What is a fault tree analysis?

A fault tree analysis is a top-down map used to identify the causes of an identified hazard or an undesirable event. This could be anything from your car being stolen to a jet crash. This method was originally used in aerospace but it's become a tool that can be used to analyze hazards in any workplace.

The way the analysis works is by drawing out a kind of map. At the very top should be the undesired event itself, something like "Jet loses power."

Under that event, you would list all possible components and systems that could have caused that event to happen. Each of them is marked by an icon that either indicates "And" or "Or." An "Or" cause is a single item that could, by itself, cause the event. An "And" indicates that the cause would only be one of the factors that contributed to the undesirable event.

So, if we take our example of the jet losing power, the "Or" items could include:

• Bird ingestion by the engine
• Internal engine failures
• Pneumatic bleed malfunctions
• Internal clearance changes

Once you've identified all of the potential causes that could lead to the negative event, you can proceed to set up control measures for them. That's what makes the fault tree analysis such a helpful tool: you don't have to wait to identify the hazard that led to the incident you want to prevent. Instead, it lets you take proactive steps to deal with any of the hazards that could lead to it.