Shiny
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P/N Marking On Internal Wiring

Mon Jan 14, 2013 9:48 am

Is there a requirement for internal (within a unit, say data recorder) wiring to be marked and if yes - above what length and what is the exact requirement stating that?

I am aware about general wiring, but specifically internal wires...?
 
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airportugal310
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RE: P/N Marking On Internal Wiring

Mon Jan 14, 2013 10:46 am

I'd assume so. During a recent our of the A380 demonstrator, I noticed all the internal wiring was colored differently...would that be the "coding" as to what controls what?

Probably easier in my simplistic mind  
I sell airplanes and airplane accessories
 
Shiny
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RE: P/N Marking On Internal Wiring

Mon Jan 14, 2013 11:22 am

No, I meant like a P/N marking, not functional identification marking.
 
AA737-823
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RE: P/N Marking On Internal Wiring

Tue Jan 15, 2013 12:30 am

Quoting airportugal310 (Reply 1):
I'd assume so. During a recent our of the A380 demonstrator, I noticed all the internal wiring was colored differently...would that be the "coding" as to what controls what?

But no, he's talking about within an actual LRU, I believe, based on this:

Quoting shiny (Thread starter):
within a unit, say data recorder)

To answer your question, I don't know. Backshop would know. But, at least in my experience, I don't think wiring internal to the boxes is required to be marked in the same way as standard aircraft wiring.
 
Legs
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RE: P/N Marking On Internal Wiring

Tue Jan 15, 2013 7:38 am

Quoting AA737-823 (Reply 3):
Backshop would know.

Backshop monkey here. Im not sure of any requirements beyond manufacturers specs to mark wires inside LRU's. However, in my experience almost all LRU internal wiring is marked with wire numbers in the same basic fashion as the rest of the plane. Some aren't marked in quite the same way, having a more basic numbering scheme, but it would make my job a lot harder if they didnt have any markings at all. Some have printed sleeves at either termination, but most are laser printed.
 
Shiny
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RE: P/N Marking On Internal Wiring

Tue Jan 15, 2013 7:50 am

Yes, my question was about LRUs.

Thanks for the responses. It seems that there is no certification requirement however for those to be marked? I'm specifically interested in unique P/N marking, not just type of wire and purpose marking...
 
tdscanuck
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RE: P/N Marking On Internal Wiring

Tue Jan 15, 2013 7:53 am

Quoting shiny (Reply 5):
It seems that there is no certification requirement however for those to be marked?

Correct. The only certification requirement is that there be instructions for continued airworthiness (ICA's), which include stuff like the WDM's and CMM's. These are greatly simplified by having good wire identification but there is no explicit certification requirement to do so. However, if your manuals + markings were so poor that a normally trained mechanic could not reasonably be expected to maintain the system, the regulators would get upset with you and you'd have to do something.

Tom.
 
MD11Engineer
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RE: P/N Marking On Internal Wiring

Tue Jan 15, 2013 9:20 am

Since wire counts a consumable (similar to standard screws, nuts or other smallparts), it won´t have a S/N on it (a P/N might be printed on it if space permits), but the P/N of the wire and the batch number will certainly be recorded somewhere in the assembly documentation of the LRU.

Jan
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Legs
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RE: P/N Marking On Internal Wiring

Tue Jan 15, 2013 8:23 pm

Quoting MD11Engineer (Reply 7):
(a P/N might be printed on it

Just about every type of aviation wiring I've ever used has the part number on it somehow. Often it is printed in light blue or green so as to be not confused with the wire number. Types like coax, triax and the like often have a thin strip of flexible plastic under the first layer of insulation with the part number printed on that.

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