EAA Sport Aviation - August 2011

(a) Except as provided in paragraph (b) of this section, no person may produce a modification or replacement part for sale for installation on a type-certificated product unless it is produced pursuant to a Parts Manufacturer Approval issued under this subpart.

(b) This section does not apply to
the following:
( 1) Parts produced under a type or
production certificate.

( 2) Parts produced by an owner or operator for maintaining or altering his own product.

( 3) Parts produced under an FAA Technical Standard Order.

( 4) Standard parts (such as bolts and nuts) conforming to established industry or U.S. specifications.

So parts sold for installation on a certif-
icated aircraft, engine, propeller, or
appliance must be either an OEM part pro-
duced under a type certificate or
production certificate or a non-OEM part
produced under a PMA or TSO. There are
two exceptions: “standard parts” and
“owner-produced parts.”
The FAA has traditionally interpreted
“standard parts” to mean fasteners and
other parts meeting National Aerospace
Standards (NAS), Air Force-Navy
Aeronautical Standard (AN), Society of
Automotive Engineers (SAE), SAE
Aerospace Standard (AS), and Military
Standard (MS). On March 5, 1997, the FAA
published a Notice of Interpretation in the
Federal Register that broadened the
definition of “standard parts” to include
standard electronic parts such as resistors,
capacitors, diodes, transistors, and non-
programmable integrated circuits. Prior to
1997, it was technically illegal to replace a
burned-out panel light rheostat or
dimming transistor with one purchased
at your local Radio Shack—now it’s
officially kosher.

The meaning of “owner-produced parts” was rather murky until April 5, 1993, when Donald P. Byrne, the FAA’s assistant chief counsel for regulations, issued a memorandum defining the term “owner (or operator) produced part” as used in FAR 21.303(b)( 2). Byrne’s memo clarifies the FAA’s interpretation of the owner-produced parts exception, and as you’ll see, that interpretation is surprisingly generous and liberal.

…AND WHAT THEY MEAN

Byrne explained that it is not necessary for
the owner to actually manufacture the
part himself for the part to be considered
an “owner-produced part.” The owner
may contract with a mechanic, a repair
station, or even a non-certificated individ-
ual or firm (e.g., a machine shop) to
manufacture the part for him, provided
that the owner “participated in controlling
the design, manufacture or quality of the
part.” The FAA deems the part to be
owner-produced if the owner does any of
the following things:
• Provides the manufacturer with design
or performance data from which to
manufacture the part—this test would
be met if the owner provides the manu-
facturer with the old part and asks that
it be duplicated; or
• Provides materials to make the part; or
• Provides fabrication processes or
assembly methods to be used in making
the part; or
• Provides quality control procedures to
be used in making the part; or
• Supervises the manufacture of the part.

In short, a part whose manufacture is contracted by the aircraft owner will qualify as “owner-produced” if the owner participates in the production of the part in any meaningful way at all.