EWIS ICA Requirements FAQ

New and revised certification specifications were introduced through CS-25 “Certification Specifications for Large Aeroplane” amendment 5 with a new Subpart H – Electrical Wiring Interconnection Systems – EWIS. The new amendment has been published as part of the ED Decision No. 2008/006/R on the 29th August 2008 and enters into force on September 5th, 2008.
The requirement for existing TC holders to develop EWIS Instructions for Continued Airworthiness (ICA) derived from the Enhanced Zonal Analysis Procedure (EZAP) is imposed through the provisions of Part 21A.3B(c)1 for existing TCs, 21A.21(c)(3) for applicants for TC and 21A.103(a)(2)(iii) for applicants for changes to TC. TC holders have been notified of the applicability of those provisions through a dedicated letter that was sent in October 2008. This letter gives further details on the affected aeroplanes (see Question 4 below), deliverables and compliance dates.
Note: The Agency has used this letter in the absence of a regulatory tool similar to FAR Part 26.

New and revised certification specifications were introduced through CS-25 “Certification Specifications for Large Aeroplane” amendment 5 with a new Subpart H – Electrical Wiring Interconnection Systems – EWIS. The new amendment has been published as part of the ED Decision No. 2008/006/R on the 29th August 2008 and enters into force on September 5th, 2008.
For STC applications received after Jan. 1st 2009, the Agency is mandating the EZAP related aspects dealing with Instructions for Continued Airworthiness of these requirements through a generic Certification Review Item with a Special Condition based on Part 21A.16B(a)3 that will be therefore part of the Certification Basis for that STC.

Potentially affected applicants have been advised through a dedicated letter that was sent in October 2008, giving further details on affected aeroplanes, deliverables and compliance dates.

For TC holders for the affected aeroplanes, EWIS ICA requirements are applicable to any changes to TC.
 
For STC applicants for the affected aeroplanes, due to the nature of the tool used (Special Conditions levied on STC applications received), applicability of EWIS ICA requirements will be limited to new STCs or major changes to STCs. This is applicable to the transition period until mid 2010 when all the TC holders EWIS ICA programmes have been established and published.

The affected aeroplane types are indicated in the letters sent to all affected TC holders and potential STC applicants.. The affected aircraft types are large aeroplanes with a type certificate issued after 1st January 1958, that, as a result of original type certification or later increase in capacity, have -

1. a maximum type-certificated passenger capacity of 30 or more; or
2. a maximum payload capacity of 3402 kg (7500 pounds) or more.

No, EASA does not have a “pre-defined” list of excluded aeroplane types (similar to FAR 26.11(g)). On a case-by-case basis, the TC Holders for the affected aeroplanes may ask the Agency to accept a non-compliance with EWIS ICA requirements.

The Agency is considering making public (possibly through the web site) the list of aeroplane types for which EWIS ICAs have been produced. The exact form has not yet been defined. The list should be available by the end of 2009. Plan is also to have Special Condition formalised and referenced in the TCDS of the affected product.

By principle, the classification of the change is driven by Part 21A.91. The fact that EWIS ICA may be revised is not in itself a driver for the classification.
For STCs, see also question 3.
It must be noted that for FAR Part 26 compliance, the FAA will require that if the change requires a revision to the previously developed and approved EWIS ICA, then the revised EWIS-ICA must be submitted to the FCAA for approval, independently of the change classification.

The effect of extra work and additional hours needs to be accounted for.
Simple STCs may be subject to change from “simple” to “standard” due to an EWIS impact. Nevertheless, not all STCs affected by EWIS become automatically standard.
Classification between simple/standard will be managed according to the processes in place and the possible need to involve more than one Panel for this specific task.

Yes, this is under consideration.
For TC Holders determination of impact of modifications on EWIS ICA is left to the applicant (no systematic check for each mod.). This assumes that the appropriate DOA procedures are in place and have been checked by EASA.

Yes, the plan is to use the CRI Process and Special Condition tool and make it become part of the Certification Basis.
The intent of those CRIs and the Special Condition that will be attached is to complement the letters that have been sent to the Design Approval Holders, not to replace them. Their objective is to state in an easily identifiable manner the certification basis to ease future modifications and STCs. Objective is to have that in place by end 2009. This will hopefully save the need to issue a SC for each STC after June 2010 assuming this SC is clearly identified in the cert basis/TCDS of the affected aeroplane.

Yes, once the CRI is concurred and it is established that the STC is affected by the new rules then the applicant has to send an additional application aimed to cover the aspects related to the EWIS Rules additional demonstration of compliance and possible revised ICAs.
The STC can be issued with a statement in the “Limitations and Conditions” section that will be cleared when final justification is produced.

The question is a practical one and also applicable to other aspects of certification than EWIS ICAs. EASA should point out to the applicants any concurrent application that may impact the validity of the EZAP analysis.

No, if the certification basis is the CS-25 Amdt 5, all the large aeroplanes covered by CS-25 shall have to demonstrate compliance with the EWIS regulations without exception.

From a safety perspective this would be welcomed but from a practical point of view it may not be the best option when this is not required by Part 21. By electing to comply with CS-25 Amdt 5 all new requirements have to be complied with, which are not limited to EWIS ICA. Due to the nature of the new subpart H, this will induce additional justifications and possibly design changes and will affect the time needed to approve a project.