← All chapters Chapter 16

Qualitative Fault Tree Analysis and Minimal Cut Sets

The cut sets are already in the tree; reading them is mechanical.

A minimal cut set is a combination of faults that together cause the malfunction, and its order tells single points from double faults at a glance. Because the tree was derived along the signal path, each cut set is a real fault-propagation combination that can be trusted. The chapter triages long lists with importance measures and argues the qualitative road matters most: it forces the questions safety turns on.