Solar storms could ground flights and disrupt aircraft electronics

Extreme bursts of high-energy solar particles could drive radiation at cruising altitude sharply higher and upset the electronics aircraft rely on, according to University of Surrey research published in the Journal of Space Weather and Space Climate on 11 August 2026.

The study asks whether solar storms could ground flights and concludes that airlines need clear trigger points for rerouting, descending or holding aircraft on the ground.

For UK business travellers the risk is concentrated on long-haul polar routes, where the Earth’s magnetic field gives the least protection. The researchers stress that a typical solar flare is not about to close airports and that grounding would be a drastic step reserved for a very rare event.

Radiation at cruising altitude

Airliners fly at roughly 8 to 14 km, where crews and passengers already pick up more cosmic radiation than on the ground, and the shielding from the atmosphere and magnetic field thins with height and towards the poles. During November 2025’s major solar storm, high-altitude readings hit nearly ten times the usual level. Analysis of the far stronger February 1956 event suggests a comparable storm could deliver in one flight about as much cosmic radiation as a passenger normally accumulates from a year of flying.

Why aircraft electronics are the bigger worry

Operationally, the researchers think aircraft systems may prove the harder problem. Incoming particles can cause Single Event Upsets, or bit flips, which corrupt data or knock a computer off its task, and ICAO’s space weather manual acknowledges semiconductor-based avionics can misbehave in a solar radiation event.

Redundancy and fault-tolerant design soak up isolated faults, but the study estimates an extreme event could lift upset rates from a handful an hour to thousands, far beyond what those defences were built for. Airbus temporarily grounded 6,000 A320s last year over a flight control computer vulnerable to intense solar radiation.

“The recent Airbus A320 grounding linked to cosmic radiation shows that space weather is not a theoretical risk; it is already affecting aviation,” said lead author Dr Fan Lei, Senior Research Fellow at Surrey Space Centre.

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When would solar storms ground flights?

ICAO rates flights over and near the poles as the most exposed and warns that a geomagnetic storm can spread the affected area to lower latitudes. The Surrey team singles out routes such as London Heathrow to Vancouver International, noting that a severe storm can extend the effects over the UK. Regular Heathrow users will find the basics in our Heathrow airport guide.

Grounding is a last resort, since rerouting or descending cuts exposure as shielding improves at lower altitudes and away from the poles. ICAO’s North Atlantic contingency guidance lists lost communications, degraded GNSS, avionics anomalies and higher radiation among space weather effects that could force crews to descend, reroute, turn back or divert. An event causing all of them at once would put grounding on the table.

The team’s answer is an aviation-specific atmospheric radiation scale matching severity to response: closer monitoring, then rerouting, then grounding for the gravest events. ICAO has operated a worldwide space weather advisory service since November 2019, issuing round-the-clock bulletins on HF radio, satellite navigation and radiation, but the researchers argue the sector has no way of converting those readings into operational decisions.

“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,” said co-author Professor Clive Dyer, Visiting Professor at Surrey Space Centre.

Surrey Space Centre head Professor Keith Ryden said there is currently “no consistent way for the aviation sector to assess and respond to extreme space weather risks”, and the scale should help “operators act quickly to protect passengers, crew and critical onboard systems”

The Civil Aviation Authority lists weather incompatible with safe operation among the extraordinary circumstances that rule out compensation, and a solar storm grounding would very likely qualify. Airlines would still owe rerouting or a refund, plus care during the wait, so it pays to know your rights when a flight is delayed or cancelled. The Sun is a remote threat, but one the researchers want the industry ready for before the next big storm.