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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.

With bowtie being a tool for risk assessment, the information contained within the model can be used and helpful when using a risk matrix to allocate a risk score as well as building an SMS hazard log.

Bowtie is most commonly used within the ARMS methodology (Aviation Risk Management Solutions) regarding the ERC (Event Risk Classification) barrier effectiveness assessment and also with regards to SIRA (Safety Issue Risk Assessment).

There is also a place for bowtie in the common ICAO 5x5 risk matrix as bowtie provides a structure approach to the severity of the event.

As previously mentioned the terminology within bowtie and SMS differ slightly therefore the below image may assist with demonstrating how the elements of a bowtie can be transferred into a standard hazard log within SMS.

Download this diagram as a PDF

Using a bowtie within a risk assessment