[Federal Register Volume 62, Number 43 (Wednesday, March 5, 1997)]
[Rules and Regulations]
[Pages 9923-9925]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5437]


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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]
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