"George Patterson" wrote in message
news:UDA9f.10245$bD.4407@trndny01...
It is *not* ok to use a non-certified part. My take on the matter is that,
if an aircraft was certified to use Delco part number AC-9732-5, I can
install a Delco AC-9732-5 that I bought at the local NAPA dealer. I have
heard that certain assholes in the FAA feel that a Delco AC-9732-5
purchased from NAPA isn't ok; that you have to buy it from, say, Piper for
it to be legal. My take on that is that they are wrong, and, given that
nobody can tell where I bought my Delco AC-9732-5 unless I tell them, I
*will* "get away with it."

IMHO, a caveat here is that sometimes parts are manufactured in bulk, and
then certified through additional testing by another party (such as the
aircraft manufacturer). Just because the part is manufactured by the same
manufacturer who made it for the aircraft doesn't mean it's certified for
that use.

However, as far as I know, when the part is certified through the third
party, it's labeled as such. You wouldn't find an aircraft type certificate
specifying "Delco AC-9732-5" if that part was certified through the aircraft
manufacturer; it would be relabled something else.

The problem comes in when one looks at the part being replaced, rather than
the type certificate, maintenance manual, etc. The part itself may not have
any of its markings changed after going through another layer of inspection.
For that matter, the installed part might not be legal.

It might seem silly to worry about a light bulb, but it may be that the
"certified" version of the bulb has been tested to ensure a variety of
things that are important for aircraft, but not as important for other uses.
Fire hazard comes to mind, for example. I mean, you don't really want your
bulb catching things on fire regardless of where you're using it, but being
on fire while in the air in an aircraft is especially bad news.

Not that I know bulbs are actually tested for fire hazard...it's just
something I expect they could be tested for. My point is simply that if one
doesn't know for a fact that a part from one source is identical IN EVERY
WAY to the same part from another source, one should make sure they've
obtained the part through an aviation-approved source.

Pete