UK looks to decommission ground-based navigation aids

Let’s first start with the background as this currently is a topic only for the UK, although other countries could potentially follow suit in the future. Earlier this year, the UK Civil Aviation Authority released CAP 1616. The purpose of this document addressed airspace change: Guidance on the regulatory process for changing the notified airspace design, planned and permanent redistribution of air traffic, and on how to provide airspace information.

In the middle of the summer, CAP 1781 followed with more information related to ground-based navigation aids. Airspace modernisation in UK is following the ICAO concept of Performance-based Navigation (PBN) with Reliance on Area Navigation (RNAV). The shift to RNAV results in the reliance on satellite-based navigation positioning and a reduced dependency on conventional ground-based navigation aids such as Doppler Very High Frequency Omni Range (DVOR), Distance Measuring Equipment (DME) and non-directional beacon (NDB).

This ultimately impacts the number of such facilities that NATS will retain in its future navigation infrastructure. The CAA has approved the decommissioning of 27 en-route DVORs and the removal of all en-route NDBs. DME facilities will be optimised for geometry and coverage. The dependency of aerodrome procedures on en-route ground-based navigation aid facilities has evolved over time and the decommissioning of these facilities has implications on the support of terminal procedures.

These changes are intended to result in decreased maintenance requirements, whereby reducing the number of required workers to support these facilities, and increased flexibility. Although airports are the change sponsors for these topics, ANSPs need to be heavily involved in this planning. The shift to the use of GPS also allows for additional security concerns that need to be addressed. Additionally, the move to satellite navigation aids could result in interference in areas where wind farms are located. This topic is still under discussion.

Air Navigation Solutions (ANSL), the ANSP for Gatwick and Edinburgh airports is carrying out impact assessments and working to provide expert guidance during the transition of these changes. Additionally, they are planning to provide services in the future to help airports who have limited resources internally but need to identify, develop and implement alternative solutions.

It seems this whole transition is in the ‘stay tuned’ category to see how these changes are ultimately implemented toward the stated deadline of the end of 2022. But there are certainly many topics that need to be further tested, refined and discussed before implementation.