Extreme space weather events could force aircraft to reroute or even ground flights, according to new research led by the University of Surrey. The research, published in the Journal of Space Weather and Space Climate, details the scale of radiation risks to passengers, crew and onboard systems.

Researchers at the Surrey Space Centre (SCC) found that these events can significantly increase radiation exposure at typical flight altitudes of 8-14 km and trigger faults in aircraft electronics – posing a challenge for flight safety.

Although the atmosphere provides some protection, radiation exposure on many commercial flights remains significantly higher than at ground level and can surge during solar storms. A major solar storm in November 2025 caused radiation levels to briefly rise to nearly ten times normal flight conditions at high altitudes, according to measurements led by SSC, while historical data shows the strongest solar storm on record in 1956 could have exposed passengers to the equivalent of a year’s worth of flight-related cosmic radiation.

The study also highlights the increasing vulnerability of aircraft systems. High-energy particles from space can interfere with onboard electronics, causing what is called Single Event Upsets (SEUs) – small errors that can accumulate and disrupt critical systems. Only last year, Airbus temporarily grounded 6,000 A320 aircraft after discovering a vulnerability to ‘intense solar radiation’ in a flight control computer. This was exposed by an incident in October 2025, in which a JetBlue flight from Cancún to Newark had to make an emergency landing in Florida.

In many cases, these disruptions may present a greater operational challenge than radiation exposure to passengers and crew by increasing pilot workload and the risk of in-flight issues. In extreme scenarios, SEUs could rise from a few per hour to thousands.

The biggest risks are on polar flight routes between airports such as London Heathrow and Vancouver International in Canada, where the Earth’s magnetic shielding is weakest. However, during severe geomagnetic storms, these effects can extend much further south, including over the UK.

Dr Fan Lei, Senior Research Fellow at the Surrey Space Centre, University of Surrey, and lead author of the study, said:

“The recent Airbus A320 grounding linked to cosmic radiation shows that space weather is not a theoretical risk; it is already affecting aviation. As aircraft systems become more advanced and increasingly reliant on electronics, understanding and preparing for these events will be critical to maintaining flight safety.”

The findings highlight a gap in current aviation safety frameworks, which mostly focus on routine radiation exposure without fully accounting for extreme space weather events. The study calls for clearer guidance and better integration of space weather data into flight planning to make sure air travel is safe and reliable.

To help the aviation sector respond more effectively, the research team has proposed a new atmospheric radiation scale. Designed specifically for aviation, it provides clearer thresholds for when action should be taken – from increased monitoring to rerouting or grounding flights during severe events.

Professor Keith Ryden, leader of the Space Environment and Protection research team at the Surrey Space Centre and co-author of the study, said:

“At the moment, there is no consistent way for the aviation sector to assess and respond to extreme space weather risks. We’ve introduced a clearer, aviation-specific radiation scale to help support more informed decision-making in aviation, helping operators act quickly to protect passengers, crew and critical onboard systems.”

Professor Clive Dyer, Visiting Professor at the Surrey Space Centre and co-author of the study, added:

“An atmospheric radiation scale has been needed for a long time, as current alerts based on low-energy proton events give at least ten false alerts for every true alert. The new scale is based on high-energy proton measurements in space and ground-level neutron monitors, as installed at Surrey, Lerwick and Camborne, and scales human dose and avionics upset rates from the study on the February 1956 event. In combination with our radiation modelling (MAIRE) and monitors (SAIRA) on aircraft, this should provide the basis for a proportionate response.”

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