This is a series on MIL-HDBK-525 EWIS Overview. The seventh article in the series on Electrical Wire Interconnection Systems (EWIS) Service Life Extension Programs (SLEPs) develops an action plan and mitigation techniques based on the EWIS risk assessment (Task 5).
If you missed any of the articles, here are the links to the previous ones:
- MIL-HDBK-525 Overview
- MIL-HDBK-525 Overview – Task 1: EWIS Documentation
- MIL-HDBK-525 Overview – Task 2: Data Analysis
- MIL-HDBK-525 Overview – Task 3: EWIS Inspection
- MIL-HDBK-525 Overview – Task 4: Component Assessment
- MIL-HDBK-525 Overview – Task 5: Risk Assessment
There are multiple factors (project, platform, engineering and risk tolerances) to consider when determining what action and/or mitigation techniques need to be implemented. Mitigation techniques developed in this section consider all factors and the EWIS risk assessment (Task 5). Three important mitigation techniques discussed are design changes, replacement, and maintenance changes.
1. Design changes
Identify and develop a mitigation strategy for components with high failure severity values. Some of the design changes may include harness rerouting, additional protective sleeving, or changing of circuit protection devices. Once a mitigation strategy is developed, a secondary risk assessment should be performed to determine the impact.
This method should only be considered when design changes do not provide the desired reduction in failure severity (determined in Task 5) or the equipment has been determined to be at or near the end of its service life. The need for replacement should be based on the individual platform needs and constraints.
3. Maintenance changes
The EWIS inspection program, covered in Task 3, should be directed toward monitoring components that are deteriorating at high rates through periodic inspections and monitoring maintenance in hot-spot areas (main drivers of maintenance action). Maintenance procedures should include periodic inspection of areas or components with measured degradation.
The mitigation techniques implemented on the platform should be based on the risk severity determined the overall EWIS analysis performed in task #5. The next article in this series discusses the Enhanced Zonal Analysis Procedures (EZAP) process that is used to improve maintenance and extend the EWIS component life cycle on aircraft.