MEA, FMECA, Failure Mode and Effects Analysis, RPN


Failure Mode and Effects (and Criticality) Analysis

A failure mode and effects analysis (FMEA) or failure mode, effects, and criticality analysis (FMECA) is a reliability evaluation and design review technique that examines the potential failure modes within a system or function, or lower level in the system/function hierarchy, to determine the effects of failures on system/function performance. Each failure mode is classified according to its impact on system/function operating success and personnel safety.

FMEA/FMECA uses an inductive logic on a "bottom up" system analysis. This approach begins at the lowest level of the system/functional hierarchy and traces up through the system/functional hierarchy to determine the end effect on system/function performance.

The maximum benefit of performing a FMEA/FMECA is realized from an early application in the system's life cycle rather than after the system's design is finalized.


  • Determines the effects of each failure mode on system performance.
  • Emphasizes identification of single-point failures.
  • Provides data for developing fault tree analysis and reliability block diagram models.
  • Provides a basis for identifying root failure causes and developing corrective actions.
  • Facilitates investigation of design alternatives to consider high reliability at the conceptual stages of the design.
  • Aids in developing test methods and troubleshooting techniques.
  • Provides a foundation for qualitative reliability, maintainability, safety and logistics analyses.
  • Uses a documented, systematic, and uniform method.
  • Can provide an early identification of single failure points and system interface problems.
  • Provides a mechanism for verifying that switching between redundant elements is not jeopardized by postulated single failures.
  • Provides an effective method for evaluating the effect of proposed to the design on mission success.
  • Provides the criteria for early planning of tests to characterize the weaknesses of the design.
  • Provides a basis for the safety analysis that is done as part of evaluating the safety characteristics of the design.
  • Provides a basis for operational troubleshooting and for locating performance monitoring and fault-detection devices within the system.


  • Highlighting areas needing corrective action.
  • Ranking failures according to severity of equipment operation and personal safety.
  • Identifying reliability and safety critical components.
  • Visibility of system interface features and problems
  • Locating performance monitoring and fault sensing test equipment or test points.