Step
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Description
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1. Define the system or process to analyze.
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You create the system definition by breaking down the system or process into discrete elements. Complete system definition includes identification of internal and interface functions, expected performance at all hierarchical levels, system restraints, and failure definitions. You can break down the system definition to any level desired. For example, you can break down a large hardware system into a number of subsystems and assemblies. If desired, you can then break down assemblies into individual components or parts. For more information, see FMEA Types.
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2. Obtain or construct diagrams to ensure that the system is fully understood.
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Functional and reliability block diagrams that illustrate the operation, interrelationships, and interdependencies of functional entities involved in the use or operation of the system.
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3. Identify all potential failure modes.
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Determine all of the ways in which the items in the system definition can potentially fail. A failure mode is simply a definition of what can cause an item failure to occur.
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4. Evaluate each failure mode to determine worst-case effects and assign a severity classification.
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Beginning at the lowest level of the breakdown, evaluate each potential failure mode independently to determine the worst-case effects that this failure mode can have on:
• The immediate item or function
• The system
• The mission
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5. Identify failure detection methods, corrective actions, and the effects of corrective actions.
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For critical failure modes, you can identify failure detection methods and compensating provisions for if the failure mode occurs. You can also determine if design changes can eliminate a critical failure mode. If not, perhaps design changes can reduce either the likelihood of occurrence or the impact of the effects. You repeat this analysis until all potential failure modes pose an acceptable level of risk. The individual or agent authorizing the FMEA must clearly define what constitutes an acceptable level of risk. After this iterative process is complete, you would document problems that design changes could not correct in a summary.
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