Failure Modes, Effects, and Criticality Analysis

FMECA

Section 06: System Safety & Functional Safety

Definition

An extension of FMEA that adds a criticality assessment to each failure mode. The criticality analysis ranks failure modes based on a combination of the severity of their end effect and their probability of occurrence. This ranking helps prioritize design mitigation efforts and focus verification activities on the most safety-critical failure modes. FMECA combines the qualitative failure mode and effects analysis with a quantitative or semi-quantitative criticality assessment.

Where This Shows Up

FMECA is particularly useful when many failure modes have been identified through FMEA and engineering resources must be prioritized. The criticality ranking helps focus design improvements, testing, and maintenance actions on the failure modes that pose the greatest risk.

Primary Sources

MIL-STD-1629A — Procedures for Performing a Failure Mode, Effects and Criticality Analysis

The foundational standard for FMECA methodology, defining criticality analysis procedures.

SAE ARP4761A — Safety Assessment Guidelines

References FMECA as an analysis method within the safety assessment process.

Related Terms

Failure Modes and Effects Analysis (FMEA)Failure Modes and Effects Summary (FMES)Risk

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