Terrestrial navigation aids (NAVAIDS) such as Instrument Landing System (ILS), Distance Measuring Equipment (DME) or VHF Omnidirectional Range (VOR) continue to play an important role in navigation alongside GPS satellite navigation. To ensure terrestrial NAVAIDS continue to emit safe and high-quality signals which are essential to smooth and safe operations across the EUROCONTROL network and beyond, regular flight inspections by calibration aircraft are required.
However, the pandemic has made regular inspections of NAVAIDs more problematic for many States, with flight inspection providers having to adapt to non-rotating crews, returning to their home base after each inspection, and applying a variety of mitigating health and safety measures. To help, EUROCONTROL supported ICAO right at the start of the pandemic in publishing a Quick Reference Guide on the Periodicity of flight inspection of radio navigation aids which guides States on how to maintain inspection intervals of terrestrial NAVAIDS, or extend them safely.