Using a PMA's replacement for to establish equivalence?

[KirbyWan]

Howdy all,

I was looking for a set of switches, 813387-3/-4/-5 and they each have a long list of PMA parts. Removing duplicates there are 23 separate PMA parts that are common to all three of these parts. These 23 PMA parts are approved as alternates for multiple OEM parts. In fact there are 25 different OEM parts that these PMA parts are allowed alternates for. 19 of the PMA parts have the same list of 23 OEM Parts they replace.

So I expect these switches are all identical, with perhaps the only difference being wire length, but they list a different P/N for each top level part number they go on. Could I use this to justify using an alternate OEM part number to use an equivalent, perhaps identical switch from a different part?

Thanks,

-Kirby



Kirby Wilkerson

Remember, first define the problem, then solve it.

 

[rb1957]

how do you spell "money making scheme" ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[SWComposites]

Maybe you could justify it if the replacement OEM part is from the same OEM as original.
But don’t you need to get FAA/TC approval anyway?

 

[WKTaylor]

KW... Hmmmm...

PN [switches] 813387-3/-4/-5 makes no sense: is this a vendor #? MIL-S-#? MS#? etc... digits seem to long for MIL/MS.

Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov

 

[KirbyWan]

I think this has the economic benefit that rb1957 suggests, and a legal benefit that if there is a problem, something that could turn into an AD, it limits the scope of the AD. I also think the OEM may have different cable lengths and all the PMA options probably have enough extra to trim as needed. but that's all just spit-balling.

SWComposites It's the same OEM for all the "equivalent" non-PMA parts. But yeah, it feels wrong to just say use this part from a different valve, it'll be okay.

Thanks all,

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

 

[debodine]

I must be way off base, but I use the FAA DRS web site a lot for FAA-PMA so I thought I would look up your question. Note that everything I list is public information from the drs.faa.gov website. I found only the following for each part number:

813387-3AEC
813387-4AEC
813387-5AEC

In each case the PMA is held by Aviation Engineering Consultants under FAA-PMA PQ1685CE, Supplement 38 Amendment 1 for most Boeing, McDonnel-Douglas and Airbus transport category aircraft.

In addition I found only the following:

813387-3AEC

Again Aviation Engineering Consultants holds the FAA-PMA but under PQ1685CE, Supplement 51 for most ERJ aircraft.

I am unable to understand what document you are seeing that lists any other FAA-PMA articles?