13 Aviation Introduction 13.1 This topic chapter reports on the potential impacts of the proposed TKOWF project in relation to civil and military aviation. The assessment carried out for this chapter consists of a review of the project specific assessments and studies and a summary of consultations with aviation stakeholders. Consultation and scoping 13.2 As part of the preliminary EIA process for the TKOWF project, a formal Scoping Opinion (see Volume 3: Annex A) was received by the IPC in September 2010 commenting on the TKOWF Scoping Report (see Volume 3: Annex B). This Scoping Opinion has been used to inform the scope and content of the EIA activities and this PEI. In addition to the scoping, further consultation has been undertaken with relevant bodies and organisations. 13.3 Specifically in relation to aviation issues, the following organisations and groups have been consulted: i) National Air Traffic Services (NATS); ii) Civil Aviation Authority (CAA); iii) Defence Estates (now Defence Infrastructure Organisation) division of the Ministry of Defence (MoD); iv) Helicopter operators; and v) Gas platform operators 13.4 A summary of the key issues raised by the consultees is presented in Table 13.1. Table 13.1 Summary of Key Concerns in relation to Aviation Consultee, document and date Consultation summarised comment Section where comment addressed Civil Aviation Authority (CAA), Scoping Opinion: (September 2010). NATS En-Route Plc (NERL), Scoping Opinion: (September 2010). Consultation meeting 23/04/2010 Helicopter Operators (CHC-Scotia, Bond Offshore, Bristow Helicopter). Meeting September 2010 (to discuss Technical Report to Assess the Risk to Safety to Access the Platforms). Defence Infrastructure Organisation (MoD) Memorandum dated 19 April 2010 BP (meetings held on 29 June 2009, 15 September 2010 and 2 March 2011) Conoco Philips (meetings held 12 August 2008, 16 June 2009, 15 September 2009 and 3 March 2011) Potential impact upon Helicopter Main Routes (HMRs); need for consultation with MoD and NATS En-Route Plc. Generic comments regarding key aviation issues for OWFs and requested consultation with the CAA to update charts as soon as construction time frames established. TKOWF will be seen by of the Primary Surveillance Radars (PSR) at Claxby and Cromer radars with a corresponding generation of clutter in the NERL s ATC operations in the Lower North Sea, specifically that of the Anglia Radar sector. De-sensitisation of radars to low altitude aircraft overhead. For traffic on HMRs, potential inability to maintain air traffic service levels. Operators were consulted on and provided input into a technical report to assess the risks to safety to access the platforms, i.e. details of their operational procedures. TKOWF will be seen by RAF air defence radars at Staxton Wold and Trimingham, impacting on their operations. Commercial and safety issues related to helicopter access to Amethyst B1D platform. Impact identified included the use of Helicopter Main Route (HMR) 6, the use of air traffic control (ATC) radars and helicopter obstacle avoidance. : paragraph 13.18 : paragraph 13.41 RPS 218 RWE
Methodology 13.5 The assessment considered the potential interaction of TKOWF project infrastructure, as described in Volume 1: Chapter 7, with the current aviation operations in the region. The scope of the assessment has been defined through consultation with aviation stakeholders set out in the preceding section 13.6 Information on aviation was initially collected through a desktop review of GIS datasets through a constraints mapping process in order to identify features and operators that may be potentially affected by the TKOWF project. Stakeholder consultation enabled the scope of the subsequent impact assessment to be defined. 13.7 A project specific study has subsequently been undertaken by Spaven Consulting to investigate the potential effects from the TKOWF project on helicopter operations to and from adjacent gas platforms in the Southern North Sea (Volume 3 : Annex N). The assessment was completed in response to CAA guidance that states that vertical obstructions should not be placed within a 6 nm distance of helideck-equipped offshore installations, noting that exceptions are possible within that radius where a safety assessment demonstrates that impacts would not be significant. The results of this assessment have been used to inform this PEI and to develop appropriate mitigation measures to avoid interference with helicopter activities, subject to agreement with the affected operators. 13.8 Nats En Route plc (NERL) provides air traffic services including operating a network of navigation systems including surveillance radar (CNS) used by MOD amongst others. The NERL policy statement (2011) presents potential mitilary and civil aviation industry conflicts of interest in advance of the regional development of offshore wind farm infrastructure of the UK east coast in the coming decade. A consortium, of developers is working with the MOD and stakeholders towards a regional solution to avoid interference with defence radar system operations to which this assessment refers. 13.9 In addition, guidance provided within the Draft National Policy Statements for Overarching Energy Infrastructure (EN-1) and Renewable Energy Infrastructure (EN- 3); (DECC, 2010) were considered in undertaking the assessment on civil (and military) aviation. NPS EN-1 includes guidance on what matters are to be included in an applicant s assessment of potential impacts to civil (and military) aviation and are summarised below in Table 13.2. NPS EN-3 presents guidance acknowledging avoidance is the preferred approach but that commercial operations including aviation interests can reach mutually satisfactory agreements should conflicts arise. Table 13.2 Summary of NPS EN-1 guidance on assessment of overarching energy infrastructure Summary of NPS EN-3 guidance on assessment of overarching energy infrastructure Any proposed energy development should minimise impact on civil aviation operational procedures and licensing of infrastructure Should a conflict of interest arise between national energy policy and military operations and training, both parties should reach a mutually acceptable and pragmatic compromise Any proposed development should avoid disruption or interference with safe operation of air traffic control systems Triton Knoll assessment Assessment may identify predicted impacts during construction, the operational life or of the wind farm Mitigation may include avoidance through adjustments to development layout, operational changes and or lighting of structures Table 13.3 Summary of NPS EN-3 guidance of assessment on oil and gas and other offshore infrastructure and activitiesand consideration in the TKOWF assessment Summary of NPS EN-3 guidance on assessment of oil and gas and other offshore infrastructure and activities Assessment of the potential effect on existing or permitted offshore infrastructure or activities. Establish stakeholder engagement with interested parties in the offshore sector early in the development phase and continue throughout the life of the development. Ensure site selection and site design with a view to avoiding or minimising disruption or economic loss or any adverse effect on safety to other offshore industries. Assessment criteria and assignment of significance Triton Knoll assessment The TKOWF assessment has considered each of these potential effects and provided an assessment of their likely significance, considering each phase of the development process (i.e. construction, operation and ). 13.10 The impact assessment for aviation has been carried out in accordance with the approach described in Volume 1: Chapter 5 (Approach to Assessment) which incorporates the requirements of the Infrastructure Planning (EIA) Regulations 2009. 13.11 The sensitivities of aviation activities and operators were defined by both their potential vulnerability and recoverability from impact. 13.12 Magnitude was defined by a series of factors including a consideration of the maintenance of safe separation distances as defined through consultation, the spatial extent of any potential interaction with project infrastructure (primarily turbines) and the likelihood, duration and frequency of any potential impact. 13.13 The combination of sensitivity of receptor and magnitude of impact assigned a level of impact defined through the matrix of significance presented in Volume 1: Chapter 5. Definitions were rated between low, where no impact is foreseen, to high where significant interaction between the project infrastructure (primarily turbines) and aviation activity and/or operation is predicted to occur. RPS 219 RWE
13.14 The scope of this assessment included the issues listed in Table 13.3, identified through desk based assessment and consultation and with due regard to the guidance set out in NPS EN-1 and EN-3. Table 13.4 Aviation key issues for assessment Assessed issues Helicopter Main Routes (HMRs) Helicopter instrument approaches (for support to oil and gas platforms) Civil aviation radars (NATS operated) Air defence radars (RAF operated) Military Practice Areas Baseline environment Risk of interaction with helicopter support operations to oil and gas infrastructure during construction, operation and of wind farm Risk of interaction with helicopter operations to oil and gas infrastructure during construction, operation and of wind farm Risk of interference with air traffic control systems during operation of wind farm Risk of interference with defence radars during operation of the wind farm Risk of interference with military flights during construction, operation and of wind farm 13.15 There are a number of aviation activities/users in and around the TKOWF project area that may be potentially affected by the project (Table 13.4). These include MOD operations, helicopter main routes (HMRs), helicopter approaches to oil and gas platforms and aviation and defence radars (NERL primary surveillance radars and RAF air defence radars). Figure 13.1 shows these activities/uses within the vicinity of the TKOWF. Table 13.5 Summary of civil (and military) aviation activities relevant to the TKOWF project Activity Operator Status Distance (km) from TKOWF main site boundary Helicopter Main Route 6 (HMR 6) NERL Active Central line traverses through northern section of TKOWF project area Helicopter access to seven offshore platforms within 10nm of the TKOWF area Primary surveillance radars at Cromer and Claxby Air defence radars at Staxton Wold and Trimingham Bristow Helicopters, Bond Offshore, CHC-Scotia Active Closest point is 2.8 km to Amethyst B1D platform NERL Active N/A Both radars will have line of sight of TKOWF MoD Active N/A Both radars will have line of sight of TKOWF Military Practice Areas MoD Active 9.0 km (Area Southern MDA) Key parameters for assessment 13.16 The TKOWF project infrastructure is described in Volume 1: Chapter 7 of this PEI. As discussed in that chapter, a development envelope based on the Rochdale principle has been developed for the project EIA. Table 13.5 describes the Rochdale envelope scenario assessed for each potential effect on aviation operators/activities upon which this environmental assessment has been based. RPS 220 RWE
Triton Knoll Offshore Wind Farm Ltd Figure 13.1 TKOWF project area, regional location and civil (and military) aviation activities including PEXA areas and Oil and Gas infrastructure RPS 221 RWE
Table 13.6 Rochdale envelope scenario assessed Potential effect Construction/Operation/Decommissioning: Effect on aircraft detection tower and blades disturbing line of sight for civil and air defence radars likely to generate false plots Effect on aircraft detection towers and blades reducing detection of small aircraft overhead the wind farm, and in the shadow areas behind the wind farm Physical obstruction turbines creating permanent obstacles for helicopter approaches to gas platforms, especially for instrument approaches. Physical obstruction turbines creating permanent obstacles for Helicopter Main Route 6. Cumulative: Physical presence of TKOWF turbines (for lifetime of TKOWF) and all existing and planned R1 and R2 OWFs cumulative impact on civil and defence radars and on HMRs in the Greater Wash area. Rochdale envelope scenario assessed 333 x 3.6 MW is the maximum risk window causing detrimental effect according to width, i.e. greatest number of turbines with greatest number of rotating blades likely to create false plots. Up to 5 meteorological monitoring masts 200 m height Up to 8 offshore substations 100 m height 150 x 8 MW is the worst case as the shadow area will increase with the height of the turbines 150 x 8 MW is the worst case as instrument approaches have to start 1500 ft above any vertical obstacle. Depending on wind direction, the presence of the turbines could make the descent gradient too steep to approach the platform into the wind. Wind farm boundary, all turbine/layout scenarios. The CAA recommends that, due to the requirement for helicopters to transit at low level in icing conditions, HMRs should be obstaclefree 2 nm either side of the centreline. Maximum total physical obstruction due to turbines (tallest and widest rotor diameter) expected for TKOWF and R1/R2 OWFs in the vicinity. Range of scenario assessed 333 x 3.6 MW 150 x 8 MW turbines Up to 5 met masts Up to 8 substations 333 x 3.6 MW 150 x 8 MW turbines Up to 5 met masts Up to 8 substations 333 x 3.6 MW 150 x 8 MW turbines 333 x 3.6 MW 150 x 8 MW turbines Up to 5 met masts Up to 8 substations Relevant dimensions for turbines/rotor diameters for other OWFs Note that the effects on helicopter operations and civil and military radar can result only from the above water elements of the Triton Knoll project. As such the preliminary assessments set out in the following sections are considered insensitive to the below water design permutations set out in Volume 1: Chapter 7 (for example, foundations, subsea cables etc). Effects from vessels engaged in construction, operation or are also not considered relevant to impacts on civil and military aviation. 13.17 There are two ways in which the construction of a wind turbine or wind farm may have an impact upon aviation operations: i) The physical obstruction to flying aircraft caused by a tall structure; and/or ii) The effects that the supporting structure and rotating turbine blades can have on the communications, navigation and surveillance (CNS) systems (including radar) and other equipment. 13.18 The extent of the impact depends upon the design and size of the turbines used. Wind turbines are assessed as a vertical obstruction in relation to their presence in the vicinity of aerodromes and/or within the UK Low Flying System (UKLFS). The UKLFS covers the whole of the open airspace of the UK and surrounding oversea areas up to 3 nautical miles offshore, from the surface to 2000 feet above ground or sea level (DTI 2002). Helicopters are defined as low flying when operating at less than 500 feet msd (minimum separation distance) and may operate down to ground level (DTI 2002). Although the TKOWF is not in the direct flight path of any major aerodrome, it is in the flight path of a Helicopter Main Route (HMR). These routes are published in UK Air Pilot (AIP) and used as a means to enhance flight safety by recommending other airspace users to avoid them. NERL is required to provide traffic de-confliction services on these routes to avoid collisions between helicopters and other aircraft. Horizontal obstacle-free space is required each side of the HMR especially for traffic deconfliction during icing conditions. The affected HMR is HMR6, which crosses the northern boundary of the TKOWF project area (Figure 13.1). 13.19 In addition to the HMR, physical obstruction of the turbines has an impact on access to gas platforms around the TKOWF site. The CAA and Joint Aviation Authority recommend a 6nm obstacle-free zone around the platforms (JAR-OPS). The 6nm zone aims to provide a volume of airspace within which a controlled approach and, in the event of a pilot not being able to complete his approach, missed approach profile can be safely flown. However, the CAA accepts that developments within that radius may be acceptable if a safety assessment demonstrates that the impact would not be significant. For example, the safety assessment for helicopter access to the Douglas platform near the Gwynt y Môr offshore wind farm in the Liverpool Bay has concluded that a 3 nm buffer is sufficient. 13.20 Helicopter instrument approaches are particularly affected by physical obstruction. Helicopters conducting instrument approaches to offshore platforms require the final approach path to be at least 1nm laterally clear of all obstacles. This means that any obstacles placed within a radius of approximately 10nm of offshore platforms may place constraints on those instrument approaches (Vol 3, Annex N). RPS 222 RWE
13.21 The second basic effect of a wind farm on aviation activities is through the masking of real aircraft, which can occur in two ways (DTI 2002): i) reflecting or deflecting the radar such that aircraft flying in the shadow of the turbines are not detected; and ii) presenting such a large number of returns from the towers and the blades that the returns from actual aircraft are lost in the clutter. 13.22 While shadowing will only affect returns from low-flying aircraft, the effects of radar clutter will have an impact on all aircraft flying at all altitudes over the area affected, making this effect far more critical (DTI 2002). Physical obstruction interaction with oil and gas support operations 13.23 HMR 6 passes through the northern parts of the TKOWF project area. The CAA recommends that, due to the requirement for helicopters to transit at low level in conditions where icing may occur, HMRs should be free of obstacles 2 nm either side of the centreline. TKOWF overlaps over a distance of approximately 10 km along the centreline of the HMR, meaning that helicopters will not be able to use HMR6. NERL will not be able to provide safe and reliable traffic de-confliction services on the HMR6 over the wind farm in icing conditions. 13.24 Other wind farm development in the Greater Wash Strategic Area present a similar impact on HMRs (Westermost Rough, Humber Gateway, Dudgeon East). During consultations with NATS, the possibility of redesigning the HMR structure in the Southern North Sea has been identified. 13.25 Regarding the impact on helicopter access to adjacent gas platforms, a study has been conducted by Spaven Consulting to assess the potential impact of the TKOWF project on helicopter operations to and from adjacent gas platforms within 10nm of the TKOWF site. Three of these platforms are within 6nm: Amethyst B1D, A1D and A2D. The study investigated potential effects from TKOWF on day visual operations, night visual operations and instrument flight rules operations, which are summarised below and discussed in detail within the technical assessment report in Volume 3: Annex N. 13.26 The closest platform to TKOWF is Amethyst B1D (Figure 13.1), located at 1.5 nm (2.8 km) North of the wind farm boundary; it is a normally unmanned platform (NUI). Due to requirements for helicopters to land and take off substantially into wind, in some cases helicopters will not be able to access the B1D platform, especially during night and bad visibility conditions. 13.27 It is estimated that approximately one out of every fourteen night visual flights to the platform would be affected by the wind farm and 25% of night visual take-offs would be affected from B1D. However, night operations on B1D are only conducted in the short days of winter and do not constitute the majority of flights. 13.28 Night visual operations to the other platforms in the vicinity of Triton Knoll would not be affected by the wind farm. 13.29 With the presence of the Triton Knoll wind farm, conventional instrument approach procedures to the Amethyst A1D, A2D, B1D and C1D and the Pickerill A platforms will be precluded on Final Approach Tracks (FATs) ranging from 11.4% of the compass in the case of Amethyst C1D to 32.2% in the case of the Amethyst B1D. 13.30 Wind speed and direction data for the area, combined with an estimate of 10% of helicopter flights to the Amethyst B1D platform requiring an instrument approach, indicate that helicopter access to the Amethyst B1D would be precluded by the Triton Knoll wind farm on a maximum of 2.2% of occasions. The use of alternative criteria for out-of-wind approaches could reduce this to 0.01% of occasions. 13.31 Helicopter access to the other platforms would be precluded by the Triton Knoll wind farm with a frequency ranging from zero to 1.29% of occasions, depending on the criteria used for acceptability of out-of-wind approaches (see Volume 3; Annex J). 13.32 Other potential interactions with helicopters identified during consultation included obstacle avoidance for helicopters accessing platforms. Consultation with helicopter operators concluded that flying over the wind farms would be possible except in low cloud cover and icing conditions, whereby helicopters would fly around the wind farm. This was not identified as a significant issue by the helicopter operators. Mitigation measures 13.33 NERL has identified the re-design of the HMR structure (including HMR 6) in the Southern North Sea area as a regional solution to mitigate impacts from several of the wind farms in the Greater Wash area, in order to avoid the need for helicopters to fly over wind farms. This HMR re-design process is being lead by NERL and in consultation with the helicopter operators and the CAA. Final approval for re-designed HMR routes is expected in September 2011. 13.34 Mitigation measures for the impacts to helicopter approach to and take-off from Amethyst B1D would involve a re-design of helicopter procedures, including: i) minimum visibility and cloudbase requirements for departures; ii) use of circling approaches; iii) approach conducted to a nearby platform (Amethyst A1D, Amethyst A2D or Pickerill A) following by a visual transit to Amethyst B1D; iv) restricting operations on the Amethyst B1D to daylight only; and v) lighting on the turbines (see below). 13.35 In addition, satellite-based approach procedures for offshore platforms are expected to be implemented prior to the construction of the TKOWF, which would improve the stability and reliability of out-of-wind (i.e. not into wind) approaches carried out close to the wind farm boundaries. RPS 223 RWE
13.36 The study on helicopter approach has been carried out in consultation with the helicopter operators operating in the Southern North Sea. Their judgement was that the platforms other than B1D should be accessible as usual. They commented on the safety assessment and their comments were included in the final report. 13.37 In line with CAA requirements, the following general mitigation measures regarding lighting, colouring/marking and promulgation, (i.e. formal notification to users), have been incorporated into the TKOWF project design, as described in outline in Chapter 7: i) Turbines will be equipped with aviation warning lighting and sound signals, in accordance with the UK Air Navigation Order 2009, CAA and UK Maritime Coastguard Agency (MCA) s requirements; ii) Rotor blades, nacelle and the upper two-thirds of the supporting mast of wind turbines that are deemed to be an aviation obstruction should be painted white, unless otherwise indicated by an aeronautical study; and iii) Aviation Promulgation the TKOWF turbines will be charted for aviation purposes. The Defence Geographic Centre and CAA will be kept fully apprised of the TKOWF s so that charts may be updated to inform the aviation community as of the TKOWF turbines as aviation obstacles. Likely environmental effects 13.38 With the application of mitigation measures identified within the Greater Wash Strategic Search Area regional solution, it is predicted that there will be negligible impacts to helicopter operators using HMR 6 during construction, operation and/or of the TKOWF (Cox et al, 2010). 13.39 With the application of the proposed mitigation measures, it is predicted that there will be a negligible impact on safety of access to Amethyst B1D gas platform during the operation of the wind farm. A minor impact on the commercial operation of the B1D platform is predicted (see Chapter 12) due to the potential restriction of access for planned and unplanned maintenance. This issue is the subject of ongoing discussions with the platform operators and helicopter service providers. 13.40 A negligible impact on the other platforms in the vicinity of TKOWF is predicted. Effect on aircraft detection impact on civil aviation and defence radars 13.41 The NATS En Route (NERL) primary surveillance radars at Cromer and Claxby will be affected by the TKOWF. Turbines at TKOWF would be in line of sight of these radars. 13.42 The turbines are likely to interfere with radars through disruption to air traffic management as described in paragraph 13.21. When a number of turbines are present in a wind farm, the combination of blades from different turbines can give the appearance of a moving object on the radar screen, which may cause air traffic controllers to perceive this as an unidentified aircraft and to take action to ensure that other aircraft avoid it (DTI 2002). A large area of clutter is a distraction for Air Traffic Controllers, potentially having significant safety implications (NATS consultation, April 2010). In addition, the turbines may give rise to a reduction in the probability of detection of small aircraft overhead the wind farm, and in the shadow areas behind the wind farm. 13.43 Other wind farms in the Greater Wash area will be in the line of sight of the primary radars. A regional solution has therefore been identified by NERL as having a greater potential for collective success. 13.44 RAF air defence radars at Staxton Wold and Trimingham will also have line of sight to the TKOWF turbines. The effects on the radar will be the same as for the NERL radar, but with potential impact on national security. Again, a regional solution has been deemed to be the most efficient way to address the issues from all of the Greater Wash round 2 OWF. Mitigation measures 13.45 The effects on the NERL radars will be mitigated through a regional solution covering the Greater Wash Strategic Search Area, developed by NATS (Cox et al. 2010). This will comprise: i) blanking of the affected primary radars coverage over wind farms; ii) creation of three Transponder Mandatory Zones (TMZs) in the Humber (one zone) and the Wash (two zones); and iii) provision of air traffic services in the affected areas using Secondary Surveillance Radar (SSR) only within TMZs. 13.46 A regional solution has also been agreed to address the impact on air defence radar. With the assistance of The Crown Estate, the Greater Wash wind farm developers have agreed to purchase a new radar (the Lockheed Martin TPS77 ) for the MoD, which would incorporate a new technology that allows it to function without being affected by the wind farms. Likely environmental effects 13.47 With the application of mitigation measures identified within the Greater Wash Strategic Search Area regional solutions, it is predicted that there will be negligible impacts on civil and/or military radar activities during the construction, operation and/or of the TKOWF. RPS 224 RWE
Cumulative effects 13.48 Following discussions between NERL and all OWF developers it has been agreed that a regional solution for the Greater Wash Strategic Search Area will satisfactorily address cumulative impacts on aviation radar and helicopter routes from all OWF developments in this region. The condition to be included in the TKOWF Development Consent Order has been agreed and the Airspace Change Process (ACP) contract has been signed on 1 December 2010 with NERL, outcome of which should be available in September 2011. 13.49 Cumulative impact has also been addressed through regional solution for impact on defence radar. Agreements are in place between the Greater Wash OWF developers, the MoD and The Crown Estate. A condition to be included in the TKOWF Development Consent Order has been agreed with the MoD. NERL (2011) NERL Policy Statement Issue 3.1: Mitigating the effects of wind turbines on NATS En- Route Ltd (NERL) operations. Available at: http://www.nats.co.uk/wp-content/uploads/2011/01/ Mitigating-the-effects-of-wind-turbinesV3.1.pdf (Accessed 12.05.11) Conclusions 13.50 There will be no significant impacts on civil or military aviation following the application of the agreed mitigation, as follows: i) Civil aviation radars the effects on the civil aviation radars will be mitigated through a regional solution covering the Greater Wash Strategic Search Area developed by NERL; ii) Summary Defence radars the effects on the RAF radars will be mitigated through a regional solution by way of new technology turbine-proof radar; iii) Oil and gas helicopter operations the effects on helicopter main routes HMRs will be mitigated as part of the regional re-design of the HMR structure in the Southern North Sea; iv) Gas platform access The frequency of impacts on access to the gas platform Amethyst B1D can be reduced through mitigations which will be agreed with the helicopter and platform operators. 13.51 No significant impacts are predicted to aviation operations from the proposed TKOWF following the regional mitigation solutions and potential changes in procedures for helicopter access to platforms. References Cox, C., West, T., Cutts, R. and Kirkland, K. (2010). Engineering and Programmes Greater Wash Regional Solution Feasibility and Options Study Final Report October 2010. Issue 1, Final V41. NATS En Route plc. DTI (2002). Wind Energy and Aviation Interests Interim Guidelines. Report by the Wind Energy, Defence and Civil Aviation Interests Working Group. RPS 225 RWE