Failure mode, effects, and criticality analysis

Failure mode, effects, and criticality analysis (FMECA) is a method used to identify potential failures in a system and determine how severe their consequences would be. It is an extension of Failure mode and effects analysis (FMEA). While FMEA identifies how a product might fail, FMECA adds a criticality analysis to rank those failures based on their probability and severity.

The process acts as a structured safety check during the design phase. Engineers systematically review every component to ask: "What if this part fails?" (Failure Mode), "What happens to the system?" (Failure Effect), and "Is this risk acceptable?" (Criticality). For example, in an aircraft design, a failure in a navigation light might be ranked as low criticality (minor inconvenience), while a failure in the landing gear would be ranked as high criticality (catastrophic). This prioritization helps engineering teams focus their limited resources on fixing the most dangerous problems first.

Originally developed by the United States Armed Forces in the 1940s to improve the reliability of munitions, FMECA became a standard procedure for NASA during the Apollo program to prevent accidents in spaceflight. Today, it is widely used in high-risk industries including civil aviation, automotive manufacturing, and healthcare.