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

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Resea rch into the Improvement of the

Mana gement of Helicopter Noise

June 2008

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

Performed on behalf of Defra

DEFRA NANR235: Project report

Executive Summary

Introduction 3) Problems related to noise generated 2) The UK has world-class expertise This report describes research undertaken on the ground at aerodromes should regarding community response to to investigate the improvement of the be referred to the Local Authority. soundscapes. This expertise could be management of helicopter noise in the 4) Consultative committees to enable exploited in future research, and to UK. This work was carried out on behalf dialogue between residents, councils improve dose-response relationships of the Department for Environment, Food and heliport operators have been for helicopter noise. and Rural Affairs (Defra) by the University shown to improve understanding and 3) The UK has world-class expertise in of Salford and QinetiQ (Farnborough) Ltd. acceptance by the public. helicopter noise propagation prediction The aims of this study were to determine 5) The failure to act on complaints is one and in the measurement of source the issues and the extent of the reported of the largest causes of dissatisfaction noise from helicopters. This expertise, problem of noise from helicopter and resentment amongst the currently only available within MOD operations in the UK, and to develop public. programmes, could be exploited in practical guidance on the management of future civil noise mapping. helicopter noise, including improvements Rules and regulations governing Recommendations in the handling of complaints. helicopter operations 1) Academic research is required to 1) BHAB codes of practice aim to Methodology better understand the human persuade helicopter pilots and The methodology used to achieve these response to helicopter noise. In operators to take more notice of aims included a worldwide literature defining new approaches, the low environmental noise issues. search, a survey of stakeholders, and a incidence rate of most helicopter 2) Helicopter noise certification does not One-day Meeting carried out under the operations and the non-acoustic auspices of the Institute of Acoustics. address community annoyance caused factors, also known as ‘virtual noise’, by helicopter noise. A gradual which encompasses community Conclusions reduction in the certification levels will attitudes and fears towards the Nature and extent of the concern not address public acceptability. operations, should be considered. about helicopters noise in the UK 3) In England, the current land use 2) Complaints should be collected and 1) Problems due to helicopter noise are planning guidance (PPG24) states that logged in a central database. This centred on helicopter infrastructure noisy and noise sensitive land uses should embrace all sources including such as holding areas, heliports and should be kept apart. PPG24 provides the CAA, the MOD, local authorities, aerodromes. However, unlike fixed- advice to assist with the consideration operators and airfield managers. wing aircraft noise, helicopter noise is of new residential development near Attention should be paid to methods often not directly attributable to a existing sources of aircraft noise, but utilised in Australia where monthly specific heliport or airfield. the guidance states that it should be reports on complaint statistics are 2) Compared with fixed-wing aircraft, the used with caution where there is provided to stakeholders. ratio of movements to the number of existing helicopter noise. PPG24 3) Pilots should be made more aware of complaints received is generally small contains limited planning guidance on helicopter noise, perhaps during for most helicopter operations. the noise impact of new heliports. training for the Private Pilots Licence 3) The consensus among stakeholders is (PPL) or Basic Flying Training for the that there is increasing opposition to Dose response relationships military pilot. Such a scheme, the HAI’s the development of heliports on the 1) Helicopters can be up to 15dB more ‘Fly neighbourly’ program, is grounds of noise disturbance. annoying than fixed-winged aircraft. successfully operated in the US, 4) There is no comprehensive database However, helicopter noise levels alone Germany and other countries. This can of helicopter movements in the UK. do not account for annoyance trends be part of the best practical means of Consequently, it is impossible to in communities. minimising noise complaints. determine the extent to which noise 2) There is no single satisfactory noise 4) Applied research is required so that nuisance is a growing concern. index for the measurement or land use planning guidance, such as 5) Precise determination of the scale of prediction of the impact of noise on PPG24 in England, can be revised. public concern about helicopter noise the community. Specific land use planning guidance would require a careful social study. 3) Noise maps displaying Lden are not needs to be developed for the Procedures in place for handling suitable to be used for the prediction assessment of noise from helicopter helicopter noise complaints of subjective response of communities operations. 1) The CAA acts as a focal point for to helicopter noise. 5) Developers need to be encouraged to receiving and responding to aircraft- enhance sound insulation in new / related environmental complaints Opportunities for improvements change-of-use builds near helicopter from the public1. The CAA 1) The UK has world-leading expertise in bases. encourages noise complaints to be the sound insulation of residences 6) For accurate prediction of made directly to the airport operator. from helicopter noise. This expertise environmental noise from helicopter 2) Complaints regarding military flights could be exploited by designers and operations, and for noise maps, data should be addressed to the base's planners with regard to future on the source noise of civil helicopters community liaison officer. building developments in the vicinity needs to be obtained. of helicopter operations. 1CAP 724 Airspace Charter, November 2007 (Directorate of Airspace Policy, CAA).

DEFRA NANR235: Project report

Summary

I) Objectives wing aircraft for the same or lower operations over London. RAF Shawbury 1) To investigate the reported adverse measured sound level. Studies attempting reports receiving 313 noise complaints in impacts of helicopter noise and to to relate dose-response with annoyance due 2007. provide information on the nature and to helicopter operations have produced As a result of debate at the One-day extent of the concern about helicopters poor correlation and have been broadly meeting it was revealed that the ratio of noise in the UK. criticised. There is no straightforward helicopter movements to number of 2) Compile a summary of procedures in relationship between objective noise and complaints received is generally very small place for handling helicopter noise subjective annoyance. No good correlation for most operations. The consensus complaints and the roles, responsibilities with complaints has been found with LAeq, amongst stakeholders is that there is not a and powers of the related authorities LCeq, LAmax, L10 and LAmax-L90. Studies significant helicopter noise problem in the and organisations. addressing the noise from light aircraft and UK. However, problems do exist and these 3) Compile a summary of the current rules microlights reveal similar issues; that noise are centred on helicopter infrastructure such and regulations governing helicopter level may be a secondary issue and different as specific heliports and aerodromes. operations, any current relevant industry indices may be required for low volume However, this may simply be because codes of practice, and any existing operations. complainers near to an airfield/heliport reported dose response relationships. Reaction to helicopter noise is determined know who to complain to, whereas those 4) Identify opportunities for improvement that live further away do not. and make recommendations on how by acoustic and non-acoustic 'virtual' noise. improvements could be implemented. Non-acoustic factors are thought to be of equal or greater importance and may be V) Results – procedures for handling II) Methodology triggered by impulsive/tonal noise generated complaints, roles and The methodology used to complete these by the rotors. This means that addressing responsibilities and noise reduction aims and objectives consisted of a acoustic noise limits may be unlikely to The CAA acts as a focal point for receiving worldwide literature search, a survey of significantly improve public acceptance of and responding to aircraft-related stakeholders and a One-day meeting carried helicopter noise. 'Virtual' noise by factors environmental complaints from the general out under the auspices of the Institute of other than noise including flight safety, public. However, the CAA does not have Acoustics. Key literature was identified by privacy, soundscape, locus of control and the legal power to prevent aviation activity searching technical journals, conference mental health. Perceived effect on house on solely environmental grounds, except proceedings, the internet, libraries, and price has also been shown to be a when considering changes to the structure through stakeholder contact. A significant factor. Highest annoyance has of controlled airspace. An independent telephone/email survey of stakeholders was been correlated with uncommon or review is considering greater powers for the conducted to investigate the extent of the exceptional helicopter events and CAA over environmental matters. concern about helicopter noise in the UK. complaints have been found to be more The CAA encourages noise complaints to Additionally stakeholders were asked about likely if the resident has a negative attitude be made directly to the airport operator. procedures for handling complaints, current towards the helicopter operator. It is However, this only works if the complainant rules and regulations, and industry codes of suggested that the term annoyance does knows where the helicopter is operating practice governing helicopter operations. not fully describe the subjective response to from/to. Problems related to noise Stakeholders were identified through the helicopter noise and perhaps a multifactor generated on the ground at aerodromes, Defra technical working group, contact with approach similar to the approach of other than in association with the normal the BHAB, contact with the MOD, contacts classifying work-related stress may be operation of aircraft, should be referred to in local government and as a result of the adopted. The following classifications, the Local Authority. MOD complaints should literature review. Stakeholders identified and amongst others, may be important; be addressed to the base's community contacted included; helicopter operators; intrusion, distress, startle, disturbance, locus liaison officer or via the MOD complaints helicopter pilots, airport management, of control. telephone line. environmental health officers, public Consultative committees to enable dialogue pressure groups, helicopter manufacturers, IV) Results – extent of the concern between residents, councils and heliport private consultants and emergency services about helicopter noise operators have been shown to improve amongst others. A One-day Meeting was The Chartered Institute for Environmental understanding and acceptance by the held on the 6th February and all contacted Health (CIEH) conducts an annual survey of public. When operated successfully, the stakeholders were invited. The IoA environmental health departments but has public appreciate that their concerns are publicised the meeting and a good only in the past two years started to record being taken seriously. This is because they attendance was achieved. Speakers at the helicopter noise complaints. On average, for represent a neutral position from which to meeting included representatives from those two years, helicopter complaints influence operators to change operational Defra, CAA, AgustaWestland, MOD, BHAB, make up about 5% percent of the overall procedures. Consultation with the public in QinetiQ and Wandsworth council. This number of noise complaints received from a number of instances has encouraged provided opportunity for debate between all transport, in 2005-2006 there were 45 operators to make operational changes key stakeholders. individual complaints and in 2006-2007 with a positive outcome for the III) Results – nature of the concern there were 37. The CAA reports that there complainants, examples include; about helicopter noise were 370 noise complaints resulting from establishment of voluntary avoid areas, Social surveys indicate that helicopters can helicopter operations in the UK in 2007, 80 circuit rotation for training flights and be up to 15dBA more annoying than fixed- of which were regarding helicopter improved pilot awareness.

DEFRA NANR235: Project report

BHAB codes of practice aim to persuade the The Lden is not an informative parameter Consultative committees can be effective in helicopter pilots and operators to take more for the depiction of helicopter noise, since managing the public’s concern about notice of environmental noise issues. helicopter noise arises from individual flights helicopter noise and help lobby operators to Although pilots are aware of noise issues, as opposed to the average of a large change operational procedures. factors such as safety are considered more number of flights. Noise maps displaying To ensure there is accountability related to important. Pilots should be made more Lden are therefore unlikely to be suitable for environmental noise problems caused by aware of helicopter noise. This could form the prediction of community response to helicopter operations, it is suggested that part of the training for the Private Pilots helicopter noise. complaints are collected and logged in a Licence (PPL) or Basic Flying Training for central database from all sources including military pilots. This can be part of the best VII) Conclusions – nature of the concern MOD, CAA, local authorities, operators and practical means of minimising noise about helicopter noise airfield managers. Attention should be paid complaints. Academic research is required to better to methods utilised in Australia where Helicopter noise certification does not take understand the human response to helicopter noise. It is suggested that new or monthly reports on complaint statistics are into account all aspects of noise from urban provided to stakeholders. operations and the subjective problems modified measurement indices need to be caused by helicopter noise are not defined that address the unique subjective A fast and sincere response is important in represented by the certification parameters. reaction to helicopter noise. In defining new keeping complainants from becoming Manufacturers are concerned that a gradual approaches the low incidence rate of most repeat complainers. The failure to act on reduction in the certification levels will helicopter operations and the non-acoustic complaints is one of the largest causes of compromise helicopter performance (or factors or ‘virtual noise’ that encompasses dissatisfaction and resentment amongst the even refusal of type certification) while not community attitudes and fears towards the public. addressing the public acceptability. operations should also be considered. X) Conclusions – planning and Two significant European projects address VIII) Conclusions – extent of the prediction noise from helicopters, FRIENDCOPTER and concern about helicopter noise Developers need to be encouraged to the "Clean Sky" JTI. Both aim to produce a Determination of the scale of public enhance sound insulation in new / significant reduction in the noise generated concern about helicopter noise would change-of-use builds near helicopter by helicopters using new technology. require a social survey. However, bases. Extending consultation to include VI) Results – planning and prediction determination of a dose-response developers may help to make developers The Planning Policy Guidance document relationship for the prediction of community more aware of the problem. response to helicopter noise would need (PPG24) lists a series of four Exposure In England, the current land use planning careful design and an extensive study. The Categories to help indicate whether guidance (PPG24) states that noisy and study would need to take into account planning permission should be granted for noise sensitive land uses should be kept socio-economic and cultural factors, and new housing near an existing source of apart. PPG24 provides advice to assist the type of helicopter activity. aircraft noise. A residential planning with the consideration of new residential application close to an operating heliport, A repeated view expressed amongst development near existing sources of when evaluated in accordance with PPG24 stakeholders was that the scale of the aircraft noise, but the guidance states that solely on the grounds of Leq, is unlikely to problem of helicopter noise could not be it should be used with caution where be rejected because of excess noise. This is estimated without the central logging of there is existing helicopter noise. PPG24 because PPG24 Exposure Categories are complaints. It was suggested that there is a contains limited planning guidance on the based on Leq levels, which are not need for a more “holistic” approach, and noise impact of new heliports. appropriate for intermittent noise events national statistics for helicopter noise such as helicopter operations. The land use complaints are required before an Applied research is required so that land planning system offers an opportunity for “informed debate”. use planning guidance, such as PPG24 in England, can be revised and specific the control of the noise impact of heliports There is consensus amongst stakeholders assessment methods suggested for noise but the current guidance is rather limited. that there may not be a helicopter noise from helicopter operations. PPG24 recommends Leq levels not be used problem now but it has the potential to to assess small operations (<30 become one. Others suggested that Appropriate data on the source noise of movements/day), although an alternative perhaps the question should not be ‘is there civil helicopters, except where they overlap method is not specified. a serious noise problem in the UK?’ but with military platforms, is not available, Noise maps and action plans are required by rather ‘Are we facing increased opposition and needs to be collected and/or the Environmental Noise Directive on a five- to the development of helicopter bases and estimated through source prediction code year cycle. Helicopters are not excluded, operations, and if so, what are we going to as a matter of priority. The UK has world- though rudimentary noise mapping of do about it?’ leading expertise in helicopter noise helicopter noise is currently restricted to prediction and in the measurement of IX) Conclusions – procedures for major airports. However, the accuracy of source noise from helicopters due to handling complaints / roles and these strategic noise maps relating to involvement in military programmes. This responsibilities / noise reduction helicopter noise is limited by the lack of expertise, currently only available within Helicopter noise certification is not directed sufficient metrological source data and MOD programmes, could be exploited in at urban operations and certification does validation of noise prediction models in this future civil noise mapping. not guarantee public acceptance. context.

DEFRA NANR235: Project report

Preface

This report presents work performed on The work was performed at the A One-day Institute of Acoustics meeting behalf of Defra by the University of University of Salford by: was held to inform this research. The Salford and QinetiQ Ltd. However, we following presenters contributed to this would like to thank the large number of Paul Kendrick work: people that assisted in this research and in David Waddington the preparation of this report. Geoff Kerry Parminder Dhillon Mags Adams Rodger Munt The work was performed with the Thurai Rahulan Kath Sixsmith assistance of the following technical group Yui Wai Lam Steven Mayner on behalf of Defra: Bob McLoughlin Tim Owens Ian Sherlock Jim Walker Richard Perkins The work was performed at Paul Freeborn Antonio Acuna QinetiQ Ltd by: Tony Pike Wendy Hartnell Stephen Turner Matthew Muirhead Colin Grimwood Ray Browne Paul Freeborn In addition, the following people Darren Rhodes commented on the draft of this report: James Deeley Steve Mayner John Leverton Colin Stanbury Tony Pike Christopher Forrest Rodger Munt Roy Strapp Lee Copley Frank Evans

4 DEFRA NANR235: Project report

Contents

EXECUTIVE SUMMARY 1 2.7. London Assembly Environment 6. MANAGEMENT OF Introduction 1 Committee Report, “London ENVIRONMENTAL NOISE FROM Methodology 1 In A Spin" 9 HELICOPTERS 24 Conclusions 1 2.8. Estimating the Scale of the Problem 6.1. Existing Procedures for Recommendations 1 of Helicopter Noise 9 Handling Noise Complaints 2.9. Summary of Chapter 2 10 from Helicopters 24 SUMMARY 2 6.2. Means of Redress for any I) Objectives 2 3. HELICOPTER OPERATIONS IN Perceived Disturbance Caused 24 II) Methodology 2 THE UK 11 6.3. Roles, Responsibilities and III) Results – Nature of the Concern 3.1. Helicopter Noise Generation and Powers of the Various Authorities About Helicopter Noise 2 Reduction Methods 11 and Regulating Organisations. 25 IV) Results – Extent of the Concern 3.2. Emergency Services 11 6.4. The Effectiveness of Dealing About Helicopter Noise 2 3.3. Military Helicopter Operations 12 with Helicopter Noise in the UK V Results – Procedures for Handling 3.4. Civilian Helicopter Operations 13 Using Current Methods 25 Complaints, Roles and 3.5. Helicopter Infrastucture 14 6.5. Comparisons with other Responsibilites and Noise 3.6. Helicopter Airspace Restrictions 15 European Countries 26 Reduction 2 3.7. Helicopter Routes 15 6.6. Comparisons with Australia 26 VI) Results – Planning and Prediction 3 3.8. Helicopter Noise Certification 15 6.7. Comparisons with the USA 27 VII) Conclusions – Nature of the 3.9. Summary of Chapter 3 15 6.8. Options for the Improvement Concern About Helicopter Noise 3 of the Management of VIII) Conclusions – Extent of the 4. RULES AND REGULATIONS Helicopter Noise 27 Concern About Helicopter Noise 3 RELATING TO HELICOPTER 6.9. Noise Prediction and Modelling 28 IX Conclusions – Procedures for OPERATIONS 16 6.10. Options for the Improvement Handling Complaints / Roles and 4.1. Rules of the Air Regulations 16 of Prediction for Noise Mapping 28 Responsibilities / Noise 4.2. Rules and Regulations Governing 6.11. Summary of Chapter 6 29 Reduction 3 Low-Flying Helicopter Operations X) Conclusions – Planning and (ANO) 16 7. CONCLUSIONS 30 Prediction 3 4.3. Relevant Sections of Planning 7.1. Exent of the Reported Problem Law 16 of Noise from Helicopter Operations PREFACE 4 4.4. Nuisance Law 17 in the UK 30 4.5. Helicopter Operations: ‘Codes of 7.2. Guidance on the Management CONTENTS 5 Practice’ 18 of Helicopter Noise 30 4.6. Guidance Provided by the British 7.3. Improving the Handling of 1. INTRODUCTION 6 Helicopter Advisory Board Complaints - Consultative 1.1. Background to the Research (BHAB). 18 Committees 30 Project 6 4.7. Helicopter Civil Noise 7.4. Opportunities for Improving 1.2. Policy Context 6 Certification 18 Dose-Response Relationships 30 1.3. Aims and Objectives 6 4.8. Rules and Regulations in 7.5. Recommendations for Planners 1.4. DEFRA Technical Working Group 6 Australia 19 and Developers 30 4.9. Rules and Regulations in Europe 19 7.6. Improvement of Predictions 30 2. THE PROBLEM OF NOISE FROM 4.10. Rules and Regulations in the HELICOPTER OPERATIONS IN USA 19 8. LIST OF ABBREVIATIONS 31 THE UK 7 4.11. Summary of Chapter 4 19 2.1. Nature of the Concern About 9. RECOMMENDATIONS OF Helicopter Noise in the UK 7 5. SUBJECTIVE RESPONSES TO LONDON IN SPIN 32 2.2. Extent of the Concern About HELICOPTER NOISE 20 Helicopter Noise in the UK 7 5.1. Social Effects 20 10. INSTITUTE OF ACOUSTICS 2.3. Noise Indices and Measurement 5.2. Health Effects 20 ONE-DAY MEETING TIMETABLE 34 Methods 7 5.3. Community Attitudes 21 2.4. Existing Dose Response 5.4. Non-Acoustic Factors 22 11. REFERENCES 35 Relationships 8 5.5. Comparison with Light 2.5. Subjective Responses to Aircraft/Microlights 23 Helicopter Noise 9 5.6. Summary of Chapter 5 23 2.6. Means of Redress for any Perceived Disturbance Caused 9

5 DEFRA NANR235: Project report

1. Introduction

1.1 Background to the research project 1.2.3. As part of the END, Action plans 2) To compile a summary of the existing 1.1.1. Helicopter noise can have a designed to manage noise issues and procedures in place for handling negative impact on the quality of life for effects including noise reduction if complaints relating to noise from some people. Affected populations are possible will have to be drawn up by 18 helicopters together with the roles, not just those living close to heliports, but July 2008 and submitted to the responsibilities and powers of the include those exposed to noise from Commission by January 2009. The airport various authorities and regulating helicopters used by emergency services, authorities are responsible for drawing up organisations. the military, commercial companies and action plans, which must be approved by 3) To compile a summary of the current private individuals. One problem identified the SoS. Action plans for other sources rules and regulations governing is that it is often difficult to complain including agglomerations will be drawn helicopter operations, any current about helicopter noise since it is unclear up by the SoS. Public and stakeholders relevant industry codes of practice and which organisation is responsible for will be consulted. any existing reported dose-response dealing with the complaint. relationships. Opportunities for 1.2.4. Helicopters are not excluded from improvement will also be reported and 1.1.2. This research project was proposed the Environmental Noise Directive but are recommendations made on how these by Defra with the objective of improving only accounted for at major airports. could be implemented. the management of noise from helicopter operations. This was due to a perceived 1.3. Aims and objectives 1.4. Defra Technical Working Group lack of information in connection with The aims of the project were: 1.4.1. Defra formed an ad-hoc technical helicopter noise, and in particular, with 1) To determine the issues and the extent working group of key stakeholders to regard to whom complaints should be of the reported problem of noise from participate in and oversee this project. addressed. Clarification was also required helicopter operations in the UK. Their role was to advise Defra on on remediation and mitigation. 2) To develop practical guidance on the information sources, current problems and management of helicopter noise, possible solutions, and to peer review the 1.1.3. Current perceptions were supported including improvements in the project deliverables. The members of this by the recent London Assembly handling of complaints. technical working group are summarised Environment Committee report, “London in the table below. in a Spin – a review of helicopter noise The objectives of the study were: October 2006”. That report states that 1) To investigate the reported adverse there is anecdotal evidence of a growing impacts of helicopter noise and to concern amongst members of the public provide information on the nature and about helicopter noise. The Department extent of the concern about helicopter for Transport (DfT) is currently working noise in the UK. with the Civil Aviation Authority (CAA) and National Air Traffic Services (NATS) in response to the key recommendations. Role Name Affiliation This report for Defra, which also looks at procedures abroad, addresses many of the Nominated Officer Antonio Acuna Defra questions raised in the London Assembly report although the scope of this study is Chairman: Richard Perkins Defra UK wide. Project Manager Ian Sherlock Defra Policy Officer: Wendy Hartnell Defra 1.2. Policy context 1.2.1. The Environmental Noise Directive Policy Adviser: Stephen Turner Bureau Veritas (END) 2002/49/EC [1] was published in the Member Colin Grimwood Bureau Veritas (PPG24) Official Journal on 18 July 2002. The aim of END is to provide a high level of health Member Paul Freeborn Bureau Veritas (BHAB) and environmental protection against Member Darren Rhodes ERCD / CAA noise. Member James Deeley ERCD / CAA 1.2.2. The END requires Member States to Member Steve Mayner Wandsworth Council make Strategic Noise Maps for major Member Colin Stanbury Wandsworth Council agglomerations (defined as areas of urban development with a population of at least Member Christopher Forrest PremiAir [BHAB] 250,000, a population density of 500 Member Roy Strapp DfT (Aviation Environmental Division) person per square kilometre and a Member Frank Evans DfT (Aviation Environmental Division) continuous urban area of at least 20 hectares) major roads, major railways and major airports within their territories. Table 1: Defra Technical Working Group - Helicopter noise

6 DEFRA NANR235: Project report

2. The Problem of Noise from Helicopter Operations in the UK

This section introduces the issues and the 5) A recent study has shown that for 2.3. Noise indices and measurement extent of the reported problem of noise every 10dB increase in night-time methods from helicopter operations in the UK. The noise level for fixed-wing aircraft (Lnight 2.3.1. In assessing the environmental nature and the extent of concern about 2300 – 0700), the risk of hypertension impact of noise on individuals and helicopter noise in the UK is presented. is increased by about 14% [5]. communities, an objective descriptor with a Objective measures and dose-response well-defined relationship with community relationships are briefly described to 2.2. Extent of the concern about annoyance is required. Annoyance is facilitate a short overview of subjective helicopter noise in the UK complex and different individuals and responses. Current means of redress for 2.2.1. The CAA reports that there were communities react differently to different any perceived disturbance caused are 370 noise complaints resulting from noise sources. A large number of indices listed before an overview of the London in helicopter operations in the UK in 2007, have been developed for various a Spin report. A short summary of the 80 of which were regarding helicopter applications. As this may lead to confusion views elicited from stakeholders at an operations over London [6]. However, this and misinterpretation of data, a number of Institute of Acoustics meeting on this is not a complete list as complaints about researchers have tried to move towards a topic is presented as part of an estimation military helicopter use and complaints standardised method of assessing aircraft of the problem of helicopter noise. These directed at operators and local authorities noise [9] but have met with little success issues are addressed in detail later in this are not included. “because of the variability and unpre- report. dictability of reaction the impact of noise 2.2.2. The London Assembly Environment has always been difficult to quantify. As a 2.1. Nature of the concern about Committee ‘London in a Spin’ report result there is no single measure of the helicopter noise in the UK states that ”anecdotal evidence from the impact on the community of noise” [10]. 2.1.1. Surveys suggest some people tend public has indicated a growing concern to be concerned about helicopter with helicopter noise” [7]. The authors 2.3.2. Noise level is measured as sound operations and the noise they create for a comment “there is no comprehensive pressure level in decibels (dB), a measure number of reasons. The main issues database of helicopter movements across describing a sound level relative to the identified in this report are summarised as London, so it is impossible to tell the threshold of human hearing (in the mid follows: extent to which this noise nuisance has frequency range). Sound level is often 1) The subjective response to aircraft increased”. averaged over a period of time, and often noise is often described in terms of frequency weighting scales are applied to community ‘annoyance’ and studies 2.2.3. Anecdotal evidence reveals sounds to take into account the human have indicated that helicopters can be 'pockets' of complaints arising around auditory response systems’ uneven nature. up to 15dB 'more annoying' than areas such as busy heliports, aerodromes The most commonly used frequency other aircraft [3]. and some RAF bases. RAF Shawbury weighting system is A-weighting which is 2) Sound levels alone do not account for reports receiving 313 noise complaints in designed to model the human auditory annoyance trends in communities. 2007. frequency response at relatively low levels People are also concerned about other (<55dB). A-weighting was also found to aspects of the operations and the 2.2.4. The Chartered Institute for correlate well with the human response noise acts as a trigger for these Environmental Health (CIEH) conducts an over a wider range of sound pressure concerns. Examples include concerns annual survey of environmental health levels. There are also B, C and D about safety, perceived intrusion of departments but has only recently (in the weightings. B and C weightings were the helicopter into one's personal past two years) started to record designed to account for the change in living space, and negative opinions helicopter noise complaints. On average, frequency response at different sound towards the purpose of the flight [3]. for those two years, helicopter complaints pressure levels of the human auditory 3) Research (primarily concerned with make up about 5% of the overall number system. The D weighting was introduced fixed wing aircraft) has shown that of noise complaints received from all to account for the spectral characteristics noise adversely affects classroom transport; all transport being fixed-wing of turbo-jet powered aircraft as an learning. It has been shown that low aircraft, motorbikes, cars and commercial approximation to Perceived Noise Level achieving students are the most vehicles (e.g. lorries, vans buses etc) [8]. (PNL) but is now obsolete. adversely affected [4]. 4) High aircraft (fixed wing) noise levels 2005-2006 2006-2007 can awaken people, but the likelihood Number of Complaints 56 40 of the average person having their sleep noticeably disturbed due to an Number of Noise Incidents complained of 45 37 individual aircraft noise event is Nuisance Ceased and Not Likely to Recur 01 relatively low [4]. However, sleep Referred to Other Services 6 1 disturbance from helicopter operations may differ considerably due to its Resolved Informally 11 1 unique modes of flight such as No Action Possible 13 4 hovering and low flying. Table 2: Helicopter noise complaints received 2005-2007 (survey of Environmental Health departments) [8].

7 DEFRA NANR235: Project report

2.3.3. A wide variety of noise indices have the average of a large number of flights. 2.4. Existing dose response been developed for use in aircraft noise The situation is illustrated by figure 1. relationships and community response studies: 2.4.1. A dose-response relationship is a ● Perceived Noise Level (PNL) 2.3.6. Civilian helicopters must undergo a function that is designed to predict the ● Effective Perceived Noise Level (EPNL) noise certification test for each type of relationship between an objective physical ● Noise and Number Index (NNI) craft. Heavy (>3175 kg) and light (≤3175 measure such as sound level, to a ● Australian Annoyance Index (AI) kg) helicopters have separately defined subjective response such as annoyance. ● Disturbance Index (Q) tests, although light helicopters may use The Aircraft Noise Index Study (ANIS), ● Equivalent Continuous Noise Level (Leq) the scheme for heavier helicopters. For published by the CAA in 1984, aimed to ● Equivalent Sound Level with Threshold heavy helicopters, noise levels are accurately measure human responses to ● Single Event Noise Exposure Level (SEL) measured at three points on the ground aircraft noise, and to find the dose- ● Exposure Forecast during three prescribed flight conditions – response relationship that best describes ● Psophic Index take-off, level flight and approach to this subjective response. The result of ● Weighted Equivalent Continuous landing. The Effective Perceived Noise ANIS was a dose-response relationship Perceived Noise Level (WECPNL) Level (EPNL) is used as a descriptor of the where the percentage of people who ● Day-Night Level (DNL) noise level. For light helicopters, found the aircraft noise unacceptable ● The 16h A-weighted Equivalent certification is based on the flyover increases from around 15% at 57dB LAeq condition only and the sound exposure roughly in a straight line to around 75% Continuous Noise Level (LAeq, 16h) level is used to categorise the noise level. at 69dB LAeq. No equivalent study has ● Day Equivalent Continuous Noise Level Both SEL and EPNL utilise only the highest been performed specifically for helicopters (Lday) 10dB of the noise event, however, sound [11]. ● Evening Equivalent Continuous Noise outside this upper 10dB region can still Level (Levening) cause annoyance, especially where high 2.4.2. DORA published DR Report 8304: ● Night Equivalent Continuous Noise levels of impulse noise are present [3]. 1982 Helicopter Disturbance Study [112], Level (Lnight) Since there is a discrepancy between noise although inconclusive, found that ● Day, Evening, Night Equivalent target limits and public acceptance, the annoyance was greater from helicopter Continuous Noise Level (Lden) use of certification levels by manufacturers noise than for fixed-wing aircraft for a 2.3.4. In the UK, NNI was used from the as design targets for acceptable noise given noise exposure level. Another government’s Wilson committee report performance may be problematic. It limited social survey was undertaken as from 1963 until 1990, when the 1984 should be noted that although military part of the 1990s London Heliport Study Aircraft Noise Index Study (ANIS) led to helicopters are expressly excluded from [113] and is mentioned in that report. As the LAeq being adopted as the UK aircraft noise certification, civil and military a result of that work, helicopter noise noise index. However, just as the NNI has variants of newly designed aircraft are contours were plotted down to 51dB been dropped in the UK, so too has the usually based on common rotor, engine LAeq 16hr (6dB lower), acknowledging Psophic index, the Dutch are about to and transmission systems so that the noise greater annoyance from helicopter traffic. drop the Kosten Index, and the Japanese characteristics are virtually identical. It A separate helicopter social survey report are about to drop WECPNL. All are follows that military helicopters are was referenced to be published shortly moving towards the use of Lden. designed to the same noise standards as after, but ultimately never appeared. 2.3.5. The 16-hour LAeq and night-time civil aircraft. Chapters 4.7 and 3.8 refer in LAeq are used in planning legislation to more detail to noise certification. determine whether planning application can be granted. Often noise levels are predicted to determine whether planning applications will be granted. As a result of the Environmental Noise Directive (END) (2002/49/EC), noise maps have been produced to identify noise climate and help develop action plans to manage noise levels. These maps show noise contours where each contour represents an average noise level. Lden is the 24-hr Leq calculated for an annual period, but with a 5 dB weighting for evening and a 10 dB weighting for night. Directive 2002/49/EC requires EU Member States to produce noise maps using the Lden noise metric, although helicopters are not currently included. The Lden is not an informative parameter for the depiction of helicopter noise, since helicopter noise Figure 1: Simulated time history (SPL) of sporadic helicopter flyovers compared arises from individual flights as opposed to with 16hr Leq.

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2.5. Subjective responses to helicopter 2.7. London Assembly Environment 2.8. Estimating the scale of the noise Committee report, “London in a Spin" problem of helicopter noise 2.5.1. Most community response 2.7.1. In 2006, the Greater London 2.8.1. On the 6th Feb 2008 an Institute of measures to acoustic stimuli are based on Authority published a review of helicopter Acoustics meeting was held at the A-weighted sound pressure levels noise in London. The report highlights University of Salford entitled “The averaged over a long period of time. “concern among a number of groups of improvement of the management of However, when dealing with only a small residents as to the impact of helicopter helicopter noise”. One of the aims of the number of acoustic events, e.g. seven noise on their quality of life”. The report meeting was to try to collect information helicopter flights over a sixteen-hour comments that “helicopter movements by engaging major stakeholders in period (see figure 1), the acoustic events have been growing over the past few structured discussion. One of the results have little bearing on the resulting years” and are a distinctive feature of of the debate was that it appears the ratio measure. The United States FAA report [4] urban living. The report makes a number of helicopter movements to number of states the current measures are deficient of short-term practical recommendations complaints received is generally very small for helicopters in terms of not only the to the Government and the Civil Aviation for most operations. A repeated view was number of events, but also in how the Authority (see chapter 9). that the scale of the problem of helicopter subjective effect is measured. In particular, 1) Develop a database to allow the noise could not be estimated without the low frequencies and the impulsive nature public to monitor helicopter central logging of complaints. It was of sound are not accounted for in current movements. suggested that there is a need for a more metrics. The FAA acknowledges this 2) Develop robust complaints procedures “holistic” approach, and national statistics problem in its 2004 report to the United to ensure the public’s concerns are for helicopter noise complaints are States Congress but continues to use the taken seriously. required before an “informed debate”. Day-Night sound level (DNL) as there is no 3) Establish a consultative committee at verified alternative. the London heliport. 2.8.2. An important point raised was the 4) Changes to the way London’s airspace need to be cautious in using complaint 2.5.2. In addition to these problems with are managed. statistics as a measure of the problem. measurement indices, studies have found 5) The possibility of a user charge for While many complaints are from repeat that current objective metrics are not operators. complainers, not everyone that is representative of annoyance, and that 6) More effective write-down incentives disturbed complains. Furthermore, with attitudes to the helicopter operations are for older, noisier helicopters. relatively few numbers of complaints a contributing factor. The term ‘virtual 7) Consideration should be given to received about helicopter noise, a noise’ is used to describe non-acoustic moving the heliport to another statistically meaningful result is difficult to factors such as fear of crashes and other location. derive. negative views of the helicopter operations [3]. 2.7.2. Use of the findings from the 2.8.3. Another suggestion to estimate the ‘London in a Spin’ report to highlight the scale of the problem involved carrying out 2.6. Means of redress for any “growing concern over helicopter noise” a national public survey. A point raised perceived disturbance caused has been criticised as anecdotal evidence. was that “canvassing opinion may raise 2.6.1. The CAA acts as a focal point for This is because data was received from the profile of the problem and aggravate receiving environmental complaints about only 132 London residents. This is a small it”. However, social survey techniques aircraft. However, the CAA has no legal proportion of those currently subjected to exist to avoid this problem. power to prevent aviation solely on noise from helicopter movements [2]. environmental grounds. Unless there is Since the report, and at least in part as a 2.8.4. A generally common view from clear evidence of a breach of the Air result of the recommendations, the delegates was that the question of Navigation Order, the CAA will advise the following steps have been taken: whether or not helicopter noise is a complainant to contact the operator 1) A consultative committee has been “problem” still needs to be determined; directly. established at the London Heliport. there does not seem to be enough 2.6.2. Often establishing communication 2) A complaints telephone line has been evidence at present to answer this and dialogue with helicopter operators established at the London Heliport. question. Recorded views included: can produce a positive outcome and an 3) The CAA has initiated changes to “Although there is an argument that it explanation of the purpose and nature of airspace classification and designated may not be (a problem) now, I feel it the operation that caused the disturbance helicopter routes to prevent helicopter certainly has the potential to become can be satisfactory. Consultative holding. one” and “perhaps the question should committees have been found to be 4) The CAA has agreed a mechanism not be ‘is there a serious noise problem in particularly helpful in raising issues with with NATS to provide helicopter the UK?’ but rather ‘Are we facing operators and ensuring operators are movement data for the public on its increased opposition to the development aware of their environmental impact. In website. of helicopter bases and operations, and if addition, making the operator aware of so, what are we going to do about it?’ problems caused can often result in changes to operational procedures to help alleviate the public disturbance.

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2.8.5. General consensus among stakeholders is that there is not a significant helicopter noise problem throughout the UK. However, problems do exist and these are centred on helicopter infrastructure such as heliports and aerodromes.

2.9. Summary of Chapter 2 2.9.1. Problems due to helicopter noise are centred on helicopter infrastructure such as heliport and aerodromes. The ratio of helicopter movements to number of complaints received is generally small for most operations. The Chartered Institute for Environmental Health (CIEH) reports that helicopter complaints make up around five per cent of the noise complaints received from all transportation. The CAA reports that there were 370 noise complaints resulting from helicopter operations in the UK in 2007. However, there is no comprehensive database of helicopter movements in the UK. Consequently, it is impossible to determine the extent to which noise nuisance is a growing concern.

2.9.2. Helicopters can be up to 15dB more annoying than fixed-winged aircraft. However, sound levels alone do not account for annoyance trends in communities from helicopter noise. There is no single satisfactory noise index for the measurement or prediction of the impact of noise on the community. The use of certified levels as design targets for acceptable noise performance is likely to be problematic, since there is a discrepancy between noise target limits and public acceptance.

2.9.3. The Lden is not an informative parameter for the depiction of helicopter noise, since helicopter noise arises from individual flights as opposed to the average of a large number of flights. Noise maps displaying Lden are therefore unlikely to be suitable for the prediction of community response to helicopter noise. It is widely recognised that while Leq or Lden are not ideal, currently there is not a better option. Further research is required to develop a dose-response relationship to accurately measure human response to helicopter noise.

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3. Helicopter operations in the UK

This section considers helicopter generated by transonic flow on advancing embarked on design initiatives addressing operations in the UK. An introduction to blades [13]. It is because of the high this, including the Westland Helicopter’s helicopter noise generation mechanisms is speed of the advancing rotor tips in quiet tail rotor (Q.T/R), the McDonnell given, together with noise reduction comparison with the speed of sound in Douglas NOTAR, and the Eurocopter’s methods relating to these mechanisms. the medium (air) that the noise output is fenestron fan-in-fin approach [3]. The helicopter operations of the often directed ahead of the helicopter emergency services, including the police, rather than behind it [13]. 3.1.6. Following a study conducted by air ambulance and search and rescue are Leverton for Bell Helicopter Textron [3] it outlined, followed by military and civilian 3.1.3. Helicopters differ from fixed wing was recommended that the Mach number operators. Finally, explanations of aircraft since the primary noise generation of the advancing blade tips should not helicopter infrastructure, helicopter routes mechanisms are also the primary lift and exceed 0.875, and should generally be and noise certification are presented, control mechanisms. For this reason, the kept at less than 0.85 to prevent the together with comparisons as appropriate realisation of a quiet helicopter must be impulsive sound becoming unacceptable. to those of fixed wing aircraft. fully integrated within the design process. Reduction in noise level is generally at the 3.1.7. As the temperature decreases, the 3.1. Helicopter noise generation and expense of performance factors such as speed of sound decreases, and therefore reduction methods payload, range and speed. The the Mach number increases. This results in 3.1.1. Helicopter noise generation differs relationship between the helicopter design a dramatic increase in the perceived from fixed wing propeller driven aircraft parameters is very close. For example, magnitude and impulsiveness of the main because the main rotor and tail rotor reducing the rotor tip speed will reduce rotor thickness noise close to the rotor operate close to the horizontal plane and the noise level however to maintain disk plane. Helicopter manufacturers often vertical plane, respectively, with axes of performance the blade area/number/shape provide noise data at the ICAO rotation normal to the flight direction. would have to be altered [3]. This certification specified temperature of Whilst for propeller driven aircraft the axis procedure was adopted in the 25oC. The possible significant variation in of the propeller is aligned to the direction development of the EH101/Merlin level and subjective character of the of travel, and the noise from each helicopter [15] the exceptional helicopter noise due to temperature propeller generally has symmetry about advancement in performance of the differences is not taken into account, and this axis. Such axial symmetry does not British Experimental Rotor Program (BERP) as such, some noise abatement exist for helicopter rotor blade noise blade was partly traded for noise, by operational procedures are not achieving sources. For this reason very few of the reducing tip speed, to produce the the noise levels predicted. This is a helicopter noise sources are similar to that quietest helicopter in its weight class. particular problem for helicopters with of its fixed wing counterparts [12]. Blade tips can be used to control BVI, see high tip speeds and unsophisticated rotor for example the vane tip programme [3]. designs. One manufacturer has recently 3.1.2. Helicopter noise is generated from Reducing tip speed can be effective but introduced flyover speed limits where a number of main sources: engine noise, usually for a loss of performance and care temperature is taken into account, and rotor noise and transmission noise. Apart is needed to prevent retreating blade stall another two have indicated that they from piston engine powered craft, the for the lower speed. intend to follow suit. [3] main noise sources are from the rotors [3]. Spectral analysis of helicopter noise reveals 3.1.4. Currently practical design 3.1.8. Operational procedures can help a series of tones generated by the main improvements aim to reduce BVI and tail reduce the environmental impact of and tail rotors. The main rotor generates a rotor noise. These are perhaps the biggest helicopters. Type specific Aircraft Flight series of tones whose fundamental is in source of complaints regarding helicopter Manuals (helicopter) contain a the range 10 to 40Hz. The tail rotor noise and the main trigger for non- performance graph that details flying generates a higher frequency tone series acoustic factors or ‘virtual noise’. Currently procedures to produce the least amount whose fundamental is usually in the range active and passive methods are being of noise although the flight envelope is 100 to 200Hz [13]. Although the tonal tested, and results have indicated varying difficult to follow due to the variety of noise dominates, broadband noise from degrees of success. Given sufficient power and airspeed configurations. A both the tail and the main rotors is development, a reduction of 6dB(A) in this reduction in speed of just 10 knots can present at a lower level. There also exist area is foreseeable. Modifications to have a significant noise reduction effect interactive effects between tail and main reduce BVI noise would not impact during [16]. rotors and the fuselage, the former noise abatement procedures and level interaction leads to combination tonal flight [3] but tail rotor noise is present in 3.2. Emergency services frequencies known as ‘Burble’[14]. all flight conditions and is a significant 3.2.1. Police: The UK police service fund Impulsive sounds also result from the trigger of ‘virtual noise’. their own helicopter operations [17]. The blade tips intercepting the vortex from a different forces will either buy or lease the preceding blade (Blade Vortex Interaction - 3.1.5. Tail rotor noise, because of its helicopter, and use either their own staff BVI) or the vortices from the main rotor higher frequency content than main rotor or pay a third party, such as PremiAir or being intercepted by the tail rotor (Tail noise, has a significant effect on the Sterling Helicopters Ltd, to operate the Rotor Interaction - TRI). In addition there subjective perception of helicopter noise. helicopter. Many police forces have exists high speed impulsive (HSI) noise A number of manufacturers have recently upgraded their fleets with quieter

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helicopters such as the McDonnell 3.3. Military helicopter operations Four of these areas are referred to as Douglas NOTAR equipped MD902, and 3.3.1. Almost all complaints generated by Dedicated User Areas (DUAs) where most the Eurocopter EC135 with its fenestron MOD helicopters will arise from low-flying of the helicopter pilot training takes place. tail rotor. Currently the EC135 is the most operations. MOD low flying operations are These are areas 1, 3, 9 and 10 on the popular police helicopter, followed by the comprehensively summarised in annual map. LFA1 contains RAF Odiham, home to MD902. These helicopters are some of the reports [24]. Low flying timetables for Chinook and Lynx, and RAF Benson, home quietest available [16]. The proportion of upcoming months are also published on to Merlin and Puma. LFA3 contains RNAS different helicopter models in the police the MOD’s website. Culdrose, home to Merlin and Sea King. force in the UK is indicated in Figure 2. LFA9 contains the Defence Flying Training Police helicopters operate from a range of 3.3.2. The MOD divides the country into School at RAF Shawbury, which runs pilot locations including RAF airfields, private 20 Low Flying Areas (LFAs) as shown in training on Gazelles, Griffins and Squirrels. general aviation aerodromes, major Figure 4. Statistics on the distribution of LFA10 contains the Army Air Corps. at airports and bespoke landing sites. military helicopter flights across the UK Wattisham, home to Apache and are then divided according to these areas. Lynx. 3.2.2. Air ambulance: Air Ambulance Services operate as charities and rely on the public for funding. A survey by Morepace revealed that only 40% of the UK public is aware of this fact [19]. 16 regional charities support 26 air ambulances in the UK. In Scotland, however, the Scottish executive funds air ambulances, whilst in London air ambulance receives partial NHS funding. Figure 3 describes the break down of the different helicopter models operating as air ambulances in the UK. The Association of Air Ambulance Charities (AAAC) supports the work of the UK’s independent air ambulance charities. The air ambulances undertake 17,500 missions in a year of which 40% involve road traffic collisions, 24% are other medical emergencies and 3% are hospital transfers[20].

3.2.3. Search and rescue (SAR): Search and rescue in the UK (on land and at sea) Figure 2: Breakdown of Police helicopter types[18] is covered by six RAF Search and Rescue teams, four civilian coastguard teams operated by the Maritime and Coastguard Agency (MCA), while the Royal Navy operates two SAR teams[21]. Before December 2005 the Maritime and Coastguard Agency contracted Bristow's Helicopters Ltd to operate 3 Sikorsky S61N helicopters and bases of operations are Sumburgh Airport (Shetland), Stornoway (Isle of Lewis) and Lee-on-Solent. All are capable of the full range of airborne search and rescue tasks. A fourth S61N helicopter stationed at Portland (near Weymouth) can operate in daylight only[22]. Announced in December 2005 CHC is now contracted to operate two S- 92s at Stornoway and two S-92s at Sumburgh, plus two AB139s based at Lee- on-Solent and an additional AB139 at Portland [23]. Figure 3: Breakdown of Air Ambulance helicopter types[18]

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3.3.3. It should be noted that military helicopters do not have to meet the civil noise certification standard unless they are also used for civilian purposes. However, variants are often used for civilian applications in which case civil certification is required and as mentioned in 2.3.6, military and civil aircraft are usually based on common rotor, engine and transmission systems so that the noise characteristics are virtually identical.

3.3.4. Helicopters outside of Dedicated User Areas (DUAs) are considered to be low flying below 500ft, but in DUAs (because of the increased number of flights) any flight below 2000ft has to be recorded as a low flying activity. In 2006/2007 there were 16,164 hours of flying recorded outside of the DUAs, and 26,041 hours of flying recorded in the four specified DUAs.

3.3.5. There are 14 major areas in the country that the MOD cannot use for low flying. These predominantly lie around airports and large built up areas. In addition, towns with more than 10,000 inhabitants are avoided and anyone is eligible to apply to the MOD for an additional avoidance area. Figure 4: Low flying areas for military aircraft. (LFA1 highlighted) 3.4. Civilian helicopter operations 3.4.1. Figure 7 indicates a steady increase in the number of civilian helicopters operating in the UK from 2002. These currently number 1,393[19]. There has been a particular increase in the number of smaller piston engine craft and this increase appears to be due to the recent popularity of the Robinson R22 and R44 helicopter.

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Types of operations include: 3.5.3. Helicopters can operate from 1) Flights that take place during major permanent landing sites such as heliports sporting events (e.g. Goodwood or aerodromes, and temporary landing Revival, British Grand Prix, Royal sites such as fields, gardens and Ascot) and other major events such as commercial premises. Refer to section 4.3 the Farnborough air show. for details on planning permission for the 2) Traffic surveillance. different types of landing sites. 3) Transporting heavy loads into inaccessible places (e.g. National Parks). 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 infrastructure 3.5.1. When compared with fixed wing aircraft with a similar personnel capacity, the fixed wing aircraft is faster and cheaper in terms of capital and operating costs. The advantage of the helicopter is that it does not require a large amount of space from which to take off and land. This means that helicopters do not require the extensive infrastructure needed by fixed wing craft, and this enables the Figure 6: Break down multi-turbine civilian helicopter types [19] helicopter to offer virtually door-to-door Data from BHAB handbook Copyright 2007 Computair Consultants: transportation [25]. email [email protected].

3.5.2. Helicopter landing / take-off sites: For ground level sites it is not possible to specify general requirements as all helicopters have different performance characteristics. A flat area around 24x16m should be sufficient for smaller types. Additionally, there should be no immediate obstructions after take-off and if possible, helicopters should be able to take off into the prevailing wind. It is the pilot’s responsibility to ensure that the landing site meets the craft’s specifications. When operated from elevated sites, such as rooftops, helicopters must meet more stringent safety requirements. For a craft to be able to operate from an elevated site, it must be 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 safely using the remaining engine thus only Figure 7: Recent trends in helicopter types [19] twin-engine craft can operate from Data from BHAB handbook Copyright 2007 Computair Consultants: elevated sites [25]. email [email protected].

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3.6. Helicopter airspace restrictions 3.7. Helicopter routes 3.9.2. The choice of rotor blade tip speed 3.6.1. UK air space can be categorised as 3.7.1. A number of helicopter routes have and to a lesser extent blade tip shape, is ‘Controlled Airspace’ (CAS) or ‘Uncontrolled been established, usually to help air traffic important because it controls the intensity Airspace’ (UCAS). Within controlled airspace, control at busy airports. The primary and character of the impulsive noise pilots must gain Air Traffic Control (ATC) function of helicopter routes is to generated by a helicopter. This applies to clearance and comply with instructions maintain separation from fixed wing both the main and tail rotors. issued. Controlled Airspace can be further aircraft. They are designed so that categorised as follows [25, 26]: helicopters will fly over open spaces 3.9.3. 3.9.3. The largest non-military user 1) Control zones are regions extending whenever possible. Routes are designed to of helicopters in the UK provides from ground level up, and span up to help helicopter pilots obey the Air transportation for the oil and gas industry. 2_ nautical miles from an aerodrome’s Navigation Order (ANO) rules. Routes are datum. not mandatory but in practice, especially 3.9.4. The majority of helicopters used by 2) Control areas are regions, which extend in London, are generally followed (though the Police and by the Air Ambulance from approximately 2000ft and 5000ft twin engine craft can request to route Service are the quietest types available. upwards. direct). The report ‘London in a Spin’ 3) Airways are corridors that are the main contains a map showing the location of routes connecting major airports. the helicopter routes in London [7]. 4) Terminal control areas are larger control areas situated around groups of airports 3.8. Helicopter noise certification where major routes converge. 3.8.1. All civil helicopter types in the UK 5) Upper airspace is the airspace from require a certificate of airworthiness. Part 19500 ft upwards. of the certification requires noise certification. This is to ensure the craft 3.6.2. The majority of air space in the UK meets certain internationally agreed noise below 2000ft is unrestricted (UCAS). standards set by the International Civil Although there is no requirement for Aviation Organisation (ICAO) of which the helicopter pilots to make contact with ATC UK is a member. The certification process when flying in UCAS, they often do so in is described in more detail in chapter 4.7. the interest of safety. Helicopter pilots must On the 28th March 2007 the European comply with ATC instruction in control zones Aviation Safety Agency (EASA) initiated around aerodromes. changes relating to the noise certification, which introduced an EASA Certificate for 3.6.3. There are relatively few areas of Noise (EASA Form 45) and set down restricted airspace over mainland UK. standard values upon which each Examples include: areas of high-density Certificate should be issued. The CAA has military activity, atomic reactors, high security commenced a programme of replacing all prisons and the residence of the Prince of CAA Noise Certificates for applicable Wales. In addition, temporary restricted EASA aircraft with Form 45 and this is areas can be set up for major incidents/ targeted for completion by March 2009 accidents, temporary helicopter landing sites [27]. and temporary hazards to aviation. Surprisingly, some military danger areas and 3.9. Summary of Chapter 3 airfields are not necessarily restricted and 3.9.1. Helicopter routing is generally only the CAS rules apply. Nevertheless, designed to assist Air Traffic Control and intentional intrusion without prior clearance to maintain separation from fixed wing is ill advised [25]. aircraft. In general, helicopter routes are designed to fly-over open spaces wherever 3.6.4. In addition to these rules of UK possible. airspace operations, the rules of the air as described in section 4.1 also impact on airspace restrictions. Refer to this section for further information.

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4. Rules and regulations relating to Helicopter operations

This section provides a summary of the 3) In the case of private pilots, the CAA 4.2.5. The 1000ft rule does not apply rules and regulations applicable to ensures that minimum standards in within controlled airspaces such as the helicopter operations and helicopter respect of flying, training, licensing, London control zone and around infrastructure in the UK. It refers to the construction and maintenance are aerodromes where air traffic control Rules of the Air Regulations, relevant met. provides a control service to aircraft. sections of planning and nuisance law, and to the codes of practice and 4.1.6. The CAA has no legal power to 4.2.6. No flying over the centre of guidance provided by the British prevent aviation on solely environmental London, except over the Thames, unless Helicopter Advisory Board (BHAB) and the grounds. Any breach in the ANO is the helicopter can fly even in the event of Civil Aviation Authority (CAA). This referred to the Aviation Regulation an engine failure. (“Specified Area rule”). section also includes explanations of Enforcement Department (ARED). The Essentially this allows twin engine craft to helicopter routes and noise certification. CAA can only act in the event of a breach fly over London where single engine craft Finally, comparisons are drawn with rules of the ANO. To prosecute, a number of must follow the Thames. and regulations from other European independent witnesses and positive countries, the USA and Australia. identification of the aircraft are required 4.2.7. No flights are permitted over or [6]. within 3000ft of gatherings of people of 4.1. Rules of the Air Regulations 1000 or more without the permission of 4.1.1. The conduct of civil aviation is set 4.1.7. An independent review is the CAA (referred to as the “crowd rule”). out in the Civil Aviation Act (1982). The considering greater powers for the CAA Air Navigation Order (ANO) is the over environmental matters [Frank Evans, 4.2.8. A blanket exemption exists document that delegates powers to the DfT, IoA meeting]. regarding flights with the purpose of Civil Aviation Authority (CAA). The ANO saving life. details exact specifications on all aspects 4.2. Rules and regulations governing of aircraft behaviour. Safety is the primary low-flying helicopter operations 4.3. Relevant sections of focus of the ANO [25]. (ANO) planning law 4.2.1. The ANO states “An aircraft shall 4.3.1. Permanent landing sites are 4.1.2. Specifically, civilian helicopter not be ﬂown below such height as would generally regarded as those that have a flights in the UK are governed by the enable it, in the event of a power unit CAA licence and that have been given Rules of the Air Regulations 1996 [28]and failure, to make an emergency landing planning permission by the local the Air Navigation (Restriction of Flying) without causing danger to persons or authority. There are only three licensed (Specified Area) Regulations 2005[29]. property on the surface”. heliports in the UK, at Battersea, Penzance and Culter Helipad near 4.1.3. The ANO and Rules of the Air 4.2.2. Unless a helicopter is taking off or Aberdeen [31]. For scheduled services to Regulations permit helicopters operated landing, in accordance with standard operate the heliport must be licensed. on behalf of the police to fly lower than aviation practice, no helicopter may fly Helicopters can land at most fixed wing would otherwise be normally permitted. closer to a person, vehicle, vessel or airfields both licensed and unlicensed. structure than 500 ft (often referred to as However, as helicopter flights should not 4.1.4. Military operations do not operate the “500 foot rule”). This does not refer cross fixed-wing aircraft landing and take- under the ANO or the rules of the air to absolute height and therefore off paths, helicopter approach and regulations. Rather, they operate to helicopters can fly lower over moorland, departures at fixed-wing airfields are side- Ministry of Defence regulations detailed for example. on to runways and are more likely to in Joint Service Publications (JSPs). The impact on properties less affected by CAA has no jurisdiction over military 4.2.3. No helicopter may fly over towns fixed-wing operations. operations and all enquiries about these or settlements at a height less than operations should be directed to the 1500ft or within 2000 ft of the highest 4.3.2. Temporary landing site use is Ministry of Defence [30]. fixed object. This rule was amended in allowed as long it is not in use for more 2004 and the minimum height reduced than 28 days in the year and permission 4.1.5. The ANO has three priorities to 1000 ft [28](referred to as the “1000 is gained for its use. (Part 4, Class B of 1) No aircraft may be operated in such a ft rule”). Schedule 2 of the Town and Country way that, even if an engine fails, third Planning General Development Order parties on the ground are put at risk. 4.2.4. Exemptions from both the 500ft 1988). Local authorities have powers to 2) If there are fare-paying passengers on and 1000ft rules are allowed with written withdraw the right to use the site, and to board an aircraft, the operator is permission from the CAA. Examples of require a planning application to be made required to ensure that certain exceptions include landing sites in city for continued use. If the direction is to mandatory safety standards are met centres, aerial photography and police remain in force for more than six months, to ensure that risk of injury to the and ambulance services. approval from the Secretary of State for passengers is minimised. the Environment is required. If planning . permission is refused or granted subject to conditions, compensation may be payable.

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4.3.3. Helicopters may operate from 4.3.9. In the original planning documents 4.3.12. When a planning application close private gardens of a property without (e.g. Circular 10/73), the criteria for to an operating heliport is sent to appeal, planning permission. However, to use an annoyance were low/medium/high, and the PPG24 will be cited as a benchmark. adjoining field, even if it is also owned by NNI index was used as the index of Generally, it is unlikely that the LAeq noise the property owner requires either annoyance. In the Planning Policy Guidance levels alone will result in a rejection of the planning permission or use as a temporary document (PPG24) [34], a series of four application. Consequently, Local landing site for up to 28 days per year. Noise Exposure Categories (NEC) called A, B, Authorities should be aware of the One issue raised was that the 28 days C and D based on LAeq levels are provided provision within PPG24 for consideration applies to a specific parcel of land and as guidance on the suitability of land for of aviation noise for low numbers of that a further 28 days would be allowable new residential development near existing movements such as helicopter operations. on an adjacent parcel of land [32]. sources of aircraft noise. Category D means planning should normally be refused. 4.3.13. In 2001, the Department for 4.3.4. Planning permission is not required Category C indicates a strong presumption Transport commissioned a study intended for helicopter operations from commercial against acceptance unless there are no to “underline the government’s properties unless the size of the helicopter acceptable alternatives; in this situation, commitment to underpin our policy on operation overtakes the size of the conditions should be imposed to ensure aircraft noise by substantial research that original business. In this case, planning adequate noise insulation. Category B commands the widest possible permission must be sought. indicates that noise should be taken into confidence”. The results were presented account in the planning process and noise in November 2007 as the ‘Attitudes to 4.3.5. Any landing site in urban and insulation is required. Category A indicates Noise from Aviation Sources in England’ congested areas requires the prior written that noise is not a factor to be taken into report (ANASE) [35], and concluded that permission of the CAA before they can account in the planning process. Exposure people were becoming increasingly operate. Categories can be used to determine annoyed by aviation noise. However, the whether planning permission should be report’s findings were rejected following 4.3.6. In 1963, the Wilson report led to granted to a new development in an area rigorous peer reviewing [36] [37] [38]. It the use of the NNI (Noise and Number with existing noise sources. It is stated should be noted however that the study Index) and defined 35 NNI as low however, that they cannot be applied in the relates to annoyance from fixed wing annoyance and 55 NNI as high reverse context. LAeq levels for any category aircraft rather than helicopters. annoyance. may be increased by up to 3 dB if there is a clear need for new residential development. 4.4. Nuisance law 4.3.7. In the early 1980s, the CAA's 4.3.10. PPG24 recommends that where an 4.4.1. If aircraft operations meet the Directorate of Operational Research and aerodrome operates less than about 30 requirements of the ANO then persons are Analysis (DORA) carried out a study movements a day, Leq should not be solely precluded from prosecuting based on commissioned by the Department of relied on. PPG24 states, “when determining nuisance (Civil Aviation Act 1982 section Transport into the use of the NNI. The NNI a planning application for a heliport the 76). Licensed heliports cannot be was considered ‘out of line’ with aircraft predicted noise should not be assessed in prosecuted under nuisance law as long as noise nuisance indices used in other isolation - account should be taken of local ANO requirements are met (Civil Aviation countries, which tended to use Leq based circumstances including the existing level of Act 1982 section 77). In addition heliports measures. This study became known as noise disturbance”. The document are specifically excluded from prosecution the Aircraft Noise Index Study (ANIS)[11]. recommends that, due to the noise due to noise and vibration caused by characteristics of helicopters, the noise helicopters landing and taking off, moving 4.3.8. ANIS revealed no ‘hard statistical exposure criteria should be treated with over ground or water and engines being evidence for an ‘N’ variation in caution. Planners may request that the operated in preparation for or after a disturbance as compared with the log N applicant discuss with NATS the flight for performance and maintenance of NNI and Leq’ and ‘If there is any establishment of helicopter routes if these reasons. (Civil Aviation Act 1982 section variation with N, then it has a much are not supplied with the application. 78 + ANO reg 12 (general)). The smaller coefficient than the log N term Environmental Protection Act (1990 Part III over a very wide range of L and N values’. 4.3.11. When individual night-time noise section 79) defines a statutory nuisance It was also demonstrated that the Leq events exceed 82 dB LAmax several times in caused by noise to be; 'noise emitted from measure correlated better with annoyance any hour, the NEC should be treated as premises so as to be prejudicial to health than NNI[33]. being category C, regardless of the LAeq,8h or a nuisance'. However subsection 6 (except where the LAeq,8h already puts the says that this 'does not apply to noise site in NEC D). site in NEC D). caused by aircraft other than model aircraft'. Therefore aircraft, including LAeq,T(dB) A B C D helicopters, are specifically excluded from 07:00 – 23:00 <57 57-66 66-72 >72 having action taken against their operators in respect of statutory noise 23.00 - 07.00 <48 48-57 57-66 >66 nuisance. Table 3: PPG24 criteria for air traffic showing LAeq(dB) for each category for differing times of day

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4.5. Helicopter Operations: 4.6.3. The BHAB handbook details general 4.7.3. Light helicopters require only one Codes of practice codes of conduct for pilots aimed at flight configuration for noise certification, 4.5.1. Operators often use Standard showing an environmentally conscious take-off flight path with maximum power, Operating Procedures (SOPs) that tend to public that helicopter operators are aware to be recorded. The noise level is include noise abatement procedures. of the need to preserve the environment measured in SEL (dB). Light helicopters PremiAir, the London Heliport operator, from unnecessary noise intrusion. The must be quieter than heavier ones.[42] commented that they actively try to BHAB handbook also details guidelines for ensure that pilots fly in an environmentally operations in national parks, and carrying 4.7.4. A window of acceptable friendly way as possible. out aerial photography, and similar work meteorological conditions and site over congested areas qualities for microphone placement is 4.5.2. Airfield management may also specified in appendix 4 of the IACO establish 'avoid' regions and other noise 4.6.4. The BHAB makes a number of Annex 16. abatement procedures. For example, at recommendations to ensure operators and Birmingham International Airport, in users minimise their environmental 4.7.5. For each flight, the EPNdB is response to a number of complaints impact. These include[39] careful selection averaged across the three microphones. received via the airport consultative of the location of helicopter landing sites, Repeated flights are carried out for each committee, a region of avoidance and a sensible flight planning which includes procedure until the 90% confidence limits minimum height recommendation were environmental impact as a factor, taking for EPNdB of ±1.5dB are achieved [41]. established. This was established by into account the meteorological forecast consultation between the ATC, the police and air traffic requirements and pilots 4.7.6. In order to pass certification the operation at the airport, and the flying in accordance with the BHAB's EPNdB values must fall below a reference environmental department. Operations are 'Pilots' Code of Conduct'. limit for each procedure. Relaxations to able to breach the rule but are these limits are made (due to the lack of encouraged to stick to the 4.7. Helicopter civil noise certification accurate noise prediction tools at the recommendations. Since implementing the 4.7.1. Noise certification for helicopters design stage) where helicopters may rule, the number of complaints has was added to Annex 16 of the exceed the EPNL dB limits by 3dB over one decreased. Convention on International Civil Aviation procedure, or by 4dB over two in 1981 by the ICAO (International Civil procedures, as long these deficits are 4.5.3. Pilots are aware of noise issues but Aviation Authority) [40]. The procedures offset across the other procedures [41]. it is not always a priority concern. From a follow closely those established for pilot’s perspective, the most important certificating fixed wing aircraft. For heavy 4.7.7. The EPNL (Effective Perceived Noise factors considered for a pilot are: how to helicopters (>3175 kg) the certification Level) and the SEL (Sound Exposure Level get back on the ground, with greatest process is defined in ICAO Annex 16 metrics utilise the upper 10dB of a flyover ease, safety and economy. Chapter 8. Light helicopter certification is time record. However, the sound of a defined in ICAO Annex 16 Chapter 11. helicopter at distance, although outside 4.6. Guidance provided by the British Chapter 11 is voluntary on the applicant, this upper 10dB region, can still cause Helicopter Advisory Board (BHAB). whether they choose to demonstrate annoyance, especially where high levels of 4.6.1. The BHAB provides codes of compliance with Chapter 11 or stay with impulse noise are present [2]. practice for helicopter pilots and Chapter 8. A very small number of operators. Codes of Practice have been helicopters have been certificated using 4.7.8. Helicopter noise certification is defined to inform potential clients of both Chapters. concerned only within specific flight some important basic facts concerning the operations and often these do not relate commercial operation of helicopters. The 4.7.2. Heavier helicopter certification uses to urban helicopter operations. An aim is to ensure that high standards of three flight procedures: takeoff, overflight example of this is the ground-running safety and professional competence are and approach, all of which are measured phase, which is ignored in the certification maintained throughout the industry. The at three microphone positions. The procedure. However, it should be noted Code of Practice has been endorsed by helicopter performs each of the three that the purpose of noise certification is to the BHAB’s Council of Management procedures a minimum of six times to encourage the design of quieter aircraft. following consultation with the Civil ensure statistically valid results and an In the case of helicopters, the design Aviation Authority. Effective Perceived Noise Level (EPNdB) is choices required to satisfy certification recorded for each procedure. A number of requirements would serve to limit noise in 4.6.2. The BHAB are actively addressing conditions, such as take off mass, speed, all operating modes. the noise issue with the Noise Action height and rotor speed, are placed on Group (NAG). The aims of this group are each procedure to ensure repeatability to persuade pilots to take more notice of and reliability of the results. In addition, environmental noise issues and to lobby corrections can be made to the EPNdB manufacturers to produce quieter levels according to variability in height, helicopters. The group has members meteorological conditions such as including senior people from various temperature and humidity and ground helicopter operators. speed of the helicopter [41].

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4.8. Rules and regulations in Australia procedures. This co-operation is intended 4.10. Rules and regulations in the USA 4.8.1. In Australia, the Civil Aviation to provide high and consistent standards 4.10.1. The Federal Aviation Safety Authority (CASA) was established of safety and a "level playing field" for Administration (FAA) regulates operations in 1995 to conduct the safety regulation competition in Europe. Much emphasis is in United States airspace. The regulations of civil air operations in Australia, and the also placed on harmonising the JAA are called the Federal Aviation Regulations operation of Australian aircraft overseas. regulations with those of the United (FAR) and are part of the Code of Federal The Civil Aviation Regulations 1988 and States’ FAA [47]. Regulations (CFR – title 14). the Civil Aviation Safety Regulations 1998, made under authority of the Civil Aviation 4.9.2. The European Aviation Safety 4.10.2. Federal Aviation Regulation Act, provide for general regulatory Agency (EASA) was set up to promote the section 91.119 [50] states that aircraft controls for the safety of air navigation highest common standards of safety and must maintain a minimum distance of [43]. environmental protection in civil aviation. 1,000 ft above the highest obstacle and a It is intended to be the centrepiece of a horizontal radius of at least 2,000 ft from 4.8.2. CASA functions as a safety new cost-efficient regulatory system in another aircraft. In other than congested regulator and Airservices Australia as a Europe and a reliable partner for areas, aircraft are required to maintain an service provider. Airservices Australia is a equivalent authorities throughout the altitude of at least 500 feet above the government-owned corporation providing world. As EASA develops the aviation surface over open water or sparsely air traffic control, air navigation support regulatory environment, it will change populated areas. Over open water or and rescue and fire fighting services [44]. some of the existing CAA processes and sparsely populated areas, aircraft may Airservices Australia are described by the procedures [48]. operate at less than 500 feet above the CASA as providing a “safe and surface provided that they do not fly environmentally sound air traffic control 4.9.3. EASA became operational on 28 closer than 500 feet to any person, vessel, management and related airside services September 2003 and it will be fully vehicle, or structure. Helicopters may be to the aviation industry” [45]. functional in 2008. It is an independent operated at less than these minimum legislative body under European law, altitudes provided that they are conducted 4.8.3. CASA summarises the rules and accountable to the Member States and without hazard to persons or property on regulations regarding helicopters the European Union institutions. EASA the surface.[50] operating under visual flight rules in the itself is not an International Civil Aviation document, ‘Visual flight rules guide - Organization (ICAO) signatory because it 4.11. Summary of Chapter 4 Version 2 - July 2007’[46]. does not constitute a State; however, it 4.11.1. 4.11.1. The CAA provides a focal works closely with ICAO and the Federal point for receiving and responding to 4.8.4. A Helicopter must not fly over any Aviation Administration (FAA) with the aircraft-related environmental complaints city, town or populous area, at a height aim of harmonising standards and from the general public. However, the lower than 1000 ft, or any other area at a promoting best aviation practice CAA does not have the legal power to height lower than 500 ft. The heights worldwide [49]. prevent aviation activity on solely specified are the heights above the environmental grounds, except when highest point of the terrain, and any 4.9.4. The creation of EASA has had a considering changes to the structure of object on it, within a radius of ≈1000 ft significant impact upon UK Registered controlled airspace. An independent (300 m) from a point on the terrain aircraft. EASA has assumed responsibility review is considering greater powers for vertically below the aircraft. for the type-certification and continued the CAA over environmental matters. airworthiness of a large number of UK 4.8.5. These rules do not apply when the registered aircraft. [49] 4.11.2. There are only three licensed height must be lower because of heliports in the UK, although helicopters metrological conditions, if the pilot has a 4.9.5. During the next few years, it is can land at most airfields. Temporary permit for low level operations, if the pilot intended that the agency will extend its landing sites can be used for up to 28 is engaged in low flying training responsibility to aircraft operations, crew days in a year. A residential planning authorised by CASA, if the aircraft is licensing and the certification of non- application close to an operating heliport, taking off or landing, if the pilot is Member State airlines [49]. The UK is when evaluated in accordance with engaged in a search/rescue, or during represented on the EASA management PPG24, should not rely solely on Leq and police operations. board by Mr. Michael Smethers (Vice should consider the intermittent nature of Chairman Director, European & helicopter operations. 4.9. Rules and regulations in Europe International Strategy Civil Aviation 4.9.1. The Joint Aviation Authorities (JAA) Authority) and Mrs. Natasha Coates (Head 4.11.3. Helicopter noise certification is not is an associated body of the European of the Aviation Safety Team, International directed at urban operations. BHAB codes Civil Aviation Conference (ECAC) Aviation & Safety Division, Aviation of practice aim to increase the helicopter representing the civil aviation regulatory Directorate, Department for Transport) pilots and operators awareness of authorities of a number of European (http://easa.europa.eu/home/g_mng_brd_ environmental noise issues. Although States who have agreed to co-operate in main.html). pilots are aware of noise issues, factors developing and implementing common such as safety are considered to be more safety regulatory standards and important.

DEFRA NANR235: Project report

5. Subjective responses to helicopter noise

This section summarises a literature review acoustic parameters and soundscape in their homes near Heathrow, Gatwick, of the subjective responses to helicopter perception and acceptance. There did, Stansted and Manchester airports. At noise. Principal references include the however, appear to be a correlation outdoor event levels below 90 dBA SEL 2004 FAA report to the US Congress, between acceptance and the (80 dBA Lmax), average sleep disturbance publications by Leverton and Pike, and the value/meaning attributed to the rates are unlikely to be affected by aircraft WHO Guidelines for Community Noise. noise/event. Sixsmith [61] has suggested noise. At higher levels, and most of the This section addresses the adverse effects that the use of the term of 'annoyance' events upon which these conclusions are of helicopter noise including sleep might be replaced with a number of other based were in the range 90 to 100 dBA disturbance, health and annoyance, terms. This suggestion stems from her SEL (80 to 95 dBA Lmax), the chance of before moving on to non-acoustic factors work with 'work-related stress', a the average person being wakened is including 'virtual noise' and building phenomenon that is now described in about 1 in 75. The report concluded that vibration. Much of this review refers to terms of 6 different factors; demands, high aircraft noise levels could awaken the effects of fixed wing and general control, support, relationships, roles and people but that the likelihood of the aviation noise on the individual. change [62]. average person having his or her sleep Throughout comparisons are drawn noticeably disturbed due to an individual between the effects of helicopter noise 5.1.4. Sensitivity to low frequency noise. A aircraft noise event was relatively low. with the effects of fixed wing aircraft number of studies over the past 30 years However, a small minority of people were noise. have suggested that a subsection of the more sensitive. Additionally, it was unclear population is more sensitive to low amongst those who suffer disturbance 5.1. Social effects frequency noise than the majority. due to noise, whether a single loud noise 5.1.1. The 2004 FAA report to US Patterson et al [63] performed tests with event or the accumulation of smaller noise Congress entitled, ‘Non-military Helicopter different frequency weightings on aircraft events causes more disturbance. It should Urban Noise Study’ [4] (henceforth noise, comparing the dB level with be noted however that study sites were referred to as the FAA report), contains a annoyance. It was reported that most of selected on the basis of arrival and comprehensive literature review on the the ratings correlated best with A- departure routes of the airports and thus effects of noise on the individual. The weighting. However, 11 out 25 subjects fix winged aircraft would have been the 2004 FAA report was itself in part based also had good correlation with C- predominate activity. upon the US military report 'Community weighting, and of the 11, 3 exhibited response to helicopter noise' [51]. This better correlation with C-weighting. For 5.2.2. In 1998, a further study was review has been used together with other this reason, it was concluded that A- commissioned by the Department for sources to summarise the effects that weighting might not be the ideal Transport[67] to review existing research in helicopter noise has on the individual. weighting. ANSI S12.9 Part 4 provides a the UK and abroad and to conduct a trial supplemental measure to A-weighting for to assess methodology and analytical 5.1.2. Studies have shown that assessing industrial noise sources with techniques and to determine whether to environmental noise, including aircraft and strong low-frequency content. Schomer proceed to a full-scale study of either traffic noise can adversely affect classroom suggested the use of equal loudness sleep prevention or total sleep loss. This learning [52-58]. It has been shown that contours as more detailed frequency involved a methodological trial to assess low achieving students were the most weighting curves for different amplitudes whether ‘aircraft noise causes harmful loss adversely affected. In addition; students and showed a 2 dB difference between of sleep throughout the night’ and ‘the with hearing impairments, students with fixed-wing and rotary wing aircraft derived effect of sleep delay and disturbance at English as a second language and music directly from these known functions of the beginning and end of the night’. A students may be particularly adversely human hearing [4]. In addition, it is found social survey was also carried out to help affected [59]. The WHO (World Health that increasing the loudness of a explore the marked difference between Organisation) recommends that in schools, modulating sound by 2-5dB produces the objectively measured and publicly a maximum equivalent indoor level of same change in perceived loudness as if it perceived disturbance due to night-time background noise not exceeding 35dBA. were a change in loudness of 10dB[64]. aircraft noise. However again it is worth This is so that the average voice level This could be significant for helicopters noting that fixed wing aircraft would have (50dBA) is at least 15dBA above the indicating one reason why they are rated been predominate. background level [59]. The FAA report differently to fixed wing craft. Likewise, states that nearly all of the studies relate Defra-funded research on the assessment 5.2.3. The Government announced on 8 to the classroom environment and that of LFN complaints concluded that 5dB was May 2001 that a new full-scale objective “at the present time, little can be said of an appropriate penalty for fluctuating low sleep disturbance study would be unlikely environmental noise effects on frequency sounds [65]. to add significantly to existing knowledge; communications and performance except it is to concentrate instead on further as it relates to the classroom setting”. 5.2. Health effects research into subjective responses to 5.2.1. The Department for Transport in aircraft during both day and night. 5.1.3. Studies carried out at RAF 1992 commissioned a report entitled Shawbury [60] which has around 114,000 ‘Report of a Field Study of Aircraft Noise helicopter movements per year indicated and Sleep Disturbance’[66]. This study no clear correlation between traditional measured the sleep disturbance of people

DEFRA NANR235: Project report

5.2.4. Laboratory experiments [68] have 5.3. Community attitudes 5.3.5. Most noise rating procedures utilise shown sleep disturbance at relatively low 5.3.1. Community attitude toward the A-weighted sound pressure level noise levels but field tests results have operations has an important effect on the integrated over a relatively long period. shown people are much less susceptible to community annoyance. Social surveys However, this may not be appropriate being disturbed. For example, field tests carried out by the CAA in 1982 and 1992 when there are a small number of events, show 1% of participants were awakened [112] [113] found that helicopters in the as discussed by Leverton: [3] “the at 60dB (A-weighted sound exposure London area were up to 15dB(A) more effectiveness of methods based on long level) while in laboratory tests at 60dB annoying at the 10% and 20% Very term averaging is questionable in those about 20% of people were disturbed. This Much Annoyed Level than fixed-wing cases where the duration of the event is is presumed to be a due to the unfamiliar aircraft. By contrast, results showed that very much shorter than the evaluation conditions in the laboratory tests. The US helicopters operated in Aberdeen, period and the number of events in that Federal Interagency Committee on servicing the North Sea oil industry, period is such that noise levels are subject Aviation Noise (FICAN) recommends using generated similar annoyance for a similar to large variations.” a dose-response curve for predicted sound level as their fixed wing awakening based upon the field data. In counterparts. This is attributed to the 5.3.6. Fields and Powell [72] studied the essence, the dose-response curve would obvious economic benefit to community reaction to low numbers of helicopter follow the “maximum percentage of the surrounding the Aberdeen helicopter noise events. There was a strong exposed population expected to be service as opposed to London, where relationship between average Leq and behaviourally awakened” related to SEL. helicopters are perceived to have no average annoyance over the range of 1 to The FAA agrees with this economic benefit to the residents. This 32 flights in 9 hours. The study found recommendation. indicates a strong non-acoustic factor in annoyance was flat in relation to Leq up the community annoyance rating. to 47dB, then a linear relationship of 5.2.5. The WHO[59] states that long term increasing annoyance up to 59dB. exposure to noise levels exceeding 65- 5.3.2. The Fields study [70] highlighted However, it was found that the number of 70dB (24 hr Leq) are known to be the following five attitudes as most noise events had little effect on associated with causing cardiovascular important . annoyance although close statistical problems. Passchier-Vermeer[69], 1) Noise prevention beliefs. analysis revealed the possibility that the commenting on results from studies 2) Fear of danger from noise source. event number has no effect on the carried out in the Netherlands, states that 3) Beliefs about the importance of the relationship could not be rejected (with the observation threshold for hypertension noise source. greater than 95% confidence). is estimated to correspond to an Ldn value 4) Annoyance with non-noise impacts Additionally, the study compared of 70 dB(A) for environmental noise from the noise sources. helicopters with an impulsive sound exposure. The FAA report states that 5) General noise sensitivity. character (UH-IH "Huey") and one with a “Helicopters rarely produce 24-hour non-impulsive sound character (UH-60A equivalent levels that exceed 70 dB. In 5.3.3. The US Environmental Protection "Black- hawk") and found “there is not fact, such worst case, high noise levels Agency (EPA) in 1974 [71] suggested that an important difference between reactions only occur near very busy military airfields the measured noise level could be to impulsive and non-impulsive types of operating heavy lift helicopters and adjusted downward by 5dB when the helicopters”. The FAA and the US army frequent flights. Thus, noise-induced noise generating party maintains good reports comment that no one has carried hearing impairment due to non-military relations with the community. On the out a study to determine a similar Leq- helicopters operations in urban other hand, it is deemed that many annoyance relationship for night-time but environments is an unlikely condition”. helicopter flights are non-essential and it that the traditional 10dB night-time is sometimes suggested that negative penalty, used in the determination of DNL, 5.2.6. Recently published work by the attitudes come from the opinion that the is consistent with community attitudinal HYENA group[5] (Hypertension and helicopter is just the rich man’s toy. data [73]. Exposure to Noise near Airports) indicated a statistically significant excess risk of 5.3.4. Leverton [3] comments that ”the 5.3.7. It was widely believed in the 1970s hypertension related to long term public acceptance of helicopters is not that helicopter noise was more annoying exposure to night-time aircraft noise. For wholly reflected by either conventional than fixed wing noise and as a result the every 10dB increase in (night-time) noise community rating procedures or the noise U.S. Department of Defense policy was level, the risk of hypertension is increased certification requirements”. This questions that a 7dB penalty should be applied “to by about 14%, with this trend seen the view of many national authorities that meter readings obtained where starting at low levels. The daytime results a reduction in the objective sound level Blade–Slap was present unless meters are were not statistically significant. that helicopters produce will make developed which more accurately reflect helicopters more acceptable to true conditions”[74]. The need for a blade community. slap penalty was based on results from laboratory tests carried out by Leverton [75]. These tests, carried out in a simulated living room, showed that the presence of blade-slap increased

21 DEFRA NANR235: Project report

annoyance by the equivalent of between blade/tip vortex interaction (BVI), main 5.4.2. It can be difficult to separate virtual 4-8dBA. The US army report recognised a rotor thickness noise and impulsive noise and acoustic noise, as these factors are number of other researchers who also resulting from shock waves commonly highly interrelated. Research referred to by identified the need for a ‘blade-slap referred to as high speed impulsive noise Leverton [3] and carried out at ISVR [83] correction factor' [76-79]. (HSI), main rotor wake/tail rotor attempted to classify complaints and interaction (TRI), and tail rotor noise (TR). quantify the ‘virtual noise’ effect in terms 5.3.8. Other researchers have offered NASA research indicates that the addition of an equivalent A-weighted correction alternative indices for measuring of a ‘correction factor’ for impulsive factor. Although the research was based community annoyance. Examples include sounds does not improve the human at general aviation airfields where mainly the ‘roughness’ of the sound quality, the response - parameter correlation. light fixed wing craft operated, results rate of the impulses, or the energy in the However, these tonal and impulse have suggested similar trends for 50-200Hz band [4]. components have a profound effect on helicopters. the human response even at levels 15 – 5.3.9. The FAA and the US army reports 25 dB below the maximum level. The 5.4.3. These results have not been shown comment that subsequent field tests have EPNL or SEL based parameters used in to translate directly to helicopter failed to support the addition of the aircraft certification, including helicopters, operations, although results from blade-slap penalty. NASA reported that “A are calculated using only the maximum helicopter operations at one base careful analysis of the evidence for and 10dB dynamic range, and therefore these indicated a similar result. In fact, the against each factor reveals that, for the effects are not accounted for. negative reaction to helicopters may be present state of scientific knowledge, even higher especially in reaction to none of these factors should be regarded 5.4. Non-acoustic factors leisure flying. The virtual noise factor can as the basis for a significant impulse 5.4.1. Leverton [3] describes the public be very low in some cases. As mentioned correction.”[80] Passchier-Vermeer acceptance of helicopter noise as a previously, in Aberdeen, helicopter commented “tests have shown on function of two factors: acoustic noise operations servicing the North Sea oil average only minor differences in and non-acoustic factors referred to as industry are seen as beneficial and are annoyance rating of more or less 'virtual noise'. The virtual noise element is more acceptable. Similarly, it may be that impulsive helicopter noise with the same related to non-acoustic factors such as helicopters following precise routes are noise levels”[81]. The FAA comments that; fears for safety, or poor community more acceptable, and therefore the virtual “There is general agreement among a relations with operators. Virtual noise is noise factor is reduced. An example of this wide range of experts that adding a not related to the absolute level of is the Helijet scheduled passenger service penalty to the A-weighted SEL to account acoustic noise although is triggered by it. between Victoria and Vancouver. ICAO for the annoyance of Blade-Slap is not It can also be triggered by visual cues. work has suggested that fear of crashes is justified.”[4]. Despite this, others dispute Annoyance is quantified in terms of the most significant factor in addition to the efficacy of EPNL and other metrics to objective acoustic parameters and low flying, sudden changes in the noise rate subjective response to helicopter therefore the virtual noise is generally signature and previous experience of noise[82]. Although the ICAO report to treated in the same manner as the crashes all contributing the most to the CAN7 (1983) concluded that EPNL is acoustic noise even though the virtual negative reaction. satisfactory, it also states that “pending component is unrelated to absolute better knowledge on this subject, acoustic levels. This means that when operational procedures should be problems stem from the virtual noise investigated in order to reduce the component, any reduction of the noise number of occasions where ‘blade slap’ or level will be ineffectual. more appropriately, impulsive noise appears”. It should be noted that the Negative reaction to leisure flying +5dB(A) positive conclusion about EPNL was, at least in part, because nothing better could Poor community/airfield relations +10dB(A) be found at the time [82]. Fear of crashes +10dB(A) Nobody acts on complaints +20dB(A) 5.3.10. Despite objective evidence that helicopters are no more annoying than Aircraft are flying too low +20dB(A) fixed wing craft, public surveys indicate a Table 4: ‘Virtual noise’ effect in terms of a equivalent A-weighted correction factor more negative reaction to helicopter noise. Leverton et al [3] holds the view that specific properties of the helicopter sound are not accounted for by conventional rating procedures and it is these properties that are among the major sources of annoyance for the community. Specifically, rating procedures do not account for noise from the main rotor

DEFRA NANR235: Project report

5.4.4. The FAA report refers to a number 5.5. Comparison with Light 5.6. Summary of Chapter 5 of tests carried out between 1985[84] and aircraft/microlights 5.6.1. Reaction to helicopter noise is 1991[85] that compared the lack of, or 5.5.1. In studies carried out at RAF bases determined by acoustic and non-acoustic presence of, audible noise induced rattle investigating the management of Light 'virtual' noise. Non-acoustic factors are of in dwellings. It was found that the aircraft and microlight noise at military equal or greater importance but are presence of a rattle could increase the airfields [9, 87], a number of similar triggered by impulsive noise generated by annoyance by an equivalent level of problems as described regarding the basic rotor mechanism. This means between 10 and 20dB. helicopter noise were found. that addressing acoustic noise limits is 1) Correlation between nuisance and unlikely to significantly improve public 5.4.5. The FAA report describes in-situ noise level is poor. It is clear that more acceptance of helicopter noise. tests carried out by Schomer and Wagner relevant descriptor metrics are [86] at residents’ properties using an required for low volume or irregular 5.6.2. Subjective responses are known to external sensor to register events for the microlight and light aircraft be influenced by factors other than noise same A-weighted sound exposure level operations. including flight safety, privacy, (ASEL). These showed that helicopter 2) It is likely that actual noise level is a soundscape, locus of control and mental sound was no more annoying than the secondary issue and that physical health. Perceived effect on house price fixed wing noise. However, the rate of intrusion and other non-acoustical has also been shown to be a significant response in terms of noticeability of the factors are more significant in factor. Highest annoyance has been helicopter noise events was higher than determining nuisance. correlated with uncommon or exceptional that for fixed wing noise events. helicopter events. Helicopters, with their distinctive sound 5.5.2. Background noise level is likely to character, are more noticeable than other be a factor as it (generally) relates to the 5.6.3. Complaints have been found to be sounds for the same ASEL. ‘rurality’ of complainants locations. Civil more likely if the resident has a negative aviation is always described in absolute attitude towards the helicopter operator. 5.4.6. At the recent IoA (Institute of terms with no reference to the Additionally, the likelihood of a member Acoustics) meeting at Salford, Pike [2] background/ ambient level. of the public making a complaint appears commented that there is a need for not to be influenced by age, length of psychoacoustics experts to work with 5.5.3. Alongside helicopters, light aircraft residence, having children or not, or industry to address the unique subjective are precluded from prosecution under health. character of helicopter noise. Furthermore, noise nuisance. workshops should be held to address the 5.6.4. Social surveys indicate that negative perception of helicopter and the 5.5.4. Both reports state that consultation helicopters are 10 to 15 dBA more ‘virtual noise’ factor. with the public will help to engage people annoying than fixed-wing aircraft for the and breed more understanding for the same or lower measured sound level. The operations. term annoyance does not fully describe the subjective response to helicopter noise. 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 to helicopter operations have produced poor correlation and have been broadly criticised. There is no generally accepted straightforward relationship between objective noise and subjective annoyance. No good correlation with complaints has been found with LAeq, LCeq, LAmax, L10 and LAmax-L90.

5.6.6. Studies addressing the noise from light aircraft and microlights reveal similar issues; that noise level may be a secondary issue and different indices may be required for low volume operations.

23 DEFRA NANR235: Project report

6. Management of Environmental Noise from Helicopters

This section considers the effectiveness of 6.1.4. Problems related to noise generated areas. Typically, aircraft should not deviate current procedures for dealing with on the ground at aerodromes, other than from these routes until above 3,000 ft. helicopter noise in the UK. Existing in association with the normal operation Details of specific NPRs are available from procedures for handling complaints are of aircraft, should be referred to the Local the airports. In the recent ‘Civil Aviation detailed and the roles, responsibilities and Authority. However, local authorities have Act (2006)’ airports are now able to apply powers of the various authorities and a statutory bar on action against aviation a charging scheme to promote the use of regulating organisations summarised. noise sources under the Environmental cleaner, quieter aircraft [90]. Comparisons are drawn with other (EPA) noise legislation. European countries, the USA and 6.2.4. At Birmingham International Australia. Finally, noise prediction and 6.1.5. MOD complaints are dealt with Airport, after receiving a number of modelling are discussed with particular centrally or through the base’s community complaints about police operations via relation to noise mapping and EU Noise liaison officer their consultative committee in 2006, the Directive (Directive 2002/49/EC). Options http://www.mod.uk/DefenceInternet/Abou airport consulted with the police for improvement are identified together tDefence/WhatWeDo/AirSafetyandAviation operators, the air traffic control and the with recommendations on how these /LowFlying/HowDoIComplainAboutMilitary environmental department at the airport could be implemented. LowFlyingActivity.htm, to implement an 'avoid' region to minimise flights close to residences. 6.1. Existing procedures for handling 6.1.6. The London Heliport at Battersea noise complaints from helicopters has established a complaints telephone 6.2.5. At RAF Shawbury, in response to an 6.1.1. The Civil Aviation Authority (CAA) is line for registering environmental noise increase in the number of complaints a a focal point for receiving environmental complaints (0207 228 0181). Complaints point of contact has been published. complaints about aircraft. When a are reported at the consultative group Observations, measurements, acoustic complaint is received, the location, aircraft meetings [16]. The heliport is not studies and trend analysis have been type and identity (registration/features) are responsible for all traffic over London and carried out and detailed records are kept. recorded and the airspace structure in that currently there is no formal complaints Some noise management is achieved by area is identified. The legislative procedure in place for helicopters flying active management of flying by rotating background to noise, and the ANO with within the London Control Zone that are routes, expanding the user area, and specifics to the location, are explained to not operating at the London Heliport. This briefing all new staff and students to the complainant. However, the CAA has is being addressed by the London make them aware of environmental no legal power to prevent aviation on Assembly and Defra but in the interim, issues. Wing Commander Tim Owens solely environmental noise grounds [6]. the Civil Aviation Authority is tasked to commented [91] that a fast response to respond to complaints [89]. complaints is important in keeping 6.1.2. The outcome of a complaint to the complainants from becoming a repeat CAA will either be; 6.2. Means of redress for any complainer. Individual invitations to visit 1) a referral to ARED (Aviation Regulation perceived disturbance caused the base and follow up contact are also Enforcement Department) in the event 6.2.1. The Department for Transport is important in order to inform and to of a breach of the ANO, or involved directly with measures to ensure the public are aware the RAF is 2) advise contact of local planning ameliorate aircraft noise at Heathrow, doing the utmost to address authority in the case of a change of Gatwick and Stansted.. Elsewhere “the environmental issues [91]. land use or to advise contact the Department expects civil aerodrome and aircraft operator directly. aircraft operators to achieve a reasonable 6.2.6. At the London Heliport, a balance between their legitimate needs consultative committee has been set up. 6.1.3. The Directorate of Airspace Policy and those of the local community” [26]. Wandsworth council commented[92] that Environmental Information Sheet - this shows residents that their concerns Number 1 entitled ‘Aircraft Noise’[88], 6.2.2. Aerodrome operators may publish are being taken seriously, increases comments that the CAA is tasked with noise abatement procedures to be awareness within the planning ensuring that procedures at airports meet followed on a voluntary basis. For department, and lets the operator be required standards of safety but the example, it may be requested that pilots confident that there is no hidden agenda. operators are responsible for the avoid overflying a certain village. However, Complaints are largely generated from environmental impact of their aircraft these procedures are voluntary and it may living standard expectations and a operations. The CAA is expected to, not always be possible to design such perception that helicopter pilots ”strike a balance between the needs of procedures due to aircraft performance demonstrate inconsiderate behaviour. It the airport/aircraft operators and the and operational constraints [90]. has been conjectured that change of land needs of the local community”. As a use from industrial to residential usage is result, the CAA encourages noise 6.2.3. Noise preferential routes (NPR) may the root of the problem. The council complaints to be made directly to the be employed at major airports although commented that enabling dialogue airport operator. these are essentially designed with fixed between residents, councils and the wing aircraft in mind. These are designed heliport operator has helped to create so that immediately after take off aircraft some understanding and acceptance by will avoid the most densely populated the public. The dialogue should be

24 DEFRA NANR235: Project report

extended to include developers so that 6.2.9. The Noise Insulation Grant Scheme 6.3.5. Airport operators deal with homes are created with sufficient sound was based on nightime operations complaints where, for example, a take-off insulation. At the recent IoA meeting, exceeding 20 movements with LAmax of appears not to follow established Steve Mayner commented that “noise more than 82dB and two daytime procedures. This is because they have mapping may be unlikely to reduce LAeq,16hr levels of 70dB and 83dB. For immediate access to data relating to that annoyance due to lack of technical the lower level of 70dB double glazing take-off. understanding by the public, but that it grants were offered and for the higher may be useful for the planners” [93]. level compulsory purchase of property 6.3.6. Local authorities have the applied. The scheme was reviewed by responsibility to deal with complaints 6.2.7. The Directorate of Safety and Ralph Weston in 1991 and it was arising from the operation of machinery or Claims (DS&C) and the Environment and concluded that the nightime LAmax level other noise not generated directly by Safety Division administrate the Noise of 82dB was inappropriate for helicopters. aircraft Insulation Grant Scheme (NIGS) on behalf Instead a 10dB penalty was suggested to of the MOD. NIGS is a non-statutory represent public disturbance due to 6.4. The effectiveness of dealing with compensation scheme that provides direct helicopter operations and subsequently a helicopter noise in the UK using assistance to members of the public who 72dB nightime maximum was proposed. current methods reside in the vicinity of military airfields Helicopters also pose a problem for noise 6.4.1. At RAF Shawbury complaints are and who may experience disturbance from insulation because double glazing is less dealt with by maintaining good relations the activities of the aircraft. NIGS is effective for the low frequency content of with the community through a swift broadly comparable with the noise helicopter noise[95]. response to all complaints, following up insulation schemes, recommended by the complaints with invitations to visit the Department of Transport, in place at the 6.2.10. BAA has established non-statutory base, acoustic studies and operational designated civil airports of Heathrow and noise insulation schemes, as the operators changes. It appears that the perceived Gatwick. The policy of the NIGS scheme is of regional airports have done. The value of the operations has been revisited every five years to ensure that it provisions vary but BAA’s latest scheme at reinforced in the public mind and is still comparable with the UK civil Stansted, for example, offers an insulation complaints have not risen in line with aviation practices [94]. package to residences within the 66dB operations [91]. LAeq (16h) (with a separate night noise 6.2.8. In January 2000 a study was criterion) and relocation assistance to 6.4.2. At the recent seminar Wandsorth completed [60] which examined the properties falling within the 69dB LAeq Council reported [93] that recent efforts relationship between noise levels and (16h) contour [96]. The 2003 Air Transport encouraging dialogue between residents, patterns of complaints caused by RAF White Paper states (para 3.24) [114] that councils and the heliport operator have Shawbury’s helicopter activity. The report insulation should be provided, in the helped to improve understanding and concluded that no residential properties context of airport development, where acceptance by the public. However, it was were eligible for assistance under the properties are exposed to noise levels of suggested that this might be a current criteria for NIGS. This triggered a 63dB LAeq or more and subject to an ‘honeymoon period’. The dialogue could review of NIGS policy and the scheme was increase of 3dB or more. be extended to include developers so that suspended pending the outcome of the homes are created with sufficient sound review. Part of the review was the MOD 6.3. Roles, responsibilities and powers insulation. Noise mapping is thought to be Aircraft Environmental Noise (AEN). of the various authorities and unlikely to reduce annoyance due to lack Results from AEN were published in 2004, regulating organisations. of technical understanding by the public its recommendations were wide ranging 6.3.1. The Department for Transport will but it may be useful for the planners. and carried implications across the whole respond on matters of overall policy. of MOD. Consultation resulting from AEN 6.4.3. The London Heliport operator is still ongoing. One of the outcomes of 6.3.2. The Civil Aviation Authority (CAA) stated that the telephone complaints line, AEN was that the NIGs scheme should be has responsibility on regulation, airspace established before working with restarted as soon as possible however a design and environmental complaints. Wandsworth Council, has significantly funding application for the scheme in However, the CAA will only advise on the helped relations between the heliport and 2005/2006 was rejected “due to other regulations; they cannot act unless there is the public. The helpline is continually funding priorities of the Defence Budget” a clear breach in the rules of the air. being refined since a more informed [94]. In April 2005 NIGS was formally and public realises that it is not always the indefinitely suspended (including carrying 6.3.3. The Ministry of Defence has heliport that is responsible for disturbance out of reviews and surveys). However “this responsibility for information and and that through traffic may be the cause suspension would be kept under review complaints related to military aircraft of the noise nuisance [16]. and if circumstances allowed the operations. reintroduction of NIGS in the future, then this would be examined at that time”[94]. 6.3.4. National Air Traffic Services has responsibility on airspace operations.

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6.5. Comparisons with other 6.5.7. ACARE goals to be obtained in residential areas by helicopters below European countries 2020 through the Technology Domains 1,500 ft AGL. 6.5.1. The Advisory Council for developed in the Clean Sky JTI program 5) Minimisation of noise impact on Aeronautics Research in Europe defines are as follows: residential areas by hovering/circling and implements the Strategic Research 1) 50% reduction of external noise. helicopters. Agenda (SRA). There are two significant 2) 50% reduction of CO2 emissions 6) Implement fly neighbourly projects that address noise from through drastic reduction of fuel procedures. helicopters; FRIENDCOPTER and the consumption. "Clean Sky" JTI [97]. 3) 80% reduction of NOx emissions. 6.6.3. However, assuming safety 4) A green design, manufacturing, conditions have been satisfied, the sole 6.5.2. FRIENDCOPTER is currently maintenance and disposal product test for moving to a lower level standard underway and is an Integrated Project of life cycle. is that the higher standard is “not the European 6th Framework Program: operationally practicable”. If lower rather "Integration of Technologies in Support of 6.5.8. The Clean Sky JTI program is than higher standards are chosen, then a Passenger and Environmentally Friendly articulated around 6 Integrated well-documented reasons for the decision Helicopter". This project was started on Technology Demonstrators (ITDs). One of are required. The noise standard chosen 1st March 2004 and is due for completion these Demonstrators is called ‘Green should be achievable for at least 90% of by 31st August 2008. The research is Rotorcraft’ which is intended to deliver movements. being carried out by a consortium of 34 innovative rotor blades and engine European partners including helicopter installation for noise reduction, lower 6.6.4. In Australia, there are several manufacturers, research establishments, airframe drag, integration of diesel avenues for people with aircraft noise and universities [98]. engine technology and advanced issues to register a complaint. These electrical systems for elimination of include the Airservices Australia Noise 6.5.3. The research goals of noxious hydraulic fluids and fuel Enquiry Unit (NEU), the relevant airport, FRIENDCOPTER are to achieve a reduction consumption reduction [100]. consultative committees and local and of; Federal politicians. Even if the 1) acoustic footprint area by 30-50%, 6.5.9. The target for the Green Rotorcraft complainant does not contact the NEU 2) fuel consumption by 6 % in high ITD is a reduction in the certification direct, the NEU will generally be speed flight, noise levels of 10EPNdB [2]. A number of contacted by the receiver of the 3) cabin vibrations below 0.05 g and major European aerospace complaint to help provide input for a 4) cabin noise levels below 75dBA. manufacturers; AgustaWestland Airbus response. More often than not, helicopter SAS, Dassault Aviation, Eurocopter SAS, complaints relate to helicopter operations 6.5.4. These research goals of Liebherr-Aerospace Lindenberg GmbH, near airports, so there is a tendency for FRIENDCOPTER are to be achieved by; Rolls-Royce plc, Safran and Thales are new complainants to make their initial 1) low noise flight procedures, involved in the Clean Sky JTI [101] and complaint to the airport owner/operator. 2) quiet engine in/outlets, additional partners will be selected via Other people, particularly those who also 3) interior noise reduction and open Calls for Proposals [102]. have issues with fixed wing aircraft noise, 4) distributed blade actuation. are familiar with the complaints reporting 6.6. Comparisons with Australia service provided by Airservices and will 6.5.5. The "Clean Sky" Joint Technology 6.6.1. Airservices Australia publishes a contact the NEU direct. [103] Initiative (JTI) program is an industry guide entitled ‘Environmental Principles driven 7-year research plan for a greener and Procedures for Minimising the 6.6.5. Some airports are very proactive in generation of European Air Transport that Impact of Aircraft Noise’. It points out resolving problems; others simply refer will radically improve impact on the that in all cases aviation safety, including complaints on to the NEU. Helicopter environment while strengthening and system safety through simplified operators are often unaware they are securing European aeronautics industry’s operating arrangements, will be given causing a problem and on receiving a competitiveness [99]. priority over noise abatement complaint will attempt to alter operations considerations [46]. to reduce the problem. Other airports, 6.5.6. The purpose of The "Clean Sky" JTI however, will simply state that they are program is to demonstrate and validate 6.6.2. The guide is written in a carrying out a legal operation and will the technological breakthroughs that are hierarchical manner with the most continue to do so without modification. necessary to reach the environmental preferred procedures for helicopter ”Fly Neighbourly“ agreements are goals set by the Advisory Council for operations given first. They are as sometimes successful, but these are Aeronautics Research in Europe (ACARE: follows: purely voluntary and have no legal the European Technology Platform for 1) No overflight of residential areas. standing [103]. Aeronautics & Air Transport). 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

26 DEFRA NANR235: Project report

6.6.6. At the end of each month, a 6.7.4. The 2004 FAA report to the United 6.8. Options for the improvement statistical report is generated and provided States Congress on non-military helicopter of the management of helicopter to stakeholders. Main problem areas are noise produced the following noise around airports and hospitals [103]. recommendations [4]: 6.8.1. Consultative committees appear to 1) Additional development of models for be successful in addressing the 6.6.7. Provided that the rules of the air characterizing the human response to community’s concern about helicopter are observed, no penalties apply. helicopter noise should be pursued. noise. They are successful because the Wherever possible, attempts are made to This recommendation has been public feels that the problem is being minimise effects of aircraft noise by incorporated into the Rotorcraft addressed and it provides a neutral consultation [103]. Research and Development Initiative platform from which to influence for Vision 100 – Century of Aviation operators to change procedures. 6.7. Comparisons with the USA Reauthorisation Act. NASA, FAA, and 6.7.1. The Federal Aviation Administration the rotorcraft industry have defined a 6.8.2. When a complaint is received, a (FAA) has procedures to respond to the 10-year rotorcraft research and prompt response is essential to public about aircraft noise questions or development plan that includes the demonstrate environmental awareness. It complaints within the United States. The study of psychoacoustics. It is is thought that a swift response will FAA website comments that “Most proposed that the research will prevent the complainant becoming a airports have an office that responds to determine human annoyance levels repeat complainant. airport noise issues, or the airport due to helicopter noise, both in its manager will respond to noise complaints. native condition and synthetically 6.8.3. Repeated contact from the operator You can also contact your local FAA modified. Studies would be conducted to the complainant after a complaint is Airports District Office (ADO) for to uncover neglected characteristics of registered is thought to reduce the assistance” [104]. noise and develop a refined metric likelihood of the person making a repeat that is more representative of the true complaint. 6.7.2. In the US, urban encroachment human response. near military bases can compromise 2) Further operational alternatives that 6.8.4. There is no central point for operations at the base. Litigation is mitigate noise should be explored. collecting and analysing information about possible [105] and public pressure can 3) Emergency helicopter services should complaints. The CAA acts as the focal lead to closures, transference or be exempt from restrictions. point for environmental complaints and modification of activities, curtailing of 4) Helicopter operators and communities has records of complaints received but operations. In the US noise contour should develop voluntary agreements many complaints are directed at operators prediction methods, such as the to mitigate helicopter noise. and the MOD. A central data collection Integrated Noise Model, are used to system for collating complaints from all reduce the environmental impact of 6.7.5. The Regional Helicopter System sources could help indicate specific military activities. Plan for the Metropolitan Washington problems with a view to inform the Area was carried out in 2004 with the operator responsible so they are aware of 6.7.3. In the US, the Helicopter aims of [109]; they are causing a problem. In Australia a Association International (HAI) [106] 1) ensuring the current helicopter system monthly report of complaint statistics is heavily promotes the Fly neighbourly meets the regions transportation and sent to stakeholders and this could also be program. This program is effective in some public service needs, done: If the industry is aware of who is areas in the US at reducing the noise 2) help reduce community noise causing the problems, this may pressure impact. [107] The Fly Neighbourly Program problems by better management, the noisier operators to look at other consists of a guide [108] and a pilot 3) establish land planning guidelines for mitigation procedures. training CD. The Program addresses noise heliports and abatement and public acceptance 4) to document the relationship between 6.8.5. Caution should be employed when objectives with programs in the following the transportation and economic well- using complaint statistics for the areas: being/public services in the area. estimation of the scale of the problem of helicopter noise. A public survey should be 1) Pilot and operator awareness The report created the following carried out to inform the industry and the 2) Pilot training and indoctrination recommendations: public about the extent of the helicopter 3) Flight operations planning 1) Create a program to collect helicopter noise problem in the UK. The study would 4) Public acceptance and safety activity data. have to take into account the socio- 5) Sensitivity to the concerns of the 2) Establish a permanent helicopter economic and cultural conditions that community working group. prevail and the type of helicopter activity. 3) Create a centralized and formal system to address helicopter noise complaints. 4) Establish a program to support helicopter operator and market needs. 5) To address zoning issues.

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6.8.6. Airservices Australia published a medium range during low flying activity 6.10. Options for the improvement of guide entitled ‘Environmental Principles emanates from the plane of the rotor, and prediction for noise mapping and Procedures for Minimising the Impact not from underneath as measured during 6.10.1. Opportunities for of Aircraft Noise’ (see 7.6.6) which lists a civil certification. Helicopters are also improvement. The EC Directive on hierarchical approach minimising the louder to the front and on the advancing Environmental Noise requires member impact of noise on the community with side of the main rotor blades. states to make strategic noise maps for the most preferred procedures for major agglomerations along major roads, helicopter operations given first. A similar 6.9.3. Another important factor with major railways and major airports within guide could be produced and publicised. regard to helicopter noise is that their territories [1]. Noise mapping for complaints usually arise from individual helicopters is not currently conducted 6.8.7. In Australia "Fly Neighbourly" flights, as opposed to the average of a because of the difficulty in accounting for agreements are sometimes successful and large number of flights as in the case of the factors discussed above. However, the in the USA, as a result of the Washington fixed wing aircraft around a busy airport. expertise exists to make good account of report on helicopter noise, helicopter This has an important impact on the way these factors, particularly in the UK, and operators are encouraged to develop in which the propagation of the noise this could be exploited in future noise these agreements. This is an approach should be modelled. In the case of mapping programmes. Appropriate data that could be encouraged more in the UK. individual flights, environmental factors on the source noise of civil helicopters, such as wind, temperature, ground except where they overlap with military 6.9. Noise prediction and modelling impedance and background noise play an platforms, is not available and needs to be 6.9.1. Noise mapping at airports for fixed important role in determining how the collected and/or estimated through source wing flights has been conducted for many sound travels and how it is perceived. prediction code as a matter of priority. years. These maps use data obtained during noise certification of the aircraft as 6.9.4. In particular the following give rise 6.10.2. Recommendations on how a basis for its noise level and apply to relatively large noise footprints: these could be implemented. First and propagation algorithms averaged over a 1) Low frequency noise propagating foremost, a sensitivity analysis on the long time period [115]. However, it further through the atmosphere. required level of helicopter noise should be noted that ECAC Doc 29 2) Sound refracting downwind. modelling needs to be carried out. It specifically excludes helicopter noise and 3) Sound refracting under temperature needs to be determined what level of the FAA INM is the only commercially inversions. modelling can be practically implemented available noise model with a limited 4) Sound propagating over acoustically in the required time frames. Variables helicopter capability. Given the large hard surfaces such as water and include the number of helicopter flights, number of flights at major airports and concrete. and the associated positional and average meteorological conditions over a meteorological data available. It is also long period, these maps produce a good 6.9.5. Although modelling of civilian important to fully understand the indication of the noise around airports helicopter noise is deemed too difficult at limitations and inaccuracies present in any from fixed wing aircraft. present, the acoustic footprint of given model. Therefore, a systematic series individual helicopter flights is of of comparisons between high and low 6.9.2. Although some limited information importance to the military. In the military fidelity models, and levels of source and on helicopters is now included in the sector, the tools and data are available to environmental data, needs to be carried some noise models, see [110], this account for the above factors and out. As a result of this work, the best way approach is not appropriate for the produce accurate noise maps [111]. forward for helicopter noise mapping can meaningful noise modelling of Comprehensive measured source noise be ascertained. It may be that a relatively helicopters.. Helicopter noise is dominated databases are available for numerous simplistic model must be used because of by the main and tail rotor tones the military platforms, together with the tools computational time constraints On the details of which cannot be retrieved from to fully model the effect of all relevant other hand, it is possible that a database civil certification data. However, INM7.0 environmental parameters. These tools of aircraft noise maps created with high and its database now includes more than could readily be adapted to accurately fidelity software given prevailing the published certification data, e.g. 1/3 map civilian operations given accurate meteorological conditions, can be called octave band spectral data and utilises positional, meteorological and source upon to generate accurate noise maps in these in the propagation algorithms. data. the future. This would yield the best Understanding the nature and possible solution for the noise mapping of propagation characteristics of these tones helicopters, which is required to meet the is central to capturing the helicopter's European Noise Directive. distinctive signature. It is this distinctive signature that contributes to noise complaints. Another factor to be considered when trying to capture helicopter source noise data is its directional variation. For example, helicopter noise heard at long and

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6.11. Summary of Chapter 6 6.11.8. The Joint Aviation Authorities 6.11.1. Consultative committees to enable (JAA) represents the civil aviation dialogue between residents, councils and regulatory authorities of a number of the heliport operator have helped to European States who have agreed to co- improve understanding and acceptance by operate in developing and implementing the public. The dialogue should be common safety regulatory standards and extended to include developers so that procedures. Regulations governing the homes are created with sufficient sound management of helicopter noise in insulation. Australia and the United States are broadly in line with those in Europe, in 6.11.2. A fast and sincere response is part due to the harmonisation work of the important in keeping complainants from Joint Aviation Authorities (JAA). becoming repeat complainers. The failure to act on complaints is one of the largest 6.11.9. Two significant European projects causes of dissatisfaction and resentment address noise from helicopters these are amongst the public. FRIENDCOPTER and the "Clean Sky" JTI. Both aim to produce a significant 6.11.3. The CAA provides a focal point for reduction in the noise generated by receiving and responding to aircraft helicopters. related environmental complaints from the public. However, the CAA currently has no 6.11.10. Noise maps and action plans are legal power to prevent aviation solely on required by the Environmental Noise environmental grounds. An independent Directive on a five-year cycle. Helicopters review is considering greater power for are not excluded, though rudimentary the CAA on environmental matters. noise mapping of helicopter noise is currently restricted to major airports. 6.11.4. The CAA encourages noise However, the accuracy of these strategic complaints to be made directly to the noise maps relating to helicopter noise is airport operator. Problems related to noise limited by the lack of sufficient source generated on the ground at aerodromes, data and validation of noise prediction other than in association with the normal models in this context. operation of aircraft, should be referred to the Local Authority. 6.11.11. The UK has world-leading expertise in helicopter noise prediction 6.11.5. MOD complaints are usually dealt and in the measurement of source noise with through the base's community liaison from helicopters. officer.

6.11.6. Properties close to helicopter bases, evaluated under the previous MOD Noise Insulation Grant Scheme (NIGS) scheme criteria, are unlikely to qualify for compensation.

6.11.7. BHAB codes of practice aim to increase helicopter pilots and operators awareness of environmental noise issues. Although pilots are aware of noise issues, factors such as safety are considered to be more important.

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7. Conclusions

7.1. Extent of the reported problem of 7.3. Improving the handling of 7.5.2. A residential planning application noise from helicopter operations in complaints - consultative committees close to an operating heliport, when the UK 7.3.1. Well-organised consultative evaluated in accordance with PPG24, 7.1.1. Reported problems with helicopter committees are successful in addressing should not rely solely on Leq and should noise in the UK are centred on helicopter environmental noise from helicopters. consider the intermittent nature of infrastructure, in particular specific helicopter operations. heliports and aerodromes. 7.3.2. When operated successfully, the public appreciate that their concerns are 7.5.3. The UK has world-leading expertise 7.1.2. The consensus among stakeholders being taken seriously. in the field of sound insulation of is that there is not currently a significant residences from helicopter noise. helicopter noise problem in the UK, except 7.3.3. This is because consultative in a few specific areas near the busiest committees represent a neutral position 7.6. Improvement of predictions heliports. On the other hand, it is thought from which to influence operators to 7.6.1. Noise mapping for helicopters is not that there is increasing opposition to the change operational procedures. currently conducted due to the lack of an development of heliports on the grounds agreed noise prediction model in the of noise disturbance. 7.4. Opportunities for improving dose- public domain and inadequate source response relationships noise data. 7.1.3. Determination of the scale of public 7.4.1. Academic research is required to concern about helicopter noise would better understand the human response to 7.6.2. Appropriate data on the source require a social survey. helicopter noise. noise of civil helicopters, except where they overlap with military platforms, is not 7.1.4. Determination of a dose-response 7.4.2. Problems caused by helicopter noise available, and needs to be collected relationship for the prediction of are not represented by the certification and/or estimated through source community response to helicopter noise parameters of helicopters. prediction code as a matter of priority. would require an extensive and carefully designed study. 7.4.3. Helicopter manufacturers are 7.6.3. The UK has world-leading expertise concerned that a gradual reduction in the in helicopter noise propagation prediction 7.1.5. The study would need to take into certification levels would compromise and in the measurement of source noise account socio-economic and cultural helicopter performance or even refusal of from helicopters, due to involvement in aspects, and the type of helicopter activity. type certification. military programmes.

7.2. Guidance on the management of 7.4.4. Annoyance by helicopter noise is 7.6.4. This expertise, currently only helicopter noise not well correlated with generally available within MOD programmes, could 7.2.1. There is a need for a more ‘holistic’ accepted acoustic parameters. The reasons be exploited in future civil noise mapping. approach to the management of for this are thought to be a related to environmental complaints from three factors: helicopters. 1) The unique subjective character of the helicopter noise not being fully 7.2.2. To ensure there is accountability addressed by the indices. related to environmental noise problems 2) The use of long-time averaged (LAeq) caused by helicopter operations, it is parameters that do not correctly suggested that complaints are collected represent single events or operations and logged in a central database from all that have a low rate of incidence. sources including the CAA, the MOD, 3) The 'virtual noise' factor, which local authorities, operators and airfield encompasses community attitudes and managers. Attention should be paid to fears towards the operations. methods utilised in Australia where monthly reports on complaint statistics are 7.4.5. The UK has world-class expertise in provided to stakeholders. the subjective response to helicopter noise. 7.2.3. The CAA provides a focal point for receiving environmental complaints from 7.5. Recommendations for planners aircraft operations but it does not have and developers any legal power to prevent aviation on 7.5.1. Developers need to be encouraged environmental grounds. An independent to enhance sound insulation in new / review is considering giving the CAA change-of-use builds near helicopter greater powers over environmental bases. matters2. This 'holistic' approach would

give a wider view and could identify 2Department for Transport press release of 9 October 2007 specific problems. http://nds.coi.gov.uk/environment/fullDetail.asp?ReleaseID= 320757&NewsAreaID=2&NavigatedFromDepartment=False

30 DEFRA NANR235: Project report

8. List of abbreviations

AAAC Association of Air Ambulance Charities ICAO International Civil Aviation Organization

ACARE Advisory Council for Aeronautics Research in Europe IoA Institute of Acoustics ADO Airports District Office ITD Integrated Technology Demonstrator AGL Above ground level JAA Joint Aviation Authorities

AI Australian Annoyance Index JSPs Joint Service Publications ANASE Attitudes to Noise from Aviation Sources in England JTI Joint Technology Initiative ANIS Aircraft Noise Index Study Leq Equivalent Continuous Noise Level ANO Air Navigation Order LFAs Low flying areas ANSI American National standards institute MCA Maritime and Coastguard Agency ARED Aviation Regulation Enforcement Department MOD Ministry of Defense ATC Air Traffic Control NAG Noise Action Group BHAB British Helicopter Advisory Board NASA National Aeronautics and Space Administration

BVI Blade Vortex Interaction NATS National Air Traffic Services CAA Civil Aviation Authority NEU (Airservices Australia) Noise Enquiry Unit CAS Controlled Airspace NHS National health service CASA Civil Aviation Safety Authority (Australia) NIGS Noise Insulation Grant Scheme CIEH Chartered Institute for Environmental Health NNI Noise and Number Index dB Decibel NOTAR NO TAil Rotor

Defra Department for Environment, Food and Rural Affairs NPR Noise preferential routes DfT The Department for Transport PNL Perceived Noise Level DNL Day-Night Level PPG 24 Planning Policy Guidance 24: Planning and noise DS&C Directorate of Safety and Claims Q Disturbance Index DUAs Dedicated User Areas Q.T/R Quiet tail rotor EASA European Aviation Safety Agency RAF Royal Airforce ECAC European Civil Aviation Conference SAR Search and rescue END Environmental Noise Directive SEL Equivalent Sound Level with Threshold

EPA US Environmental Protection Agency TR Tail Rotor EPNL Effective Perceived Noise Level TRI Tail rotor interaction FAA Federal Aviation Authority UCAS Uncontrolled Airspace

FAR Federal Aviation Regulations WECPNL Weighted Equivalent Continuous Perceived Noise Level HSI high speed impulsive (noise) WHO World Health Organization HYENA Hypertension and Exposure to Noise near Airports

31 DEFRA NANR235: Project report

9. Recommendations of London in Spin

Recommendations of London in Spin CAA; responses to the recommendations of London in Spin

The Department for Transport should undertake a full review of Not for the CAA to action. the impact of helicopter movements and noise in London over the next twelve months, with the aim of putting in place a series of policy responses designed to mitigate the impact of this form of noise pollution on Londoners’ lives.

As part of its review, the Department for Transport and Civil The CAA will review what information is available on helicopter Aviation Authority should investigate and then establish a noise modelling and provide links via its website. A mechanism mechanism to ensure that research on noise and other data on has been agreed with NATS to provide data on helicopter all helicopter movements is effectively collected, collated, movements over London and this data will be published at analysed and published regular intervals on the Directorate of Airspace Policy (DAP) section of the CAA website.

A single national web-site (for example, extending the role of A mechanism has been agreed with NATS to provide data on the national noise mapping web-site), or a clearly publicised helicopter movements over London and this will be published at portal, should be established by the Department for Transport regular intervals on the Directorate of Airspace Policy section of and/or Department for Environment, Food and Rural Affairs to the CAA website. DAP already has a well-advertised post that give public access to data on helicopters, including movements, receives noise complaints from across the UK. The contact routes used, and places where holding may be expected. telephone numbers and e-mail address have been provided in the CAA’s written evidence to the Committee.

As part of its review, the Department for Transport should take Not for the CAA to action. However, the CAA already has such a the lead to: make the public complaints procedures clearer, facility as described in response to Recommendation 3. including making any telephone number universally known; that complaints are logged, co-ordinated and dealt with effectively; and that consistent data on complaints is published.

The Civil Aviation Authority should include the London Assembly The CAA already considers the Mayor of London to be a and the Mayor of London in consultation, and seek amendment statutory consultee on matters that effect the GLA area of to legislation to make them both statutory consultees, regarding responsibility. matters that have implications for helicopter noise.

The operator of London Heliport at Battersea, in association with Not for the CAA to action. Wandsworth Council, should establish within 12 months a London Heliport Consultative Committee to, as a first priority, address local residents’ concerns about helicopter movements and noise.

The National Air Traffic Services and Civil Aviation Authority This is already underway as a follow-on to the London CTR should come forward with proposals on dealing with the issue of review that was initiated by the CAA during 2005. NATS are helicopter holding at locations across London. currently working up proposals that will include changes to airspace classification, an extension of Helicopter Route H4 to the east and a new route south-east from Battersea Heliport all of which could help reduce the requirement for helicopters to hold.

The Department for Transport should review its guidance to the Not for the CAA to action. However, the CAA view is that civil Civil Aviation Authority so that the environmental impact of helicopter noise is not specifically excluded from the current helicopter noise is included within its responsibilities. Guidance.

As part of its review, the Department for Transport should Not for the CAA to action. However, the CAA view is that investigate user charging for any additional air traffic control helicopters should be treated in the same way as any other services required for helicopters. general aviation aircraft requiring transit services through a volume of controlled airspace established to protect aircraft landing/taking off at airport.

32 DEFRA NANR235: Project report

Recommendations of London in Spin CAA; responses to the recommendations of London in Spin

Following changes to the Regulations, the Civil Aviation No anticipated change. The CAA could only take such action on Authority should impose restrictions on the use of helicopters for safety grounds or because of an airspace restriction that has advertising and media so that the environmental impact can be been created for a specific purpose. Current operations are minimised. being conducted within the Aerial Advertising Regulations.

The Department for Transport should submit proposals to the Not for the CAA to action. Treasury that would lead to a change in the finance rules to give a write down allowance of 25% for all helicopters.

The Department for Transport should establish a working group Not for the CAA to action. However, the CAA recommends that including the Civil Aviation Authority, National Air Traffic it calls a meeting of interested parties in December 2007 when Services, Metropolitan Police Air Support Unit, British Helicopter meaningful statistics will be available from NATS on the Advisory Board, helicopter/heliport/airport operators, Mayor of helicopter movements that have taken place. This will provide an London, local authorities, environmental groups and any affected opportunity for a meaningful assessment of trends. residents groups to: update estimates of future demand for helicopter movements; examine noise assessment and control issues; reappraise management of airspace; commission and undertake research; and, assess options for existing and future heliport provision.

The Civil Aviation Authority should give regard to the Mayor’s The CAA will give due regard to the Mayor’s London Ambient London Ambient Noise Strategy when developing proposals on Noise Strategy. environmental matters, including helicopter noise.

The Mayor should reflect the findings and recommendations of Not for the CAA to action. this London Assembly report in the next review of his London Ambient Noise Strategy

33 DEFRA NANR235: Project report

10. Institute of Acoustics One-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

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40 www M5 4WT Gr University ofSalfor The AcousticsResearch Centre eater Manchester .acoustics.salfor d d.ac.uk

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