On 19 Feb 2007 05:17:40 -0800, "Denny" wrote:

snip
out again the 214 is junk... Having spent part of my life in
industrial electronics I have no doubt I can install a pot of the
proper value and taper... The problem is it won't be certified if I do
and the radio shop will refuse to align it with an uncertified pot...
snip

[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]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 21

[Docket No. AIR-100-9601]


Replacement and Modification Parts: ``Standard'' Parts;
Interpretation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of interpretation.

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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 electric or electrical 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 Sec. 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
Sec. 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 Sec. 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

[[Page 9924]]

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 Sec. 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 Sec. 21.303 deals
with the production of parts for sale for installations 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 to 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 voiced 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 intrepretation.
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 and 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 manufactures 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

[[Page 9925]]

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 instruction 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.
Elizabeth Yoest,
Deputy Director, Aircraft Certification Service.
[FR Doc. 97-5437 Filed 3-4-97; 8:45 am]
BILLING CODE 4910-13-M