Why Prognostics and Health Management and Reliability, Availability, Maintainability and Safety Have Not Married Yet

RAMS (Reliability, Availability, Maintainability, Safety) and PHM (Prognostics and Health Management) are two engineering disciplines with different histories but broadly similar goals: managing risks resulting from failures, and mitigating them by acting on maintenance and operation.Therefore the question naturally arises whether those two disciplines should be merged.This paper addresses that question by reviewing, for each of those two disciplines, its concept,its applications, its methods, and finally its benefits and limitations.Then we analyze their similarities and differences.