Agenda and minutes

Apologies were received from County Councillors Ashwood and SCDC Councillor de Lacey left part way through 20/61/JDCC, at which point City Councillor Sargeant took the Chair.

The Principal Planning Officer and Principal Environmental Health Officer gave a post submission presentation on Noise in Planning – LNCH’: in the context of application 18/0481/FUL, Land North of Cherry Hinton.

Members raised the following issues:

      i.         Queried how the aircraft Leq (equivalent continuous sound level – averaged over time period) noise contours / boundaries were calculated and commented that if Marshalls did not move from the site noise levels had been calculated at the lowest operational point.

    ii.         Questioned how the bund conformed to Green Belt Policy.

   iii.         Questioned if the impact of the Ground Run Enclosure on existing residential properties had been considered.

  iv.         Disagreed with the comment that there were no tranquil areas in Cambridgeshire.

    v.         Questioned if wind direction affected sound and noise levels and asked if there was no wind whether noise carried further.

  vi.         Commented that the noise modelling showed a bend to the east, so questioned whether this meant land at Cherry Hinton would be subject to noise from the airport to the west. Also commented that noise could carry a long way (even at 4am in the morning) and be intrusive even at low levels.

 vii.         Asked if there were circumstances where the airport could operate outside of normal hours. Expressed concerns regarding the noise made by a climbing aircraft compared to an aircraft going down the runway and asked if this had been measured and what the levels were including acceptability.

viii.         Questioned how the residential properties would be marketed if they experienced noise issues.

  ix.         Commented that that the sound of a helicopter averaged over an 8 hour period was not the same as the frequency and intensity of an aircraft taking off.  This was an incredible intense pulse of sound.

    x.         Questioned if the application could be rejected if the Committee did not feel that sufficient mitigation was proposed.

  xi.         Commented that Environmental Health Officers specialising in noise were consultees for planning application purposes.  Planning Officers would form a judgement on the application taking into account consultee responses and then make a recommendation to the Committee.

In response to Members’ questions the Principal Planning Officer and Principal Environmental Health Officer said the following:

      i.         The Applicants had provided aircraft movements over a 5-year period, officers had to analyse the information which had been provided with projected aircraft (fixed wing aircraft and helicopters) movements broadly consistent with movement levels for the period 2012 to 2017 which has been consistent. The projection of movements on this basis is considered robust for noise modeling purposes. Marshall’s projected movements account for the future plans of the airport, in consultation with senior management of the Airport had said it did not envisage a significant change to their aircraft movements. In any event the noise levels would still be below action level for significant impact e.g. Aviation Policy Framework ‘approximate onset of significant community annoyance’ at a daytime noise level of 57 dB LAeq,16hr.

    ii.         The precise nature of the acoustic mitigation / bund would form part of the subsequent reserved matters application. Member’s concerns regarding the openness of the site and potential visual impact was noted and would form part of balanced judgement by the planning officer when making their recommendation to the Committee.

   iii.         Extensive noise modelling exercises of the impact of the Ground Run Enclosure (GRE) on residential amenity had been undertaken and evaluated by Environmental Health Officers at the time the GRE application was determined. It was acknowledged at that time that a small number of residential properties would experience an increase in adverse noise impact as a result of the application.  However, on balance the wider benefits and reductions at the majority of other properties including Teversham Primary School were considered to outweigh this harm. It was noted that the Applicants had offered to work with the occupiers of affected properties outside of the planning process to mitigate impacts of the GRE should the need arise. Officers confirmed that the actual noise levels associated with the operation of the GRE following commissioning are lower than those modelled and predicted.

  iv.         Confirmed that wind could carry noise mainly downwind.  The GRE south-west noise model did assume a downwind scenario but relatively stable. The model over-estimated / predicted what happens in reality for the GRE.

    v.         The airport had limited flights at night and the GRE operational times are between 8am-6pm, so the only noise during the night would be road traffic noise. Topography could have an impact on noise levels but the model had taken this into account. Noise can travel longer distances under certain meteorological conditions and nighttime could be more sensitive than during the day.

  vi.         In relation to the use of the GRE, there are a limited number of exceptional circumstances where engine testing takes place at night, for example in the interests of national security.  The noise model predicts aircraft take-offs and landings hence distinctive contour shape along the length of the runway and it was noisiest in the centre where aircraft land.

 vii.         The issue of marketing the residential properties would be a matter for the developer. The installation of noise mitigation properties in new residential properties is not unusual, for example on the North West Cambridge University site at Eddington and other urban sites close to transport sources of noise e.g. mains roads etc.

viii.         Noise levels have to comply with Government policy and for aircraft noise including helicopters, average noise levels daytime dB LAeq,16hr (0700 to 2300hrs) is the noise descriptor used. Aircraft take-offs and landings were factored in but it was not possible to assess acceptability of individual peak / short-term exposure noise descriptors (e.g.   Lmax), as there are no national / industry acceptability standards for such short periods. Commented that this was not an overly busy airport and noise levels had to be considered in accordance with Government policy.  Also mainly daytime occurrence.

  ix.         The site is allocated in the Local Plan which recognises the site is located next to an operational airport.  Planning Officers would be guided by their Environmental Health Officer colleagues with expertise in noise to provide an assessment of acceptability and consideration of good acoustic design and noise mitigation in the context of site and urban nature of noise sources. The Applicants had done extensive research, noise modelling and significance of effect assessments.