1. Steps in an operational safety analysis

A system dependability analysis can be broken down into the following main stages:

• structural and functional analysis of the system ;

• qualitative predictive analysis of the system ;

• quantitative predictive analysis of the system ;

• a summary of previous analyses and a conclusion.

The details and sequence of these steps are shown in the flow chart in figure 1 . It should be noted that these stages are not totally disjointed, and have aspects in common.