1.14. Aviation, Military and Communications

  1. Aviation, military and communications refers to the stakeholders/receptors that operate in the airspace, interacting with each other, the air traffic management provided and the relationship/effects of the physical environment. The aviation, military and communications receptors around the Array were characterised via a desktop review utilising UK and international aviation, military and communications guidance material and from establishment of the aviation, military and communications study area of regional aviation, military and communications constructs.
  2. The Array will be located within a layered area of lower, Class G uncontrolled airspace and higher, Class C Controlled Airspace (CAS). Above and surrounding the Array, the Class G airspace is used by both military and civil registered aircraft. The desktop review indicated that several discrete operators utilise the airspace surrounding the Array. Key receptors noted from the desktop review were NATS Perwinnes Primary Surveillance Radar (PSR), Aberdeen International Airport, and regional low-level airspace flight operators (Ministry of Defence (MOD), Search and Rescue (SAR) helicopters and operators supporting the offshore oil and gas industry).
  3. The information on aviation, military and communications within the aviation, military and communications study area was collected through detailed review of existing guidance and datasets to define a regional aviation, military and communications baseline encompassing the airspace structure above the aviation, military and communications study area including the following:
  • military Practice and Exercise Areas (PEXAs);
  • aerodromes, including flight procedures;
  • Communication, Navigation and Surveillance (CNS) infrastructure;
  • Helicopter Main Route Indicators (HMRI) supporting offshore oil and gas; and
  • low flying operations including MOD and helicopter SAR activities.
  1. The potential impacts on aviation, military and communications, associated with the construction, operation and maintenance, and decommissioning phases include:
  • the creation of physical obstacle to aircraft operations (including airborne search and rescue operations and low flying aircraft) during all phases; and
  • wind turbines causing interference on aviation radar systems (including Primary Surveillance Radar and Air Defence Radar) during the operation and maintenance phase.
  1. With the proposed mitigation measures in place, the impact ‘creation of physical obstacles to aircraft operations' result in effects of minor adverse significance, which is not significant in EIA terms.
  2. However, the assessment identified the potential effect of major adverse significance (significant in EIA terms) as a result of wind turbines causing interference on aviation radar systems. Operational floating wind turbines within the Array would be theoretically detectable by the NATS Perwinnes PSR, MOD Buchan and Brizlee Wood Air Defence Radar (ADR) systems. Wind turbines detectable by a PSR system might degrade the system by creating false targets, reduce system sensitivity, create radar shadowing behind the wind turbines and saturate the radar receiver leading to clutter potentially concealing real aircraft targets. Following application of secondary mitigation, the significance of the effect is considered to be minor adverse and (not significant in EIA terms).
  3. Cumulative impacts arising from the Array together with other projects and plans were assessed and predicted to result in effects of minor adverse significance (not significant in EIA terms) for the impact ‘creation of physical obstacles to aircraft operations’. The cumulative assessment identified the potential effect of major adverse cumulative significance (significant in EIA terms) as a result of wind turbines causing interference on aviation radar systems, however, following application of secondary mitigation, the significance of the effect will be reduced to be minor adverse (not significant in EIA terms).
  4. No transboundary impacts have been identified in regard to effects of the Array on the interests of EEA states.