The bowtie model for assessing risk (UK Civil Aviation Authority)

Summary

Bowtie is a visual tool which effectively depicts risk, providing an opportunity to identify and assess the key safety barriers either in place or the ones lacking, between a safety event and an unsafe outcome. This guidance from the UK Civil Aviation Authority outlines how the bowtie model works and how to use it.

Content

The bowtie model consists of different elements that build up the safety risk picture. The safety risk picture revolves around the hazard (something in, around or part of an organisation or activity which has the potential to cause damage or harm) and the top event (the release or loss of control over a hazard known as the undesired system state).

Consideration is then turned to the threats (a possible direct cause for the top event), consequences (results of the top event directly ending in loss or damage) and the controls (any measure taken which acts against some undesirable force or intention).