A third of all diversions at remote Scottish airports, and more than half at some locations, could be prevented by the UK rejoining a European Union satellite-based augmentation system, EGNOS. ch-aviation understands the British government is now looking into the financial viability of rejoining the scheme, which remains technically available in the UK.

The UK left EGNOS on June 25, 2021, at the end of a transition period on leaving the EU. This led to the loss of legal indemnity for the use of the system in the UK, and the resultant disruptions.

An internal impact report prepared by Loganair (LM, Glasgow International), seen by ch-aviation, shows that diversions at six airports that would have been avoidable if EGNOS had remained operational in the country cost the airline around GBP153,000 pounds (USD208,000) between October 2024 and November 2025. On average, 37% of diversions at these airports would have been prevented by EGNOS, but at Campbeltown and Barra, the ratio reached 75% and 64%, respectively. A lower share of avoidable diversions were recorded at Tiree, Islay, Benbecula, and Stornoway.

"The signal is still there. Our aircraft are still equipped to use it. We just don't have an approved procedure. EGNOS improves resilience. It's a lower-cost solution than installing and maintaining costly ground equipment, which in some airports is not even possible. It also has potential for the future, for upgrading landing systems in other regional airports across the UK," Simon McNamara, head of government and corporate affairs at Loganair, told ch-aviation.

Jonathan Hinkles, chief executive officer at Skybus (United Kingdom), echoed this sentiment.

"The decision for the UK to leave EGNOS was a poor decision taken on the basis of absence of information. We've done a number of things with the EU, including the sanitary and phytosanitary agreement, and also recently rejoining the Erasmus+ youth freedom of movement scheme. EGNOS is a lot less expensive than any of those. It's a relatively small sticker price, and rejoining EGNOS is essential to the future of regional air links," he said.

Skybus recorded a near 50% increase in the scale of weather-related cancellations following the loss of EGNOS. It lost 35.5 flying days in each of the 2020-21 and 2021-22 financial years due to poor weather. For the last two years, this number has increased to 52.5 days.

The lack of EGNOS also affects air ambulance and charter flights to locations that lack easy alternative means of transport.

"It’s vital that rural communities are not cut off, so we will continue to review options for future UK access to systems such as EGNOS," a spokesperson for the UK Department for Transport told ch-aviation.

The decision to rejoin is largely a political one because the appropriate infrastructure already exists, and membership is open to non-EU countries, subject to an agreement with the European Commission.

Alternative to costly investment

European Geostationary Navigation Overlay Service (EGNOS) is a European satellite-based augmentation system that improves the accuracy of satellite navigation, such as GPS or Galileo, to enable use for safety-critical applications, including precision approaches. It relies on satellite signals and ground infrastructure, such as monitoring stations. However, that infrastructure does not have to be installed at individual airports where EGNOS is used for approach procedures. This differentiates it from other systems, like the Instrument Landing System (ILS), which have to be installed individually at every airport.

The system impacts the reliability of services to remote airports as it allows for significantly lower visibility minima during precision approaches. This is particularly important at small airports often affected by fog or low cloud cover.

McNamara said: "These are flights to places that have challenging weather at certain times of the year, but they're also lifeline routes, so resilience on those routes is essential for the communities that rely on them."

For example, the lowest decision heights for Campbeltown are now 470 and 600 feet above ground, depending on the runway; the obstacle clearance altitudes for the same runways with an EGNOS approach were 357 and 310 feet, respectively.

In a letter to the DfT in December 2025, seen by ch-aviation, Skybus' Hinkles wrote that EGNOS' "removal in June 2021 means that we have no form of 'sat nav' for aviation and are compelled to revert to the same navigation by visual reference that we had in the 1950s. For pilots, it’s akin to turning off iPhone navigation for car drivers and compelling them to navigate with an old-style A-to-Z published road atlas on their lap."

Alternative precision navigation systems, such as the ILS, would require costly investment at each airport and subsequent maintenance. At some airports, notably Barra, which has beach runways, this would not even be technically viable.

McNamara stresses that EGNOS should not be seen as airspace modernisation or a new project.

"It's simply re-enabling something we had. We shouldn't try to convince ourselves that this is some new thing that we're gaining access to. We had access to it, we lost it, and we went backwards. And there's a logic in re-engaging with the EU on it," he opined.

Membership open

While the system is run by the EU, non-members can sign an agreement to join EGNOS. Iceland, Norway, and Switzerland have all done so. Channel Islands airports Jersey and Guernsey also retain access. The Channel Islands are crown dependencies and not part of the UK, and were not part of the EU before Brexit. European Commission spokesperson Thomas Regnier confirmed to ch-aviation that Ukraine also started negotiations to join EGNOS in 2020, although they were put on hold in 2022 following Russia's full-scale invasion of the country and closure of its airspace.

Technically, reinstating EGNOS access in the UK is relatively easy.

"The EGNOS signal covers the UK territory today, and there is no technical modification required to provide the safety-of-life service. However, since Brexit happened, the operational interfaces, meaning the EGNOS Working Agreement (EWA) between the EGNOS service provider and the UK operators using it, have been stopped," a spokesperson for the EU Agency for the Space Programme (EUSPA), which manages EGNOS, said.

She confirmed two EGNOS stations in the UK are currently used to provide coverage to Ireland.

To rejoin, the UK would have to file a request to the Council of the EU, the institution representing national governments. The council can then mandate the European Commission to negotiate the terms.

"We cannot speculate on the timeline for obtaining this mandate, nor on its content. The United Kingdom has not yet expressed officially its interest in joining Galileo and EGNOS," a commission spokesperson said.

"Using the EGNOS Safety of Life service in aviation isn’t just about having the technology, it also requires a strong regulatory system. Because it supports safety-critical operations, like aircraft landings, countries and the EU must ensure proper certification, oversight, and clear responsibilities," the EUSPA spokesperson underlined.

In a response to a 2022 question in the House of Lords, Lord Callanan, a Conservative life peer, revealed that at the time the costs of participation were pinned at EUR30-35 million euros (USD35-41 million) a year.

The UK regional airlines see rejoining EGNOS as a crucial step to improving the resilience of local services, already embattled after the bankruptcies of flybe., Eastern Airways, and Blue Islands.

McNamara concluded: "Fundamentally, it comes down to a willingness by the UK to negotiate with the EU, and that will need political will and ultimately funding. The cost-benefit [calculation] is clear, and the benefits to regional and local communities are obvious, but perhaps more importantly it will bring an immediate benefit. We think there is an opportunity now to urgently move this forward."