Enhanced Zonal Analysis Procedure (EZAP) – Electrical Wiring Interconnect Systems (EWIS)

The requirements to perform an Enhanced Zonal Analysis Procedure EZAP was essentially introduced due to a shortfall in the original specification of the ATA 100 MSG 3 process.

A Harmonized process involving both  the FAA and EASA  was undertaken and The EZAP is specified in EASA AMC document AMC 20-21,  ref Appendix A and is  designed to permit appropriate attention to be given to electrical wiring installations.

This process was essential undertaken by all Type Certificate Holders (TC)  Holders and Supplemental Type Certificate Holders, (STC)  This is achieved by providing a means to identify applicable and effective tasks to minimise accumulation of combustible materials and address wiring installation discrepancies that may not otherwise be reliably detected by inspections contained in existing maintenance programmes.

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The EZAP analysis is considered on a far wider basis than the original requirements and includes all additional items contained within the zone associated with the EWIS inspection, items such as plumbing, ducting, systems installations, etc., should also  be evaluated for possible contribution to wiring failures. Tasks may also be developed for the removal of contaminants dust and debris from the Electrical Wiring Interconnect Systems (EWIS)

In cases where a GVI is required to assess degradation of these items, a zonal GVI within a ZIP may be considered appropriate.However this will be understood when following the guidelines of the EZAP requirement.

For those operators that do not have a dedicated ZIP, application of the logic is likely to result in identification of a large number of wiring-related tasks that will need to be consolidated within the existing Systems/Powerplant Programme.

It should be remembered that it is an operators responsibility to ensure it complies with the requirements of EASA regulations including AMC’s, so if there is a shortfall, for example because of incomplete instructions from the TC or STC holder, the operator must develop appropriate in house procedures to satisfy it self it is meeting the requirements of AMC 20-22

Any new tasks identified by the  EZAP logic may be compared with existing tasks and  allowances made for any  equivalent tasks already contained in the maintenance programme. Operators without a ZIP may find it  necessary  to develop a ZIP in accordance with an industry-accepted best practice methodology in conjunction with application of the EZAP.

The logic and procedures identified in AMC 20-21 apply to TC, STC and other modifications. It is expected that the TC and STC holders would use the logic and procedures to identify any need for additional instructions for continued airworthiness.

It should be understood when considering the overall requirements of EZAP to satisfy EWIS requirements that, the operator  is responsible  to ensure that the appropriate logic is used to identify any such instructions for modifications or STC in cases where they are no longer supported by the design organisation or STC holder.

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