SMS / What is Bowtie Analysis

What Is Bowtie Analysis in Aviation SMS

Bowtie analysis in aviation SMS is one of the most thorough risk management tools currently available to aviation safety managers. It ties together distinct risk philosophies and tools into a single purpose.

Just a few critical risk management items that the bowtie incorporates are:

Bowtie analysis uses all of these elements in one way or another, and it does so in a single, concise visual chart. The bowtie relies on 4 elements to do this which are:

  1. Root causes that lead to the
  2. Top Event (i.e., the main issue that arises) that leads to
  3. Impacts on an organization; and
  4. The relevant risk controls to the threat/event/impact.

The bowtie will appear different from organization to organization as companies will create bowties that functionally and visually suite their needs best. Some organizations will use a simplified version of the bowtie, and others will use much more complex, verbose bowties. They may even appear different each time you use them depending on what your goals are.

What is the bowtie in aviation SMS and how to use it

Purpose of the Bowtie in Risk Management

The purpose of the bowtie is to show the flow of a safety event including:

  • Root Causes (threats) that aligned to create a problem;
  • The events that funneled “upstream” to the;
  • The Top Event (i.e. the critical safety point of the event);
  • The cascading events of the Top Event that lead “downstream” to
  • Impacts that adversely affect your organization; and
  • The failure/success of each risk control measure in the sequence of events.

Bowtie gives a visual picture of the entire issue, from root causes to impacts, including the risk control holes along the way.

The purpose of bowtie analysis is to establish the important elements of your program, namely key performance indicators and weak controls. Without the bowtie, piecing all of these elements together in a way that shows how they function in context can be difficult and error prone.

Why the Bowtie Is the Best Risk Management Visualization Tool in Existence

The bowtie is regularly successfully employed for:

  • Teaching employees what risk management is and the role of hazards in an SMS program;
  • Methodical analysis in safety incident management;
  • Documenting preventative analysis in hypothetical scenarios;
  • Understanding and assessing your risk controls in context; and
  • Identify KPIs.

The list goes on, but you get the idea. It is versatile and suited for many different uses. Companies that adopt the bowtie tend to – if they use it right – employ the bowtie with different goals for different uses.

To this end – though I have not seen it done in practice yet – I strongly advise that when you perform a bowtie analysis you should write a “purpose” or “goal” at the top of the bowtie. I recommend this for three reasons:

  1. Clarifies what you are currently looking for, and therefore what the pertinent information is;
  2. Great reference point for immediately orienting you when you are looking back at previous bowties; and
  3. Allows you to create “categories” for organizing bowties.

You could establish ahead of time, for example, 3 or 4 different goals you might have when using bowties. For example, “Hypothetical safety case analysis,” “Safety incident analysis,” “Financial Impact Analysis,” and so on.

Downside to Using Bowtie

As great as the bowtie is, there are several distinct downsides which deter organizations from employing it in their risk management programs. Namely, these downsides are:

  1. Time consuming to complete;
  2. Easy to make mistakes;
  3. Not practical for all issues; and
  4. Steeper learning curve than other risk management tools.

Bowtie analysis should be used after:

  1. Clarifying definitions of hazards, risks, mechanisms, consequences, etc.;
  2. On higher risk issues requiring deeper investigation; and
  3. After practice and review of this analysis technique (such as through risk management training).