Post-FMEA Analysis
During the design verification and validation phase, when the system is being used and supported, the accuracy of the FMEA can be assessed using applicable test results and field data. Verification is the process of proving that the system complies with its formally established requirements as well as the process of proving by special engineering inspections, analyses, demonstrations or tests that the system satisfies the requirements of its development specifications. Validation is the process of confirming that the system conforms to accepted engineering principles.
Testing during the design verification and validation phase provides a measure of the accuracy of the FMEA. Test results may show that the ground rules and assumptions should be changed or that additional iterations of analysis are necessary to maintain the integrity of the FMEA. Additional analysis may also be required to ensure that:
• End-item consequences captured from fault inspection tests and operating field data match FMEA results.
• FMEA results are clearly summarised and comprehensive recommendations are provided.
• Actions are provided for reducing the risk of single point failures, critical items and areas needing built-in test (BIT).
• Compensating provisions identified in the FMEA do lessen failure effects.
• Monitoring provisions correctly isolate the possible causes of system failure.
• Any new failure modes and consequences identified are fully assessed.
• Analysis results are being effectively communicated to enhance other programme decisions (BIT design, critical parts, reliability prediction, derating, fault tolerance, etc.).
• Related sources (analysis database, fault isolation manual, etc.) are revised as necessary.
After the product is in use, modifications to the FMEA are made based on FRACAS (Failure Reporting, Analysis and Corrective Action System) information, which provides for reporting failures in the field and tracking them to ensure that corrective actions are taken to correct the problem. Continuing to modify the FMEA throughout the life of the system results in a comprehensive and accurate record of the design analysis.