Safety case for Aveillant 3D radar


Supporting the development of sustainable energy, a growing number of wind farms are being built on UK mainland and at sea. The potentially negative effects of wind turbines on radar and ATS coverage, generally referred to as clutter, is widely recognised within the UK Air Traffic community, and the UK Civil Aviation Authority (CAA) has documented these effects within CAP764: CAA Policy and Guidelines on Wind Turbines.

Severn Trent Water built two large wind turbines at Spondon, approximately 6NM from East Midlands Airport (EMA), which impacted the airport’s Primary Surveillance Radar (PSR) and would prevent EMA from providing Terminal Services in the affected area when the turbine blades are rotating. Full operation of the wind turbines was therefore compromised until a solution to their negative effects on airport operations was demonstrated and accepted. The solution proposed by EMA and Severn Trent Water was to install the Aveillant 3D Holographic Radar™ (HR) and integrate it into EMA’s radar surveillance systems.


This was the first commercial version of the Aveillant system to be installed. Following successful demonstration of both the functional performance, integrity of the system and the completeness of the safety documentation, the system was moved into full operational use. EMA, with the support of Aveillant and Ebeni, had to produce a full Safety Case for the system in this environment (i.e. supporting separation provision in a Terminal Manoeuvring Area (TMA) with the presence of a windfarm) in order to meet all of the stringent UK ATM licensing requirements. Due to the novelty of the technology, and as this was the first operational use of the system, it was always likely to come under additional scrutiny from the UK regulator (the CAA SARG).


In order to mitigate the risks associated with certification for this novel technology, Ebeni proposed the use of tried and tested approaches:

  • 4-part safety case structure familiar to ANSPs and the UK CAA SARG, including:
    a) Development of a project Safety Management and Assurance Plan to gain early buy-in and promote discussion with the ANSP and CAA SARG;
    b) Submission of the initial Part 1 Safety Case to CAA SARG as early as possible (based on a document previously developed by Ebeni for another project, which was praised by the SARG for its high quality);
    c) Subsequent versions of the Safety Case (parts 2 to 4) cover system design and safety requirements satisfaction, integration and transition to service and continued operations;
    d) Integration and Transition are fully documented, and a related assessment included in a Transition Plan.
  • Application of widely used and accepted standards and guidance. Safety processes compliant with UK CAA SARG guidance (such as that set out in CAP760) and EUROCONTROL SAM where appropriate. Knowledge of applicable guidance such as that provided in CAP764 / CAP670 is factored into the documentation.

Building on Ebeni’s previous experience in developing safety cases for first of type surveillance systems and novel technologies in the UK, we were able to minimise the risks to the project and streamline the approval process as far as possible. Certification of the Aveillant 3D Holographic Radar™ (HR) by the UK CAA SARG was duly achieved, to the satisfaction of East Midlands Airport (and Severn Trent Water).