Introduction of onward routed radar data

Background and requirement 

A developer was planning to construct / operate a new large offshore wind farm, along with an extension to an existing offshore site. It was assessed that both wind farms would have a negative effect on the performance of the Primary Surveillance Radar (PSR) located at a UK Airport. The Air Navigation Service Provider (ANSP) providing the Surveillance Air Traffic Service (ATS) required a technical solution to mitigate the effects of the wind farms on the PSR.  

Approach 

During the period between decommissioning of the extant surveillance system and the commissioning of the new Technical Solution (the Interim Period), it was proposed that surveillance coverage be provided by Onward Routed Radar Data (ORRD) from the NATS owned PSR’s and Secondary Surveillance Radars (SSR) located at two sites. 

In order to implement the Technical Solution, the ANSP contracted their display system supplier to update the existing Radar Data Processor (RDP) and Displays at the Airport.  

Sagentia Aviation developed a safety argument and the supporting Safety Case documentation in support of the use of St Annes ORRD and the updated RDP and Displays (referred to as the “Interim Surveillance Capability (ISC)). The top-level safety claim (Claim 0) was that the ISC when introduced into service will be acceptably safe and will continue to be so.  

Outcome 

A four-part Safety Case was developed in support of the top-level safety claim. This was accepted by the ANSP and the CAA to allow the ISC to be used to provide an ATS at the Airport.