**\[Federal Register: March 5, 1997 (Volume 62, Number 43)\]**

**\[Rules and Regulations\]**

**\[Page 9923-9925\]**

**From the Federal Register Online via GPO Access
\[wais.access.gpo.gov\]**

**\[DOCID:fr05mr97-3\]**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 21**

**\[Docket No. AIR-100-9601\]**

**Replacement and Modification Parts: "Standard" Parts;**

**AGENCY:** Federal Aviation Administration (FAA), DOT.

**ACTION:** Notice of Interpretation.

**SUMMARY:** The FAA is notifying the public that the interpretation of
an acceptable U.S. government or Industry accepted specification may
include specifications that may be limited to detailed performance
criteria, complete testing procedures, and uniform marking criteria.
Manufacturers of parts that conform to such specifications are excepted
as "standard parts" from the requirement to obtain FAA Parts
Manufacturer Approval. The FAA is aware that specifications meeting the
above criteria exist for discrete electrical or electronic component
parts.

**EFFECTIVE DATE:** January 31, 1997

**FOR FURTHER INFORMATION CONTACT:** Bruce Kaplan, Aerospace Engineer,
Aircraft Engineering Division, AIR-100, FAA, 800 Independence Avenue,
SW., Washington, DC 20591, (202) 267-9588.

**SUPPLEMENTARY INFORMATION:** Section 21.303(a) of Title 14 of the Code
of Federal Regulations (CFR), Replacement and Modification Parts,
prohibits a person from producing a part for sale for installation on a
type certificated product unless that person produces the part pursuant
to an FAA Parts Manufacturer Approval (PMA). Section 21.303(b) provides
four exceptions to the requirement in § 21.303(a). One of these
exceptions is for \"Standard parts (such as bolts and nuts) conforming
to established industry or U.S. specifications.\" (14 CFR §
21.303(b)(4).)

\"Standard part\" is not otherwise defined in Title 14. Section
21.303(b)(4) has come to be understood by the aviation and manufacturing
public as meaning a part, the specification for which has been published
by a standard setting organization or by the U.S. government, and the
FAA has traditionally regulated parts production with that
understanding. Examples of such \"traditional\" standard part
specifications include National Aerospace Standards (NAS), Air
Force-Navy Aeronautical Standard (AN), Society of Automotive Engineers
(SAE), SAE Aerospace Standard (AS), and Military Standard (MS). The FAA
will continue to consider parts conforming to these specifications as
standard parts.

Prior to this notice, for a specification to be acceptable, it had to
include information on the design, materials, manufacture, and uniform
identification requirements. The specification had to include all the
information necessary to produce the part and ensure its conformity to
the specification. Furthermore, the specification must be publicly
available, so that any party is capable of manufacturing the part. The
above examples of accepted specifications fulfill those criteria.

In the past the FAA has applied §21.303(b)(4) to parts that have
specifications where a determination of physical conformity to a design
could be made. This application largely excluded classes of parts where
the parts are conformed not on the basis of their physical configuration
but by meeting the specified performance criteria. These types of parts
are best exemplified by discrete electrical and electronic parts.

Much of the componentry used in electronic devices are manufactured
under standard industry practices, often to published specifications
developed by standards organizations such as the Society of Automotive
Engineers (SAE), the American Electronics Association, Semitec, Joint
Electron Device Engineering Council, Joint Electron Tube Engineering
Council, and the American National Standards Institute (ANSI). Such
standards development by these bodies is overseen by the Institute of
Electrical and Electronics Engineers (IEEE), the IEEE Standards
Committee, as well as the electrical and electronics industry, at large,
who depends upon characteristic design standards for consistency in
operation and performance.

The FAA has determined that certain kinds of electrical and electronic
parts fit within the limits of the § 21.303(b)(4) exception; these
include resistors, capacitors, diodes, transistors, and non-programmable
integrated circuits (e.g. amplifiers, bridges, switches, gates, etc.).
Conversely, large scale, application-specific, or programmable
integrated circuits; hybrids, gate arrays, memories, CPU's, or other
programmable logic devices would not be considered standard parts, such
components are not 'discretes' since they require programming that
controls their timing, functionality, performance, and overall operating
parameters.

It is important to remember that 14 CFR Part 21 §21.303 deals with the
production of parts for sale for installation on type certificated
products. Installation of replacement or modification parts including
owner/operator-produced and standard parts, must be accomplished in
compliance with part 43 of Title 14 of the CFR (Part 43). Generally, a
standard part may be replaced with an identical standard part, in
accordance with the manufacturers maintenance instructions, without a
further demonstration of compliance with the airworthiness regulations.
Substitution of a standard part with another would require a
demonstration of acceptability in accordance with part 43.

**DISCUSSION OF COMMENTS:** The FAA published (61 FR 47671, September
10, 1996) a proposed expanded interpretation for "standard part" and
requested comments from the public on the ability of producers to
conform discrete electrical and electronic parts, and other kinds of
parts, to specified performance criteria. The FAA also requested comment
on the ability of producers to distinctly identify such parts.

A total of 19 comments were received in response the notice. These
commenters represent air carriers, aircraft manufacturers; associations
representing aircraft manufacturers, aircraft maintenance personnel, and
fixed base operators/air charter/air taxi operators/scheduled operators;
component manufacturers; and the Joint Aviation Authorities. All but one
commenter voice general support for the proposal. Five commenters concur
with no additional comment. Six commenters concur and express the desire
to include specifications for other types of parts (beyond discrete
electrical and electronic parts) under this expanded interpretation.

The substantive issues raised by the commenters are discussed in the
following discussion of comments.

*Comment:* Two commenters expressed concern about standard parts in
general. They commented that some manufacturers claim to build their
parts to these standards but do not have any proof that the parts meet
the requirements and that just because a part is marked with the
standard part type number or marking does not demonstrate that the part
in fact conforms to the established industry or U.S. Government
specifications. One commenter suggested the FAA survey suppliers to
determine if they are reliable candidates to meet the requirements of
various standards.

*FAA Response:* A standard part is one that conforms to the established
specification. Beyond just physical configuration and performance
testing almost all specifications have quality control and testing
requirements. The FAA in conducting an investigation of standard part
manufacturers would be looking for complete compliance with the
specification, and would look for the existence and proper execution of
records necessary to prove conformity. Non-conformities would be cause
for enforcement action by the FAA and could be cause for a criminal
investigation by the appropriate law enforcement agencies.

The marking of a part is the manufacturer's certification that the part
conforms to the specification. The ability of the manufacturer to make
that certification at the time of manufacture is based on the
specification requirements which include production system requirements,
test & acceptance procedures, and any additional internal quality
control requirements. The marking of parts also serves as a means by
which an installer may identify a part and establish its eligibility for
installation on an aircraft. The end users confidence in that
manufacturer's certification is based on their experience with that
manufacturer and is supplemented by their receiving inspection, and the
final determination of airworthiness as required by FAR 43.13.

Standard part manufacturers are subject to continuing in-depth audits by
their customers whether they be commercial airplane manufacturers, the
automotive industry, or the U.S. Government. The FAA feels that these
continuing process checks provide an appropriate degree of confidence.

*Comment:* Three commenters expressed concern that a part meeting a
standard specification may be used by a design approval holder in an
application that is safety-critical or outside the specified operating
tolerances requiring greater scrutiny of that part. For this reason one
commenter stipulated that parts must be designated as standard by the
design approval holder.

*FAA Response:* The qualification and quality control requirements for
any part installed on a product is established by the design approval
holder for that product. If a design approval holder utilizes a standard
part design in a safety critical application (and/or an application
requiring the part to perform outside its specified operating
tolerances) but imposes qualification or quality control requirements
beyond those of the standard specification for the part, then that
altered part would no longer be a "standard part.

Certain design approval holders are required to provide instructions for
continued airworthiness including data necessary for maintenance. It is
these maintenance instructions that are to be followed by maintenance
personnel. It would be incorrect for a design approval holder to
identify a part as a "standard part" in their maintenance instructions
when their qualification or quality control procedures exceed those of
the standard part specification.

*Comment:* Several Commenters voiced the need for including I.S.O. and
European government and industry standards.

*FAA Response:* The FAA can recognize any industry established
specification regardless of country of origin. However, under present
language of Part 21 21.303(b)(4) acceptable government specifications
are limited to those published by the U.S. Government. The Aviation
Rulemaking Advisory Committee (ARAC), Aircraft Certification Procedures
Issues Group (Part 21), Parts & Production Working Group is currently
developing a draft notice of proposed rulemaking (NPRM), for submittal
to the FAA, addressing the approval of replacement and modification
parts. This issue is under consideration; changes could be incorporated
into the forthcoming NPRM.

*Comment:* Several commenters expressed the desire to allow various
other categories of parts such as lamps, electrical connectors, and
bearings.

*FAA Response:* The FAA's Notice solicited information as to the merits
of including categories of parts other than discrete electrical or
electronic components under the interpretation. The commenters did not
state how the conformity of the parts could be established solely on the
basis of meeting a performance specification. Thus, the FAA still
regards the standard parts exclusion as applicable to a narrow segment
of the entire population of part designs.

*Comment:* One commenter expressed the desire to allow programmable
devices to be considered standard parts when there are approved
pin-for-pin alternatives. Such components only become notionally
non-standard after programming for a specific application.

*FAA Response:* Programmable devices were specifically excluded in the
proposed expanded interpretation because their performance
characteristics may vary with the instructions programmed within or
provided to such devices, or due to different applied voltages and
signals affecting logical switching conditions. Even though such devices
may be pin-to-pin compatible, the performance characteristics cannot be
assured, thus making such devices ineligible for consideration of the
\"performance\" based interpretation of the definition.

The interpretation for standard parts is effective on January 31, 1997.
The FAA is compiling a list of standard setting bodies and U.S.
government entities that establish specifications for standard parts.
That list will be published on the Aircraft Certification Home Page on
the World Wide Web by June 30, 1997.

Issued in Washington, DC on January 31, 1997.