Wind turbines can cause interference to the radar signals that air traffic controllers use to direct aircraft. Turbine blades can appear as clutter on radar screens and be mistaken for aircraft.
It was announced from Aarhus, Denmark, on 7 October that Terma’s SCANTER 4002 radar system forms part of a turnkey surveillance solution to mitigate the impact of the 19 turbine 50MW onshore Frodsham Wind Farm Ltd., owned by Peel Energy and Belltown Power, on the radar systems at both Chester Hawarden and Liverpool John Lennon airports. The equipment will be delivered into service in February 2016, it is understood. The airports are facing the Irish Sea on Britain’s mid-west coast.
This pdf introduces earlier wind turbine radar trials.