Scenario-Based Failure Modes and Effects Analysis Using Expected Cost

Failure modes and effects analysis (FMEA) uses the product of three ranked factors to compute the risk priority number (RPN). Unfortunately, the RPN components have ambiguous definitions, and multiplying ranked values is not a valid operation. As a result, the RPN produces inconsistent risk priorities. In addition, FMEA uses distinct analyses for each system level and life cycle phase, making it difficult to consolidate interrelated risk information. The goal of scenario-based FMEA is to delineate and evaluate risk events more accurately. Probability and cost provide a consistent basis for risk analysis and decision making, and failure scenarios provide continuity across system levels and life cycle phases.