2. Common principle of N&H RCM-compliant methods

2.1 Standard steps in N&H RCM analysis

Numerous methods and standards developed since 1978 claim compliance with the N&H method, and implement the main steps shown in figure 4 . They are all characterized by a functional approach associated with the tools of operational safety, with the aim of determining the functional failures of critical equipment. Then, using a decision diagram, the nature of the maintenance tasks and their intervals are specified according to their technical and economic effectiveness.