This is a series on MIL-HDBK-525 EWIS overview. The eighth article in the series Electrical Wire Interconnection Systems (EWIS) Service Life Extension Programs (SLEPs), discusses the Enhanced Zonal Analysis Procedures (EZAP) process, which aims to improve maintenance and inspection programs for all EWIS components. The EZAP process tailors the frequency of inspections based on the determined environmental conditions of a particular zone.
If you are interested in other articles on EWIS, you may want to read the article on Corrosion Compounds and EWIS.
The EZAP procedure, originally developed by the FAA back in 2007, should be designed to maintain an aircraft’s EWIS airworthiness. This is achieved through defining general guidance checklists throughout the aircraft and inspection intervals. The EZAP logic below provides a step-by-step process for determining the proper inspection procedures.
Each step provides critical information to determining the wiring inspection level and interval and provides estimates on zone density, size, environmental issues, and failure consequences for each zone. The inspection level is selected using rating tables that rate characteristics of each zone and its effect on wires. Characteristics of each zone include manufactured label zones, zone size (how large the zone is) and zone density (how close components are to one another), and failure severity (answer should be based on the failure severity assessment performed in Task #1). The inspection interval should be determined based on the environment and condition of the EWIS component. If the EWIS component is exposed to multiple harsh environments, the inspection interval should be more frequent than a component that is in a non-hostile environment.
Michael Traskos
President, Lectromec
michael.traskos@lectromec.comMichael has been involved in wire degradation and failure assessments for more than a decade. He has worked on dozens of projects assessing the reliability and qualification of EWIS components.