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UK Civil Aviation Regulations

These are published by the CAA on our UK Regulations pages. EU Regulations and EASA Access Guides published by EASA no longer apply in the UK. Our website and publications are being reviewed to update all references. Any references to EU law and EASA Access guides should be disregarded and where applicable the equivalent UK versions referred to instead.


The Earth is constantly subjected to electromagnetic and high energy particle radiation from both galactic sources and the Sun. Most of the variability is of solar origin and is collectively known as space weather. Like terrestrial weather, minor events are more common than major events. Generally, the day-to-day variation in space weather has a negligible impact on technology and humans but on average several times in each solar cycle of 11 years space weather can have an operational impact.

During the most extreme events, associated with rare solar superstorms (and not necessarily related to the solar cycle), there are a number of issues that the aviation industry should consider because the impact will be global and significant. Although extremely rare (1 in 100-200 years) the potential disruption caused by extreme space weather cannot be ignored and it was for this reason that these have been placed on the UK National Risk Register requiring that mitigation be considered. Without appropriate preparedness an extreme space weather event could create large scale disruption of the aviation industry from which it would take weeks to fully recover.

Operators are encouraged to make use of tools and techniques for assessing space weather risks, noting that aviation is a complex system of technical and human centred systems (including Airlines, Airports and ANSPs) and for that reason all hazards including those affecting environment, people, procedures and equipment should all be reviewed for potential space weather impacts.

Guidance and support


We have worked with industry to create two space weather bowties which may assist operators when assessing space weather hazards. The two space weather bowties can be found in the Bowtie document library (1.4 Loss of Control Large Commercial Air Transport and 5.4 Airborne Conflict Large Commercial Air Transport).


Impacts of space weather on aviation (CAP1428)