Failure Mode and Effects AnalysisFMEA

A Failure Mode and Effects Analysis is a structured method that lists the ways a design or a process can fail, the effect of each failure, and the controls that detect or prevent it. Each failure mode carries a Risk Priority Number — the product of Severity, Occurrence, and Detectability, scored on a 1-to-10 scale — and the high-RPN modes take corrective-action priority. The split is DFMEA for product design and PFMEA for the manufacturing process, and the analysis is updated whenever the design or the process changes, because a failure mode that was acceptable at one severity can become unacceptable after a change raises the occurrence.

FMEA is required by IATF 16949 for automotive suppliers, common in aerospace under AS9100, and used in medical device contexts under ISO 13485, and it is the analytical backbone of a risk-based quality system — the failure modes feed the risk register, the corrective actions feed the CAPA, and the residual risk feeds the management review. The weakness is the RPN as a steering number: a high severity with a low occurrence can score the same as a low severity with a high occurrence, and the two are not the same risk. The discipline that makes FMEA work is the closure — an action assigned to every high-RPN mode and verified, not a worksheet filed for the audit. See root-cause analysis, NCR, and bowtie.