Bob Noel wrote in
:

Is one {PMA} required for an STCed alteration?

Yes.

Not quite.

A part may be manufactured by the owner/operator and installed under
STC, or it may be manufactured *and installed* by the holder of the STC
without PMA. Both these minor points are seldom worthy of note, but
they are there.

For example: GAMI designed their new fuel injectors. They went through
testing and the STC was awarded. They were then allowed to make them
and install them on all aircraft/engines for which the STC applied.

The FAA would not allow the PMA application to be even be submitted
until the STC was approved. [It's not clear that this is a rule, so
much as an FSDO made up rule.] Until the PMA was approved GAMI could
not sell the injectors to anyone else for installation elsewhere. You
wanted the injectors, you flew to Oklahoma and had GAMI put them in.

Once the PMA was approved the restriction went away.

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James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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