SMS Tools


Fault Tree Analysis (FTA)

FTA is graphical tool for analysing complex systems and determining potential failure modes and problems. It uses the logic gates concept (AND, OR, NAND, NOR etc) and it works backwards, starting from the even and determining the causes. It is therefore an event oriented – reactive tool, but it can also be used proactively in a generic way (i.e. through brainstorming picking an event and working it).

The FTA has some strong advantages:

  • It combines the human error and hardware failures in the same analysis
  • It can be used proactively to identify failure before occurring
  • It is a deductive method, allowing for understanding of the combinations of the low-order events
  • Graphical representation makes it easy to understand and comprehend
  • Can be used both qualitative and quantitative

There is no universal method for producing a FTA. The big disadvantage of the method is that it assumes that all events are mutually independent which is problematic when analysis parallel based complex systems.