FMEA and FTA establish the relationship between failure cause and its effect. The probabilistic relation between cause and effect is determined through Critical Analysis (CA). Bayesian Network (BN) is a graphical model representing the joint probability distribution P(X) on a set of random variables X = {X_{1}, …., X_{n}} defining probabilities P ∈ [0,1] for each possible state (x_{1}, , x_{n}) ∈ X_{1,dom}, …,X_{n,dom} where X_{i,dom} is the domain of definition of each variable.