Planning Application

 

BENTWATERS PLANNING APPLICATION C/10/3239

pages selected for their relevance to aviation

The full document can be seen on the SCDC website by clicking this link C/10/3239

 

Updated Planning Statement – (Page 30)

15. Flying (which means taking off and landing) at the site shall be limited to one annual air show and 480 flights (or 960 movements) annually and no more than 20 flights (or 40 movements) in any one week which are not part of an air display, unless otherwise agreed in writing by the lpa. Reason: In the interest of maintaining tranquillity within the AONB and residential amenity.

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Revised Environmental Statement Vol. 3

 

Changes relating to aviation – Page 20/Paragraph 1.10.3 – Points 5 & 6

 

5. The proposed use of Building 668 has been changed from ‘processing and storage of wood products’ to ‘Spitfire propeller workshop, parts and tool store associated with 669. The effect is anticipated to be neutral.

6. The proposed use of building 669 has been changed from ‘houses one spitfire’ to ‘aviation workshop and hangar for 8 heritage display aircraft in association with 668’. This change is considered to be significant enough that previous conclusions within the ES should be revisited. There is a reasonable opportunity for negative visual or noise impacts arising from this use that will be considered further in this ES. Background information has been provided by the tenants of these buildings and can be found in Volume 4.

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Tranquility – Pages 52-53/Paragraph 3.4.53-61

 

3.4.54 A sense of tranquillity is considered to be one of the key characteristics of the Suffolk Coast and Heaths AONB, the Suffolk Coast and Heaths JCTs/NCA and a number of the LCTs in the vicinity of the site.

3.4.55 Tranquillity is generally described in qualitative terms: perceived links to ‘nature’, positive features in the landscape, the importance of wildlife, peace, quiet and calm, and an absence of disruptive behaviour from other people, noise (especially from cars) and overt signs of human development.

3.4.56 The Campaign to Protect Rural England (CPRE) has produced a national tranquillity map of England and for each county (see Figure LVIA Addendum 01 for the map of Suffolk). Tranquillity mapping attempts to relate components and detractors of tranquillity to national GIS datasets so that the tranquillity can be effectively quantified and mapped. The tranquillity map is based on quadrants of 500m by 500m. Each quadrant’s degree of tranquillity is located on a spectrum of more or less tranquil areas, determined by the combined positive and negative scores given to each grid square. Each quadrant is attributed a score based on 44 factors that either detract or contribute to tranquillity, and which are weighted according to significance. These factors and weightings were decided upon after a participatory appraisal consultation. Mitigating factors such as topography and woodland are taken into account as well. The highest tranquillity scores are indicated by the darkest green on the map, and the lowest tranquillity scores by brightest red.

3.4.57 Factors considered include: people (relative likelihood of people being in a given square), landscape (things that could be seen from and within each individual square), and noise.

3.4.58 There are no available data sets of noise distribution. GIS techniques were used to model the diffusion of noise away from sources such as roads, urban areas, railways and military training areas. Maximum noise at any time and time-average noise exposure was estimated. This enables consideration to be given to the effect of intermittent but very loud noise, and low but constant background noise on the experience of tranquillity.

3.4.59 Noises identified during consultation as being most significant were: road noise, aircraft noise, urban noise, military training, together with other noises such as explosions or railways.

3.4.60 To achieve a degree of tranquillity, background noise did not need to be absolute silence, and noises that were ‘non-human’ in origin and different from that experienced in general urban environments could exist without necessarily compromising tranquillity.

3.4.61 The CRPE study, produced in 2007, may be considered to represent baseline conditions at the site. Within Suffolk, Ipswich contains the densest areas of bright red, signifying least tranquil areas, while an area along the coast at Orford Ness is identified as the most tranquil area. In the vicinity of the site, Woodbridge is the least tranquil area. Corridors of less tranquil areas follow the routes of the main roads in the area, along the A12 towards Wickham Market, and, to a slightly lesser degree, along the A1152 through Melton, Bromswell, Rendlesham and thus adjacent to the north-west edge of the Site. Generally the area becomes more tranquil towards the south and east of the Site, in Rendlesham Forest, Tunstall Forest and the Butley River. As such, within the site, areas of least tranquillity are those approximating to the north-western side of the runway, and the most tranquil areas to the south

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Assessment of Impacts – Page 57

3.5.10 Reference to the CPRE tranquillity map (Figure LVIA Addendum 02) shows that the LCT in the immediate vicinity of the site experiences a range of tranquillity levels, with the least tranquil areas being those along the A1152 corridor, and extending to approximately the portion of the site north of the runway, save a more tranquil area in the north-eastern corner of the site. See Figure LVIA Addendum 02.

3.5.11 Following reference to the Sharps Acoustics LLP Noise impact Assessment, November 2012, Figure LVIA Addendum 01 illustrates the likely influence of noise levels arising from the eight heritage aircraft on the LCT. Within the site, and thus remote from public receptors, levels of ‘high annoyance’ would be experienced in close proximity to the north-eastern portion of the runway when it was in use for take off or landing, with the majority of the northern portion of the site being assessed as below the level of ‘low annoyance’, and the southern portion within the LCT ranging from less than ‘low annoyance’ to less than ‘moderate annoyance’. Beyond the site, all public receptors within the LCT would experience levels less than ‘low annoyance’, with the exception of the public footpath on the north-western perimeter of the site, which would correlate with the ‘low annoyance’ noise contour. The sense of tranquillity could also be affected by the presence of moving objects, and the flight paths from take off/landing would pass over a number of public footpaths within the LCT, e.g. to the south-west of the site in the vicinity of Eyke.

3.5.12 Such changes in noise levels and movement, and thus tranquillity, would not be continuous and would only be experienced when the runway was in use for take offs or landings, i.e. up to a maximum of 40 times per week, averaging six times a day.

3.5.13 As explained in Chapter 1 of this ES revision. Flight paths taken by airbourne aircraft are beyond the control of both the applicants and the local planning authority. In any event, aircraft stationed at the site are likely to move out, away from the immediate vicinity of the site, and the AONB; and are thus likely to have only nominal influence on the tranquillity of the area. Indeed it is aircraft flying to the area from airfields elsewhere and low flying military aircraft that are likely to affect tranquillity.

3.5.14 It is considered that the proposals would exert an influence of moderate magnitude (and thus medium-low adverse significance) on this portion of the Plateau Estates Farmlands LCT. Such an assessment is based on the effects of the views of vegetable boxes, wood storage, and soil product storage and the changes in tranquillity arising from noise/movement from the eight heritage aircraft using the runway (albeit experienced at a limited number of receptors , and on a limited number of occasions on any given day) Thus the no-action scenario (i.e a continuation of the baseline scenario with no mitigation measures implemented) would result in an impact of medium-low adverse significance.

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Noise - Pages 122 - 131

7.4.10 The ‘Grace Spitfire’ (ML407) is based at Bentwaters for 6 months each year (6 months at Duxford) and flies from the site occasionally sometimes to offsite display events and sometimes on local pleasure flights each which have a duration of no longer than one to two hours. This use was accounted for in the original ES and no significant environmental impacts were identified and this position was agreed with the District Council’s Environmental Health Dept.

7.4.11 When Bentwaters was an operational airbase the USAF hosted open days that were similar in extent to the 2010 Bentwaters air show, save that the USAF event had more flying displays.

7.4.12 “During its USAF occupation, the base was regularly opened to the public. These open days attracted vast crowds as well as a good variety of aircraft types and nationalities. The final open day at USAF Bentwaters on 5th September 1992. The annual open days were not the only means by which the USAF personnel interacted with the local population, they were only too pleased to extend their hospitality in numerous other ways, both on and off the base, and as such proved to be an important part of the community.”

7.4.13 Since 1992 there has been one air show in 2010. There has also been a Hangar Dance which had a ‘fly by’ and the Bentwaters Cold War Museum has annual open days with some associated but limited flying displays.

7.4.14 Bentwaters Parks Ltd (one of the applicants) intends to hold further air shows in the future due to the popularity and success of the 2010 event. However no firm dates have been set, in part because of the amount of preparation that goes into organising them. However once an organisational format has been established, it is understood that the management of the air shows becomes proportionately simpler with each event working to the format of the previous one.

7.4.15 It is considered that the undertaking of air shows is Permitted Development and as such could occur annually.

7.4.16 Because the baseline would otherwise be a mixed situation of historic open days (now ceased), museum open days and hangar dances, air shows undertaken by the site owners with the intention of further shows it is reasonable to suggest the baseline to be that an air show which occurs annually.

7.4.17 Building 669 remains a Sui generis use but is now proposed as an aviation workshop housing up to 8 aircraft. These aircraft are listed in the enclosed report by Sharps Acoustics.

7.4.18 Since the planning application was submitted in December 2010 the use of Building 668 has evolved and the previously proposed use for biomass storage will not now take place.

7.4.19 The proposed use of building 668 is will remain a Sui generis use but as a Spitfire propeller workshop and parts and tool store associated with Building 669 as set out in the email to Steve Milligan dated 20th August 2012.

7.4.20 The propeller workshop use involves taking a propeller off the Spitfire (and only Spitfire’s) and carrying out maintenance on it. This is a quiet activity and may on occasion require the maintained propeller be attached to an engine (on an aircraft tied down outside the workshop) which is run up to full speed for around 30 seconds for testing, and this activity produces less noise than taking off and landing.

7.4.21 These two buildings are occupied by Air Leasing Ltd which includes Carolyn and Richard Grace and two employees. Who carry out maintenance, restoration and operation on light and vintage aircraft, predominantly their own.

7.4.22 In order to quantify the nature of these activities Air Leasing Ltd has said that it takes around 5 years to restore a single aircraft. This use should not be interpreted as the coming and going of numerous aircraft all the time.

7.4.23 Aircraft housed in building 669 have been operating from the site for approximately 4 years and, to the knowledge of the applicants, without formal nuisance complaint. The use of the buildings allows these heritage aircraft to remain operational. Their presence at airshows provides for a positive social experience. The use of these buildings is therefore proposed to continue and the public’s opinion has clearly been demonstrated to be overwhelmingly in support. The need to formally regularise the use is recognised.

7.4.24 A varying number of small aircraft visit the site each year almost exclusively connected with the economic activity on the site and the applicants and District Council Planning Committee wish for this to continue.

7.4.25 The aircraft that visit the site on business are small private aeroplanes. Although the site is used for flying on a commercial basis there is no intention of creating a flying club or an airport. The use of the runway by business users is either incidental to an existing use or with the prospect of a future use arising from the visit.

7.4.26 Business visitors already visit the site by light aircraft. This use is in connection with existing and potential businesses. It is estimate that in recent years there were up to 10 flights a month of this nature to the Bentwaters site; a similar figure to that suggested by a Councillor at 7th September 2012 Planning Committee.

7.4.27 With an operational runway and businesses operating on site this use is likely to continue and it is assumed at the existing frequency.

7.4.28 Finally, consideration will be made of the impact of use of the various buildings and land at the site. The majority of the units operate without the benefit of planning permission however the regularisation of use of these buildings will help us understand whether they have a noise impact that requires mitigation.

7.4.29 Buildings on the site requiring consideration include B1, B2 and B8 uses such as car repair workshops and storage facilities which make up the majority of the units. The occasional use accommodation for film crews using the site (C1) and the Cold War Museum (D1) as well as other business use units do not need consideration as they make no discernable noise. No fixed plant is associated with these units. For a fuller list of building and land uses please see the building and land use schedule in combination with the masterplan.

The Proposal

Air plane flights and air shows

7.5.8 As already discussed, air plane flights occur at the application site. This takes the form of airshows, flights by visitors and tenants of building 668 and 669. Bentwaters has two operational runways orientated approximately east-west. These consist of the main runway and a reserve runway running parallel to the south.

7.5.9 Aircraft prefer to depart into and arrive into the wind. This results in a modal split of 70% and 30% with the maximum departures and arrivals towards the west. This modal split has been assumed in this noise assessment. Air planes typically taxi from building no. 669 and typically take off from the runway in a south westerly direction.

7.5.10 At large, well-used airfields and airports it is necessary to consider the departure and arrival tracks – since there will be many of each. In the case of Bentwaters, the activity level is relatively low and, therefore only straight-out and straight-in flight tracks need to be considered (some “dispersion” around the departure track has been modelled).

7.5.11 In terms of the air shows it would seem reasonable at the outset to predict the potential for significant adverse impact arising from aviation noise during the air show itself. However the perception of aviation noise associated with an event such as an air show is in varying degrees influenced by its association with historic aircraft and military history. This perception may, for a great number of people, not be adverse at all. Also it is important to bear in mind that the air show would occur only over two days in the year and it would be well publicised giving advance notice of the event.

7.5.12 Because the assessment of potential significant environmental impact is both spatial and temporal it is necessary to consider the immediate adverse impacts in the context of the overall timeframe. I.e. there would not be an air show occurring for 363 days in the year. Indeed there may be years with no air show at all.

7.5.13 The issue of tranquillity is potentially more subjective than other potential impacts. However the considerations include two principal elements which can be objectively assessed; that of noise impact and visual impact. Insofar as the intermittent air shows are concerned it is unlikely that due to the short term nature of their impacts that they could have a significant adverse impact of a temporal nature.

7.5.14 Air shows are by their nature likely to occur at Bentwaters at the weekend, so there should be very little likelihood of a cumulative impact with the commercial activities on the site which activities are, in the main, occurring on week days. There could be a cumulative impact with other large local events but with no confirmed dates for an air show it cannot yet be known whether this situation is likely to arise. Suffice it to say that organisers of large events are likely to avoid hosting their event at the time in case it clashes with another local event in order not to lose visitor numbers.

7.5.15 Accordingly the likelihood of a significant environmental impact arising from the use when considered spatially and temporally is expected to be low. It is argued by the applicants that because of the nostalgia likely to be associated with an air show the noise impacts associated with it are unlikely to be perceived by many people as adverse. It is not comparable with the impact of a Civil Aviation Airport with its many regular flights occurring on a daily basis. Good local publicity is effective in raising awareness in advance of such an event so that the impact ‘on the day’ should be anticipated and understood.

7.5.16 Effects may occur to biodiversity interests, in particular nesting birds. However one of the greatest sources of disturbance to nesting birds is from direct interaction (audio, visual) with people and people walking dogs. While it is possible that an air show could have a direct short term effect on local wildlife there is no reason to suggest this would extend into the longer term leading to significant adverse impact.

7.5.17 The annual air shows are considered unlikely to have the potential to cause significant adverse environmental impact to the identified receptors such that the previous conclusions of the ES require amendment.

7.5.18 In terms of the occasional flights associated with business visitors to Bentwaters noise assessment for the Spitfire provides a basis for understanding their noise impact. Also when undertaking its occasional pleasure flights the Spitfire is more likely to circle the site and remain in the vicinity for longer than a small aircraft coming in to land and take off again sometime later. Accordingly it is likely to provide a useful baseline from which to understand the likelihood of significant impact small private aircraft. It can therefore be assumed that a small business aircraft flying to and from Bentwaters would at most have occasional, minor, negative and localised effect.

7.5.19 Another aspect to realise is that this use by business aircraft visiting the site is not a use directly caused by or generated from Bentwaters. The aircraft do not fly from and return to the site, it is the opposite way round. The planning system has no control over the intent of these aircraft making business visits, assuming they originate from licensed airfields. The key issues here are whether as a consequence there is a resultant and significant adverse environmental impact requiring control by way of mitigation.

7.5.20 The next issue is to consider whether more than one aircraft would have a cumulative impact. However with frequencies of up to 10 visiting aircraft per month over recent years this averages out at one every three days. It is difficult to see how this could be considered to present a potential adverse and for significant environmental impact on receptors by virtue of noise or visual impact, similarly it is difficult to see any adverse or significant environmental impact on the AONB.

7.5.21 This is reinforced by the fact that to the best of the applicant’s knowledge no noise nuisance complaints have been made formally to the District Council in respect of aircraft directly associate with Bentwaters Parks.

7.5.22 Consideration also needs to be given whether this visitor activity could have a potential for cumulative impact in combination with other uses. To understand this it is necessary to reiterate that the effects of most interest here arise from noise and visual impact. The earlier noise assessment focussed on two sources for potential significant environmental impact and found none which could not be mitigated. Based on the intermittent nature of the business flights it is difficult to see how this activity, even in combination with an assessed situation of no residual impact from the two assessed noise sources, would lead to potential for significant and cumulative environmental impacts requiring formal assessment. Therefore the original ES conclusion remains sound in this respect.

7.5.23 Next to consider are the flights associated with the revised use of Buildings 668 and 669 as a propeller and aviation workshop.

7.5.24 The original noise assessment included the following in relation to the Spitfire: “As the Spitfire will only affect receptors for short periods of time on an irregular basis […] the impact will therefore be occasional, minor, negative and local.” It is necessary to consider whether this conclusion remains sound wit the additional aircraft using these buildings.

7.5.25 The aircraft that utilise these buildings make a number of return flights a week. In our assessment a conservative allowance of 40 has been made. This averages out at 6 a day. However it is understood that the aircraft depart for air displays elsewhere, and do not necessarily leave at the same time. This use is somewhat restricted temporally because the air shows that the aircraft display at do not necessarily operate in the winter. This is not considered to be an intensive activity. In fact since Carolyn Grace has been stationed at Bentwaters there has been a decrease in the number of aircraft ‘buzzing’ the airfield because their tail numbers are taken and they are contacted and politely requested not to buzz the site in future. In fact pleasure flying from visiting pilots is discouraged as historically the air space above the airfield was a favourite practice place for aerobatic enthusiasts.

7.5.26 The occupants of buildings 668 and 669 have issued NOTAMs to local flying clubs to this effect.

7.5.27 The issue of tranquillity is potentially more subjective than other potential impacts. However the considerations include two principal elements which can be objectively assessed; that of noise impact and visual impact causing intrusion into an undisturbed area thereby reducing its tranquil character. The latter is dealt with in the Landscape and Visual Impact section.

7.5.28 Again it is emphasised that the purpose of the flying activity is to attend sites elsewhere, the purpose is not to display to the public at the site. This is important when considering the issue of cumulative impact. It would be unlikely for there to be a cumulative effect with the business flights which by their nature would take place during the week, with these activities more likely to take place at weekends. It is also unlikely that these activities would have a cumulative impact with other activities on the site for the same reason.

7.5.29 Therefore the issue is whether these flights have an in-combination effect with each other. On the basis that they would need to utilise the runway independently of each other in most circumstances, this is unlikely to lead to an in-combination effect which has the potential for a significant environmental impact.

7.5.30 Another issue to consider is in-combination effects with other users of the airspace above the site. But as discussed above this activity forms part of the baseline so the effect of the planning application is negligible on top of that baseline.

7.5.31 The use of buildings 668 and 669 and the resultant flights associated with them has been formally assessed by SAL as not resulting in even low levels of annoyance.

7.5.32 The computer modelling of noise emission levels and production of noise contours requires knowledge of the average number of flights (departures and arrivals) on an average summer day. This calculation should ignore one-off or very infrequent events such as an air-show. It is difficult to assess this likely level of usage, precisely. However, in discussions with the applicant, Mr Bainbridge has concluded that a maximum figure is 40 movements a week or 6 movements a day – a “movement” being an aircraft departure (take-off) or arrival (landing). This assumes that, on average, half of the aircraft will depart and arrive back at the site every summer day. This is a conservative assumption and one which could be controlled by planning condition.

7.5.33 The assessment of aggregate noise emission levels is conventionally undertaken using generic aircraft types. There are two generic categories for “general aviation” aircraft: GASEFP – fixed pitch propeller aircraft and GASEVP – variable pitched propeller aircraft.

7.5.34 The latter of these aircraft tend to be those used for air-shows and displays; they are the noisier due to the higher power developed by the engine. Of the above aircraft, only the YAK has a variable pitched propeller. However, in order to introduce a safety margin into the assessment of noise emission levels, it is assumed in the modelling that all the aircraft at Bentwaters have variable pitched propellers.

7.5.35 The appendix to the SAL report shows the contours that result from the assessment assumptions. These contours have been drawn at the values discussed above.

7.5.36 It can be seen that the LAeq16hr = 50 dB contour does not extend to any residential or other noise sensitive premises. Therefore, the proposal would not result in even low annoyance. Accordingly, the proposal would not result in “significant adverse impacts on health or quality of life” – the test within NPPF.

7.5.37 The SAL assessment of noise impact is solely from the introduction of the additional aircraft. However, it is appropriate to consider the cumulative impact for these aircraft with the Spitfire already operating at the site and the Spitfire that may operate in future. With eight aircraft operating rather than six, the noise emission levels would increase by 1.25 dB (10*log8/6). Such an increase in noise level is not material in impact terms.

7.5.38 The impact will therefore be occasional, minor, negative and local. Accordingly, the proposal would not result in significant adverse impacts on health or quality of life.

7.5.39 As such the imposition of a planning condition which sets a limit as the number of flights to reflect existing activities in noise terms is unnecessary and the previous conclusion of the ES remains sound.
Buildings and Land

7.6 Mitigation and Monitoring

Operational Phase

Airplane Flights

7.6.3 A planning condition has been recommended (in the landscape and visual impact section) to mitigate potential impacts on tranquility in the AONB. That condition is not considered necessary in noise terms.

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Sharps Acoustic Report

Subject: Briefing note – Bentwaters 21st November 2012

Introduction

Sharps Acoustics LLP (“SAL”) has been commissioned by Bentwaters Parks Ltd to undertake an assessment of the likely noise impact from aviation activity associated with a recent application at Bentwaters.

Details of the author of this Briefing Note are appended.

Mr Bainbridge of, Evolution Town Planning, has provided planning advice to SAL in this matter. We understand from Mr Bainbridge that a planning application has been made for a proposal that includes for one Spitfire aircraft based at Bentwaters. However, it is now envisaged that there would be eight aircraft based at Bentwaters in Buildings 668 and 669.

SAL has been asked to consider whether the noise impact that is likely to result from activity associated with this number of aircraft is likely to be “significant”, therefore, requiring assessment under the provisions of the “Town and Country Planning (Environmental Impact Assessment) Regulations, 2011”.

This information is intended to assist in the “general provisions relating to screening” – Part 2 of the regulations.

Assessment methodology and criteria

Conventional assessment methods

Since the Wilson Committee on the Problem of Noise released its “Final Report”, in 1963, aircraft noise has been assessed using three benchmark figures: LAeq16hr = 57 dB equating to “little annoyance”; LAeq16hr = 63 dB equating to “moderate annoyance” and LAeq16hr = 69 dB equating to “very much annoyance”. At that time the index used was the “noise and number index” but the LAeqT levels are equivalent values. These criteria relate to the impact from commercial aircraft.

These equivalent levels for “general aviation” noise are 7 dB more stringent and the impact descriptors have changed. These have been employed in this assessment of impact:

➢ LAeq16hr = 50 dB – low annoyance.
➢ LAeq16hr = 56 dB – moderate annoyance.
➢ LAeq16hr = 62 dB – high annoyance.

The contours of noise emission levels around Bentwaters have been based on these three levels.

The LAeq16hr index is, in effect, the average noise energy level over the 16 hr day period, 0700 to 2300 hours.

The National Planning Policy Framework

The National Planning Policy Framework (NPPF) was released on 27th March 2012. PPG 24 “Planning and Noise, was “replaced” by NPPF upon its release.
The NPPF states that planning decisions should: Aim to avoid noise from giving rise to significant adverse impacts on health and quality of life as a result of new development (Ref: NPPF paragraph 123).

** BCG notes that NPPF 123 also states that decisions should aim to "Identify and protect areas of tranquillity which have remained relatively undisturbed by noise and are prized for their recreational and amenity value for this reason."

The NPPF does not provide prescriptive advice in relation to noise. Therefore, it is necessary to consider advice, which may assist in the assessment of significant adverse impacts on health and quality of life, in other guidance documents. This available advice is discussed, below.

WHO Guidelines for Community Noise

The World Health Organisation, Guidelines for Community Noise, 1999, contain a matrix of guideline values showing “health” effects of noise in terms of “serious annoyance” and “moderate annoyance” during the day. It can be seen that in so far as the WHO Guidelines consider impacts in terms of “health” effects they are in accordance with the NPPF assessment criterion discussed above.

The WHO defines “health” as a state of complete physical, mental and social well-being and not just the absence of disease or infirmity. The WHO criteria for daytime (annoyance) may be considered to be “health” effects in this context.

The use of the word “critical” within the WHO Guidelines indicates that the guideline values are negative criteria, that is, they are values below which noise effects (such as annoyance) can be assumed to be negligible. They are not limits above which significant effects may necessarily occur; however, they are levels above which one should consider noise mitigation.

The WHO guideline values are LAeq16hr = 50 dB (moderate annoyance) and 55 dB (serious annoyance); and

NPL Interpretation of the WHO Guidelines

A report written by the National Physical Laboratory, commissioned by the Department for the Environment Transport and the Regions (1988), contains a section on the interpretation of a 1995 draft of the final 1999 Guidelines. There is not a material difference between the draft and the final document and, so the NPL advice is pertinent to the 1999 Guidelines.

The NPL report states:

“In essence, the WHO guidelines represent a consensus view of international expert opinion on the lowest threshold noise levels below which the occurrence rates of particular effects can be assumed to be negligible. Exceedances of the WHO guideline values do not necessarily imply significant noise impact and indeed, it may be that significant impacts do not occur until much higher degrees of noise exposure are reached.” (emphasis added).
It can be seen that the NPL report provides advice on likely noise levels that would result in “significant noise impact”. As such, the advice within the NPL report is in accordance with the criteria within NPPF and the EIA Regulations (see above).

“Much higher degrees of exposure” is not defined in noise level terms by NPL. However, a 3 dB change in ambient noise levels is not perceptible and a 10 dB change is roughly a doubling of loudness. On this basis, it is believed that a 10 dB change equates to the NPL criterion of “much higher degrees of exposure”.

Therefore, in SAL’s judgement, a “significant impact” would, therefore, result at a10 dB higher level than the WHO guideline values.

Although couched in different terms than the Wilson Committee derived assessment criteria, the NPPF assessment criteria are very similar.

Assessment of aircraft noise emission levels

The assessment of aircraft noise emission levels is conventionally undertaken by the use of a computer program. SAL uses the Integrated Noise Model (“INM”) which was designed by the Federal Aviation Authority.

INM allows a topographical ground model to be input to the program. Overlaid onto this ground model are the coordinates of runways and noise sensitive receivers. The operational variables, discussed above, which affect the noise emission levels from the site, are then input to the INM model.

The computer model then calculates the noise emission levels at ground level over what is termed a Cartesian grid. The grid size can be specified but was 1 metre by 1 metre in this case.

The INM model then joins noise emission levels at like values to form a set of contours – which are “smoothed” by the program. The values of the contours can be specified in the program.

Assessment assumptions

The impact of aircraft noise is conventionally undertaken by assessing the noise emission level that would result on an average summer day (92 days from mid June to mid September).

Bentwaters has two operational runways orientated approximately east-west. These consist of the main runway and a reserve runway running parallel to the south. Aircraft prefer to depart into and arrive into the wind. This results in a modal split of 70% and 30% with the maximum departures and arrivals towards the west. This modal split has been assumed in this noise assessment.

At large, well-used airfields and airports it is necessary to consider the departure and arrival tracks – since there will be many of each. In the case of Bentwaters, the activity level is relatively low and, therefore only straight-out and straight-in flight tracks need to be considered (some “dispersion” around the departure track has been modelled).

It is understood from Bentwaters Parks Ltd that aerobatics will not be undertaken in the vicinity of the site but that aircraft will depart to, or arrive from, distant locations. This has been assumed in this assessment.

The significant separation distances and prevalence of structures and landscape features between aviation facilities on site and residential properties are such that the noise impact from ground operations would not be material or significant.

The types of aircraft that would use the facility are as follows:

• A Spitfire – (double cockpit) - already accounted for in the planning application

• A Spitfire – currently in pieces and not expected to be flying for another couple of years

• A YAK3

• Three Pitts Specials

• A Piper Super Cub

• A Piper L4 Cub

Therefore, the assessment has considered the impact of six aircraft (the YAK, three Pitts and two Pipers).

The computer modelling of noise emission levels and production of noise contours requires knowledge of the average number of flights (departures and arrivals) on an average summer day. This calculation should ignore one-off or very infrequent events such as an air-show. It is difficult to assess this likely level of usage, precisely. However, in discussions with the applicant, Mr Bainbridge has concluded that a maximum figure is 40 movements a week or 6 movements a day – a “movement” being an aircraft departure (take-off) or arrival (landing).

This assumes that, on average, half of the aircraft will depart and arrive back at the site every summer day. This is a conservative assumption and one which could be controlled by planning condition.

The assessment of aggregate noise emission levels is conventionally undertaken using generic aircraft types. There are two generic categories for “general aviation” aircraft:

• GASEFP – fixed pitch propeller aircraft;

• GASEVP – variable pitched propeller aircraft.

The latter of these aircraft tend to be those used for air-shows and displays; they are the noisier due to the higher power developed by the engine. Of the above aircraft, only the YAK has a variable pitched propeller. However, in order to introduce a safety margin into the assessment of noise emission levels, it is assumed in the modelling that all the aircraft at Bentwaters have variable pitched propellers.

Noise impact assessment

The attached appendix shows the contours that result from the above input assumptions. These contours have been drawn at the values discussed above.

It can be seen that the LAeq16hr = 50 dB contour does not extend to any residential or other noise sensitive premises. Therefore, the proposal would not result in even low annoyance. Accordingly, the proposal would not result in “significant adverse impacts on health or quality of life” – the test within NPPF.

The above assessment of noise impact is solely from the introduction of the six aircraft discussed above. However, it is appropriate to consider the cumulative impact for these aircraft with the Spitfire already operating at the site and the Spitfire that may operate in future. With eight aircraft operating rather than six, the noise emission levels would increase by 1.25 dB (10*log8/6). Such an increase in noise level is not material in impact terms.
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GOVLOGO

 

 

 

The National Planning Policy Framework sets out government policy for planners. Clause 123 sets out national government guidance to council planners, but the applicant appears to have ignored the key fourth paragraph relating to tranquility and focuses instead on its environmental report on the health aspects. This appears highly selective! Obviously, in an relatively lightly populated AONB, tranquility is the key issue, not health!

National Planning Policy Framework - page 29

Achieving sustainable development 

122. In doing so, local planning authorities should focus on whether the development itself is an acceptable use of the land, and the impact of the use, rather than the control of processes or emissions themselves where these are subject to approval under pollution control regimes. Local planning authorities should assume that these regimes will operate effectively. Equally, where a planning decision has been made on a particular development, the planning issues should not be revisited through the permitting regimes operated by pollution control authorities.

123Planning policies and decisions should aim to:

● avoid noise from giving rise to significant adverse impacts on health and quality of life as a result of new development;
● mitigate and reduce to a minimum other adverse impacts on health and quality of life arising from noise from new development, including through the use of conditions;
● recognise that development will often create some noise and existing businesses wanting to develop in continuance of their business should not have unreasonable restrictions put on them because of changes in nearby land uses since they were established; and
● identify and protect areas of tranquillity which have remained relatively undisturbed by noise and are prized for their recreational and amenity value for this reason.

124. Planning policies should sustain compliance with and contribute towards EU limit values or national objectives for pollutants, taking into account the presence of Air Quality Management Areas and the cumulative impacts on air quality from individual sites in local areas. Planning decisions should ensure that any new development in Air Quality Management Areas is consistent with the local air quality action plan.

125. By encouraging good design, planning policies and decisions should limit the impact of light pollution from artificial light on local amenity, intrinsically dark landscapes and nature conservation.

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Agenda Item 4 – DM10-14 Bentwaters Rendlesham – PDF