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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 bowtie templates were developed in consultation with Subject Matter Experts (SMEs) from relevant sectors of the aviation industry in collaboration between the CAA and commercial operators.

Extensive use was made of the workshop format with working groups of approximately six to eight participants guided by experienced bowtie facilitators.

This process was used in order to capture accurate information relevant to the wide range of industry sectors involved.

  • An initial framework of hazard / top event combinations was developed outside of the workshop environment based on the Significant Seven.
  • In order to make efficient use of the workshops, the bowties were pre-populated with threats and consequences that provided a starting point for the workshop discussions.

Core bowties

In total, three bowties for each of the Significant Seven were identified with a ‘core’ bowtie selected and developed for each topic in order to address the highest risk scenarios.

These core bowties were fully developed over the course of two to three facilitated workshop sessions. They include all of the basic bowtie components plus additional classifications and ratings for the various diagram elements in order to maximise their potential. For example, the expert judgement of the SMEs was an important component for decisions related to the control effectiveness ratings.

The core bowties are complemented by additional supplementary bowties in order to address other important aspects within the Significant Seven. These supplementary bowties were developed through to the stage of identifying the basic controls to provide a starting point for further refinement.