[Federal Register Volume 62, Number 85 (Friday, May 2, 1997)]
[Proposed Rules]
[Pages 24288-24299]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-11205]


      

[[Page 24287]]

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Part VII





Department of Transportation





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Federal Aviation Administration



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14 CFR Parts 11, 21, and 25



Type Certification Procedures for Changed Products; Proposed Rule

  Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed 
Rules  

[[Page 24288]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 11, 21, and 25

[Docket No. 28903; Notice No. 97-7]
RIN 2120-AF68


Type Certification Procedures for Changed Products

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to amend the procedural regulations for 
the certification of changes to type certificated products. The 
amendments are need to address the trends toward fewer products that 
are of completely new design and more products with repeated changes of 
previously approved designs. Safety would be enhanced by applying the 
latest airworthiness standards, to the greatest extent practicable, for 
the certification of design changes of aircraft engines, and 
propellers.

DATES: Comments must be received on or before September 2, 1997.

ADDRESSES: Comments on this proposal must be mailed in triplicate to: 
Federal Aviation Administration, Office of the Chief Counsel, 
Attention: Rules Docket (AGC-200, Docket No. 28903, 800 Independence 
Avenue SW, Washington, DC 20591, or delivered in person to room 915G at 
the same address. Comments may also be submitted electronically to the 
following Internet address: [email protected]. Comments submitted 
must be marked: Docket No. 28903. Comments may be inspected in room 
915G weekdays, except Federal holidays, between 8:30 am and 5:00 pm.

FOR FURTHER INFORMATION CONTACT: Lyle C. Davis, Certification 
Procedures Branch (AIR-110), Aircraft Certification Service, Federal 
Aviation Administration, 800 Independence Avenue, SW, Washington, DC 
20591, telephone (202) 267-9588.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the proposed 
rulemaking by submitting such written data, views, or arguments as they 
may desire. Commenters should identify the regulatory docket or notice 
number and submit comments in triplicate to the Rules Docket at the 
address specified above. All comments will be considered by the 
Administrator before action on the proposed rulemaking is taken. The 
proposals contained in this notice may be changed in light of the 
comments received. All comments will be available in the Rules Docket, 
both before and after the closing date for comments, for examination by 
interested persons. A report summarizing each substantive public 
contact with Federal Aviation Administration (FAA) personnel concerning 
this rulemaking will be filed with the docket. Commenters wishing the 
FAA to acknowledge receipt of their comments must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No 28903.'' The postcard will 
be dated and time stamped and returned to the commenter.

Availability of NPRMs

    An electronic copy of this document may be downloaded using a 
modern and suitable communications software from the FAA regulations 
section of the Fedworld electronic bulletin board service (telephone: 
703-321-3339), the Federal Register's electronic bulletin board service 
(telephone: 202-512-1661), or the FAA's Aviation Rulemaking Advisory 
Committee Bulletin Board service (telephone: 202-267-5948).
    Internet users may reach the FAA's web page at http://www.faa.gov 
or the Federal Register's web page at http://www.access.gpo.gov/
su__docs for access to recently published rulemaking documents.
    Any person may obtain a copy of this NPRM by submitting a request 
to the Federal Aviation Administration, Office of Rulemaking, ARM-1, 
800 Independence Avenue SW, Washington, DC 20591; or by calling (202) 
267-9680. Communications must identify the notice number or docket 
number of this NPRM.
    Persons interested in being placed on the mailing list for future 
NPRM's should request from the above office a copy of Advisory Circular 
No. 11-2A, Notice of Proposed Rulemaking Distribution System, that 
describes the application procedure.

Background

Statement of the Problem

    Under the regulations in effect prior to the early 1940's, an 
applicant for a change product, such as an alternate engine 
installation, was required to apply for a new type certificate and 
comply with the standards current at the time of application. This did 
not present an unreasonable burden on the applicant then because the 
airworthiness standards did not change appreciably over short periods 
of time. That is, the standards current at the time of an application 
were essentially the same as those with which the original product had 
to comply. Since the early 1940's, however, rapid changes in technology 
have resulted in significant changes in the airworthiness standards 
over relatively short periods of time. Therefore, an applicant for an 
extensive change to a type certificated product, which required a new 
type certificate, could be faced with complying with safety standards 
that varied considerably from the standards for the original product. 
To relieve this situation, the FAA's predecessor agency required an 
application for a new type certificate only if the change was quite 
extensive.
    In recent years, a trend has developed towards fewer products that 
are of such significantly new design that a new type certificate is 
required. In many cases, over a period of time, a series of changes 
could permissively be made to a product by amending its original type 
certificate such that the resultant model is substantially different 
from the original model. Although each changed product in such a series 
of changes may differ little from its immediate predecessor, the 
changes could collectively result in a product with substantial 
differences from the original product. As a result, many newly 
manufactured aeronautical products are not being required to comply 
with the more recent airworthiness standards. The procedural 
regulations need to be changed to correspond with this trend toward 
fewer new type certificates.

History of Type Certification

    Title 49 U.S.C. Sec. 44701 authorizes the FAA Administrator to 
promote safety of flight of civil aircraft in air commerce by 
prescribing and revising minimum standards governing the design and 
construction of aircraft, aircraft engines, and propellers as may be 
required in the interest of safety, and such minimum standards 
governing appliances as may be required in the interest of safety.
    Under 49 U.S.C. Sec. 44704, the FAA may issue type certificates, 
including supplemental type certificates, for aircraft, aircraft 
engines, and propellers. The FAA may prescribe in any such certificates 
the duration of the certificate, and the terms, conditions, and 
limitations as required in the interest of safety.
    The general certification procedures for products (aircraft, 
aircraft engines, and propellers) and parts are set forth in 14 CFR 
part 21 (part 21). As described

[[Page 24289]]

in Secs. 21.13 and 21.15, any interested person may apply for a type 
certificate by submitting an application accompanied by the required 
documentation to the FAA. Sections 21.16 through 21.21, 21.101, and 
21.115 specify certain regulations and designate the applicable 
airworthiness standards for type certification of both new and changed 
products.
    Section 21.17 designates the applicable regulations for the 
issuance of type certificates. In order to be issued a type 
certificate, the applicant must show that the product complies with the 
airworthiness standards contained in one of the following 14 CFR parts, 
as applicable; part 23 for normal, utility, acrobatic, and commuter 
category airplanes; part 25 for transport category airplanes; part 27 
for normal category rotorcraft; part 29 for transport category 
rotorcraft; part 31 for manned free balloons; part 33 for aircraft 
engines; part 35 for propellers; and part 21 (Sec. 21.17 (b) and (f)) 
for special classes of aircraft and primary category aircraft 
respectively.
    The airworthiness standards in these parts of the regulations may 
be amended as needed to reflect continually changing technology, 
correct design deficiencies, and provide for safety enhancements. An 
applicant for a type certificate is required under current Sec. 21.17, 
with certain exceptions, to show that the product meets the applicable 
airworthiness standards that are in effect at the date of the 
application. The exceptions include instances in which the 
Administrator specifies otherwise or in which the applicant either 
elects or is required under specific circumstances to comply with later 
effective amendments. In addition, the Administrator may prescribe 
special conditions.
    Under Sec. 21.16, special conditions may be prescribed if the 
Administrator finds that the existing airworthiness standards do not 
contain adequate or appropriate safety standards because of novel or 
unusual design features of the product to be type certificated relative 
to the design features considered in the applicable airworthiness 
standards. Also, under Sec. 21.21(b)(1), if any applicable 
airworthiness standards are not complied with, an applicant may 
nevertheless be entitled to a type certificate if the Administrator 
finds that those standards not complied with are compensated for by 
factors that provide an equivalent level of safety. Such determinations 
are commonly referred to as ``equivalent safety findings'' and are made 
with respect to the level of safety intended by the applicable 
standard. In addition, under Sec. 21.21(b)(2), an applicant may be 
denied a type certificate if the Administrator finds an unsafe feature 
or characteristic of the aircraft for the category in which type 
certification is requested, even though the aircraft may comply fully 
with the applicable airworthiness standards.
    Taken together Secs. 21.16, 21.17, and 21.21 designate the 
applicable airworthiness regulations for type certification and 
accommodate those circumstances when the airworthiness standards do not 
adequately cover the design features of a product. These sections 
recognize and balance the following four important considerations:
    (1) The obligation of the FAA, under 49 U.S.C. Sec. 44701, to keep 
the airworthiness standards required in the interest of safety, (i.e., 
parts 23, 25, 27, 29, 31, 33 and 35) as current as practicable;
    (2) The type certificate applicant needs to know, early in a 
certification program, what the applicable airworthiness standards will 
be in order to finalize the detailed design of its product and to 
enable the applicant to make reasonable performance guarantees to its 
potential customers;
    (3) In the interest of safety, rapid technological advances 
presently being made by the civil aircraft industry necessitate that 
the FAA be able to issue special conditions to address novel or unusual 
design features that it has, as yet, not had an opportunity to address 
in the airworthiness standards through the general rulemaking process, 
or to address novel or unusual design features that were not considered 
by the appropriate airworthiness standards applicable to changes to 
type certificates; and
    (4) To allow flexibility in design. Wherever possible, the 
airworthiness standards of 14 CFR Chapter 1, subchapter C, are 
intentionally objective in nature, and the procedural regulations 
permit design changes over the operational life of a product.
    Originally, the FAA would issue special conditions informally as an 
interpretation of the ``no unsafe feature or characteristic'' 
regulations; however, in 1967, the FAA formalized the process with the 
adoption of Sec. 21.16. As provided in that section, special conditions 
are issued as regulations in accordance with public comment provisions 
of 14 CFR part 11 (part 11). The adoption of Sec. 21.16 extended the 
special condition process to include aircraft engines and propellers. 
The provision in Sec. 21.21(b)(2), that a type certificate would be 
issued for an aircraft only if no unsafe feature or characteristic 
existed, remained unchanged.
    The phrase ``novel or unusual'' is used in describing design 
features for the issuance of special conditions under the provisions of 
Sec. 21.16. These design features involve a state of technology not 
considered for the applicable airworthiness standards at the time they 
were written; in some areas, the state of the regulations may lag the 
state of the art of new designs. This disparity is due to both the 
rapidity in which the state of the art is advancing in civil 
aeronautical design and the need to develop a sufficient experience 
base with new technology before proceeding with general rulemaking. 
Therefore, there may be instances in which special conditions are 
required for design features considered ``state of the art'' in the 
aircraft industry. Conversely, many new design features that might be 
thought of as ``novel or unusual'' in the context of the product's 
original certification basis may already be covered by existing 
regulations, thereby obviating the need to issue special conditions. 
This fact is recognized in existing Sec. 21.101(b)(1).
    For example, in 1980, the holder of a small airplane type 
certificate who installed turboprop engines in place of reciprocating 
engines did so by complying with appropriate later regulations. Because 
appropriate regulations were available for the installation of 
turboprop engines, special conditions were not issued for installation 
of the engines. These changes were made through the FAA issuing an 
amendment to the type certificate originally issued in 1964. The 
airworthiness regulations, part 23, were changed to accommodate 
turboprop engines in 1969.
    Special conditions are not issued for general upgrading of the 
applicable airworthiness standards to achieve a higher level of safety. 
Whenever the FAA concludes that a compelling need exists for a higher 
level of safety in type designs, rulemaking is proposed in accordance 
with the general rulemaking procedures of part 11, the Administrative 
Procedure Act, and Executive Order 12866. Finally, Secs. 23.2, 25.2, 
27.2, and 29.2 provide retroactive regulations in the airworthiness 
standards. A complete statement of the FAA intent with respect to the 
application of special conditions is found in the preamble to amendment 
51 to Part 21 (45 FR 60154, September 11, 1980). That intent is in no 
way changed by the proposals herein.
    Sometimes new airworthiness standards contain provisions that, in 
the interest of safety, should be applied

[[Page 24290]]

retroactively to existing aircraft. Typically this is accomplished by 
proposing changes to 14 CFR parts 121 and 135, and sometimes part 91, 
through rulemaking procedures.

History of Type Certification of Changes

    Part 21 designates the applicable airworthiness standards for 
changed products. Section 21.19 describes the circumstances in which an 
applicant for type certification of a changed product must apply for a 
new type certificate. Prior to the early 1940's, an applicant for a 
changed product, such as an airplane with an alternate engine 
installation, was required to apply for a new type certificate. The 
regulations in effect prior to the early 1940's required an applicant 
for a changed product to apply for a new type certificate for a change 
such as an alternate engine installation. When a new type certificate 
was required, the applicant had to comply with the standards current at 
the time of application. This did not present an unreasonable burden on 
the applicant then because the airworthiness standards did not change 
appreciably over a period of time. The then current standards were, 
therefore, essentially the same as those with which the original 
product had to comply. Later, more rapid changes in technology resulted 
in significant changes in the airworthiness standards over relatively 
short periods of time. An applicant for a type certificate for a 
changed product could thus be faced with complying with airworthiness 
standards that varied considerably from those with which the original 
product complied. In some instances, the differences in standards could 
be so great that an applicant would be discouraged from making any 
changes, including changes that would, in themselves, contribute to the 
safety of the product. To relieve this situation, by the early 1940's, 
an application for a new type certificate was required only if the 
change was extensive.
    Section 21.19(a) requires a new type certificate when a change is 
considered so extensive that a substantially complete investigation of 
compliance with the regulations is required. In addition, Secs. 21.19 
(b), (c), and (d) provide specific types of changes that require an 
application for a new type certificate because those types had already 
been determined to be substantial per Sec. 21.19(a). For a normal, 
utility, acrobatic, commuter, or transport category aircraft, paragraph 
(b) requires a new aircraft type certificate if the proposed change is 
(1) in the number of engines or rotors, or (2) to engines or rotors 
using different principles of propulsion or to rotors using different 
principles of operation. Similarly, paragraph (c) requires a new engine 
type certificate if the proposed change is in the engine's principle of 
operation, and paragraph (d) requires a new propeller type certificate 
if the proposed change is in the number of blades or in the principle 
of pitch change operation.
    The basis for Sec. 21.19(b)(1) originated in the early 1950's 
following the issuance of an amended type certificate to an applicant 
who altered a popular single-engine, four-passenger, light airplane 
into a twin-engine model. Although that conversion was approved by an 
amendment to the original type certificate, the agency recognized that 
the conversion from one to two engines added considerable complexity to 
the airplane and greatly affected its handling characteristics. 
Therefore, the predecessor of Sec. 21.19(b)(1) was adopted requiring a 
new type certificate for a change in the number of engines or rotors. 
The regulatory language was broad enough in scope to include any change 
in the number of engines or rotors whether such changes would simplify 
or add complexity to the type design.
    The FAA does not require an applicant to apply for a new type 
certificate to add small auxiliary engines to an aircraft. In the 
1960's with the development of small turbojet engines to be used as 
auxiliary engines, the FAA defined a jet engine that develops less than 
50 percent of the static thrust developed by one of the primary 
propulsion engines as an auxiliary engine. The FAA considers the 
``number of engines'' as used in Sec. 21.19(b)(1) to refer to the 
number of primary propulsion engines and not to any auxiliary engines 
to be installed. The FAA has issued a large number of exemptions from 
the regulation concerning a change in the number of engines.
    Prior to 1957, predecessors of current Sec. 21.19(b)(2) stated that 
an applicant must make a new application for type certificate if the 
proposed change was to engines employing different principles of 
operation or propulsion. This meant that an applicant desiring to 
replace reciprocating engines with the same number of turbopropeller 
engines would have to apply for a new type certificate. During that 
period, it was recognized that considerable advances in safety, 
reliability, and passenger comfort could be realized by replacing 
reciprocating engines in certain transport category airplanes with 
turbopropeller engines. In order to encourage such beneficial changes, 
the reference to different principles of operation was deleted in 1957 
for transport category airplanes. As a result, an applicant may be 
granted approval for a conversion of this nature without applying for a 
new type certificate providing the applicant complies with certain 
later standards applicable to turbine-powered airplanes. In the 
broadest sense, all powered airplanes achieve propulsion by 
accelerating a mass of air and/or exhaust gases. In the narrower 
context of Sec. 21.19(b)(2), however, ``principles of propulsion'' 
means propeller-driven versus turbojet.
    Section 21.19(b)(2) also states that an applicant must make a new 
application for a type certificate if the proposed change is to rotors 
employing different principles of operation or propulsion. The FAA is 
not aware of any instance in which this specific section was the basis 
for requiring an application for a new type certificate; any change of 
this nature, together with all related changes, would have been so 
extensive that a new type certificate would have been required under 
the provisions of Sec. 21.19(a).
    The FAA has never granted any exemptions from the regulation for a 
new aircraft type certificate for a change to engines or rotors using 
different principles of propulsion. Similarly, no exemptions have been 
granted from the engine or propeller type certificate regulations for 
changes involving the principle of engine operation, for changes in the 
number of propeller blades, or for changes in the principle of pitch 
change operation.
    Under Sec. 21.101, the original type certificate may be amended to 
include changes to the product when the applicant demonstrates that it 
complies with the same airworthiness standards as the original product 
plus appropriate special conditions, and the change does not warrant 
making a new application for a type certificate under Sec. 21.19. 
Because Sec. 21.101 (a) and (b) are incorporated by reference in 
Sec. 21.115, these procedures are equally applicable to persons 
applying for supplemental type certificates.
    Section 21.101(a) requires that an applicant for a change to a type 
certificate must comply with either the regulations incorporated by 
reference in the type certificate or the applicable regulations in 
effect at the date of application, plus any other amendments the 
Administrator finds to be directly related. The ``regulations 
incorporated by reference'' are the regulations that were the 
certification basis for the original issuance of the type certificate. 
They are frequently referred to as the ``original certification 
basis.''

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    If an applicant chooses to show compliance with the regulations in 
effect at the date of the application for the change, the applicant 
must also comply with any other amendments that are directly related. 
In some instances, a regulation may be amended to become less 
stringent, but a related regulation may become more stringent. In a 
situation of this nature, the applicant must also comply with the 
related compensating regulation as well. Current Sec. 21.101(a) does 
not otherwise require compliance with later amendments and does not 
grant the Administrator the authority to require compliance with later 
regulations as a method to increase the level of safety of a product.
    An applicant for a change to a type certificated product is 
responsible for showing that the entire product, as altered, not just 
that the change itself, complies with the certification basis, because 
areas that have not been changed may be affected by the change. 
However, the applicant need not resubstantiate those areas of the 
product where the original substantiation has not been invalidated by 
the change.
    Section 21.101(b) pertains to changes for which the regulations 
incorporated by reference do not provide adequate standards. Such 
changes generally involve features that were not envisaged at the time 
the regulations incorporated by reference were adopted and are, 
therefore, novel or unusual with respect to those regulations. For 
these changes, the applicant must comply with regulations in effect at 
the date of application for the change as found necessary to provide a 
level of safety equal to that established by the regulations 
incorporated by reference. In this case, the applicant is not able to 
select any amendment of the regulation it chooses between those 
incorporated by reference and those in existence at the date of the 
application. When regulations in effect at the date of application for 
the change fail to provide adequate standards, the applicant must 
comply with special conditions to provide a level of safety equal to 
that established by the regulations incorporated by reference.

Trends in Type Certification of Changes

    In recent years, a trend has developed toward fewer products that 
are of completely new designs, which would require new type 
certificates. Over a period of time, a series of changes to an original 
product may have been made so that the current model is substantially 
different from the original model. Although each changed product in 
such a series of changes may differ little from its immediate 
predecessor, the changes could result collectively in a product with 
substantial differences from the original product.
    For example, one model originally manufactured as a normal category 
airplane with two reciprocating engines has been changed through a 
series of alterations to incorporate turbopropeller engines, a 
stretched and heightened fuselage, a tricycle landing gear, a modified 
wing planform and a 42 percent increase in maximum takeoff weight. In 
this particular case, the majority of changes were made through the 
FAA's issuing supplemental type certificates to modifiers other than 
type certificate holder. However, the type certificate holder could 
have made the same incremental changes without applying for a new type 
certificate each time.
    In another instance, a type certificate holder effected significant 
changes in the design of a turbojet transport category airplane without 
obtaining a new type certificate by making a series of changes to its 
existing type certificate. Each incremental change, by itself, was 
determined not to be so extensive as to require a new type certificate 
under Sec. 21.19(a). This airplane evolved into a configuration 
approximately 40 percent greater in fuselage length and with a 92 
percent greater maximum takeoff weight than the original model. These 
changes, which have been incorporated into newly manufactured 
airplanes, are possible because the FAA issued amendments to the type 
certificate.
    Another trend in manufacturing is to keep products in production 
over several decades. Some currently manufactured transport category 
airplanes have, for example, evolved from airplane models originally 
type-certificated 25 years ago. This does not imply that those 
airplanes are ``unsafe,'' because they do, in practice, have features 
that address the intent of most of the current airworthiness standards. 
However, current procedural regulations (part 21) do not require that 
changed products comply with the current airworthiness standards.
    The basic premise behind the FAA's current policies for the 
procedures and airworthiness standards for type certification is that 
the highest possible degree of safety in the public interest, should be 
achieved by products being certificated at any given time. In dealing 
with this premise, the FAA has had to continually weigh the desire for 
the highest level of safety with the cost to the manufacturers, 
operators, and traveling public for achieving that highest possible 
degree of safety in the public interest. This balance between safety 
and cost has been exacerbated by the introduction of highly 
sophisticated products whose development and manufacture have become 
enormously expensive. This is one reason why, as stated before, 
manufacturers choose to produce more and more changed products that, by 
the FAA regulations, are not required to have new type certificates.
    The FAA maintains that the issue should not be whether a product is 
produced under a new type certificate or an amended one. The issue is 
whether or not the level of safety of the product, embodied in the 
airworthiness standards it complies with, is as high as practicable. In 
addition, to require areas unaffected by the change to comply with the 
later standards is not only unreasonably costly but may reduce the 
level of safety of the product due to unforeseen developmental 
problems. The manufacturers are constantly issuing service information 
that describes approved alterations that users may make to improve the 
level of safety of the product. Thus, it is common place that products 
in service today possess a level of safety significantly greater than 
that embodied in their certification basis.
    When establishing the highest practicable level of safety for a 
changed product, the FAA has determined that it is appropriate to 
assess the service history of a product as well as the later 
airworthiness standards. It makes little sense to mandate changes to 
well understood designs, whose service experience has been acceptable, 
merely to comply with new standards. The clear exception to this 
premise is where the new standards were issued to address a deficiency 
in the design in question or where the service experience is not 
applicable to the new standards. This consideration of airworthiness 
standards and service experience should form the basis for developing 
the ceritifcaiton basis for a change in a product.
    It can be argued, for consistency, that new airworthiness standards 
should apply across the board to the entire aircraft fleet; however, 
application of new standards would not be practicable in every case. 
Although newly designed aircraft are required to meet all applicable 
current airworthiness standards, in many cases a product being changed, 
for which only an amended type certificate is needed, is required to 
meet only the standards referenced in the original type certificate. 
Thus, there may be a considerable difference between the standards 
required for a new product and for a product undergoing change. A

[[Page 24292]]

product undergoing change that met the applicable standards at the time 
of original type certification is not currently required to meet more 
current airworthiness standards except in those instances where 
retroactive regulations have been issued or the applicant elects to 
comply with later amendments.
    In recent rulemakings, the FAA has carefully considered whether 
corresponding retroactive action is warranted whenever a change to the 
airworthiness standards for type certification was proposed. In those 
cases where it has been deemed that a safety benefit commensurate with 
the cost could be achieved, the rulemaking has also included a proposal 
to change the relevant operating regulations to require newly 
manufactured airplanes and/or airplanes in service to comply 
retroactively with the new standards, regardless of whether such 
compliance would be required as a condition of type certification. For 
instance, some of the regulations implemented in recent revisions to 
part 25 for newly manufactured airplanes were required for the existing 
fleet and were implemented in the operating regulations, such as part 
121.
    In 1965, the FAA granted an exemption from the provisions of 
Sec. 21.19(b)(1) to permit conversion of a four-engine amphibian to a 
twin-engine configuration without the applicant applying for a new type 
certificate. During the 1980's three applicants petitioned for 
exemptions from the above regulations so they could convert Boeing 727 
airplanes from the original three-engine configuration to ones with two 
engines without having to apply for new type certificates. Another 
applicant petitioned for a similar exemption to replace the four 
engines of a Lockheed 1329 Jetstar aircraft with two engines of more 
recent vintage. The FAA granted each exemption with the condition that 
the petitioner comply with the provisions of then current part 25 in 
all areas, systems, components, equipment, or appliances affected by 
the conversion.
    The FAA also granted a number of exemptions that permitted 
increasing the number of engines without the need for the applicants to 
obtain new type certificates. In 1985, an applicant received an 
exemption to replace two reciprocating engines in Grumman Albatross 
amphibians with four turbo propeller engines without having to obtain a 
new type certificate. In granting the exemption, the FAA concurred that 
the alteration should improve the Albatross by increasing safety, 
increasing power plant reliability, and improving overall aircraft 
efficiency. The exemption noted that compliance with Sec. 21.19(b)(1) 
would have required changes to some basic systems that had provided 
satisfactory performance for many years and had contributed to the 
safety record of those airplanes. Applying then-current regulations to 
components and systems not affected by the installation of the four 
engines would have been time consuming and costly, and would not 
necessarily have contributed any safety benefits. As with the 
exemptions to reduce the number of engines, this exemption was granted 
with the condition that the petitioner comply with the provisions of 
then current part 25 in all areas, systems, components, equipment, or 
appliances affected by the conversion.
    A similar exemptions also granted in 1989 to enable an applicant to 
increase the number of engines from one to two in certain Bel 206 
series rotorcraft. The petitioner cited the increased safety afforded 
by a twin-engine configuration in the event a failure occurred during 
hover, and also the enhanced altitude performance. As a condition of 
the grant of exemption, the applicant was required to show that the 
altered rotorcraft complied with the standards of part 27 in effect at 
the date of application for the change for all areas, systems, 
equipment, or appliances that were changed or significantly affected by 
the change.
    These exemptions point out an important feature that has been 
included in this proposed rulemaking. The number of engines is not, in 
itself, an appropriate criterion for requiring an application for a new 
type certificate as long as the type design complies with the 
regulations effective at the date of the application for the change in 
those areas changed or affected by the change.

Recent FAA Actions

    Apart from safety considerations, there has also been a growing 
international concern that some changed products are given an unfair 
competitive advantage over those that are of new design and must comply 
with later standards.
    Because of these concerns, the FAA participated in the activities 
of an ad hoc committee sponsored by the Aerospace Industries 
Association of America, known as the International Certification 
Procedures Task Force (ICPTF). In addition to the FAA, this task force 
included representatives of the European Joint Aviation Authorities, 
Transport Canada, Aerospace Industries Association of America, Air 
Transport Association of America, General Aviation Manufacturers 
Association, International Air Transport Association, Association 
Europeenne des Constructeurs de Materiel Aerospatial, Aerospace 
Industries Association of Canada, Air Line Pilots Association, and 
Association of European Airlines.
    The ICPTF was organized to develop the philosophy and the necessary 
regulatory text and advisory material that would provide for the 
implementation of later regulatory amendments applicable to 
aeronautical products undergoing change, products in production, and 
products in service. The specific tasks of the ICPTF were: (1) Develop 
the type certification philosophy for changes to aeronautical products, 
including revisions to the regulations and associated advisory 
material; (2) Develop the necessary guidance information on the use of 
``service experience'' in the type certification process; and (3) 
Develop a method to evaluate the safety impact and cost effectiveness 
of revisions to the airworthiness standards.
    In order to develop future proposed safety standards by using a 
system-type analysis, the FAA chartered a committee of safety experts, 
known as the Aviation Rulemaking Advisory Committee (ARAC), on February 
5, 1991. This committee established the International Certification 
Procedures Working Group, which consists of the original ad hoc 
committee formerly known as the ICPTF. The task assigned to this 
working group was to present to ARAC various proposals pursuant to its 
area of expertise. ARAC then had the option to submit these 
recommendations to the FAA, and the FAA would decide whether or not to 
issue a proposal based on the ARAC recommendations.
    The Working Group presented to ARAC an NPRM and associated advisory 
material concerning the type certification procedures for changes to 
aeronautical products, newly manufactured products, and products 
already in service. ARAC, in turn, submitted these documents as 
recommendations to the FAA. The FAA recognizes the difficult task the 
working group undertook in the effort to address the issues in this 
proposed rule and in the advisory material. Much of the work done 
within the working group could not have been accomplished without the 
assistance of working group members representing the aviation 
community. The rulemaking proposed by the FAA in this notice reflects 
the ARAC recommendations in the type certification procedures for 
changed products with only minor changes. Similar proposed changes have 
been published by the Joint Aviation Authorities.

[[Page 24293]]

FAA's Proposed Policy on Changed Products

    The FAA intends to require that applicants for changes to type 
certificated products show compliance with the latest amendments to the 
airworthiness standards that are applicable to the product being 
changed. Exceptions to requiring a showing of compliance with the later 
amendments would be provided to accommodate variations in the kinds of 
type certificated products, of changes to these type certificated 
products, and revisions of the airworthiness standards. These 
exceptions would permit compliance with regulations issued prior to the 
regulations in effect at the date of the application for the change.
    This proposed rulemaking would amend the type certification 
procedures for changes to type certificated products to bring the 
certification basis for changed products and for newly type 
certificated products closer together. The intent is to ensure that 
when an essentially new product is developed through a series of 
changes, regardless of the extent of each change, the final product 
achieves a level of safety similar to that of a comparable new product. 
This concept will be tempered with the knowledge that a good design 
does not become unsafe as soon as a new regulation has been published.
    Some differences may be acceptable between the certification basis 
for a product undergoing a change and the current regulations that 
would be applicable if a new product was being type certificated. This 
acceptance would be based on whether there is a defined safety issue 
involved in the specific product.
    The FAA is already encouraging applicants of certain type 
certificated products undergoing alterations to comply with later 
amendments of the airworthiness standards. By this rulemaking, the FAA 
proposes to require all proposed changes for all type certificated 
products to comply with later amendments of the airworthiness 
standards. The long term result of this approach will be that an 
amended type certificate will have a certification basis that provides 
a similar level of safety to that provided by the certification basis 
of a new type certificate for the same product.
    The FAA will issue an advisory circular based on this rulemaking. 
This advisory circular will provide guidance on determining the 
certification basis for changed aeronautical products, including 
identifying the conditions under which it will be necessary to apply 
for a new type certificate. By separate notice, in this issue of the 
Federal Register, the FAA is also inviting interested persons to 
comment on the proposed advisory circular. The FAA will consider 
comments from this notice and comments received on the advisory 
circular before taking any final action on either.

Discussion of the Proposed Rulemaking

    Sections 11.11, 21.19, 21.101, 21.115, and 25.2 would be amended as 
follows to implement the policy discussed above in relation to changes 
to products:

Section 11.11

    Current Sec. 11.11 lists special conditions required as prescribed 
under Sec. 21.101(b)(2) as an FAA record that is maintained in current 
docket form in the Office of the Chief Counsel. To remain consistent 
with the proposed changes to Sec. 21.101, described later, it is 
necessary to amend Sec. 11.11 to refer to Sec. 21.101(c) instead of 
Sec. 21.101(b)(2). This would not be a substantive change.

Section 21.19

    Current Sec. 21.19(a) states that any person who proposes to change 
a product must make a new application for a type certificate if the 
Administrator finds that the proposed change in design, configuration, 
power, power limitation (engines), speed limitations (engines), or 
weight is so extensive that a substantially complete investigation of 
compliance with the applicable regulations is required. This sentence 
has caused confusion because it covers several types of changes for all 
products--airplanes, rotorcraft, aircraft engines, and propellers. In 
addition, current paragraph (b), (c), and (d) list other specific types 
of changes that mandate a new application for a type certificate. Only 
the general language of current paragraph (a) would be incorporated 
into the new Sec. 21.19, while the previously listed specific changes 
would be subject to case-specific evaluations to determine whether they 
are substantial. Application of Sec. 21.19 would depend upon an 
evaluation of whether the proposed change in ``design, power, thrust, 
or weight'' would necessitate a substantially complete investigation of 
the compliance of the changed product. Each of the following airplane 
design changes, considered alone, could typically be regarded as 
substantial design change:
    (1) Change from a high wing to a low wing airplane, or vice versa;
    (2) Change of empennage configuration for larger airplanes 
(cruciform vs `T' or `V' tail);
    (3) Complete repositioning of engines (tail to wing, etc.); and
    (4) An increase in airplane design complexity resulting from an 
increase in the number of engines.
    Currently Sec. 21.19(b) describes specific changes for which the 
applicant must apply for a new aircraft type certificate. These include 
(1) changes in the number of engines or rotors; and (2) changes to 
engines or rotors using different principles of propulsion or to rotors 
using different principles of operation. Historically, these types of 
changes have fallen into one of two categories--those that were not 
extensive enough to require a new application for a type certificate, 
as evidenced by the large number of exemptions that have been granted 
over the past quarter century, or those that were so extensive that a 
new application was required because a complete investigation of 
compliance is required. Accordingly, the provisions of current 
Sec. 21.19(b) are not needed and are not included in this proposal. The 
exemptions that have been granted from current Sec. 21.19(b) have 
typically required that those areas, systems, components, equipment, 
and appliances that are changed or significantly affected by the change 
must comply with the applicable regulations in effect at the date of 
the application for that change. This requirement would be embodied in 
proposed Sec. 21.101, which would generally require that an applicant 
for a change to a type certificate must comply with the regulations in 
effect at the date of the application for that change, with an 
exception, however, that those areas, systems, components, equipment, 
and appliances not affected by the change could continue to comply with 
the regulations incorporated in the reference type certification basis. 
Accordingly, this proposed amendment would be consistent with the 
exemptions that have been granted on changes in the number of engines. 
The need for requiring a new application for a type certificate would 
be alleviated in many instances by the proposed changes to Sec. 21.101.
    Current Sec. 21.19(c) describes another specific change in which 
the applicant must apply for a new aircraft engine type certificate. 
This change is in the principle of operation. Also, current 
Sec. 21.19(d) describes specific changes in which the applicant must 
apply for a new propeller type certificate. These changes are in the 
number of blades or principle of pitch change operation. Invariably, 
the type of changes set forth in both of these sections are so 
extensive that a new application would be required in any event because 
a

[[Page 24294]]

complete investigation of compliance is required. Accordingly, this 
proposal would delete these types of changes from Sec. 21.19. Under 
proposed Sec. 21.101, with certain exceptions, these types of changes 
and all areas, systems, components, equipment, and appliances affected 
by the changes would have to comply with the regulations in effect at 
the date of application for the change to the type certificate.

Section 21.101

    Current Sec. 21.101(a) states that if a person applies for a change 
in a type certificate, the product must comply with either the 
regulations referenced in the type certificate or the applicable 
regulations in effect at the date of the application for the change, if 
elected by the applicant, plus any other amendments the Administrator 
finds to be directly related.
    Current paragraph (b) addresses novel or unusual design features 
where the Administrator finds that the regulations incorporated by 
reference in the type certificate do not provide adequate standards. In 
this case the applicant must comply with the regulations in effect at 
the date of the application for the change and any necessary special 
conditions ``to provide a level of safety equal to that established by 
the regulations incorporated by reference in the type certificate for 
the product.'' This means that the level of safety must be at least 
equal to the level of safety that was required by the regulations 
referenced in the type certificate.
    To ensure that the products meet the latest airworthiness standards 
wherever practicable, proposed Sec. 21.101 would specify that, with 
certain exceptions, the applicant for a change must comply with the 
applicable regulations in effect at the date of the application for the 
change. The intent of this proposal is to apply the applicable 
regulations in effect at the date of the application to those areas, 
systems, components, equipment, and appliances affected by the change. 
For those areas, systems, components, equipment, and appliances not 
affected by the change, continued compliance with the regulations 
incorporated by reference in the type certificate is considered 
acceptable.
Section 21.101(a)
    This proposed paragraph would require an applicant for a change to 
a type certificate to comply with the applicable regulations in effect 
at the date of the application for the change, also referred to as the 
later regulations, and with parts 34 and 36.
Section 21.101(b)
    This proposed paragraph would provide exceptions to the regulation 
in proposed paragraph (a), permitting the applicant to comply with 
earlier amendments to the regulations. A ``regulation'' as used herein 
means individual paragraphs of the Federal Aviation Regulations or 
predecessor regulations. When choosing the amendment level of a 
regulation, all related regulations associated with that amendment 
level would have to be included. The amendment level chosen would not 
be allowed to predate either the existing basis or anything required by 
the retroactive sections, Secs. 23.2, 25.2, 27.2, or 29.2. Design 
changes vary in both complexity and magnitude so it is necessary for 
each proposed change to be evaluated on a case by case basis, taking 
into account previous changes and their certification basis. Individual 
incremental changes may be modest; however, the cumulative effect can 
result in a significant overall change. In this context, the following 
factors should be considered: (1) the extent of the previous changes 
and the extent to which later amendments have been addressed for these 
individual changes; and (2) the extent of revisions to the 
airworthiness standards from those of the original certification basis 
of the model being changed. When an essentially new product is 
developed, step by step, through a series of non-substantial design 
changes, it should achieve a level of safety similar to that of a 
comparable new product.
    Substantial changes are addressed in Sec. 21.19. Those that are not 
substantial will be either nonsignificant or significant. A small 
weight increase or the installation of a flight management system is an 
example of a non-significant change. The installation of a cargo door 
is an example of a significant change. A change from a low wing to a 
high wing is an example of a substantial change.
    In evaluating a design and making the final determination of 
nonsignificant or significant, under the exceptions provided for in 
Sec. 21.101(b), the FAA would rely on documented engineering, safety, 
and economic data. Any data submitted by the applicant should have the 
same degree of thoroughness and engineering quality expected for 
initial compliance with airworthiness standards.
Section 21.101(b)(1)
    This proposed paragraph would provide the first exception to the 
regulation in proposed paragraph (a), to show compliance with the later 
applicable regulations. The proposed paragraph would state that the 
applicant would be allowed to demonstrate compliance with earlier 
regulations, but not earlier than the regulations incorporated in the 
existing certification basis, if the effect of the proposed change is 
not significant, taking into account earlier design changes and 
previous updating of the type certification basis.
    There may be concurrent significant and non-significant changes 
made to a product. For example, there may be a small change in the 
model of engines used at the same time large changes are made to the 
airframe. Each part of the total change would be evaluated to determine 
its significance on its own merit. It must be recognized, however, that 
a number of related non-significant changes may collectively represent 
a significant change to the product.
Section 21.101(b)(2)
    This proposed paragraph would provide the second exception to the 
regulation in proposed paragraph (a), to show compliance with the later 
applicable regulations. The proposed paragraph would state that the 
applicant may show compliance with earlier regulations for those areas, 
systems, components, equipment, and appliances that are not affected by 
the change.
    The FAA recognizes that arbitrarily requiring compliance with later 
regulations in areas, systems, components, equipment, and appliances 
not affected by the change may cause redesign of components that have 
an acceptable service record without an attendant improvement in 
safety, or may have the counterproductive effect of discouraging any 
changes at all, including those that would provide a notable 
improvement in safety.
Section 21.101(b)(3)
    This proposed paragraph would provide the third exception to the 
regulation in proposed paragraph (a) to show compliance with the later 
applicable regulations. If compliance with a regulation in effect at 
the date of the application for the change would not contribute 
materially to the level of safety of the product to be changed, or 
would be impractical, the applicant may demonstrate compliance with an 
earlier amendment of a regulation provided that the amended regulation 
does not precede either the corresponding regulation in Secs. 23.2, 
25.2, 27.2, or 29.2 of this chapter, or the corresponding regulation 
incorporated by reference in the type certificate.
    Compliance with the later amendment would be considered to ``not 
materially

[[Page 24295]]

contribute to the level of safety'' if the level of safety achieved by 
the existing design with the proposed design change would not be 
enhanced by compliance with that later amendment. In demonstrating 
this, the applicant would show that the level of safety achieved by the 
existing design incorporating the proposed design change would achieve 
a safety level similar to that reflected in the later amendment.
    The factors that would be considered in comparing the level of 
safety achieved by the existing design incorporating the proposed 
design change with the level of safety achieved by compliance with the 
later amendment would include: whether the product has compensating 
design features; the extent that the service experience of the product 
shows that the operational performance and reliability of the product 
provides a level of safety similar to that of later amendments; and 
whether compliance with a later amendment, notably when it necessitates 
a redesign, would have an adverse effect on safety in terms of 
operational performance and reliability.
    Nothing would limit the future operation or transfer of a product 
after a design change is approved with an older certification basis; 
furthermore, the intent of this proposal is to establish certification 
bases appropriate to the designs of the products and the designs of the 
changes. Therefore, if an applicant for a design change is changing one 
or two items of a product, and another applicant is making the same 
change to 100 items of the same product, the applicant's design changes 
should be certificated to the same basis.
    Demonstrating that compliance with later regulations would not 
materially contribute to the level of safety could necessitate analyses 
of the safety features of the existing design and the proposed change, 
and an analysis of the safety concerns addressed by the relevant 
amendment. The evaluation may be accomplished using a numerical-
statistical approach, subject to the availability and relevance of 
applicable data. In practice, engineering judgment, based on 
scientific, rational, and reasoned analysis of the relevant data, would 
be used in the development of this evaluation. The essentials of the 
evaluation would involve:
    a. A clear understanding of the regulatory change and what prompted 
the change;
    b. A detailed knowledge of the proposed design feature; and
    c. A comprehensive review of the applicable service experience.
    An applicant may be unable to show that compliance with the 
original certification basis, together with the level of safety 
demonstrated by the applicable service experience, provides a level of 
safety similar to that of the later airworthiness regulations. If 
compliance with the later airworthiness regulations would then involve 
a design change, the benefits of such a redesign would be considered in 
the light of any possible adverse effects of the redesign on safety.
    An applicant for a change to a type certificate would not be 
required to demonstrate that the changed product complies with a later 
amendment to an airworthiness standard if the applicant shows that such 
compliance would be ``impractical.'' Compliance with a later amendment 
would be considered ``impractical'' when the applicant can establish 
that the cost of the design change and related changes necessary to 
demonstrate compliance with the amendment would not be commensurate 
with the resultant safety benefit. Where compliance with the later 
amendment would prompt a redesign, the cost of redesigning other parts 
of the product to accommodate this redesign also would be considered.
    The FAA continually weighs the desire for the maximum level of 
safety with the cost to the manufacturers, operators, and traveling 
public for achieving that level of safety. If the designer of an 
aircraft in development is tasked with incorporating a ``change'' to a 
system in that new design, the designer usually has many more options 
in making ``changes'' to related systems to accommodate the ``change.'' 
Conversely, the systems related to a system to be changed in a 
certificated design have been established, and there may be few such 
options, if any. These restraints are exacerbated by a change in the 
certification basis, and the consideration of the service experience of 
the product. Under these conditions, it may become unreasonably costly 
for the change to comply with the latest standards.
    A safety benefit-resource evaluation could be used to assist in 
determining impracticality, and would be discussed between the 
applicant and the Administrator while establishing the certification 
basis. The economic issues associated with compliance with the later 
amended airworthiness standards would be a major portion of this 
evaluation.
    Any safety benefit-resource evaluation used to determine 
``impractical'' should evaluate the enhancement of the safety involved 
with complying with the airworthiness regulation under consideration 
along with the cost associated with this compliance. This evaluation 
would weigh the factors associated with the safety benefit and the 
factors associated with the cost of compliance.
    The factors involved with the safety issue could include 
seriousness of the consequences of the hazard that the regulatory 
change addresses, frequency, of those consequences, and the 
effectiveness of applying the regulatory change to the changed product. 
The factors involved with the cost of compliance could include labor, 
new capital equipment needed, materials, operating cost increase, and 
revenue loss. The agency is seeking comments on this concept of using 
``Impractical'' as defined herein.
Associated Advisory Circular
    The proposed associated advisory circular includes guidance for 
purposes of complying with the requirements of this proposed rule. This 
advisory circular also contains a safety benefit-resources evaluation 
guide, which was recommended by the ARAC to be an acceptable means of 
compliance with the exceptions of proposed Sec. 21.101(b). As elsewhere 
in this edition of the Federal Register, the safety benefit-resource 
evaluation guide has been included in the draft advisory circular for 
purposes of information only. The safety benefit-resource guide does 
describe some of the kinds of issues that the applicant would address, 
and the FAA would consider, in determining the certification basis in 
accordance with this proposed rule.
Section 21.101(c)
    This proposed paragraph would contain the provisions of current 
Sec. 21.101(b)(2) concerning special conditions. For consistency with 
the other proposed changes to Sec. 21.101, this paragraph would state 
that an applicant for a change must comply with any special conditions, 
and amendments to those special conditions, if needed, that would 
provide a level of safety equal to that established by the regulations 
in effect at the date of the application for the change. The 
interpretation of ``novel or unusual design features'' shall be the 
same as present practice under current Sec. 21.101(b)(2). The 
provisions of current Sec. 21.101(b)(1), concerning the use of later 
regulations when the regulations incorporated by reference do not 
provide adequate standards with respect to the proposed change, would 
no longer be needed and would not be incorporated into the proposed 
regulation. This is because proposed Sec. 21.101(a) would require the 
use of later regulations.

[[Page 24296]]

    The provisions of current Sec. 21.101(c), concerning the 
replacement of reciprocating engines with turbopropeller engines, are 
not incorporated into the proposed regulation. A change of this nature 
would be considered a significant change, and compliance with the 
regulations in effect at the date of application for the change, 
therefore, would be required.
Section 21.101(d)
    This proposed paragraph would state that an application for a 
change to a type certificate for a transport category aircraft would be 
effective for 5 years, and an application for a change to a type 
certificate for all other products would be effective for 3 years. 
These proposed effectivity periods for an application are the same as 
those in current Sec. 21.17 (c) and (d) for an application for a type 
certificate. Because current Sec. 21.101 requires compliance with the 
regulations incorporated by reference in the type certificate and 
because the certification basis of the original product doesn't change, 
having an effectivity period for an application for a design change has 
not been necessary. Under the proposed Sec. 21.101, which would require 
meeting the airworthiness standards in effect at the date of the 
application for the change, it is necessary to limit the effectivity of 
the application for a change, to support the intent of the proposed 
regulation. This proposed section would state that if an application 
for a design change expires, an applicant may file a new application or 
apply for an extension of the original application as in present 
Sec. 21.17 (c) and (d).
Section 21.101(e)
    This proposed paragraph would contain procedures that would be 
applicable for changes of aircraft, aircraft engines, and propellers 
that have been type certificated using the airworthiness standards 
listed in Chapter 1. Proposed paragraph (e)(1) of Sec. 21.101 would 
mandate that the certification basis for a change to a product 
certificated under the applicable regulations that preceded parts 23, 
25, 27, 29, 31, 33, or 35 would be established in the same manner as a 
change to a product certificated under one of these parts. For example, 
an applicant would be required to show compliance with the latest 
amendment(s) under part 23 that would apply to a change to a small 
airplane originally certificated under Part 3 of the Civil Air 
Regulations (CAR 3). A change to an airplane type certificated under 
Special Federal Aviation Regulation No. 41 (SFAR 41), would be handled 
somewhat differently. The SFAR 41 requirements incorporated by 
reference in the type certificate of such an airplane have expired, and 
may no longer be used for purposes of issuing certificates; 
accordingly, under proposed Sec. 21.101, only the latest amendments of 
the part 23 requirements of the SFAR 41 certification basis would be 
applicable for a change to an SFAR 41 airplane design.
    Applicability of this proposed regulation would include changes to 
products type certificated under Secs. 21.21 and 21.29. In addition, 
these proposed procedures would be applicable for changes of aircraft 
that have been type certificated under Secs. 21.24, 21.25, 21.27, and 
special classes of aircraft, where a part of the certification basis 
contains regulations from the airworthiness standards listed in Chapter 
1.
    At first glance, because some of the certification basis of 
aircraft type certificated under Secs. 21.24, 21.25, 21.27, and special 
classes of aircraft do not completely consist of airworthiness 
standards of the Federal Aviation Regulations, aircraft type 
certificated under these regulations may not appear to completely 
benefit from the procedures of this proposed rulemaking. However, after 
careful consideration, the FAA has determined that the level of safety 
of changes to an aircraft that has been type certificated under any of 
these regulations, would benefit from the enhanced safety associated 
with the appropriate later amendments of those portions of the 
airworthiness standards that are a part of the certification basis. 
This takes into consideration that the certification basis, in some 
cases, may consist of airworthiness standards as well as other 
requirements found by the Administrator to be necessary to provide an 
equivalent level of safety.
    For example, the certification basis for a special class aircraft 
or primary category aircraft may be based, in part, on portions of 
those airworthiness standards contained in Chapter 1 that were found by 
the Administrator to be appropriate for the specific type design. Since 
revisions are frequently made to the airworthiness standards to upgrade 
the minimum level of safety required for civilian aircraft and to 
incorporate certification standards for modern-state-of-the-art 
technology, it seems logical that the level of safety of changes to 
special class aircraft would benefit from compliance with the later 
airworthiness standards. These proposed procedures would apply only to 
those parts of the certification basis that were obtained from the 
airworthiness standards listed in Chapter 1.
    Joint Aviation Requirements, JAR 22, is a published regulation 
being used as a means of compliance by the FAA for gliders, as a 
special class of aircraft, but this regulation is not listed in Chapter 
1; therefore, the proposed procedures would not be applicable in this 
case. Although these procedures are not intended to be applicable to 
the Joint Aviation Requirements, an applicant may comply with thee 
procedures when the Administrator finds them acceptable for a specific 
application.
    Surplus military aircraft, type certificated in the restricted 
category under Sec. 21.25(a)(2), normally are accepted on the basis of 
the previous military qualifications acceptance and service record in 
lieu of showing compliance with airworthiness standards in Chapter 1. 
However, a change to these aircraft for a special purpose operation 
usually is not supported by the military service history and needs to 
comply with an airworthiness standard. Compliance with the later 
amended airworthiness standard for the change would not be appropriate 
as the aircraft did not meet an airworthiness standard initially.
    Limited category aircraft are surplus military aircraft, mostly 
from World War II, that were type certificated under Part 9 of the 
Civil Air Regulations for use other than air transport. These aircraft 
were not intended to carry persons or property for compensation or 
hire, and normally were accepted on the basis of their previous 
military qualifications acceptance and service record. However, a 
change to these aircraft usually is not supported by the military 
service history, therefore, the change must comply with appropriate 
airworthiness standards. It seems logical that the level of safety of 
changes to aircraft that have not been type certificated to an 
airworthiness standard would not benefit from compliance with the later 
airworthiness standards.

Section 21.115

    The type certificate holder may obtain approval for a change either 
by amending the type certificate under Sec. 21.101 or by obtaining a 
supplemental type certificate under Sec. 21.115. Any other modifier 
would have to obtain a supplemental type certificate under Sec. 21.115. 
There should not be a difference in the certification basis for a 
change to a type certificated product between these two methods of 
approval, amended type certificate or supplemental type certificate.
    Current Sec. 21.115 incorporates the provisions of current 
Sec. 21.101(a) and (b)

[[Page 24297]]

by reference, making the provisions of the latter section equally 
applicable to applicants for supplemental type certificates. In view of 
the proposed changes to Sec. 21.101, it is necessary to amend 
Sec. 21.115 to refer simply to Sec. 21.101 rather than specifically to 
Sec. 21.101(a) and (b). This would not be a substantive change.

Section 25.2

    Current Sec. 25.2(c) incorporates the provisions of current 
Secs. 21.101(a)(2) and (b) by reference, addressing the subsequent 
revisions to the special retroactive regulations. To remain consistent 
with the proposed changes to Sec. 21.101, it is necessary to amend 
Sec. 25.2(c) to refer to Sec. 21.101(a). This would not be a 
substantive change.

Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1980 (Pub. L. 96-
511), there are no requirements for information collection associated 
with this proposed rule.

International Compatibility

    The proposal results, primarily, from a recommendation harmonized 
with the aviation authorities of Canada and Europe. Similar 
corresponding changes to regulations governing type certification 
procedures for changed products are being proposed by Transport Canada 
and the Joint Aviation Authorities.

Regulatory Evaluation, Regulatory Flexibility Determination, and Trade 
Impact Assessment

    Changes to federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs Federal agencies to 
promulgate new regulations or modify existing regulations only if the 
potential benefits to society outweigh the potential costs. Second, the 
Regulatory Flexibility Act of 1980 requires agencies to analyze the 
economic impact of regulatory changes on small entities. Finally, the 
Office of Management and Budget directs agencies to assess the effects 
of regulatory changes on international trade. In conducting these 
assessments, the FAA has determined that this proposed rule: (1) would 
generate benefits exceeding its costs and is not ``significant'' as 
defined in Executive Order 12866; (2) would not be ``significant'' as 
defined in DOT's Policies and Procedures; (3) would not have a 
significant impact on a substantial number of small entities; and (4) 
would not restrain international trade. These analyses, available in 
the docket, are summarized below.

Regulatory Evaluation Summary

    The following discussion of costs and benefits is provided because 
the proposed procedures would be explicitly incorporated into formal 
regulations. By administrative policy, the FAA is already urging 
designers to show that certain changed products comply with selected 
amendments that were adopted after the initial application for type 
certification of the base product. It is likely that such 
administrative decisions would continue, to some unknown degree for an 
unknown proportion of type certificated products, in the absence of the 
proposed rule.
    The proposed rule would not initiate a specific certification 
standard or requirement per se, but instead, would formally alter the 
manner in which existing and future standards would be determined to be 
applicable. As a result, the FAA can describe, but is not able to 
quantify, the costs and benefits of the proposal. A quantification of 
the impacts would require a forecast of potential future changes to all 
commuter and transport category airplane models; all rotorcraft; and 
all other categories of regulated aircraft, aircraft engines, and 
propellers. In addition, a quantified evaluation would require a review 
of all applicable regulations that have been adopted during the 
intervening period after the type certification of the product, plus 
engineering appraisals of the intended changes for each product, the 
effects of those changes on other systems and components, and the 
economics associated with bringing each affected system and component 
up to the standards of the intervening regulations. No reasonably 
accurate estimate of these factors can be made.
    In addition to the absence of a comprehensive estimate, no examples 
of such cost estimates are available for this evaluation. In some 
instances, the FAA has urged manufacturers of changed products to 
comply with later regulations. In association with these actions, 
individual manufacturers of proposed changed products have evaluated 
the costs and benefits that would be incurred to meet the pertinent 
standards. Due to competitive economic considerations, however, such 
information is considered proprietary and is not available.
    The attributable costs of this proposal are the incremental costs 
that would be incurred to meet any additional or more stringent 
standards, adopted after the application for type certification of the 
initial product, that would not be required in the absence of this 
proposal. Similarly, the direct benefit of the proposal is the 
augmented safety that would result from meeting such standards. 
Although the attributable costs and benefits cannot actually be 
quantified, the proposed rule is premised on an analysis to verify that 
any actions taken pursuant to it would be cost beneficial.
    As noted in the description of the proposal, compliance with later 
regulations would not be required for a change that is not classified 
as being significant, for those areas or components not affected by the 
change, or where compliance with later regulations would not contribute 
materially to the level of safety or would be ``impractical.'' 
Compliance with later amendments would be considered impractical if the 
applicant can show that such compliance would result in costs that are 
not consistent with the possible safety benefits. Further guidance on 
the definition of what constitutes a significant change would be 
provided in an advisory circular.
    In addition to the benefits of any individual action taken pursuant 
to the proposed rule, the proposal would also generate procedural 
benefits. The formalization of this policy by regulation would expedite 
decisions about the certification basis of proposed changed products 
and, therefore, would provide manufacturers and modifiers with earlier 
and more dependable information on which to base their product 
development decisions. In addition, the proposed procedures have been 
harmonized with the foreign aviation authorities of Canada and Europe 
and the resulting common standards would reduce the costs and delays 
necessary to formally determine and fulfill dissimilar international 
requirements.
    Although the attributable costs and benefits of the proposed rule 
cannot be quantified, the FAA holds that it would be cost beneficial.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (RFA) was enacted by 
Congress to ensure that small entities are not unnecessarily or 
disproportionately burdened by Government regulations. The RFA requires 
a Regulatory Flexibility Analysis if a proposed rule would have a 
significant economic impact, either detrimental or beneficial, on a 
substantial number of small entities. FAA Order 2100.14A, Regulatory 
Flexibility Criteria and Guidance, establishes threshold cost values 
and small entity size standards for complying with RFA review 
requirements in FAA rulemaking actions. The proposed amendments

[[Page 24298]]

would not have a significant economic impact on a substantial number of 
small entities.

Trade Impact Assessment

    The proposed rule would not constitute a barrier to international 
trade, including the export of American goods and services to foreign 
countries and the import of foreign goods and services into the United 
States. Instead, the proposed type certification procedures for changed 
products have been harmonized with those of foreign aviation 
authorities and would lessen the restraints on trade.

Federalism Implications

    The regulations proposed herein will not have substantial direct 
effects on the states, on the relationship between the national 
government and the states, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposed would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.

Conclusion

    For the reasons discussed in the preamble, and based on the 
findings in the Regulatory Flexibility Determination and the 
International Trade Impact Analysis, the FAA has determined that this 
proposed regulation is not a significant regulatory action under 
Executive Order 12866. In addition, the FAA certifies that this 
proposal, if adopted, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. This proposal is 
considered nonsignificant under DOT Regulatory Policies and Procedures 
(44 FR 11034; February 26, 1979). An initial regulatory evaluation of 
the proposal, including a Regulatory Flexibility Determination and 
International Trade Impact Analysis, has been placed in the docket. A 
copy may be obtained by contacting the person identified under FOR 
FURTHER INFORMATION CONTACT.

List of Subjects

14 CFR Part 11

    Administrative practice and procedure, Reporting and recordkeeping 
requirements.

14 CFR Part 21

    Aircraft, Aviation safety, Safety, Type certification

14 CFR Part 25

    Aircraft, Aviation safety, Safety, Type certification

The Proposed Amendments

    Accordingly, the FAA proposes to amend 14 CFR parts 11, 21, and 25 
as follows:

PART 11--GENERAL RULEMAKING PROCEDURES

    1. The authority citation for part 11 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40101, 40103, 40105, 40109, 40113, 
44110, 44502, 44701--44702, 44711, 46102.

    2. The first sentence of Sec. 11.11 is revised to read as follows:


Sec. 11.11  Docket.

    Official FAA records relating to rulemaking actions are maintained 
in current docket form in the Office of the Chief Counsel. These 
records include: Proposals, notices of proposed rulemaking, written 
material received in response to notices, petitions for rulemaking and 
exemptions, written material received in response to summaries of 
petitions for rulemaking and exemptions, petitions for rehearing or 
reconsideration, petitions for modification or revocation, notices 
denying petitions for rulemaking, notices granting or denying 
exemptions, summaries required to be published under Sec. 11.27, 
special conditions required as prescribed under Secs. 21.16 or 
21.101(c), written material received in response to published special 
conditions, reports of proceedings conducted under Sec. 11.47, notices 
denying proposals, and final rules or order. * * *

PART 21--CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS

    3. The authority citation for part 21 continues to read as follows:

    Authority: 42 U.S.C. 7572; 49 U.S.C. 106(g), 40105, 40113, 
44701-44702, 44707, 44709, 44711, 44713, 44715, 45303.

    4. Section 21.19 is revised to read as follows:


Sec. 21.19  Changes requiring a new type certificate.

    Each person who proposes to change a product must apply for a new 
type certificate if the Administrator finds that the proposed change in 
design, power, thrust, or weight is so extensive that a substantially 
complete investigation of compliance with the applicable regulations is 
required.
    5. Section 21.101 is revised to read as follows:


Sec. 21.101  Designation of applicable regulations.

    (a) Except as provided in paragraph (b) of this section, an 
applicant for a change to a type certificate must show that the changed 
product complies with:
    (1) Each regulation in parts 23, 25, 27, 29, 31, 33, and 35 of this 
chapter that is applicable to the changed product and that is in effect 
at the date of the application for the change; and
    (2) Parts 34 and 36 of this chapter.
    (b) The applicant may show that the changed product complies with 
an earlier amendment of a regulation required by paragraph (a)(1) of 
this section, and of any other regulation the Administrator finds is 
directly related, provided that the amended regulation does not precede 
either the corresponding regulation in Secs. 23.2, 25.2, 27.2, or 29.2 
of this chapter, or the corresponding regulation incorporated by 
reference in the type certificate:
    (1) For a change the effect of which, combined with all previous 
relevant changes, the Administrator finds is nonsignificant;
    (2) For each area, system, component, equipment, or appliance that 
the Administrator finds is not affected by the change; and
    (3) For each area, system, component, equipment, or appliance that 
is affected by the change, if the Administrator also finds that 
compliance with a regulation described in paragraph (a)(1) of this 
section would not contribute materially to the level of safety of the 
changed product or would be impractical.
    (c) If the Administrator finds that the regulations in effect at 
the date of the application for the change do not provide adequate 
standards with respect to the proposed change because of a novel or 
unusual design feature, the applicant must also comply with special 
conditions, and amendments to those special conditions, prescribed 
under the provisions of Sec. 21.16, to provide a level of safety equal 
to that established by the regulations in effect at the date of the 
application for the change.
    (d) An application for a change to a type certificate for a 
transport category aircraft is effective for 5 years, and an 
application for a change to any other type certificate is effective for 
3 years. If the change has not been approved, or it is clear that it 
will not be approved under the time limit established under this 
paragraph, the applicant may--
    (1) File a new application for a change to the type certificate and 
comply with all the provisions of paragraph (a) of this

[[Page 24299]]

section applicable to an original application for a change; or
    (2) File for an extension of the original application and comply 
with the provisions of paragraph (a) of this section for an effective 
date of application, to be selected by the applicant, not earlier than 
the date that precedes the date of approval of the change by the time 
period established under this paragraph for the original application 
for the change.
    (e) For purposes of this section, ``each regulation that is 
applicable to the change'' includes:
    (1) Each regulation that is applicable to the change that would 
apply to the same change in a product type certificated prior to the 
codification of the applicable part(s) of this chapter, if that product 
were type certificated at the date of the application for the change; 
and
    (2) Each regulation that the Administrator found to be appropriate 
to a product type certificated under Secs. 21.24, 21.25, or 21.27, or 
an aircraft type certificated under Sec. 21.17(b), where the type 
certificate incorporated regulations from parts 23, 25, 27, 29, 31, or 
35, based on the nature of the product design and the proposed change.
    6. Paragraph (a) of 21.115 is revised to read as follows:


Sec. 21.115  Applicable requirements.

    (a) Each applicant for a supplemental type certificate must show 
that the altered product meets applicable requirements specified in 
Sec. 21.101 and, in the case of an acoustical change described in 
Sec. 21.93(b), show compliance with the applicable noise requirements 
of part 36 of this chapter and, in the case of an emissions change 
described in Sec. 21.93(c), show compliance with the applicable fuel 
venting and exhaust emissions requirements of part 34 of this chapter.
* * * * *

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

    7. The authority citation for part 25 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44704.

    8. Paragraph (c) of Sec. 25.2 is revised to read as follows:


Sec. 25.2  Special retroactive requirements.

* * * * *
    (c) Compliance with subsequent revisions to the sections specified 
in paragraph (a) or (b) of this section may be elected or may be 
required in accordance with Sec. 21.101(a) of this chapter.

    Issued in Washington, DC, on April 22, 1997.
Ava L. Mims,
Acting Director, Aircraft Certification Service.
[FR Doc. 97-11205 Filed 5-1-97; 8:45 am]
BILLING CODE 4910-13-M