Shiny
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Ewis ICA Development Procedures (AC 25-27A)

Tue Nov 27, 2012 12:42 am

Anyone with knowledge about it and more specifically the required procedures per AC 25-27A?
 
tdscanuck
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RE: Ewis ICA Development Procedures (AC 25-27A)

Tue Nov 27, 2012 2:43 am

Quoting Shiny (Thread starter):
Anyone with knowledge about it and more specifically the required procedures per AC 25-27A?

What exactly are you looking for? The AC itself includes a lot of information on the required procedures:
http://rgl.faa.gov/Regulatory_and_Gu...771f0053a1d6/$FILE/AC%2025-27A.pdf

This rule dovetails with the CDCCL requirements that came out of SFAR88 (the rule coming from TWA800). It's basically the electrical wiring side of the maintenance procedures required to maintain the flammability protection features.

Tom.
 
Shiny
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RE: Ewis ICA Development Procedures (AC 25-27A)

Tue Nov 27, 2012 8:15 am

I am very aware of the reason and purpose. What I don't quite understand however is the practical application of the Appendixes as suggested procedure.

Appendix A is the EZAP
Appendix B is review of existing EWIS ICA

Both start pretty much with the same few questions. Appendix B however leads to either EZAP (Step 6) (hence Appendix A) or an alternative path to determine appropriate inspection type in case one does not have the data required to perform EZAP.

And this is what confuses me. The way I understand it, in reality for a given modification in a zone one would first have to start with the more general Appendix B and if EZAP data is available, perform EZAP (Appendix A) as a part of Appendix B!?
Then the question comes why the same questions twice (Step 1 in Flowchart 1 from Appendix B vs. Worksheet 2 from EZAP) and why EZAP which is just a part of the process comes first in AC 25-27A...!?
 
mtraskos
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RE: Ewis ICA Development Procedures (AC 25-27A)

Fri Nov 30, 2012 2:10 pm

Appendix A of 25-27A goes into details for the overall EZAP process. So if you are a new aircraft manufacturer or maintaining an existing aircraft, then this is the process to consider starting with.

Appendix B is the particular application for a modification. There is some overlap between the two processes, but that is necessary because not all modifications affect the EWIS. Further, because a modification may only affect the EWIS of a single zone, only the EZAP needs to be updated/modified for that area (assuming that an EZAP has already been created).

If you would like any additional help on this, let me know.
 
Shiny
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RE: Ewis ICA Development Procedures (AC 25-27A)

Fri Nov 30, 2012 2:24 pm

Thank you very much!!
That gave me confidence I am understanding it correctly.

So if I am designing/certifying an EWIS-related modification, I would start with a procedure iaw. Appendix B, whereas, if (and only if) I have the required for EZAP data I will perform it for each zone iaw. Appendix A. Is that correct?

And obviously EZAP is not mandatory if one does not have the data required to perform it (adequately), in which case the alternative "path" in Appendix B will be used to determine maint. type and interval... ?

Please correct me if I'm wrong.
 
mtraskos
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RE: Ewis ICA Development Procedures (AC 25-27A)

Fri Nov 30, 2012 9:30 pm

It is my understanding that all aircraft should have an EZAP at this point. With the rules implemented in 2007/2008, I remember operators had 18 months to comply with the EZAP rules. This was extended to 35 months from the rule effective date. As such, all aircraft after March 2011 should have an EZAP. If this information is not available, then, based on my understanding, this needs to be generated.

If you are making changes/additions to the wiring system, then the impact on the EZAP must be considered. I don’t see where ‘lack of information’ is acceptable for not performing the impact assessment.
 
Shiny
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RE: Ewis ICA Development Procedures (AC 25-27A)

Sat Dec 01, 2012 1:02 pm

Yes, all (major commercial) aircrafts do have EZAP at this point. However my question refers to Question 3 in Flowchart 1 of Appendix B...?

Imo. it implies that EZAP must not necessarily be performed if you do not have access to the latest EZAP for the zone and all relevant information...?
 
mtraskos
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RE: Ewis ICA Development Procedures (AC 25-27A)

Sat Dec 01, 2012 5:05 pm

I have looked through Appendix B twice and don’t see anything that may indicate that the impact on EZAP is optional based on if information is available or not. I have included the language from the AC below.

“Appendix B – Flowchart 1 - Question 3: Determine whether existing EWIS ICA tasks for the zones affected by the modification require revision (NOTE: * Modification means any change to an existing type design accomplished through any of the following: #1 An amended type certificate (including service bulletin design changes),#2 A supplemental type certificate (STC), or #3 Changes to an existing STC”

Guidance: “STEP 3: Determine whether existing EWIS ICA tasks for the zones affected by the modification require revision. Once the modification’s EZAP has been accomplished, a comparison of these EWIS ICA can be made with the existing EWIS ICA. If the existing task is adequate, then no further action regarding EWIS maintenance actions for the STC is necessary. An existing EWIS ICA task is adequate if it is the same task, performed at the same interval, as the EWIS ICA task identified as a result of the EZAP performed in STEP 2.”

Perhaps I have missed something in the AC. Could you identify the area which may indicate it may be optional?
 
Shiny
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RE: Ewis ICA Development Procedures (AC 25-27A)

Sat Dec 01, 2012 7:26 pm

Question 3 in Flowchart 1 of Appendix B:

"Are you the holder of the airplane models TC, or do you have access to the most recent EZAP analysis performed on the zone(s) you are modifying, or all design and installation data that is necessary to answer all the questions that are asked while performing the EZAP analysis as described in appendix A of this AC?"

The last part of the question implies imo. that (as it is quite often in reality) a DO that is not the TC or STC holder of that zone may not have (reliable) answers to all questions...?

Furthermore, the "invitation" to perform EWIS appears only if you answer YES to the above. If you answer NO, you are forwarded to page 3, which contains what seems to be an alternative (simplified) procedure for determination of required task and interval.

Or do you see it differently?

Obviously if you are a TC-holder EZAP is a must by default, but seen from the point of view of a DO or generally a third party maybe not?
 
mtraskos
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RE: Ewis ICA Development Procedures (AC 25-27A)

Wed Dec 12, 2012 2:14 pm

Looks like I grabbed an older version of the AC - sorry for the confusion.

You are correct in your assessment. Without all of the information, you would proceed to the Appendix B-Flowchart 1-Page 3 and continue the assessment based on the flowchart there.
 
Shiny
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RE: Ewis ICA Development Procedures (AC 25-27A)

Sat Dec 15, 2012 12:09 am

Thank you!  
You must agree it is a bit confusing, not to mention how many mistakes AC 25-27 contains ...

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