace,pilots must gain Air Traffic Control (ATC)clearance and comply with instructionsissued. Controlled Airspace can be furthercategorised as follows [25, 26]:1) Control zones are regions extending

from ground level up, and span up to2_ nautical miles from an aerodrome’sdatum.

2) Control areas are regions, which extendfrom approximately 2000ft and 5000ftupwards.

3) Airways are corridors that are the mainroutes connecting major airports.

4) Terminal control areas are larger controlareas situated around groups of airportswhere major routes converge.

5) Upper airspace is the airspace from19500 ft upwards.

3.6.2. The majority of air space in the UKbelow 2000ft is unrestricted (UCAS).Although there is no requirement forhelicopter pilots to make contact with ATCwhen flying in UCAS, they often do so inthe interest of safety. Helicopter pilots mustcomply with ATC instruction in control zonesaround aerodromes.

3.6.3. There are relatively few areas ofrestricted airspace over mainland UK.Examples include: areas of high-densitymilitary activity, atomic reactors, high securityprisons and the residence of the Prince ofWales. In addition, temporary restrictedareas can be set up for major incidents/accidents, temporary helicopter landing sitesand temporary hazards to aviation.Surprisingly, some military danger areas andairfields are not necessarily restricted andonly the CAS rules apply. Nevertheless,intentional intrusion without prior clearanceis ill advised [25].

3.6.4. In addition to these rules of UKairspace operations, the rules of the air asdescribed in section 4.1 also impact onairspace restrictions. Refer to this section forfurther information.

3.7. Helicopter routes 3.7.1. A number of helicopter routes havebeen established, usually to help air trafficcontrol at busy airports. The primaryfunction of helicopter routes is tomaintain separation from fixed wingaircraft. They are designed so thathelicopters will fly over open spaceswhenever possible. Routes are designed tohelp helicopter pilots obey the AirNavigation Order (ANO) rules. Routes arenot mandatory but in practice, especiallyin London, are generally followed (thoughtwin engine craft can request to routedirect). The report ‘London in a Spin’contains a map showing the location ofthe helicopter routes in London [7].

3.8. Helicopter noise certification 3.8.1. All civil helicopter types in the UKrequire a certificate of airworthiness. Partof the certification requires noisecertification. This is to ensure the craftmeets certain internationally agreed noisestandards set by the International CivilAviation Organisation (ICAO) of which theUK is a member. The certification processis described in more detail in chapter 4.7.On the 28th March 2007 the EuropeanAviation Safety Agency (EASA) initiatedchanges relating to the noise certification,which introduced an EASA Certificate forNoise (EASA Form 45) and set downstandard values upon which eachCertificate should be issued. The CAA hascommenced a programme of replacing allCAA Noise Certificates for applicableEASA aircraft with Form 45 and this istargeted for completion by March 2009[27].

3.9. Summary of Chapter 33.9.1. Helicopter routing is generallydesigned to assist Air Traffic Control andto maintain separation from fixed wingaircraft. In general, helicopter routes aredesigned to fly-over open spaces whereverpossible.

3.9.2. The choice of rotor blade tip speedand to a lesser extent blade tip shape, isimportant because it controls the intensityand character of the impulsive noisegenerated by a helicopter. This applies toboth the main and tail rotors.

3.9.3. 3.9.3. The largest non-military userof helicopters in the UK providestransportation for the oil and gas industry.

3.9.4. The majority of helicopters used bythe Police and by the Air AmbulanceService are the quietest types available.

16


4. Rules and regulations relating to Helicopter operations

This section provides a summary of therules and regulations applicable tohelicopter operations and helicopterinfrastructure in the UK. It refers to theRules of the Air Regulations, relevantsections of planning and nuisance law,and to the codes of practice andguidance provided by the BritishHelicopter Advisory Board (BHAB) and theCivil Aviation Authority (CAA). Thissection also includes explanations ofhelicopter routes and noise certification.Finally, comparisons are drawn with rulesand regulations from other Europeancountries, the USA and Australia.

4.1. Rules of the Air Regulations4.1.1. The conduct of civil aviation is setout in the Civil Aviation Act (1982). TheAir Navigation Order (ANO) is thedocument that delegates powers to theCivil Aviation Authority (CAA). The ANOdetails exact specifications on all aspectsof aircraft behaviour. Safety is the primaryfocus of the ANO [25].

4.1.2. Specifically, civilian helicopterflights in the UK are governed by theRules of the Air Regulations 1996 [28]andthe Air Navigation (Restriction of Flying)(Specified Area) Regulations 2005[29].

4.1.3. The ANO and Rules of the AirRegulations permit helicopters operatedon behalf of the police to fly lower thanwould otherwise be normally permitted.

4.1.4. Military operations do not operateunder the ANO or the rules of the airregulations. Rather, they operate toMinistry of Defence regulations detailedin Joint Service Publications (JSPs). TheCAA has no jurisdiction over militaryoperations and all enquiries about theseoperations should be directed to theMinistry of Defence [30].

4.1.5. The ANO has three priorities1) No aircraft may be operated in such a

way that, even if an engine fails, thirdparties on the ground are put at risk.

2) If there are fare-paying passengers onboard an aircraft, the operator isrequired to ensure that certainmandatory safety standards are metto ensure that risk of injury to thepassengers is minimised.

.

3) In the case of private pilots, the CAAensures that minimum standards inrespect of flying, training, licensing,construction and maintenance aremet.

4.1.6. The CAA has no legal power toprevent aviation on solely environmentalgrounds. Any breach in the ANO isreferred to the Aviation RegulationEnforcement Department (ARED). TheCAA can only act in the event of a breachof the ANO. To prosecute, a number ofindependent witnesses and positiveidentification of the aircraft are required[6].

4.1.7. An independent review isconsidering greater powers for the CAAover environmental matters [Frank Evans,DfT, IoA meeting].

4.2. Rules and regulations governinglow-flying helicopter operations(ANO)4.2.1. The ANO states “An aircraft shallnot be flown below such height as wouldenable it, in the event of a power unitfailure, to make an emergency landingwithout causing danger to persons orproperty on the surface”.

4.2.2. Unless a helicopter is taking off orlanding, in accordance with standardaviation practice, no helicopter may flycloser to a person, vehicle, vessel orstructure than 500 ft (often referred to asthe “500 foot rule”). This does not referto absolute height and thereforehelicopters can fly lower over moorland,for example.

4.2.3. No helicopter may fly over townsor settlements at a height less than1500ft or within 2000 ft of the highestfixed object. This rule was amended in2004 and the minimum height reducedto 1000 ft [28](referred to as the “1000ft rule”).

4.2.4. Exemptions from both the 500ftand 1000ft rules are allowed with writtenpermission from the CAA. Examples ofexceptions include landing sites in citycentres, aerial photography and policeand ambulance services.

4.2.5. The 1000ft rule does not applywithin controlled airspaces such as theLondon control zone and aroundaerodromes where air traffic controlprovides a control service to aircraft.

4.2.6. No flying over the centre ofLondon, except over the Thames, unlessthe helicopter can fly even in the event ofan engine failure. (“Specified Area rule”).Essentially this allows twin engine craft tofly over London where single engine craftmust follow the Thames.

4.2.7. No flights are permitted over orwithin 3000ft of gatherings of people of1000 or more without the permission ofthe CAA (referred to as the “crowd rule”).

4.2.8. A blanket exemption existsregarding flights with the purpose ofsaving life.

4.3. Relevant sections of planning law4.3.1. Permanent landing sites aregenerally regarded as those that have aCAA licence and that have been givenplanning permission by the localauthority. There are only three licensedheliports in the UK, at Battersea,Penzance and Culter Helipad nearAberdeen [31]. For scheduled services tooperate the heliport must be licensed.Helicopters can land at most fixed wingairfields both licensed and unlicensed.However, as helicopter flights should notcross fixed-wing aircraft landing and take-off paths, helicopter approach anddepartures at fixed-wing airfields are side-on to runways and are more likely toimpact on properties less affected byfixed-wing operations.

4.3.2. Temporary landing site use isallowed as long it is not in use for morethan 28 days in the year and permissionis gained for its use. (Part 4, Class B ofSchedule 2 of the Town and CountryPlanning General Development Order1988). Local authorities have powers towithdraw the right to use the site, and torequire a planning application to be madefor continued use. If the direction is toremain in force for more than six months,approval from the Secretary of State forthe Environment is required. If planningpermission is refused or granted subjectto conditions, compensation may bepayable.

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4.3.3. Helicopters may operate fromprivate gardens of a property withoutplanning permission. However, to use anadjoining field, even if it is also owned bythe property owner requires eitherplanning permission or use as a temporarylanding site for up to 28 days per year.One issue raised was that the 28 daysapplies to a specific parcel of land andthat a further 28 days would be allowableon an adjacent parcel of land [32].

4.3.4. Planning permission is not requiredfor helicopter operations from commercialproperties unless the size of the helicopteroperation overtakes the size of theoriginal business. In this case, planningpermission must be sought.

4.3.5. Any landing site in urban andcongested areas requires the prior writtenpermission of the CAA before they canoperate.

4.3.6. In 1963, the Wilson report led tothe use of the NNI (Noise and NumberIndex) and defined 35 NNI as lowannoyance and 55 NNI as highannoyance.

4.3.7. In the early 1980s, the CAA'sDirectorate of Operational Research andAnalysis (DORA) carried out a studycommissioned by the Department ofTransport into the use of the NNI. The NNIwas considered ‘out of line’ with aircraftnoise nuisance indices used in othercountries, which tended to use Leq basedmeasures. This study became known asthe Aircraft Noise Index Study (ANIS)[11].

4.3.8. ANIS revealed no ‘hard statisticalevidence for an ‘N’ variation indisturbance as compared with the log Nof NNI and Leq’ and ‘If there is anyvariation with N, then it has a muchsmaller coefficient than the log N termover a very wide range of L and N values’.It was also demonstrated that the Leqmeasure correlated better with annoyancethan NNI[33].

4.3.9. In the original planning documents(e.g. Circular 10/73), the criteria forannoyance were low/medium/high, and theNNI index was used as the index ofannoyance. In the Planning Policy Guidancedocument (PPG24) [34], a series of fourNoise Exposure Categories (NEC) called A, B,C and D based on LAeq levels are providedas guidance on the suitability of land fornew residential development near existingsources of aircraft noise. Category D meansplanning should normally be refused.Category C indicates a strong presumptionagainst acceptance unless there are noacceptable alternatives; in this situation,conditions should be imposed to ensureadequate noise insulation. Category Bindicates that noise should be taken intoaccount in the planning process and noiseinsulation is required. Category A indicatesthat noise is not a factor to be taken intoaccount in the planning process. ExposureCategories can be used to determinewhether planning permission should begranted to a new development in an areawith existing noise sources. It is statedhowever, that they cannot be applied in thereverse context. LAeq levels for any categorymay be increased by up to 3 dB if there is aclear need for new residential development.

4.3.10. PPG24 recommends that where anaerodrome operates less than about 30movements a day, Leq should not be solelyrelied on. PPG24 states, “when determininga planning application for a heliport thepredicted noise should not be assessed inisolation - account should be taken of localcircumstances including the existing level ofnoise disturbance”. The documentrecommends that, due to the noisecharacteristics of helicopters, the noiseexposure criteria should be treated withcaution. Planners may request that theapplicant discuss with NATS theestablishment of helicopter routes if theseare not supplied with the application.

4.3.11. When individual night-time noiseevents exceed 82 dB LAmax several times inany hour, the NEC should be treated asbeing category C, regardless of the LAeq,8h

(except where the LAeq,8h already puts thesite in NEC D). site in NEC D).

4.3.12. When a planning application closeto an operating heliport is sent to appeal,PPG24 will be cited as a benchmark.Generally, it is unlikely that the LAeq noiselevels alone will result in a rejection of theapplication. Consequently, LocalAuthorities should be aware of theprovision within PPG24 for considerationof aviation noise for low numbers ofmovements such as helicopter operations.

4.3.13. In 2001, the Department forTransport commissioned a study intendedto “underline the government’scommitment to underpin our policy onaircraft noise by substantial research thatcommands the widest possibleconfidence”. The results were presentedin November 2007 as the ‘Attitudes toNoise from Aviation Sources in England’report (ANASE) [35], and concluded thatpeople were becoming increasinglyannoyed by aviation noise. However, thereport’s findings were rejected followingrigorous peer reviewing [36] [37] [38]. Itshould be noted however that the studyrelates to annoyance from fixed wingaircraft rather than helicopters.

4.4. Nuisance law4.4.1. If aircraft operations meet therequirements of the ANO then persons areprecluded from prosecuting based onnuisance (Civil Aviation Act 1982 section76). Licensed heliports cannot beprosecuted under nuisance law as long asANO requirements are met (Civil AviationAct 1982 section 77). In addition heliportsare specifically excluded from prosecutiondue to noise and vibration caused byhelicopters landing and taking off, movingover ground or water and engines beingoperated in preparation for or after aflight for performance and maintenancereasons. (Civil Aviation Act 1982 section78 + ANO reg 12 (general)). TheEnvironmental Protection Act (1990 Part IIIsection 79) defines a statutory nuisancecaused by noise to be; 'noise emitted frompremises so as to be prejudicial to healthor a nuisance'. However subsection 6says that this 'does not apply to noisecaused by aircraft other than modelaircraft'. Therefore aircraft, includinghelicopters, are specifically excluded fromhaving action taken against theiroperators in respect of statutory noisenuisance.

Table 3: PPG24 criteria for air traffic showing LAeq(dB) for each category for differingtimes of day

LAeq,T(dB) A B C D

07:00 – 23:00 <57 57-66 66-72 >72

23.00 - 07.00 <48 48-57 57-66 >66

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4.5. Helicopter Operations:Codes of practice 4.5.1. Operators often use StandardOperating Procedures (SOPs) that tend toinclude noise abatement procedures.PremiAir, the London Heliport operator,commented that they actively try toensure that pilots fly in an environmentallyfriendly way as possible.

4.5.2. Airfield management may alsoestablish 'avoid' regions and other noiseabatement procedures. For example, atBirmingham International Airport, inresponse to a number of complaintsreceived via the airport consultativecommittee, a region of avoidance and aminimum height recommendation wereestablished. This was established byconsultation between the ATC, the policeoperation at the airport, and theenvironmental department. Operations areable to breach the rule but areencouraged to stick to therecommendations. Since implementing therule, the number of complaints hasdecreased.

4.5.3. Pilots are aware of noise issues butit is not always a priority concern. From apilot’s perspective, the most importantfactors considered for a pilot are: how toget back on the ground, with greatestease, safety and economy.

4.6. Guidance provided by the BritishHelicopter Advisory Board (BHAB). 4.6.1. The BHAB provides codes ofpractice for helicopter pilots andoperators. Codes of Practice have beendefined to inform potential clients ofsome important basic facts concerning thecommercial operation of helicopters. Theaim is to ensure that high standards ofsafety and professional competence aremaintained throughout the industry. TheCode of Practice has been endorsed bythe BHAB’s Council of Managementfollowing consultation with the CivilAviation Authority.

4.6.2. The BHAB are actively addressingthe noise issue with the Noise ActionGroup (NAG). The aims of this group areto persuade pilots to take more notice ofenvironmental noise issues and to lobbymanufacturers to produce quieterhelicopters. The group has membersincluding senior people from varioushelicopter operators.

4.6.3. The BHAB handbook details generalcodes of conduct for pilots aimed atshowing an environmentally consciouspublic that helicopter operators are awareof the need to preserve the environmentfrom unnecessary noise intrusion. TheBHAB handbook also details guidelines foroperations in national parks, and carryingout aerial photography, and similar workover congested areas

4.6.4. The BHAB makes a number ofrecommendations to ensure operators andusers minimise their environmentalimpact. These include[39] careful selectionof the location of helicopter landing sites,sensible flight planning which includesenvironmental impact as a factor, takinginto account the meteorological forecastand air traffic requirements and pilotsflying in accordance with the BHAB's'Pilots' Code of Conduct'.

4.7. Helicopter civil noise certification 4.7.1. Noise certification for helicopterswas added to Annex 16 of theConvention on International Civil Aviationin 1981 by the ICAO (International CivilAviation Authority) [40]. The proceduresfollow closely those established forcertificating fixed wing aircraft. For heavyhelicopters (>3175 kg) the certificationprocess is defined in ICAO Annex 16Chapter 8. Light helicopter certification isdefined in ICAO Annex 16 Chapter 11.Chapter 11 is voluntary on the applicant,whether they choose to demonstratecompliance with Chapter 11 or stay withChapter 8. A very small number ofhelicopters have been certificated usingboth Chapters.

4.7.2. Heavier helicopter certification usesthree flight procedures: takeoff, overflightand approach, all of which are measuredat three microphone positions. Thehelicopter performs each of the threeprocedures a minimum of six times toensure statistically valid results and anEffective Perceived Noise Level (EPNdB) isrecorded for each procedure. A number ofconditions, such as take off mass, speed,height and rotor speed, are placed oneach procedure to ensure repeatabilityand reliability of the results. In addition,corrections can be made to the EPNdBlevels according to variability in height,meteorological conditions such astemperature and humidity and groundspeed of the helicopter [41].

4.7.3. Light helicopters require only oneflight configuration for noise certification,take-off flight path with maximum power,to be recorded. The noise level ismeasured in SEL (dB). Light helicoptersmust be quieter than heavier ones.[42]

4.7.4. A window of acceptablemeteorological conditions and sitequalities for microphone placement isspecified in appendix 4 of the IACOAnnex 16.

4.7.5. For each flight, the EPNdB isaveraged across the three microphones.Repeated flights are carried out for eachprocedure until the 90% confidence limitsfor EPNdB of ±1.5dB are achieved [41].

4.7.6. In order to pass certification theEPNdB values must fall below a referencelimit for each procedure. Relaxations tothese limits are made (due to the lack ofaccurate noise prediction tools at thedesign stage) where helicopters mayexceed the EPNL dB limits by 3dB over oneprocedure, or by 4dB over twoprocedures, as long these deficits areoffset across the other procedures [41].

4.7.7. The EPNL (Effective Perceived NoiseLevel) and the SEL (Sound Exposure Levelmetrics utilise the upper 10dB of a flyovertime record. However, the sound of ahelicopter at distance, although outsidethis upper 10dB region, can still causeannoyance, especially where high levels ofimpulse noise are present [2].

4.7.8. Helicopter noise certification isconcerned only within specific flightoperations and often these do not relateto urban helicopter operations. Anexample of this is the ground-runningphase, which is ignored in the certificationprocedure. However, it should be notedthat the purpose of noise certification is toencourage the design of quieter aircraft.In the case of helicopters, the designchoices required to satisfy certificationrequirements would serve to limit noise inall operating modes.

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4.8. Rules and regulations in Australia 4.8.1. In Australia, the Civil AviationSafety Authority (CASA) was establishedin 1995 to conduct the safety regulationof civil air operations in Australia, and theoperation of Australian aircraft overseas.The Civil Aviation Regulations 1988 andthe Civil Aviation Safety Regulations 1998,made under authority of the Civil AviationAct, provide for general regulatorycontrols for the safety of air navigation[43].

4.8.2. CASA functions as a safetyregulator and Airservices Australia as aservice provider. Airservices Australia is agovernment-owned corporation providingair traffic control, air navigation supportand rescue and fire fighting services [44].Airservices Australia are described by theCASA as providing a “safe andenvironmentally sound air traffic controlmanagement and related airside servicesto the aviation industry” [45].

4.8.3. CASA summarises the rules andregulations regarding helicoptersoperating under visual flight rules in thedocument, ‘Visual flight rules guide -Version 2 - July 2007’[46].

4.8.4. A Helicopter must not fly over anycity, town or populous area, at a heightlower than 1000 ft, or any other area at aheight lower than 500 ft. The heightsspecified are the heights above thehighest point of the terrain, and anyobject on it, within a radius of ≈1000 ft(300 m) from a point on the terrainvertically below the aircraft.

4.8.5. These rules do not apply when theheight must be lower because ofmetrological conditions, if the pilot has apermit for low level operations, if the pilotis engaged in low flying trainingauthorised by CASA, if the aircraft istaking off or landing, if the pilot isengaged in a search/rescue, or duringpolice operations.

4.9. Rules and regulations in Europe4.9.1. The Joint Aviation Authorities (JAA)is an associated body of the EuropeanCivil Aviation Conference (ECAC)representing the civil aviation regulatoryauthorities of a number of EuropeanStates who have agreed to co-operate indeveloping and implementing commonsafety regulatory standards and

procedures. This co-operation is intendedto provide high and consistent standardsof safety and a "level playing field" forcompetition in Europe. Much emphasis isalso placed on harmonising the JAAregulations with those of the UnitedStates’ FAA [47].

4.9.2. The European Aviation SafetyAgency (EASA) was set up to promote thehighest common standards of safety andenvironmental protection in civil aviation.It is intended to be the centrepiece of anew cost-efficient regulatory system inEurope and a reliable partner forequivalent authorities throughout theworld. As EASA develops the aviationregulatory environment, it will changesome of the existing CAA processes andprocedures [48].

4.9.3. EASA became operational on 28September 2003 and it will be fullyfunctional in 2008. It is an independentlegislative body under European law,accountable to the Member States andthe European Union institutions. EASAitself is not an International Civil AviationOrganization (ICAO) signatory because itdoes not constitute a State; however, itworks closely with ICAO and the FederalAviation Administration (FAA) with theaim of harmonising standards andpromoting best aviation practiceworldwide [49].

4.9.4. The creation of EASA has had asignificant impact upon UK Registeredaircraft. EASA has assumed responsibilityfor the type-certification and continuedairworthiness of a large number of UKregistered aircraft. [49]

4.9.5. During the next few years, it isintended that the agency will extend itsresponsibility to aircraft operations, crewlicensing and the certification of non-Member State airlines [49]. The UK isrepresented on the EASA managementboard by Mr. Michael Smethers (ViceChairman Director, European &International Strategy Civil AviationAuthority) and Mrs. Natasha Coates (Headof the Aviation Safety Team, InternationalAviation & Safety Division, AviationDirectorate, Department for Transport)(http://easa.europa.eu/home/g_mng_brd_main.html).

4.10. Rules and regulations in the USA4.10.1. The Federal AviationAdministration (FAA) regulates operationsin United States airspace. The regulationsare called the Federal Aviation Regulations(FAR) and are part of the Code of FederalRegulations (CFR – title 14).

4.10.2. Federal Aviation Regulationsection 91.119 [50] states that aircraftmust maintain a minimum distance of1,000 ft above the highest obstacle and ahorizontal radius of at least 2,000 ft fromanother aircraft. In other than congestedareas, aircraft are required to maintain analtitude of at least 500 feet above thesurface over open water or sparselypopulated areas. Over open water orsparsely populated areas, aircraft mayoperate at less than 500 feet above thesurface provided that they do not flycloser than 500 feet to any person, vessel,vehicle, or structure. Helicopters may beoperated at less than these minimumaltitudes provided that they are conductedwithout hazard to persons or property onthe surface.[50]

4.11. Summary of Chapter 44.11.1. 4.11.1. The CAA provides a focalpoint for receiving and responding toaircraft-related environmental complaintsfrom the general public. However, theCAA does not have the legal power toprevent aviation activity on solelyenvironmental grounds, except whenconsidering changes to the structure ofcontrolled airspace. An independentreview is considering greater powers forthe CAA over environmental matters.

4.11.2. There are only three licensedheliports in the UK, although helicopterscan land at most airfields. Temporarylanding sites can be used for up to 28days in a year. A residential planningapplication close to an operating heliport,when evaluated in accordance withPPG24, should not rely solely on Leq andshould consider the intermittent nature ofhelicopter operations.

4.11.3. Helicopter noise certification is notdirected at urban operations. BHAB codesof practice aim to increase the helicopterpilots and operators awareness ofenvironmental noise issues. Althoughpilots are aware of noise issues, factorssuch as safety are considered to be more

important.

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5. Subjective responses to helicopter noise

This section summarises a literature reviewof the subjective responses to helicopternoise. Principal references include the2004 FAA report to the US Congress,publications by Leverton and Pike, and theWHO Guidelines for Community Noise.This section addresses the adverse effectsof helicopter noise including sleepdisturbance, health and annoyance,before moving on to non-acoustic factorsincluding 'virtual noise' and buildingvibration. Much of this review refers tothe effects of fixed wing and generalaviation noise on the individual.Throughout comparisons are drawnbetween the effects of helicopter noisewith the effects of fixed wing aircraftnoise.

5.1. Social effects5.1.1. The 2004 FAA report to USCongress entitled, ‘Non-military HelicopterUrban Noise Study’ [4] (henceforthreferred to as the FAA report), contains acomprehensive literature review on theeffects of noise on the individual. The2004 FAA report was itself in part basedupon the US military report 'Communityresponse to helicopter noise' [51]. Thisreview has been used together with othersources to summarise the effects thathelicopter noise has on the individual.

5.1.2. Studies have shown thatenvironmental noise, including aircraft andtraffic noise can adversely affect classroomlearning [52-58]. It has been shown thatlow achieving students were the mostadversely affected. In addition; studentswith hearing impairments, students withEnglish as a second language and musicstudents may be particularly adverselyaffected [59]. The WHO (World HealthOrganisation) recommends that in schools,a maximum equivalent indoor level ofbackground noise not exceeding 35dBA.This is so that the average voice level(50dBA) is at least 15dBA above thebackground level [59]. The FAA reportstates that nearly all of the studies relateto the classroom environment and that“at the present time, little can be said ofenvironmental noise effects oncommunications and performance exceptas it relates to the classroom setting”.

5.1.3. Studies carried out at RAFShawbury [60] which has around 114,000helicopter movements per year indicatedno clear correlation between traditional

acoustic parameters and soundscapeperception and acceptance. There did,however, appear to be a correlationbetween acceptance and thevalue/meaning attributed to thenoise/event. Sixsmith [61] has suggestedthat the use of the term of 'annoyance'might be replaced with a number of otherterms. This suggestion stems from herwork with 'work-related stress', aphenomenon that is now described interms of 6 different factors; demands,control, support, relationships, roles andchange [62].

5.1.4. Sensitivity to low frequency noise. Anumber of studies over the past 30 yearshave suggested that a subsection of thepopulation is more sensitive to lowfrequency noise than the majority.Patterson et al [63] performed tests withdifferent frequency weightings on aircraftnoise, comparing the dB level withannoyance. It was reported that most ofthe ratings correlated best with A-weighting. However, 11 out 25 subjectsalso had good correlation with C-weighting, and of the 11, 3 exhibitedbetter correlation with C-weighting. Forthis reason, it was concluded that A-weighting might not be the idealweighting. ANSI S12.9 Part 4 provides asupplemental measure to A-weighting forassessing industrial noise sources withstrong low-frequency content. Schomersuggested the use of equal loudnesscontours as more detailed frequencyweighting curves for different amplitudesand showed a 2 dB difference betweenfixed-wing and rotary wing aircraft deriveddirectly from these known functions ofhuman hearing [4]. In addition, it is foundthat increasing the loudness of amodulating sound by 2-5dB produces thesame change in perceived loudness as if itwere a change in loudness of 10dB[64].This could be significant for helicoptersindicating one reason why they are rateddifferently to fixed wing craft. Likewise,Defra-funded research on the assessmentof LFN complaints concluded that 5dB wasan appropriate penalty for fluctuating lowfrequency sounds [65].

5.2. Health effects5.2.1. The Department for Transport in1992 commissioned a report entitled‘Report of a Field Study of Aircraft Noiseand Sleep Disturbance’[66]. This studymeasured the sleep disturbance of people

in their homes near Heathrow, Gatwick,Stansted and Manchester airports. Atoutdoor event levels below 90 dBA SEL(80 dBA Lmax), average sleep disturbancerates are unlikely to be affected by aircraftnoise. At higher levels, and most of theevents upon which these conclusions arebased were in the range 90 to 100 dBASEL (80 to 95 dBA Lmax), the chance ofthe average person being wakened isabout 1 in 75. The report concluded thathigh aircraft noise levels could awakenpeople but that the likelihood of theaverage person having his or her sleepnoticeably disturbed due to an individualaircraft noise event was relatively low.However, a small minority of people weremore sensitive. Additionally, it was unclearamongst those who suffer disturbancedue to noise, whether a single loud noiseevent or the accumulation of smaller noiseevents causes more disturbance. It shouldbe noted however that study sites wereselected on the basis of arrival anddeparture routes of the airports and thusfix winged aircraft would have been thepredominate activity.

5.2.2. In 1998, a further study wascommissioned by the Department forTransport[67] to review existing research inthe UK and abroad and to conduct a trialto assess methodology and analyticaltechniques and to determine whether toproceed to a full-scale study of eithersleep prevention or total sleep loss. Thisinvolved a methodological trial to assesswhether ‘aircraft noise causes harmful lossof sleep throughout the night’ and ‘theeffect of sleep delay and disturbance atthe beginning and end of the night’. Asocial survey was also carried out to helpexplore the marked difference betweenobjectively measured and publiclyperceived disturbance due to night-timeaircraft noise. However again it is worthnoting that fixed wing aircraft would havebeen predominate.

5.2.3. The Government announced on 8May 2001 that a new full-scale objectivesleep disturbance study would be unlikelyto add significantly to existing knowledge;it is to concentrate instead on furtherresearch into subjective responses toaircraft during both day and night.

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5.2.4. Laboratory experiments [68] haveshown sleep disturbance at relatively lownoise levels but field tests results haveshown people are much less susceptible tobeing disturbed. For example, field testsshow 1% of participants were awakenedat 60dB (A-weighted sound exposurelevel) while in laboratory tests at 60dBabout 20% of people were disturbed. Thisis presumed to be a due to the unfamiliarconditions in the laboratory tests. The USFederal Interagency Committee onAviation Noise (FICAN) recommends usinga dose-response curve for predictedawakening based upon the field data. Inessence, the dose-response curve wouldfollow the “maximum percentage of theexposed population expected to bebehaviourally awakened” related to SEL.The FAA agrees with thisrecommendation.

5.2.5. The WHO[59] states that long termexposure to noise levels exceeding 65-70dB (24 hr Leq) are known to beassociated with causing cardiovascularproblems. Passchier-Vermeer[69],commenting on results from studiescarried out in the Netherlands, states thatthe observation threshold for hypertensionis estimated to correspond to an Ldn valueof 70 dB(A) for environmental noiseexposure. The FAA report states that“Helicopters rarely produce 24-hourequivalent levels that exceed 70 dB. Infact, such worst case, high noise levelsonly occur near very busy military airfieldsoperating heavy lift helicopters andfrequent flights. Thus, noise-inducedhearing impairment due to non-militaryhelicopters operations in urbanenvironments is an unlikely condition”.

5.2.6. Recently published work by theHYENA group[5] (Hypertension andExposure to Noise near Airports) indicateda statistically significant excess risk ofhypertension related to long termexposure to night-time aircraft noise. Forevery 10dB increase in (night-time) noiselevel, the risk of hypertension is increasedby about 14%, with this trend seenstarting at low levels. The daytime resultswere not statistically significant.

5.3. Community attitudes5.3.1. Community attitude towardoperations has an important effect on thecommunity annoyance. Social surveyscarried out by the CAA in 1982 and 1992[112] [113] found that helicopters in theLondon area were up to 15dB(A) moreannoying at the 10% and 20% VeryMuch Annoyed Level than fixed-wingaircraft. By contrast, results showed thathelicopters operated in Aberdeen,servicing the North Sea oil industry,generated similar annoyance for a similarsound level as their fixed wingcounterparts. This is attributed to theobvious economic benefit to communitysurrounding the Aberdeen helicopterservice as opposed to London, wherehelicopters are perceived to have noeconomic benefit to the residents. Thisindicates a strong non-acoustic factor inthe community annoyance rating.

5.3.2. The Fields study [70] highlightedthe following five attitudes as mostimportant .1) Noise prevention beliefs.2) Fear of danger from noise source.3) Beliefs about the importance of the

noise source.4) Annoyance with non-noise impacts

from the noise sources.5) General noise sensitivity.

5.3.3. The US Environmental ProtectionAgency (EPA) in 1974 [71] suggested thatthe measured noise level could beadjusted downward by 5dB when thenoise generating party maintains goodrelations with the community. On theother hand, it is deemed that manyhelicopter flights are non-essential and itis sometimes suggested that negativeattitudes come from the opinion that thehelicopter is just the rich man’s toy.

5.3.4. Leverton [3] comments that ”thepublic acceptance of helicopters is notwholly reflected by either conventionalcommunity rating procedures or the noisecertification requirements”. This questionsthe view of many national authorities thata reduction in the objective sound levelthat helicopters produce will makehelicopters more acceptable tocommunity.

5.3.5. Most noise rating procedures utilisethe A-weighted sound pressure levelintegrated over a relatively long period.However, this may not be appropriatewhen there are a small number of events,as discussed by Leverton: [3] “theeffectiveness of methods based on longterm averaging is questionable in thosecases where the duration of the event isvery much shorter than the evaluationperiod and the number of events in thatperiod is such that noise levels are subjectto large variations.”

5.3.6. Fields and Powell [72] studied thereaction to low numbers of helicopternoise events. There was a strongrelationship between average Leq andaverage annoyance over the range of 1 to32 flights in 9 hours. The study foundannoyance was flat in relation to Leq upto 47dB, then a linear relationship ofincreasing annoyance up to 59dB.However, it was found that the number ofnoise events had little effect onannoyance although close statisticalanalysis revealed the possibility that theevent number has no effect on therelationship could not be rejected (withgreater than 95% confidence).Additionally, the study comparedhelicopters with an impulsive soundcharacter (UH-IH "Huey") and one with anon-impulsive sound character (UH-60A"Black- hawk") and found “there is notan important difference between reactionsto impulsive and non-impulsive types ofhelicopters”. The FAA and the US armyreports comment that no one has carriedout a study to determine a similar Leq-annoyance relationship for night-time butthat the traditional 10dB night-timepenalty, used in the determination of DNL,is consistent with community attitudinaldata [73].

5.3.7. It was widely believed in the 1970sthat helicopter noise was more annoyingthan fixed wing noise and as a result theU.S. Department of Defense policy wasthat a 7dB penalty should be applied “tometer readings obtained whereBlade–Slap was present unless meters aredeveloped which more accurately reflecttrue conditions”[74]. The need for a bladeslap penalty was based on results fromlaboratory tests carried out by Leverton[75]. These tests, carried out in asimulated living room, showed that thepresence of blade-slap increased

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annoyance by the equivalent of between4-8dBA. The US army report recognised anumber of other researchers who alsoidentified the need for a ‘blade-slapcorrection factor' [76-79].

5.3.8. Other researchers have offeredalternative indices for measuringcommunity annoyance. Examples includethe ‘roughness’ of the sound quality, therate of the impulses, or the energy in the50-200Hz band [4].

5.3.9. The FAA and the US army reportscomment that subsequent field tests havefailed to support the addition of theblade-slap penalty. NASA reported that “Acareful analysis of the evidence for andagainst each factor reveals that, for thepresent state of scientific knowledge,none of these factors should be regardedas the basis for a significant impulsecorrection.”[80] Passchier-Vermeercommented “tests have shown onaverage only minor differences inannoyance rating of more or lessimpulsive helicopter noise with the samenoise levels”[81]. The FAA comments that;“There is general agreement among awide range of experts that adding apenalty to the A-weighted SEL to accountfor the annoyance of Blade-Slap is notjustified.”[4]. Despite this, others disputethe efficacy of EPNL and other metrics torate subjective response to helicopternoise[82]. Although the ICAO report toCAN7 (1983) concluded that EPNL issatisfactory, it also states that “pendingbetter knowledge on this subject,operational procedures should beinvestigated in order to reduce thenumber of occasions where ‘blade slap’ ormore appropriately, impulsive noiseappears”. It should be noted that thepositive conclusion about EPNL was, atleast in part, because nothing better couldbe found at the time [82].

5.3.10. Despite objective evidence thathelicopters are no more annoying thanfixed wing craft, public surveys indicate amore negative reaction to helicopternoise. Leverton et al [3] holds the viewthat specific properties of the helicoptersound are not accounted for byconventional rating procedures and it isthese properties that are among the majorsources of annoyance for the community.Specifically, rating procedures do notaccount for noise from the main rotor

blade/tip vortex interaction (BVI), mainrotor thickness noise and impulsive noiseresulting from shock waves commonlyreferred to as high speed impulsive noise(HSI), main rotor wake/tail rotorinteraction (TRI), and tail rotor noise (TR).NASA research indicates that the additionof a ‘correction factor’ for impulsivesounds does not improve the humanresponse - parameter correlation.However, these tonal and impulsecomponents have a profound effect onthe human response even at levels 15 –25 dB below the maximum level. TheEPNL or SEL based parameters used inaircraft certification, including helicopters,are calculated using only the maximum10dB dynamic range, and therefore theseeffects are not accounted for.

5.4. Non-acoustic factors5.4.1. Leverton [3] describes the publicacceptance of helicopter noise as afunction of two factors: acoustic noiseand non-acoustic factors referred to as'virtual noise'. The virtual noise element isrelated to non-acoustic factors such asfears for safety, or poor communityrelations with operators. Virtual noise isnot related to the absolute level ofacoustic noise although is triggered by it.It can also be triggered by visual cues.Annoyance is quantified in terms ofobjective acoustic parameters andtherefore the virtual noise is generallytreated in the same manner as theacoustic noise even though the virtualcomponent is unrelated to absoluteacoustic levels. This means that whenproblems stem from the virtual noisecomponent, any reduction of the noiselevel will be ineffectual.

5.4.2. It can be difficult to separate virtualand acoustic noise, as these factors arehighly interrelated. Research referred to byLeverton [3] and carried out at ISVR [83]attempted to classify complaints andquantify the ‘virtual noise’ effect in termsof an equivalent A-weighted correctionfactor. Although the research was basedat general aviation airfields where mainlylight fixed wing craft operated, resultshave suggested similar trends forhelicopters.

5.4.3. These results have not been shownto translate directly to helicopteroperations, although results fromhelicopter operations at one baseindicated a similar result. In fact, thenegative reaction to helicopters may beeven higher especially in reaction toleisure flying. The virtual noise factor canbe very low in some cases. As mentionedpreviously, in Aberdeen, helicopteroperations servicing the North Sea oilindustry are seen as beneficial and aremore acceptable. Similarly, it may be thathelicopters following precise routes aremore acceptable, and therefore the virtualnoise factor is reduced. An example of thisis the Helijet scheduled passenger servicebetween Victoria and Vancouver. ICAOwork has suggested that fear of crashes isthe most significant factor in addition tolow flying, sudden changes in the noisesignature and previous experience ofcrashes all contributing the most to thenegative reaction.

Table 4: ‘Virtual noise’ effect in terms of a equivalent A-weighted correction factor

Negative reaction to leisure flying +5dB(A)

Poor community/airfield relations +10dB(A)

Fear of crashes +10dB(A)

Nobody acts on complaints +20dB(A)

Aircraft are flying too low +20dB(A)

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5.4.4. The FAA report refers to a numberof tests carried out between 1985[84] and1991[85] that compared the lack of, orpresence of, audible noise induced rattlein dwellings. It was found that thepresence of a rattle could increase theannoyance by an equivalent level ofbetween 10 and 20dB.

5.4.5. The FAA report describes in-situtests carried out by Schomer and Wagner[86] at residents’ properties using anexternal sensor to register events for thesame A-weighted sound exposure level(ASEL). These showed that helicoptersound was no more annoying than thefixed wing noise. However, the rate ofresponse in terms of noticeability of thehelicopter noise events was higher thanthat for fixed wing noise events.Helicopters, with their distinctive soundcharacter, are more noticeable than othersounds for the same ASEL.

5.4.6. At the recent IoA (Institute ofAcoustics) meeting at Salford, Pike [2]commented that there is a need forpsychoacoustics experts to work withindustry to address the unique subjectivecharacter of helicopter noise. Furthermore,workshops should be held to address thenegative perception of helicopter and the‘virtual noise’ factor.

5.5. Comparison with Lightaircraft/microlights5.5.1. In studies carried out at RAF basesinvestigating the management of Lightaircraft and microlight noise at militaryairfields [9, 87], a number of similarproblems as described regardinghelicopter noise were found.1) Correlation between nuisance and

noise level is poor. It is clear that morerelevant descriptor metrics arerequired for low volume or irregularmicrolight and light aircraftoperations.

2) It is likely that actual noise level is asecondary issue and that physicalintrusion and other non-acousticalfactors are more significant indetermining nuisance.

5.5.2. Background noise level is likely tobe a factor as it (generally) relates to the‘rurality’ of complainants locations. Civilaviation is always described in absoluteterms with no reference to thebackground/ ambient level.

5.5.3. Alongside helicopters, light aircraftare precluded from prosecution undernoise nuisance.

5.5.4. Both reports state that consultationwith the public will help to engage peopleand breed more understanding for theoperations.

5.6. Summary of Chapter 55.6.1. Reaction to helicopter noise isdetermined by acoustic and non-acoustic'virtual' noise. Non-acoustic factors are ofequal or greater importance but aretriggered by impulsive noise generated bythe basic rotor mechanism. This meansthat addressing acoustic noise limits isunlikely to significantly improve publicacceptance of helicopter noise.

5.6.2. Subjective responses are known tobe influenced by factors other than noiseincluding flight safety, privacy,soundscape, locus of control and mentalhealth. Perceived effect on house pricehas also been shown to be a significantfactor. Highest annoyance has beencorrelated with uncommon or exceptionalhelicopter events.

5.6.3. Complaints have been found to bemore likely if the resident has a negativeattitude towards the helicopter operator.Additionally, the likelihood of a memberof the public making a complaint appearsnot to be influenced by age, length ofresidence, having children or not, orhealth.

5.6.4. Social surveys indicate thathelicopters are 10 to 15 dBA moreannoying than fixed-wing aircraft for thesame or lower measured sound level. Theterm annoyance does not fully describethe subjective response to helicopternoise. The following classifications,amongst others, are also important;intrusion, distress, startle, disturbance,locus of control.

5.6.5. Studies attempting to relate dose-response with annoyance due tohelicopter operations have produced poorcorrelation and have been broadlycriticised. There is no generally acceptedstraightforward relationship betweenobjective noise and subjective annoyance.No good correlation with complaints hasbeen found with LAeq, LCeq, LAmax, L10and LAmax-L90.

5.6.6. Studies addressing the noise fromlight aircraft and microlights reveal similarissues; that noise level may be a secondaryissue and different indices may berequired for low volume operations.

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6. Management of Environmental Noise from Helicopters

This section considers the effectiveness ofcurrent procedures for dealing withhelicopter noise in the UK. Existingprocedures for handling complaints aredetailed and the roles, responsibilities andpowers of the various authorities andregulating organisations summarised.Comparisons are drawn with otherEuropean countries, the USA andAustralia. Finally, noise prediction andmodelling are discussed with particularrelation to noise mapping and EU NoiseDirective (Directive 2002/49/EC). Optionsfor improvement are identified togetherwith recommendations on how thesecould be implemented.

6.1. Existing procedures for handlingnoise complaints from helicopters 6.1.1. The Civil Aviation Authority (CAA) isa focal point for receiving environmentalcomplaints about aircraft. When acomplaint is received, the location, aircrafttype and identity (registration/features) arerecorded and the airspace structure in thatarea is identified. The legislativebackground to noise, and the ANO withspecifics to the location, are explained tothe complainant. However, the CAA hasno legal power to prevent aviation onsolely environmental noise grounds [6].

6.1.2. The outcome of a complaint to theCAA will either be; 1) a referral to ARED (Aviation Regulation

Enforcement Department) in the eventof a breach of the ANO, or

2) advise contact of local planningauthority in the case of a change ofland use or to advise contact theaircraft operator directly.

6.1.3. The Directorate of Airspace PolicyEnvironmental Information Sheet -Number 1 entitled ‘Aircraft Noise’[88],comments that the CAA is tasked withensuring that procedures at airports meetrequired standards of safety but theoperators are responsible for theenvironmental impact of their aircraftoperations. The CAA is expected to,”strike a balance between the needs ofthe airport/aircraft operators and theneeds of the local community”. As aresult, the CAA encourages noisecomplaints to be made directly to theairport operator.

6.1.4. Problems related to noise generatedon the ground at aerodromes, other thanin association with the normal operationof aircraft, should be referred to the LocalAuthority. However, local authorities havea statutory bar on action against aviationnoise sources under the Environmental(EPA) noise legislation.

6.1.5. MOD complaints are dealt withcentrally or through the base’s communityliaison officerhttp://www.mod.uk/DefenceInternet/AboutDefence/WhatWeDo/AirSafetyandAviation/LowFlying/HowDoIComplainAboutMilitaryLowFlyingActivity.htm,

6.1.6. The London Heliport at Batterseahas established a complaints telephoneline for registering environmental noisecomplaints (0207 228 0181). Complaintsare reported at the consultative groupmeetings [16]. The heliport is notresponsible for all traffic over London andcurrently there is no formal complaintsprocedure in place for helicopters flyingwithin the London Control Zone that arenot operating at the London Heliport. Thisis being addressed by the LondonAssembly and Defra but in the interim,the Civil Aviation Authority is tasked torespond to complaints [89].

6.2. Means of redress for anyperceived disturbance caused6.2.1. The Department for Transport isinvolved directly with measures toameliorate aircraft noise at Heathrow,Gatwick and Stansted.. Elsewhere “theDepartment expects civil aerodrome andaircraft operators to achieve a reasonablebalance between their legitimate needsand those of the local community” [26].

6.2.2. Aerodrome operators may publishnoise abatement procedures to befollowed on a voluntary basis. Forexample, it may be requested that pilotsavoid overflying a certain village. However,these procedures are voluntary and it maynot always be possible to design suchprocedures due to aircraft performanceand operational constraints [90].

6.2.3. Noise preferential routes (NPR) maybe employed at major airports althoughthese are essentially designed with fixedwing aircraft in mind. These are designedso that immediately after take off aircraftwill avoid the most densely populated

areas. Typically, aircraft should not deviatefrom these routes until above 3,000 ft.Details of specific NPRs are available fromthe airports. In the recent ‘Civil AviationAct (2006)’ airports are now able to applya charging scheme to promote the use ofcleaner, quieter aircraft [90].

6.2.4. At Birmingham InternationalAirport, after receiving a number ofcomplaints about police operations viatheir consultative committee in 2006, theairport consulted with the policeoperators, the air traffic control and theenvironmental department at the airportto implement an 'avoid' region tominimise flights close to residences.

6.2.5. At RAF Shawbury, in response to anincrease in the number of complaints apoint of contact has been published.Observations, measurements, acousticstudies and trend analysis have beencarried out and detailed records are kept.Some noise management is achieved byactive management of flying by rotatingroutes, expanding the user area, andbriefing all new staff and students tomake them aware of environmentalissues. Wing Commander Tim Owenscommented [91] that a fast response tocomplaints is important in keepingcomplainants from becoming a repeatcomplainer. Individual invitations to visitthe base and follow up contact are alsoimportant in order to inform and toensure the public are aware the RAF isdoing the utmost to addressenvironmental issues [91].

6.2.6. At the London Heliport, aconsultative committee has been set up.Wandsworth council commented[92] thatthis shows residents that their concernsare being taken seriously, increasesawareness within the planningdepartment, and lets the operator beconfident that there is no hidden agenda.Complaints are largely generated fromliving standard expectations and aperception that helicopter pilotsdemonstrate inconsiderate behaviour. Ithas been conjectured that change of landuse from industrial to residential usage isthe root of the problem. The councilcommented that enabling dialoguebetween residents, councils and theheliport operator has helped to createsome understanding and acceptance bythe public. The dialogue should be

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extended to include developers so thathomes are created with sufficient soundinsulation. At the recent IoA meeting,Steve Mayner commented that “noisemapping may be unlikely to reduceannoyance due to lack of technicalunderstanding by the public, but that itmay be useful for the planners” [93].

6.2.7. The Directorate of Safety andClaims (DS&C) and the Environment andSafety Division administrate the NoiseInsulation Grant Scheme (NIGS) on behalfof the MOD. NIGS is a non-statutorycompensation scheme that provides directassistance to members of the public whoreside in the vicinity of military airfieldsand who may experience disturbance fromthe activities of the aircraft. NIGS isbroadly comparable with the noiseinsulation schemes, recommended by theDepartment of Transport, in place at thedesignated civil airports of Heathrow andGatwick. The policy of the NIGS scheme isrevisited every five years to ensure that itis still comparable with the UK civilaviation practices [94].

6.2.8. In January 2000 a study wascompleted [60] which examined therelationship between noise levels andpatterns of complaints caused by RAFShawbury’s helicopter activity. The reportconcluded that no residential propertieswere eligible for assistance under thecurrent criteria for NIGS. This triggered areview of NIGS policy and the scheme wassuspended pending the outcome of thereview. Part of the review was the MODAircraft Environmental Noise (AEN).Results from AEN were published in 2004,its recommendations were wide rangingand carried implications across the wholeof MOD. Consultation resulting from AENis still ongoing. One of the outcomes ofAEN was that the NIGs scheme should berestarted as soon as possible however afunding application for the scheme in2005/2006 was rejected “due to otherfunding priorities of the Defence Budget”[94]. In April 2005 NIGS was formally andindefinitely suspended (including carryingout of reviews and surveys). However “thissuspension would be kept under reviewand if circumstances allowed thereintroduction of NIGS in the future, thenthis would be examined at that time”[94].

6.2.9. The Noise Insulation Grant Schemewas based on nightime operationsexceeding 20 movements with LAmax ofmore than 82dB and two daytimeLAeq,16hr levels of 70dB and 83dB. Forthe lower level of 70dB double glazinggrants were offered and for the higherlevel compulsory purchase of propertyapplied. The scheme was reviewed byRalph Weston in 1991 and it wasconcluded that the nightime LAmax levelof 82dB was inappropriate for helicopters.Instead a 10dB penalty was suggested torepresent public disturbance due tohelicopter operations and subsequently a72dB nightime maximum was proposed.Helicopters also pose a problem for noiseinsulation because double glazing is lesseffective for the low frequency content ofhelicopter noise[95].

6.2.10. BAA has established non-statutorynoise insulation schemes, as the operatorsof regional airports have done. Theprovisions vary but BAA’s latest scheme atStansted, for example, offers an insulationpackage to residences within the 66dBLAeq (16h) (with a separate night noisecriterion) and relocation assistance toproperties falling within the 69dB LAeq(16h) contour [96]. The 2003 Air TransportWhite Paper states (para 3.24) [114] thatinsulation should be provided, in thecontext of airport development, whereproperties are exposed to noise levels of63dB LAeq or more and subject to anincrease of 3dB or more.

6.3. Roles, responsibilities and powersof the various authorities andregulating organisations.6.3.1. The Department for Transport willrespond on matters of overall policy.

6.3.2. The Civil Aviation Authority (CAA)has responsibility on regulation, airspacedesign and environmental complaints.However, the CAA will only advise on theregulations; they cannot act unless there isa clear breach in the rules of the air.

6.3.3. The Ministry of Defence hasresponsibility for information andcomplaints related to military aircraftoperations.

6.3.4. National Air Traffic Services hasresponsibility on airspace operations.

6.3.5. Airport operators deal withcomplaints where, for example, a take-offappears not to follow establishedprocedures. This is because they haveimmediate access to data relating to thattake-off.

6.3.6. Local authorities have theresponsibility to deal with complaintsarising from the operation of machinery orother noise not generated directly byaircraft

6.4. The effectiveness of dealing withhelicopter noise in the UK usingcurrent methods6.4.1. At RAF Shawbury complaints aredealt with by maintaining good relationswith the community through a swiftresponse to all complaints, following upcomplaints with invitations to visit thebase, acoustic studies and operationalchanges. It appears that the perceivedvalue of the operations has beenreinforced in the public mind andcomplaints have not risen in line withoperations [91].

6.4.2. At the recent seminar WandsorthCouncil reported [93] that recent effortsencouraging dialogue between residents,councils and the heliport operator havehelped to improve understanding andacceptance by the public. However, it wassuggested that this might be a‘honeymoon period’. The dialogue couldbe extended to include developers so thathomes are created with sufficient soundinsulation. Noise mapping is thought to beunlikely to reduce annoyance due to lackof technical understanding by the publicbut it may be useful for the planners.

6.4.3. The London Heliport operatorstated that the telephone complaints line,established before working withWandsworth Council, has significantlyhelped relations between the heliport andthe public. The helpline is continuallybeing refined since a more informedpublic realises that it is not always theheliport that is responsible for disturbanceand that through traffic may be the causeof the noise nuisance [16].

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6.5. Comparisons with otherEuropean countries6.5.1. The Advisory Council forAeronautics Research in Europe definesand implements the Strategic ResearchAgenda (SRA). There are two significantprojects that address noise fromhelicopters; FRIENDCOPTER and the"Clean Sky" JTI [97].

6.5.2. FRIENDCOPTER is currentlyunderway and is an Integrated Project ofthe European 6th Framework Program:"Integration of Technologies in Support ofa Passenger and Environmentally FriendlyHelicopter". This project was started on1st March 2004 and is due for completionby 31st August 2008. The research isbeing carried out by a consortium of 34European partners including helicoptermanufacturers, research establishments,and universities [98].

6.5.3. The research goals ofFRIENDCOPTER are to achieve a reductionof;1) acoustic footprint area by 30-50%,2) fuel consumption by 6 % in high

speed flight,3) cabin vibrations below 0.05 g and 4) cabin noise levels below 75dBA.

6.5.4. These research goals ofFRIENDCOPTER are to be achieved by; 1) low noise flight procedures, 2) quiet engine in/outlets, 3) interior noise reduction and 4) distributed blade actuation.

6.5.5. The "Clean Sky" Joint TechnologyInitiative (JTI) program is an industrydriven 7-year research plan for a greenergeneration of European Air Transport thatwill radically improve impact on theenvironment while strengthening andsecuring European aeronautics industry’scompetitiveness [99].

6.5.6. The purpose of The "Clean Sky" JTIprogram is to demonstrate and validatethe technological breakthroughs that arenecessary to reach the environmentalgoals set by the Advisory Council forAeronautics Research in Europe (ACARE:the European Technology Platform forAeronautics & Air Transport).

6.5.7. ACARE goals to be obtained in2020 through the Technology Domainsdeveloped in the Clean Sky JTI programare as follows:1) 50% reduction of external noise. 2) 50% reduction of CO2 emissions

through drastic reduction of fuelconsumption.

3) 80% reduction of NOx emissions. 4) A green design, manufacturing,

maintenance and disposal productlife cycle.

6.5.8. The Clean Sky JTI program isarticulated around 6 IntegratedTechnology Demonstrators (ITDs). One ofthese Demonstrators is called ‘GreenRotorcraft’ which is intended to deliverinnovative rotor blades and engineinstallation for noise reduction, lowerairframe drag, integration of dieselengine technology and advancedelectrical systems for elimination ofnoxious hydraulic fluids and fuelconsumption reduction [100].

6.5.9. The target for the Green RotorcraftITD is a reduction in the certificationnoise levels of 10EPNdB [2]. A number ofmajor European aerospacemanufacturers; AgustaWestland AirbusSAS, Dassault Aviation, Eurocopter SAS,Liebherr-Aerospace Lindenberg GmbH,Rolls-Royce plc, Safran and Thales areinvolved in the Clean Sky JTI [101] andadditional partners will be selected viaopen Calls for Proposals [102].

6.6. Comparisons with Australia 6.6.1. Airservices Australia publishes aguide entitled ‘Environmental Principlesand Procedures for Minimising theImpact of Aircraft Noise’. It points outthat in all cases aviation safety, includingsystem safety through simplifiedoperating arrangements, will be givenpriority over noise abatementconsiderations [46].

6.6.2. The guide is written in ahierarchical manner with the mostpreferred procedures for helicopteroperations given first. They are asfollows:1) No overflight of residential areas.2) No overflight of residential areas

below 1,500 ft AGL.3) Minimisation of incidence of

helicopters flying below 1,500ft AGL.4) Minimisation of noise impact on

residential areas by helicopters below1,500 ft AGL.

5) Minimisation of noise impact onresidential areas by hovering/circlinghelicopters.

6) Implement fly neighbourlyprocedures.

6.6.3. However, assuming safetyconditions have been satisfied, the soletest for moving to a lower level standardis that the higher standard is “notoperationally practicable”. If lower ratherthan higher standards are chosen, thenwell-documented reasons for the decisionare required. The noise standard chosenshould be achievable for at least 90% ofmovements.

6.6.4. In Australia, there are severalavenues for people with aircraft noiseissues to register a complaint. Theseinclude the Airservices Australia NoiseEnquiry Unit (NEU), the relevant airport,consultative committees and local andFederal politicians. Even if thecomplainant does not contact the NEUdirect, the NEU will generally becontacted by the receiver of thecomplaint to help provide input for aresponse. More often than not, helicoptercomplaints relate to helicopter operationsnear airports, so there is a tendency fornew complainants to make their initialcomplaint to the airport owner/operator.Other people, particularly those who alsohave issues with fixed wing aircraft noise,are familiar with the complaints reportingservice provided by Airservices and willcontact the NEU direct. [103]

6.6.5. Some airports are very proactive inresolving problems; others simply refercomplaints on to the NEU. Helicopteroperators are often unaware they arecausing a problem and on receiving acomplaint will attempt to alter operationsto reduce the problem. Other airports,however, will simply state that they arecarrying out a legal operation and willcontinue to do so without modification.”Fly Neighbourly“ agreements aresometimes successful, but these arepurely voluntary and have no legalstanding [103].

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6.6.6. At the end of each month, astatistical report is generated and providedto stakeholders. Main problem areas arearound airports and hospitals [103].

6.6.7. Provided that the rules of the airare observed, no penalties apply.Wherever possible, attempts are made tominimise effects of aircraft noise byconsultation [103].

6.7. Comparisons with the USA 6.7.1. The Federal Aviation Administration(FAA) has procedures to respond to thepublic about aircraft noise questions orcomplaints within the United States. TheFAA website comments that “Mostairports have an office that responds toairport noise issues, or the airportmanager will respond to noise complaints.You can also contact your local FAAAirports District Office (ADO) forassistance” [104].

6.7.2. In the US, urban encroachmentnear military bases can compromiseoperations at the base. Litigation ispossible [105] and public pressure canlead to closures, transference ormodification of activities, curtailing ofoperations. In the US noise contourprediction methods, such as theIntegrated Noise Model, are used toreduce the environmental impact ofmilitary activities.

6.7.3. In the US, the HelicopterAssociation International (HAI) [106]heavily promotes the Fly neighbourlyprogram. This program is effective in someareas in the US at reducing the noiseimpact. [107] The Fly Neighbourly Programconsists of a guide [108] and a pilottraining CD. The Program addresses noiseabatement and public acceptanceobjectives with programs in the followingareas:

1) Pilot and operator awareness2) Pilot training and indoctrination3) Flight operations planning4) Public acceptance and safety5) Sensitivity to the concerns of the

community

6.7.4. The 2004 FAA report to the UnitedStates Congress on non-military helicopternoise produced the followingrecommendations [4]:1) Additional development of models for

characterizing the human response tohelicopter noise should be pursued.This recommendation has beenincorporated into the RotorcraftResearch and Development Initiativefor Vision 100 – Century of AviationReauthorisation Act. NASA, FAA, andthe rotorcraft industry have defined a10-year rotorcraft research anddevelopment plan that includes thestudy of psychoacoustics. It isproposed that the research willdetermine human annoyance levelsdue to helicopter noise, both in itsnative condition and syntheticallymodified. Studies would be conductedto uncover neglected characteristics ofnoise and develop a refined metricthat is more representative of the truehuman response.

2) Further operational alternatives thatmitigate noise should be explored.

3) Emergency helicopter services shouldbe exempt from restrictions.

4) Helicopter operators and communitiesshould develop voluntary agreementsto mitigate helicopter noise.

6.7.5. The Regional Helicopter SystemPlan for the Metropolitan WashingtonArea was carried out in 2004 with theaims of [109];1) ensuring the current helicopter system

meets the regions transportation andpublic service needs,

2) help reduce community noiseproblems by better management,

3) establish land planning guidelines forheliports and

4) to document the relationship betweenthe transportation and economic well-being/public services in the area.

The report created the followingrecommendations:1) Create a program to collect helicopter

activity data. 2) Establish a permanent helicopter

working group. 3) Create a centralized and formal

system to address helicopter noisecomplaints.

4) Establish a program to supporthelicopter operator and market needs.

5) To address zoning issues.

6.8. Options for the improvementof the management of helicopternoise 6.8.1. Consultative committees appear tobe successful in addressing thecommunity’s concern about helicopternoise. They are successful because thepublic feels that the problem is beingaddressed and it provides a neutralplatform from which to influenceoperators to change procedures.

6.8.2. When a complaint is received, aprompt response is essential todemonstrate environmental awareness. Itis thought that a swift response willprevent the complainant becoming arepeat complainant.

6.8.3. Repeated contact from the operatorto the complainant after a complaint isregistered is thought to reduce thelikelihood of the person making a repeatcomplaint.

6.8.4. There is no central point forcollecting and analysing information aboutcomplaints. The CAA acts as the focalpoint for environmental complaints andhas records of complaints received butmany complaints are directed at operatorsand the MOD. A central data collectionsystem for collating complaints from allsources could help indicate specificproblems with a view to inform theoperator responsible so they are aware ofthey are causing a problem. In Australia amonthly report of complaint statistics issent to stakeholders and this could also bedone: If the industry is aware of who iscausing the problems, this may pressurethe noisier operators to look at othermitigation procedures.

6.8.5. Caution should be employed whenusing complaint statistics for theestimation of the scale of the problem ofhelicopter noise. A public survey should becarried out to inform the industry and thepublic about the extent of the helicopternoise problem in the UK. The study wouldhave to take into account the socio-economic and cultural conditions thatprevail and the type of helicopter activity.

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6.8.6. Airservices Australia published aguide entitled ‘Environmental Principlesand Procedures for Minimising the Impactof Aircraft Noise’ (see 7.6.6) which lists ahierarchical approach minimising theimpact of noise on the community withthe most preferred procedures forhelicopter operations given first. A similarguide could be produced and publicised.

6.8.7. In Australia "Fly Neighbourly"agreements are sometimes successful andin the USA, as a result of the Washingtonreport on helicopter noise, helicopteroperators are encouraged to developthese agreements. This is an approachthat could be encouraged more in the UK.

6.9. Noise prediction and modelling6.9.1. Noise mapping at airports for fixedwing flights has been conducted for manyyears. These maps use data obtainedduring noise certification of the aircraft asa basis for its noise level and applypropagation algorithms averaged over along time period [115]. However, itshould be noted that ECAC Doc 29specifically excludes helicopter noise andthe FAA INM is the only commerciallyavailable noise model with a limitedhelicopter capability. Given the largenumber of flights at major airports andaverage meteorological conditions over along period, these maps produce a goodindication of the noise around airportsfrom fixed wing aircraft.

6.9.2. Although some limited informationon helicopters is now included in thesome noise models, see [110], thisapproach is not appropriate for themeaningful noise modelling ofhelicopters.. Helicopter noise is dominatedby the main and tail rotor tones thedetails of which cannot be retrieved fromcivil certification data. However, INM7.0and its database now includes more thanthe published certification data, e.g. 1/3octave band spectral data and utilisesthese in the propagation algorithms.Understanding the nature andpropagation characteristics of these tonesis central to capturing the helicopter'sdistinctive signature. It is this distinctivesignature that contributes to noisecomplaints. Another factor to beconsidered when trying to capturehelicopter source noise data is itsdirectional variation. For example,helicopter noise heard at long and

medium range during low flying activityemanates from the plane of the rotor, andnot from underneath as measured duringcivil certification. Helicopters are alsolouder to the front and on the advancingside of the main rotor blades.

6.9.3. Another important factor withregard to helicopter noise is thatcomplaints usually arise from individualflights, as opposed to the average of alarge number of flights as in the case offixed wing aircraft around a busy airport.This has an important impact on the wayin which the propagation of the noiseshould be modelled. In the case ofindividual flights, environmental factorssuch as wind, temperature, groundimpedance and background noise play animportant role in determining how thesound travels and how it is perceived.

6.9.4. In particular the following give riseto relatively large noise footprints:1) Low frequency noise propagating

further through the atmosphere.2) Sound refracting downwind.3) Sound refracting under temperature

inversions.4) Sound propagating over acoustically

hard surfaces such as water andconcrete.

6.9.5. Although modelling of civilianhelicopter noise is deemed too difficult atpresent, the acoustic footprint ofindividual helicopter flights is ofimportance to the military. In the militarysector, the tools and data are available toaccount for the above factors andproduce accurate noise maps [111].Comprehensive measured source noisedatabases are available for numerousmilitary platforms, together with the toolsto fully model the effect of all relevantenvironmental parameters. These toolscould readily be adapted to accuratelymap civilian operations given accuratepositional, meteorological and sourcedata.

6.10. Options for the improvement ofprediction for noise mapping6.10.1. Opportunities forimprovement. The EC Directive onEnvironmental Noise requires memberstates to make strategic noise maps formajor agglomerations along major roads,major railways and major airports withintheir territories [1]. Noise mapping forhelicopters is not currently conductedbecause of the difficulty in accounting forthe factors discussed above. However, theexpertise exists to make good account ofthese factors, particularly in the UK, andthis could be exploited in future noisemapping programmes. Appropriate dataon the source noise of civil helicopters,except where they overlap with militaryplatforms, is not available and needs to becollected and/or estimated through sourceprediction code as a matter of priority.

6.10.2. Recommendations on howthese could be implemented. First andforemost, a sensitivity analysis on therequired level of helicopter noisemodelling needs to be carried out. Itneeds to be determined what level ofmodelling can be practically implementedin the required time frames. Variablesinclude the number of helicopter flights,and the associated positional andmeteorological data available. It is alsoimportant to fully understand thelimitations and inaccuracies present in anygiven model. Therefore, a systematic seriesof comparisons between high and lowfidelity models, and levels of source andenvironmental data, needs to be carriedout. As a result of this work, the best wayforward for helicopter noise mapping canbe ascertained. It may be that a relativelysimplistic model must be used because ofcomputational time constraints On theother hand, it is possible that a databaseof aircraft noise maps created with highfidelity software given prevailingmeteorological conditions, can be calledupon to generate accurate noise maps inthe future. This would yield the bestpossible solution for the noise mapping ofhelicopters, which is required to meet theEuropean Noise Directive.

29


6.11. Summary of Chapter 66.11.1. Consultative committees to enabledialogue between residents, councils andthe heliport operator have helped toimprove understanding and acceptance bythe public. The dialogue should beextended to include developers so thathomes are created with sufficient soundinsulation.

6.11.2. A fast and sincere response isimportant in keeping complainants frombecoming repeat complainers. The failureto act on complaints is one of the largestcauses of dissatisfaction and resentmentamongst the public.

6.11.3. The CAA provides a focal point forreceiving and responding to aircraftrelated environmental complaints from thepublic. However, the CAA currently has nolegal power to prevent aviation solely onenvironmental grounds. An independentreview is considering greater power forthe CAA on environmental matters.

6.11.4. The CAA encourages noisecomplaints to be made directly to theairport operator. Problems related to noisegenerated on the ground at aerodromes,other than in association with the normaloperation of aircraft, should be referred tothe Local Authority.

6.11.5. MOD complaints are usually dealtwith through the base's community liaisonofficer.

6.11.6. Properties close to helicopterbases, evaluated under the previous MODNoise Insulation Grant Scheme (NIGS)scheme criteria, are unlikely to qualify forcompensation.

6.11.7. BHAB codes of practice aim toincrease helicopter pilots and operatorsawareness of environmental noise issues.Although pilots are aware of noise issues,factors such as safety are considered to bemore important.

6.11.8. The Joint Aviation Authorities(JAA) represents the civil aviationregulatory authorities of a number ofEuropean States who have agreed to co-operate in developing and implementingcommon safety regulatory standards andprocedures. Regulations governing themanagement of helicopter noise inAustralia and the United States arebroadly in line with those in Europe, inpart due to the harmonisation work of theJoint Aviation Authorities (JAA).

6.11.9. Two significant European projectsaddress noise from helicopters these areFRIENDCOPTER and the "Clean Sky" JTI.Both aim to produce a significantreduction in the noise generated byhelicopters.

6.11.10. Noise maps and action plans arerequired by the Environmental NoiseDirective on a five-year cycle. Helicoptersare not excluded, though rudimentarynoise mapping of helicopter noise iscurrently restricted to major airports.However, the accuracy of these strategicnoise maps relating to helicopter noise islimited by the lack of sufficient sourcedata and validation of noise predictionmodels in this context.

6.11.11. The UK has world-leadingexpertise in helicopter noise predictionand in the measurement of source noisefrom helicopters.

30


7. Conclusions

7.1. Extent of the reported problem ofnoise from helicopter operations inthe UK7.1.1. Reported problems with helicopternoise in the UK are centred on helicopterinfrastructure, in particular specificheliports and aerodromes.

7.1.2. The consensus among stakeholdersis that there is not currently a significanthelicopter noise problem in the UK, exceptin a few specific areas near the busiestheliports. On the other hand, it is thoughtthat there is increasing opposition to thedevelopment of heliports on the groundsof noise disturbance.

7.1.3. Determination of the scale of publicconcern about helicopter noise wouldrequire a social survey.

7.1.4. Determination of a dose-responserelationship for the prediction ofcommunity response to helicopter noisewould require an extensive and carefullydesigned study.

7.1.5. The study would need to take intoaccount socio-economic and culturalaspects, and the type of helicopter activity.

7.2. Guidance on the management ofhelicopter noise 7.2.1. There is a need for a more ‘holistic’approach to the management ofenvironmental complaints fromhelicopters.

7.2.2. To ensure there is accountabilityrelated to environmental noise problemscaused by helicopter operations, it issuggested that complaints are collectedand logged in a central database from allsources including the CAA, the MOD,local authorities, operators and airfieldmanagers. Attention should be paid tomethods utilised in Australia wheremonthly reports on complaint statistics areprovided to stakeholders.

7.2.3. The CAA provides a focal point forreceiving environmental complaints fromaircraft operations but it does not haveany legal power to prevent aviation onenvironmental grounds. An independentreview is considering giving the CAAgreater powers over environmentalmatters2. This 'holistic' approach wouldgive a wider view and could identifyspecific problems.

7.3. Improving the handling ofcomplaints - consultative committees7.3.1. Well-organised consultativecommittees are successful in addressingenvironmental noise from helicopters.

7.3.2. When operated successfully, thepublic appreciate that their concerns arebeing taken seriously.

7.3.3. This is because consultativecommittees represent a neutral positionfrom which to influence operators tochange operational procedures.

7.4. Opportunities for improving dose-response relationships7.4.1. Academic research is required tobetter understand the human response tohelicopter noise.

7.4.2. Problems caused by helicopter noiseare not represented by the certificationparameters of helicopters.

7.4.3. Helicopter manufacturers areconcerned that a gradual reduction in thecertification levels would compromisehelicopter performance or even refusal oftype certification.

7.4.4. Annoyance by helicopter noise isnot well correlated with generallyaccepted acoustic parameters. The reasonsfor this are thought to be a related tothree factors:1) The unique subjective character of the

helicopter noise not being fullyaddressed by the indices.

2) The use of long-time averaged (LAeq)parameters that do not correctlyrepresent single events or operationsthat have a low rate of incidence.

3) The 'virtual noise' factor, whichencompasses community attitudes andfears towards the operations.

7.4.5. The UK has world-class expertise inthe subjective response to helicopternoise.

7.5. Recommendations for plannersand developers7.5.1. Developers need to be encouragedto enhance sound insulation in new /change-of-use builds near helicopterbases.

7.5.2. A residential planning applicationclose to an operating heliport, whenevaluated in accordance with PPG24,should not rely solely on Leq and shouldconsider the intermittent nature ofhelicopter operations.

7.5.3. The UK has world-leading expertisein the field of sound insulation ofresidences from helicopter noise.

7.6. Improvement of predictions7.6.1. Noise mapping for helicopters is notcurrently conducted due to the lack of anagreed noise prediction model in thepublic domain and inadequate sourcenoise data.

7.6.2. Appropriate data on the sourcenoise of civil helicopters, except wherethey overlap with military platforms, is notavailable, and needs to be collectedand/or estimated through sourceprediction code as a matter of priority.

7.6.3. The UK has world-leading expertisein helicopter noise propagation predictionand in the measurement of source noisefrom helicopters, due to involvement inmilitary programmes.

7.6.4. This expertise, currently onlyavailable within MOD programmes, couldbe exploited in future civil noise mapping.

2Department for Transport press release of 9 October 2007http://nds.coi.gov.uk/environment/fullDetail.asp?ReleaseID=320757&NewsAreaID=2&NavigatedFromDepartment=False

31


8. List of abbreviations

AAAC Association of Air Ambulance Charities

ACARE Advisory Council for Aeronautics Research in Europe

ADO Airports District Office

AGL Above ground level

AI Australian Annoyance Index

ANASE Attitudes to Noise from Aviation Sources in England

ANIS Aircraft Noise Index Study

ANO Air Navigation Order

ANSI American National standards institute

ARED Aviation Regulation Enforcement Department

ATC Air Traffic Control

BHAB British Helicopter Advisory Board

BVI Blade Vortex Interaction

CAA Civil Aviation Authority

CAS Controlled Airspace

CASA Civil Aviation Safety Authority (Australia)

CIEH Chartered Institute for Environmental Health

dB Decibel

Defra Department for Environment, Food and Rural Affairs

DfT The Department for Transport

DNL Day-Night Level

DS&C Directorate of Safety and Claims

DUAs Dedicated User Areas

EASA European Aviation Safety Agency

ECAC European Civil Aviation Conference

END Environmental Noise Directive

EPA US Environmental Protection Agency

EPNL Effective Perceived Noise Level

FAA Federal Aviation Authority

FAR Federal Aviation Regulations

HSI high speed impulsive (noise)

HYENA Hypertension and Exposure to Noise near Airports

ICAO International Civil Aviation Organization

IoA Institute of Acoustics

ITD Integrated Technology Demonstrator

JAA Joint Aviation Authorities

JSPs Joint Service Publications

JTI Joint Technology Initiative

Leq Equivalent Continuous Noise Level

LFAs Low flying areas

MCA Maritime and Coastguard Agency

MOD Ministry of Defense

NAG Noise Action Group

NASA National Aeronautics and Space Administration

NATS National Air Traffic Services

NEU (Airservices Australia) Noise Enquiry Unit

NHS National health service

NIGS Noise Insulation Grant Scheme

NNI Noise and Number Index

NOTAR NO TAil Rotor

NPR Noise preferential routes

PNL Perceived Noise Level

PPG 24 Planning Policy Guidance 24: Planning and noise

Q Disturbance Index

Q.T/R Quiet tail rotor

RAF Royal Airforce

SAR Search and rescue

SEL Equivalent Sound Level with Threshold

TR Tail Rotor

TRI Tail rotor interaction

UCAS Uncontrolled Airspace

WECPNL Weighted Equivalent Continuous Perceived Noise Level

WHO World Health Organization

32


9. Recommendations of London in Spin

Recommendations of London in Spin

The Department for Transport should undertake a full review ofthe impact of helicopter movements and noise in London overthe next twelve months, with the aim of putting in place a seriesof policy responses designed to mitigate the impact of this formof noise pollution on Londoners’ lives.

As part of its review, the Department for Transport and CivilAviation Authority should investigate and then establish amechanism to ensure that research on noise and other data onall helicopter movements is effectively collected, collated,analysed and published

A single national web-site (for example, extending the role ofthe national noise mapping web-site), or a clearly publicisedportal, should be established by the Department for Transportand/or Department for Environment, Food and Rural Affairs togive public access to data on helicopters, including movements,routes used, and places where holding may be expected.

As part of its review, the Department for Transport should takethe lead to: make the public complaints procedures clearer,including making any telephone number universally known; thatcomplaints are logged, co-ordinated and dealt with effectively;and that consistent data on complaints is published.

The Civil Aviation Authority should include the London Assemblyand the Mayor of London in consultation, and seek amendmentto legislation to make them both statutory consultees, regardingmatters that have implications for helicopter noise.

The operator of London Heliport at Battersea, in association withWandsworth Council, should establish within 12 months aLondon Heliport Consultative Committee to, as a first priority,address local residents’ concerns about helicopter movementsand noise.

The National Air Traffic Services and Civil Aviation Authorityshould come forward with proposals on dealing with the issue ofhelicopter holding at locations across London.

The Department for Transport should review its guidance to theCivil Aviation Authority so that the environmental impact ofhelicopter noise is included within its responsibilities.

As part of its review, the Department for Transport shouldinvestigate user charging for any additional air traffic controlservices required for helicopters.

CAA; responses to the recommendations of London in Spin

Not for the CAA to action.

The CAA will review what information is available on helicopternoise modelling and provide links via its website. A mechanismhas been agreed with NATS to provide data on helicoptermovements over London and this data will be published atregular intervals on the Directorate of Airspace Policy (DAP)section of the CAA website.

A mechanism has been agreed with NATS to provide data onhelicopter movements over London and this will be published atregular intervals on the Directorate of Airspace Policy section ofthe CAA website. DAP already has a well-advertised post thatreceives noise complaints from across the UK. The contacttelephone numbers and e-mail address have been provided in theCAA’s written evidence to the Committee.

Not for the CAA to action. However, the CAA already has such afacility as described in response to Recommendation 3.

The CAA already considers the Mayor of London to be astatutory consultee on matters that effect the GLA area ofresponsibility.


This is already underway as a follow-on to the London CTRreview that was initiated by the CAA during 2005. NATS arecurrently working up proposals that will include changes toairspace classification, an extension of Helicopter Route H4 to theeast and a new route south-east from Battersea Heliport all ofwhich could help reduce the requirement for helicopters to hold.

Not for the CAA to action. However, the CAA view is that civilhelicopter noise is not specifically excluded from the currentGuidance.

Not for the CAA to action. However, the CAA view is thathelicopters should be treated in the same way as any othergeneral aviation aircraft requiring transit services through avolume of controlled airspace established to protect aircraftlanding/taking off at airport.

33


Recommendations of London in Spin

Following changes to the Regulations, the Civil AviationAuthority should impose restrictions on the use of helicopters foradvertising and media so that the environmental impact can beminimised.

The Department for Transport should submit proposals to theTreasury that would lead to a change in the finance rules to givea write down allowance of 25% for all helicopters.

The Department for Transport should establish a working groupincluding the Civil Aviation Authority, National Air TrafficServices, Metropolitan Police Air Support Unit, British HelicopterAdvisory Board, helicopter/heliport/airport operators, Mayor ofLondon, local authorities, environmental groups and any affectedresidents groups to: update estimates of future demand forhelicopter movements; examine noise assessment and controlissues; reappraise management of airspace; commission andundertake research; and, assess options for existing and futureheliport provision.

The Civil Aviation Authority should give regard to the Mayor’sLondon Ambient Noise Strategy when developing proposals onenvironmental matters, including helicopter noise.

The Mayor should reflect the findings and recommendations ofthis London Assembly report in the next review of his LondonAmbient Noise Strategy

CAA; responses to the recommendations of London in Spin

No anticipated change. The CAA could only take such action onsafety grounds or because of an airspace restriction that hasbeen created for a specific purpose. Current operations arebeing conducted within the Aerial Advertising Regulations.


Not for the CAA to action. However, the CAA recommends thatit calls a meeting of interested parties in December 2007 whenmeaningful statistics will be available from NATS on thehelicopter movements that have taken place. This will provide anopportunity for a meaningful assessment of trends.

The CAA will give due regard to the Mayor’s London AmbientNoise Strategy.


34


10. Institute of AcousticsOne-day meeting timetable

Improvement of the management of helicopter noise, IoA meeting, 6th Feb 2008

10:00 Coffee and Introduction Chairman Geoff Kerry (University of Salford)

10:30 Defra policy perspective Parminder Dhillon (Defra)

11:00 Helicopter noise management Rodger Munt (QinetiQ)

11:30 Psychological aspects of helicopter noise Kath Sixsmith

12:00 Management of environmental noise from helicopters Steve Mayner (Wandsworth Council)– Local Authority perspective

12:30 Management of environmental noise from helicopters Bob Mclaughlin – RAF perspective Wg.Cmd. Tim Owens (RAF)

13:00 Lunch & structured discussion

14:00 Management of environmental noise from helicopters Jim Walker (CAA)- Civil Aviation Authority

14:20 Summary of helicopter operations in the UK Paul Freeborn (BHAB)

14:40 Helicopter noise - what is important from a Tony Pike (AgustaWestland)community prospective

15:10 Coffee & structured discussion

15:40 Summaries

16.00 End

35


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[112] “Helicopter Disturbance Study: Main Report”, DR Report8304, 1983.

[113] “London Heliport Study Noise subgroup Report”, DOT,Nov, 1994.

[114] “The Future of Air Transport”, DfT, Dec, 2003.[115] “ECAC.CEAC Doc 29 : Report on Standard Method of

Computing Noise Contours around Civil Airports”European Civil Aviation Conference, 2-3 July, 1997

38


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Documents

Research into the improvement of the management …usir.salford.ac.uk/30805/1/nanr235-project-report.pdf1 DEFRA NANR235: Project report Executive Summary Introduction This report describes