Airworthiness Standards; Propellers, 63339-63349 [E8-25418]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 73, Number 207 (Friday, October 24, 2008)]
[Rules and Regulations]
[Pages 63339-63349]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-25418]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 23, 25, 33, and 35

[Docket No.: FAA-2007-27310; Amendment Nos. 23-59, 25-126, 33-28, and 
35-5]
RIN 2120-AI95


Airworthiness Standards; Propellers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA amends the airworthiness standards for issuance of 
original and amended type certificates for airplane propellers. The 
previous propeller requirements did not adequately address the 
technological advances of the past twenty years. The new standards 
address these advances in technology and harmonize FAA and European 
Aviation Safety Agency propeller certification requirements, thereby 
simplifying airworthiness approvals for imports and exports.

DATES: These amendments become effective December 23, 2008.

FOR FURTHER INFORMATION CONTACT: For questions concerning this final 
rule contact Jay Turnberg, Engine and Propeller Directorate Standards 
Staff, ANE-110, Federal Aviation Administration, 12 New England 
Executive Park, Burlington, Massachusetts 01803-5299; telephone (781) 
238-7116; facsimile (781) 238-7199, e-mail: jay.turnberg@faa.gov.

SUPPLEMENTARY INFORMATION: 

Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation 
Programs, describes in more detail the scope of the agency's authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, section 44701, ''General 
requirements.'' Under that section, the FAA is charged with prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce, including minimum safety 
standards for aircraft propellers. This final rule is within the scope 
of that authority because it updates existing regulations for airplane 
propellers.

Background

    Over the past decade, advances in technology have required repeated 
application of special conditions or special tests for many propeller 
certification programs. In addition, the need to demonstrate compliance 
with both FAA and European Aviation Safety Agency (EASA) requirements 
placed additional burdens on propeller manufacturers who required 
foreign certification. Therefore, we concluded that part 35 should be 
substantially revised. This action harmonizes FAA part 35 propeller 
certification requirements with most of EASA's Certification 
Specifications for Propellers (CS-P).

Summary of the Notice of Proposed Rulemaking

    On April 11, 2007 (72 FR 18136), the FAA proposed changes to 
propeller requirements in Title 14 Code of Federal Regulations (14 CFR) 
parts 23, 25, 33, and 35. We proposed to amend the airworthiness 
standards for issuance of original and amended type certificates for 
aircraft propellers to address advances in technology and harmonize FAA 
requirements with EASA's CS-P. The comment period closed on June 11, 
2007. We reopened the comment period on June 20, 2007 (72 FR 33925) for 
an additional 45 days in response to requests from propeller 
manufacturers for more time to comment. The comment period closed again 
on August 6, 2007.

Summary of the Final Rule

    This final rule on propeller requirements contains no significant 
changes from the Notice of Proposed Rulemaking (NPRM) published on 
April 11, 2007. We made minor changes to several sections to ensure 
clarity and more consistency with EASA regulations in response to the 
comments we received. This rule harmonizes FAA and EASA regulations for 
most of part 35, updates Sec. Sec.  23.907 and 25.907 and links part 35 
to Sec. Sec.  23.905, 25.901, 25.905, and 33.19.

[[Page 63340]]

Summary of Comments

    Six commenters made approximately 50 comments on the proposed rule. 
The commenters included two industry associations, two propeller 
manufacturers, a foreign aviation regulatory authority, and an 
individual. Five commenters support the rule and only requested changes 
that clarify specific rule language. For example, the Aircraft Owners 
and Pilots Association (AOPA) agreed the proposed rule would clarify 
what is expected from the FAA for propeller certification. AOPA is 
concerned, however, about the effect of the proposed rule on the owners 
of older general aviation aircraft that were type certified with 
propellers that are no longer being manufactured. EASA agreed in 
principle with the rule, but noted that it is not harmonized with the 
latest amendment to its Certification Specifications for Propellers.
    The General Aviation Manufacturers Association (GAMA) commented 
that FAA's effort to harmonize airworthiness standards for propellers 
will help ensure that a streamlined certification process achieves the 
highest level of safety. Only one commenter, MT-Propeller, a German 
propeller manufacturer, objected to the rule, suggesting the rule is 
not compatible with the needs of a modular propeller system in which 
different propellers are manufactured for a variety of airplanes.

Discussion of the Final Rule

    Below is a more detailed discussion of the rule as it relates to 
the comments we received.

Propeller Safety Analysis

    We revised the text and title of Sec.  35.15 to require applicants 
to conduct a safety analysis of the propeller. The objective of the 
safety analysis is to ensure the collective risk from all propeller 
failure conditions is acceptably low. The safety analysis provides a 
level of assurance that an acceptable total propeller design risk is 
achievable through managing individual risks to acceptable levels. The 
safety analysis emphasizes reducing the risk of an event proportionally 
with the severity of the hazard it represents. Our revision adds 
definitions in Sec.  35.15(g) for hazardous and major propeller effects 
based on CS-P, historical JAR-P requirements, and the propeller special 
conditions listed under ``Reference Material'' in the NPRM. We received 
several comments on various aspects of the safety analysis of the 
propeller.
    GAMA recommended the FAA consider removing two hazardous propeller 
effects from those listed under proposed Sec.  35.15(g)(1). The two 
effects are: ``(i) A significant overspeed of the propeller''; and 
``(vi) the unintended movement of the propeller blades below the 
established minimum in-flight low-pitch position.'' GAMA argued that a 
significant propeller overspeed does not by itself create a hazardous 
propeller effect, but rather, it may be a precursor to either excessive 
propeller drag or release of a major portion of the propeller. GAMA 
claimed that since both of these effects are already proposed as 
hazardous propeller effects, the effect under proposed paragraph (i) 
should be eliminated. GAMA also noted that the unintended movement of 
the propeller blades below the established minimum in-flight low-pitch 
position does not by itself create a hazardous propeller effect, but 
rather, it may be a precursor to excessive drag. GAMA said that since 
the effect of excessive drag is already proposed as a hazardous 
propeller effect, the hazardous propeller effect under proposed 
paragraph (vi) should be eliminated.
    EASA contended their definition of propeller hazardous effects does 
not include ``A significant overspeed of the propeller'' or ``The 
unintended movement of the propeller blades below the established 
minimum in-flight low-pitch position'' because these events are not 
hazardous propeller effects by themselves. EASA argued that these 
events only become hazardous if they result in the development of 
excessive drag or the release of a portion of the propeller, both of 
which are already in the list of hazardous effects.
    We agree these two hazardous propeller effects, a significant 
overspeed of the propeller and the unintended movement of the propeller 
blades below the established minimum in-flight low-pitch position, are 
precursors to the hazardous propeller effects of either excessive 
propeller drag or release of a major portion of the propeller. We 
revised the final rule to remove these hazardous propeller effects.
    GAMA and Hamilton Sundstrand requested clarification about use of 
the term ``serviceability'' in Sec.  35.15(e)(1). In the proposed rule, 
the sentence read: ``This includes the verification of the 
serviceability of items that could fail in a latent manner.'' GAMA 
noted the term has two common interpretations ``airworthiness'' and 
``inspectability.''
    We agree the term ``serviceability'' may not be clear in this 
usage. By ``serviceability,'' we mean the items are functioning 
properly. We, therefore, removed the term ``serviceability'' from the 
final rule and replaced it with the phrase ``are functioning properly'' 
in Sec.  35.15(e)(1).
    Hamilton Sundstrand also asked for clarification of the term 
``appropriate procedures'' in Sec.  35.15(e)(1) in the sentence 
``Additionally, if errors in maintenance of the propeller system could 
lead to hazardous propeller effects, the appropriate maintenance 
procedures must be included in the relevant propeller manuals.''
    In general, appropriate procedures are statements and warnings in 
the propeller maintenance manual, overhaul manual, or other relevant 
manuals. For example, if scheduled maintenance is required on a 
critical part of both propellers on a twin engine airplane, a note 
should be added that maintenance should be scheduled to be conducted at 
different times so an error is not introduced on both propellers at the 
same time. Another example of ``appropriate procedures'' is to require 
an independent check during the installation of a critical part to 
validate that it is installed correctly. Section 35.15(e)(1) is adopted 
as proposed.
    Section 35.15(e)(3) lists ``The provision of specific 
instrumentation not otherwise required'' as items that must be 
identified and substantiated if the safety analysis depends on those 
items. GAMA and Hamilton Sundstrand asked for clarification of the term 
``provision.''
    The term ``provision'' means providing or supplying something. If 
the safety analysis depends on data provided by specific 
instrumentation that is not otherwise required, the instrumentation 
must be identified in the analysis and appropriately substantiated. We 
find the wording of the rule is consistent with our intent.

Harmonization With S-P Amendment 1

    EASA commented the proposed rule does not consider changes 
introduced by CS-P Amendment 1. This amendment, effective on November 
16, 2006, revised the CS-P to add new definitions and to modify the 
propeller safety analysis and critical parts requirements (CS-P 150 and 
160, respectively). Amendment 1 also added a requirement that propeller 
components located in a fire zone be ``fire resistant.''
    We are aware of the differences brought about as a result of 
Amendment 1. The Aviation Rulemaking Advisory Committee has accepted a 
task and established a new Propeller Working Group that is assessing 
critical parts and will make recommendations to the FAA for revised 
propeller critical parts requirements.
    We do not believe additional changes to fire resistant requirements 
are needed for propeller components located in a

[[Page 63341]]

fire zone. Section 35.23(b)(2) provides that a fire cannot lead to 
hazardous propeller effects. This requirement is consistent with 
similar fire resistant requirements in EASA's Certification 
Specifications for Propellers.

Modular Propeller System

    Under part 35, a propeller is issued a type certificate independent 
of the airplane and engine on which it is installed.
    MT-Propeller recommended the rule be crafted so it can be complied 
with by a company with a modular propeller system in which a variety of 
propeller models, with different blade types and diameters, can be 
certificated for different airplanes.
    This rule does not require all potential engine/aircraft 
applications be listed on the propeller's type certificate data sheet, 
and this is not required for propeller certification. We find, 
therefore, that companies that produce propellers for a variety of 
engine/aircraft installations can comply with the rule.

Effect of New Part 35 on Older General Aviation Aircraft

    This final rule, like the proposed rule, does not make any changes 
to Appendix A to Part 35 or to Sec.  35.4, Instructions for Continued 
Airworthiness. AOPA commented the FAA should consider and evaluate the 
effect the proposed rule would have on propeller airworthiness options 
for owners of older general aviation aircraft. This population of 
aircraft may be type certificated with propellers that are no longer 
being manufactured or that can no longer be overhauled to comply with 
applicable instructions for continued airworthiness. AOPA stated that a 
supplemental type certificate may be the ``only option'' for these 
aircraft. AOPA argued, therefore, that any aircraft or propeller that 
falls into this category should be exempt from these proposed changes.
    We considered the effect this rule will have on aircraft that were 
type certificated with propellers no longer being manufactured or with 
propellers that cannot be overhauled to comply with applicable 
airworthiness instructions. If the propeller type design is unchanged, 
this rule will have no effect on the propellers cited by AOPA. The new 
part 35 only affects existing propellers when the propeller type design 
is changed. In that case, the applicable propeller requirements would 
then be assessed in accordance with Sec.  21.101.

Propeller and Airplane Certification

    We are adding a new paragraph (c) to Sec.  35.1, Applicability, in 
the final rule to more clearly define the relationship between 
propeller and airplane certification. This paragraph notes that a 
propeller may not be installed on an airplane unless the applicant has 
shown compliance with either Sec. Sec.  23.907 or 25.907, Propeller 
vibration and fatigue, as applicable, or unless compliance is not 
required for installation on that airplane.
    GAMA is concerned that Sec.  35.1(c) might be interpreted as not 
allowing experimental or pre-production configuration flight testing to 
occur. GAMA suggested that changing the word ``installed'' to 
``approved'' would accomplish the FAA's objectives while eliminating 
confusion. Hamilton Sundstrand also requested that Sec.  35.1(c) be 
clarified to allow installation of propellers for flight tests.
    An airplane conducting pre-production or experimental flights would 
fly under an experimental certificate. An airplane with an experimental 
certificate does not need to show compliance with Sec. Sec.  23.907 or 
25.907. Our wording ``or compliance is not required for installation on 
that airplane * * *'' permits the installation of the propeller on an 
airplane with an experimental certificate. Further, we do not agree 
with GAMA that changing ``installed'' to ``approved'' would eliminate 
confusion. Our rule language allows the installation of propellers on 
airplanes that do not require compliance with either Sec. Sec.  23.907 
or 25.907 and prevents installation of propellers on airplanes that do 
require compliance with either Sec. Sec.  23.907 or 25.907. For 
instance, a propeller installed on an airplane with an experimental 
certificate is an approved configuration.

Features of the Propeller

    The new Sec.  35.7, Features and characteristics, requires a 
propeller not have any features or characteristics that make it unsafe 
for the purposes for which it is being certificated. Section 35.7(b) 
sets forth the applicant's responsibilities if a failure occurs during 
a certification test.
    Hamilton Sundstrand commented the term ``failure,'' as used in 
Sec.  35.7(b) ``If a failure occurs during a certification test * * *'' 
is vague. Hamilton claimed some conditions that could affect 
airworthiness might not be interpreted as ``failures'' by the 
applicant. In addition, not all failures necessarily drive design 
changes (for instance, life limits may be imposed instead). Hamilton 
noted that analysis should be added as an option when acceptable to the 
Administrator. Hamilton Sundstrand recommended deleting ``failure 
occurs'' from Sec.  35.7(b) and replacing it with ``test plan objective 
is not met''.
    The phrase ``test plan objective is not met'' does not encompass 
the intent of the rule. A ``failure'' may represent a `failure of the 
component being tested' or `a failure of the test rig such that the 
certification test cannot be completed.' Both of these instances fit 
the term ``failure'' and allow for appropriate review by the 
Administrator. Therefore, we find that the term ``failure'' best 
describes the intent of the rule.

Feathering Propellers

    We added a new Sec.  35.22, Feathering propellers, that 
incorporates requirements for feathering propellers formerly located in 
Sec.  35.23(b) as well as requirements from EASA's CS-P 220, 
``Feathering Propellers.'' The new section requires that feathering 
propellers be designed to feather from all normal and emergency 
conditions in flight, considering likely wear and leakage. It also 
requires that applicants document the feathering characteristics and 
limitations in the appropriate manuals. Section 35.22(c) requires that 
the applicant design the propeller to be capable of unfeathering at the 
minimum declared outside air temperature after stabilization to a 
steady-state temperature.
    GAMA requested the FAA change the wording of Sec.  35.22(a) as 
follows: ``Feathering propellers are intended to be featherable from 
all flight conditions, taking into account expected wear and leakage; 
however, any feathering or unfeathering limitations must be documented 
in the appropriate manuals.'' GAMA claimed that if feathering 
propellers must be capable of being feathered from all conditions in-
flight, then it is contradictory to require documentation of 
unfeathering limitations.
    We agree and modified Sec.  35.22(a) in the final rule to remove 
the requirement that propellers be designed to feather from all 
conditions in flight.
    GAMA asked for clarification in advisory material for Sec.  
35.22(c), since there is no declared test duration or required 
unfeathering rate, and Hamilton Sundstrand suggested changing the 
paragraph wording for clarification.
    We agree and changed Sec.  35.22(c) in the final rule to read: 
``Feathering propellers must be designed to be capable of unfeathering 
after the propeller system has stabilized to the

[[Page 63342]]

minimum declared outside air temperature.''

Bird Impact

    We added a new Sec.  35.36, Bird impact, to part 35 to address bird 
impact with the propeller. The new Sec.  35.36 requires the propeller 
to withstand a 4-pound bird impact without contributing to a major or 
hazardous propeller effect. This requirement is based on extensive 
service history and applies to all propeller designs, except fixed-
pitch wood propellers of conventional design.
    GAMA commented that metal propellers of conventional design, given 
their substantial and positive service experience, should be exempt 
from the proposed changes to Sec.  35.36. MT-Propellers stated that if 
metal propellers are exempt then propellers with detachable wooden 
blades should also be exempt.
    Service experience with current type certificated metal propeller 
designs has shown that these designs are able to withstand the impact 
of a 4-pound bird. This section is adopted as proposed.

Fatigue Evaluation of the Propeller

    We proposed to revise Sec.  35.37, which was not harmonized with 
CS-P 370, to more adequately address composite materials. The new Sec.  
35.37 expands the requirement to all materials and components 
(including controls system components, if applicable) whose failure 
would cause a hazardous propeller effect. It also adds environmental 
effects to the factors that must be considered when establishing 
fatigue limits. We also proposed adding a requirement in Sec.  35.37(c) 
for applicants to conduct a fatigue evaluation of the propeller to show 
that hazardous propeller effects due to fatigue will be avoided 
throughout the intended operational life of the propeller, and we 
renamed Sec.  35.37 from ``Fatigue limit tests'' to ``Fatigue limits 
and evaluation.''
    GAMA commented the requirement for a fatigue evaluation in Sec.  
35.37(c) is unnecessary and compliance with this paragraph is unclear. 
GAMA indicated this requirement duplicates the requirements in proposed 
Sec. Sec.  23.907 and 25.907, which also require a fatigue evaluation.
    We established the fatigue evaluation in Sec.  35.37(c) so that, at 
a minimum, the propeller will be shown to be acceptable for fatigue on 
a typical airplane. If the airplane installation is known at the time 
of propeller certification, then the same fatigue evaluation may be 
used to show compliance with Sec. Sec.  23.907 or 25.907. If the 
airplane installation is not known, a typical airplane will be assumed. 
Without this requirement, a propeller that does not have the capability 
to be installed on an airplane could be certificated. This section is 
adopted as proposed.

Lightning Strike

    We added a new Sec.  35.38, Lightning strike, to harmonize with CS-
P 380, Lightning Strike. Part 35 formerly had no lightning strike 
requirements. Section 35.38 requires that composite propellers 
withstand a lightning strike without contributing to a major or 
hazardous propeller effect. The new requirement applies to metallic 
blades but allows compliance by experience from similar designs. We 
excluded conventional fixed-pitch wood propellers from the requirement 
because of their satisfactory service experience.
    GAMA commented that, based on substantial and positive service 
experience, metal propellers of conventional design should be exempt 
from the requirements of Sec.  35.38.
    Service experience with current type certificated metal propeller 
designs has shown that these designs are able to withstand lightning 
strike. Proposed Sec.  35.38 allows for use of service experience on 
similar designs to show compliance with lightning strike provisions. 
This section is adopted as proposed.

Overspeed and Overtorque

    We added a new overspeed and overtorque requirement in Sec.  35.41 
to harmonize with CS-P 410(a). This section requires that applicants 
verify the declared transient overspeed and overtorque limits of the 
propeller.
    GAMA commented that Sec.  35.41(a)(1) and (b)(1), which refer to 
the applicant seeking approval for transient maximum propeller 
overspeed and overtorque, respectively, should be part of advisory 
material rather than the rule as they represent one method, but not the 
only method, of compliance. GAMA claimed the requirements of paragraphs 
(a)(1) and (b)(1) are inconsistent with the requirements of CS-P as 
EASA does not require demonstration that ``* * * the propeller is 
capable of further operation without maintenance action.''
    Transient overspeed conditions will occur over the life of the 
propeller. This rule establishes a limit where no maintenance is 
required. It does not prevent an applicant from establishing other 
overspeed limits that do require maintenance action. The sentence is 
included in the requirement to define the intent of an overspeed limit. 
It is consistent with EASA definitions.

Propeller Accessories

    We revised Sec. Sec.  23.905, Propellers, and 25.905, Propellers, 
to ensure that propeller controls that are certified as part of the 
airplane or engine type design meet the same requirements as propeller 
controls that are certified as part of the propeller design.
    GAMA and Hamilton Sundstrand suggested the FAA consider including 
requirements in Sec.  23.905 for propeller accessories, such as 
spinners and de-icing equipment, to satisfy the requirement of Sec.  
35.35(c) for overload. GAMA noted in many cases this equipment is not 
type certificated with the propeller, but rather aircraft manufacturers 
or modifiers may install their own spinners and de-icing equipment and 
in these cases no similar tests are required.
    Part 23 requirements for airplane components requirements are 
beyond the scope of the proposed rule.

Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA consider the impact of paperwork and other information 
collection burdens imposed on the public. We have determined there is 
no current or new requirement for information collection associated 
with this amendment.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to comply with 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA has 
reviewed the corresponding ICAO Standards and Recommended Practices and 
has identified no differences with these regulations.

Regulatory Evaluation, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall propose or adopt a regulation only upon a reasoned determination 
that the benefits of the intended regulation justify its costs. Second, 
the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires 
agencies to analyze the economic impact of regulatory changes on small 
entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits 
agencies from setting standards that create unnecessary obstacles to 
the foreign commerce of the United States. In

[[Page 63343]]

developing U.S. standards, this Trade Act requires agencies to consider 
international standards and, where appropriate, that they be the basis 
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 
(Pub. L. 104-4) requires agencies to prepare a written assessment of 
the costs, benefits, and other effects of proposed or final rules that 
include a Federal mandate likely to result in the expenditure by State, 
local, or tribal governments, in the aggregate, or by the private 
sector, of $100 million or more annually (adjusted for inflation with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impacts of this final rule.
    Department of Transportation Order DOT 2100.5 prescribes policies 
and procedures for simplification, analysis, and review of regulations. 
If the expected cost impact is so minimal that a proposed or final rule 
does not warrant a full evaluation, this order permits that a statement 
to that effect and the basis for it be included in the preamble if a 
full regulatory evaluation of the cost and benefits is not prepared. 
Such a determination has been made for this final rule. The reasoning 
for this determination follows.
    To a great extent this final rule requires propeller manufacturers 
to certificate future production propellers for sale in the United 
States to the same European standards that these firms already meet. 
EASA became responsible for certification of aircraft, engines, parts 
and appliances on September 28, 2003 by Commission Regulation (EC) 
1702/2003. Because the U.S. and European effort to have common 
certification propeller regulations was almost completed when EASA 
became operational, the proposed part 35 and the European propeller 
requirements CS-P are almost identical. CS-P is now an official rule of 
a foreign regulatory agency while this is a final rule. To export 
propellers to Europe, U.S. manufacturers now must meet the European 
requirements. Before EASA issued these requirements, industry provided 
us with a cost estimate of $31 million over a 25-year analysis period 
for them to be in compliance with the FAA proposed propeller 
requirements which would have codified existing special tests and 
conditions. However, as manufacturers are already in compliance with 
these now harmonized requirements, there are no additional compliance 
costs.
    This final rule has only one regulation stricter than EASA's CS-P. 
This rule will codify the current special condition 4-pound bird strike 
test for composite propeller blades. CS-P requires newly certificated 
propellers to withstand a 4-pound bird strike for equivalent part 25 
airplanes. However, CS-P requires newly certificated propellers to 
withstand a 2.8-pound bird strike for equivalent part 23 commuter 
airplanes and does not require a bird strike test for other equivalent 
part 23 airplanes. U.S. propeller manufacturers provided us with their 
estimated costs to meet the proposed 4-pound requirement. Over a 25-
year analysis period (based on the operational life of a propeller) we 
estimate the total cost for 635 future propellers to be $458,000 or 
$213,000 in present value (7 percent discount rate) or approximately 
$335 per propeller. For the NPRM we stated this cost would be minimal. 
We received no comments disputing this finding; therefore we believe 
our finding is correct.
    The benefits from this higher bird-strike requirement are the 
expected continuation of over 50 million flight hours with no accidents 
attributed to bird impacts against composite propellers despite many 
bird strikes. Between 1990 and 2004, there have been over 150 bird 
strikes to part 23 propellers (see the FAA National Wildlife Strike 
Database, Version 6.0, February 26, 2005; available online at https://
wildlife.pr.erau.edu/public/index1.html).
    No substantive changes were made to the proposed rule as a result 
of the comments received. One comment was received on the regulatory 
evaluation. The commenter agreed with the FAA that the economic effects 
on the industry would be minimal. Therefore, the regulatory evaluation 
did not change the determination that the benefits exceed the costs and 
the rule imposes minimal costs.
    FAA has, therefore, determined that this final rule is not a 
``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, and is not ``significant'' as defined in DOT's 
Regulatory Policies and Procedures.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``* * * as a principle of regulatory issuance that agencies 
shall endeavor, consistent with the objectives of the rule and of 
applicable statutes, to fit regulatory and informational requirements 
to the scale of the business, organizations, and governmental 
jurisdictions subject to regulation. To achieve this principle, 
agencies are required to solicit and consider flexible regulatory 
proposals and to explain the rationale for their actions to assure that 
such proposals are given serious consideration.'' The RFA covers a wide 
range of small entities, including small businesses, not-for-profit 
organizations and small governmental jurisdictions.
    Agencies must perform a review to determine whether a rule will 
have a significant economic impact on a substantial number of small 
entities. If the determination is that it will, the agency must prepare 
a regulatory flexibility analysis as described in the RFA.
    However, if an agency determines that a rule is not expected to 
have a significant economic impact on a substantial number of small 
entities, section 605(b) of the RFA provides that the head of the 
agency may so certify and a regulatory flexibility analysis is not 
required. The certification must include a statement providing the 
factual basis for this determination, and the reasoning should be 
clear.
    The purpose of this FRFA is to ensure that the agency has 
considered all reasonable regulatory alternatives that would minimize 
the final rule's economic burdens for affected small entities, while 
achieving its safety objectives.
    Under Section 603 of the RFA, the analysis must address:
    1. Reasons for this final rule.
    2. Significant issues raised in public comments in response to the 
Initial Regulatory Flexibility Analysis (IRFA).
    3. Estimated number of small entities to which this rule would 
apply.
    4. Recordkeeping and other compliance requirements of this rule.

1. Reasons for This Rule

    The FAA revised the airworthiness standards for the issuance of 
original and amended type certificates for airplane propellers. The 
previous propeller requirements did not adequately address the 
technological advances of the past 20 years. The new standards address 
the current advances in technology and harmonize the FAA requirements 
with the existing requirements of Certification Specifications for 
Propellers of the EASA. This final rule establishes nearly uniform 
standards for aircraft propellers certified by the United States under 
FAA standards and by European countries under EASA standards, thereby 
simplifying airworthiness approvals for import and export products.

2. Significant Issues Raised in Public Comments in Response to the IRFA

    We received no comments on the IRFA. Therefore, no changes were 
made to the IRFA as a result of comments received.

[[Page 63344]]

3. Estimated Number of Small Firms Potentially Impacted

    Under the RFA, the FAA must determine whether or not a proposal 
significantly affects a substantial number of small entities. This 
determination is typically based on small entity size and cost 
thresholds that vary depending on the affected industry. The Small 
Business Administration (SBA) uses the NAICS (North American Industry 
Classification System) 2002 to determine size standards for small 
businesses. There is no entry in the NAICS 2002 for propeller 
manufacturers. However, the NAICS 2002 does list under Sectors 31-33, 
Manufacturing, Subsector 336, Transportation Equipment Manufacturing, 
which in turn lists the following numbers and number of employees as 
shown in the following table:

------------------------------------------------------------------------
                                                             Number of
        NAICS 2002 No.                Description            employees
------------------------------------------------------------------------
336411.......................  Aircraft Manufacturing...           1,500
336412.......................  Aircraft Engine and                 1,000
                                Engine Parts
                                Manufacturing.
336413.......................  Other Aircraft Part and             1,000
                                Auxiliary Equipment.
------------------------------------------------------------------------

Propeller manufacturing could be included in 336412, Aircraft 
Engine and Aircraft Parts Manufacturing; or 336413, Other 
Aircraft Parts and Auxiliary Equipment Manufacturing. Both these 
categories use 1,000 employees to define a small business. Therefore, 
the FAA defines a small business in the variable pitch propeller 
manufacturing industry as a business with 1,000 or less employees. In 
accordance with SBA usage, this number applies to the ultimate 
ownership of the company.
    In 2008, the American airplane variable pitch propeller industry 
consisted of three firms. These firms were Hamilton Sundstrand, 
Hartzell Propeller, and McCauley Propeller Systems. Hamilton Sundstrand 
is a subsidiary of United Technologies which employed approximately 
226,000 people and had annual revenues of approximately $55 billion in 
2007.\1\ McCauley Propeller Systems is owned by Cessna, which, in turn, 
is owned by Textron, Inc. Textron employed some 44,000 people and had 
annual revenues of some $13 billion in 2007.\2\ Hartzell Propeller, 
Inc. employed 300 employees in 2007 and had annual revenues between $20 
and $50 million in 2007.\3\
---------------------------------------------------------------------------

    \1\ United Technologies Corporation--Our Profile, https://
www.utc.com/profile/facts/index.htm, (Accessed 04/10/2008).
    \2\ https://www.textron.com/about/company/index.jsp (Accessed 04/
10/2008).
    \3\ Reference USA, Version 2008.4, https://www.referenceusa.com/
bd/results.asp?backHistory=true (Accessed 04/11/2008).
---------------------------------------------------------------------------

    In conclusion, using the above criteria, Hartzell is a small 
business and Hamilton Sundstrand and McCauley are not small businesses. 
As only one small entity will be affected by the rule and the rule 
imposes only minimal costs, there are not a substantial number of small 
entities that will be adversely affected by this rule. Therefore, as 
the acting FAA Administrator, I certify that this rule will not have a 
significant economic impact on a substantial number of small entities.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal 
agencies from establishing any standards or engaging in related 
activities that create unnecessary obstacles to the foreign commerce of 
the United States. Legitimate domestic objectives, such as safety, are 
not considered unnecessary obstacles. The statute also requires 
consideration of international standards and, where appropriate, that 
they be the basis for U.S. standards. The FAA has assessed the 
potential effect of this final rule and determined that it is in accord 
with the Trade Agreements Act as the final rule uses European standards 
as the basis for United States regulation.

Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(in 1995 dollars) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.'' The FAA currently 
uses an inflation-adjusted value of $136.1 million in lieu of $100 
million.
    This final rule does not contain such a mandate; therefore, the 
requirements of Title II of the Act do not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this final rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action will not have a substantial direct effect on the States, or the 
relationship between the national Government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, and, therefore, does not have federalism implications.

Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this rulemaking action qualifies for the categorical 
exclusion identified in paragraph 312d and involves no extraordinary 
circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this final rule under Executive Order 13211, 
Actions Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant energy action'' under the executive order because it is 
not a ``significant regulatory action'' under Executive Order 12866, 
and it is not likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

Availability of Rulemaking Documents

    You can get an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (https://
www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at  https://
www.faa.gov/regulations_policies; or
    3. Accessing the Government Printing Office's Web page at https://
www.gpoaccess.gov/fr/.
    You can also get a copy by sending 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. Make 
sure to

[[Page 63345]]

identify the amendment number or docket number of this rulemaking.
    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may visit 
https://DocketsInfo.dot.gov.

Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires FAA to comply with small entity requests for information 
or advice about compliance with statutes and regulations within its 
jurisdiction. If you are a small entity and you have a question 
regarding this document, you may contact your local FAA official, or 
the person listed under the FOR FURTHER INFORMATION CONTACT heading at 
the beginning of the preamble. You can find out more about SBREFA on 
the Internet at https://www.faa.gov/regulations_policies/rulemaking/
sbre_act/.

List of Subjects in 14 CFR Parts 23, 25, 33 and 35

    Air transportation, Aircraft, Aviation safety, Safety.

The Amendment

0
In consideration of the foregoing, the Federal Aviation Administration 
amends parts 23, 25, 33, and 35 of Title 14 Code of Federal Regulations 
as follows:

PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND 
COMMUTER CATEGORY AIRPLANES

0
1. The authority citation for part 23 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44704.
0
2. Revise Sec.  23.905(d) to read as follows:

Sec.  23.905  Propellers.

* * * * *
    (d) The propeller blade pitch control system must meet the 
requirements of Sec. Sec.  35.21, 35.23, 35.42 and 35.43 of this 
chapter.
* * * * *

0
3. Revise Sec.  23.907 to read as follows:


Sec.  23.907  Propeller vibration and fatigue.

    This section does not apply to fixed-pitch wood propellers of 
conventional design.
    (a) The applicant must determine the magnitude of the propeller 
vibration stresses or loads, including any stress peaks and resonant 
conditions, throughout the operational envelope of the airplane by 
either:
    (1) Measurement of stresses or loads through direct testing or 
analysis based on direct testing of the propeller on the airplane and 
engine installation for which approval is sought; or
    (2) Comparison of the propeller to similar propellers installed on 
similar airplane installations for which these measurements have been 
made.
    (b) The applicant must demonstrate by tests, analysis based on 
tests, or previous experience on similar designs that the propeller 
does not experience harmful effects of flutter throughout the 
operational envelope of the airplane.
    (c) The applicant must perform an evaluation of the propeller to 
show that failure due to fatigue will be avoided throughout the 
operational life of the propeller using the fatigue and structural data 
obtained in accordance with part 35 of this chapter and the vibration 
data obtained from compliance with paragraph (a) of this section. For 
the purpose of this paragraph, the propeller includes the hub, blades, 
blade retention component and any other propeller component whose 
failure due to fatigue could be catastrophic to the airplane. This 
evaluation must include:
    (1) The intended loading spectra including all reasonably 
foreseeable propeller vibration and cyclic load patterns, identified 
emergency conditions, allowable overspeeds and overtorques, and the 
effects of temperatures and humidity expected in service.
    (2) The effects of airplane and propeller operating and 
airworthiness limitations.

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

0
4. The authority citation for part 25 continues to read as follows:

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


0
5. Revise Sec.  25.901(b)(1)(i) to read as follows:


Sec.  25.901  Installation.

* * * * *
    (b) * * *
    (1) * * *
    (i) The installation instructions provided under Sec. Sec.  33.5 
and 35.3 of this chapter; and
* * * * *

0
6. Revise Sec.  25.905(c) to read as follows:


Sec.  25.905  Propellers.

* * * * *
    (c) The propeller blade pitch control system must meet the 
requirements of Sec. Sec.  35.21, 35.23, 35.42 and 35.43 of this 
chapter.
* * * * *

0
7. Revise Sec.  25.907 to read as follows:


Sec.  25.907  Propeller vibration and fatigue.

    This section does not apply to fixed-pitch wood propellers of 
conventional design.
    (a) The applicant must determine the magnitude of the propeller 
vibration stresses or loads, including any stress peaks and resonant 
conditions, throughout the operational envelope of the airplane by 
either:
    (1) Measurement of stresses or loads through direct testing or 
analysis based on direct testing of the propeller on the airplane and 
engine installation for which approval is sought; or
    (2) Comparison of the propeller to similar propellers installed on 
similar airplane installations for which these measurements have been 
made.
    (b) The applicant must demonstrate by tests, analysis based on 
tests, or previous experience on similar designs that the propeller 
does not experience harmful effects of flutter throughout the 
operational envelope of the airplane.
    (c) The applicant must perform an evaluation of the propeller to 
show that failure due to fatigue will be avoided throughout the 
operational life of the propeller using the fatigue and structural data 
obtained in accordance with part 35 of this chapter and the vibration 
data obtained from compliance with paragraph (a) of this section. For 
the purpose of this paragraph, the propeller includes the hub, blades, 
blade retention component and any other propeller component whose 
failure due to fatigue could be catastrophic to the airplane. This 
evaluation must include:
    (1) The intended loading spectra including all reasonably 
foreseeable propeller vibration and cyclic load patterns, identified 
emergency conditions, allowable overspeeds and overtorques, and the 
effects of temperatures and humidity expected in service.
    (2) The effects of airplane and propeller operating and 
airworthiness limitations.

[[Page 63346]]

PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES

0
8. The authority citation for part 33 continues to read as follows:

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

0
9. Revise Sec.  33.19(b) to read as follows:


Sec.  33.19  Durability.

* * * * *
    (b) Each component of the propeller blade pitch control system 
which is a part of the engine type design must meet the requirements of 
Sec. Sec.  35.21, 35.23, 35.42 and 35.43 of this chapter.

PART 35--AIRWORTHINESS STANDARDS: PROPELLERS

0
10. The authority citation for part 35 continues to read as follows:

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

Subpart A--General

0
11. Amend Sec.  35.1 by adding new paragraphs (c) and (d) to read as 
follows:


Sec.  35.1  Applicability.

* * * * *
    (c) An applicant is eligible for a propeller type certificate and 
changes to those certificates after demonstrating compliance with 
subparts A, B and C of this part. However, the propeller may not be 
installed on an airplane unless the applicant has shown compliance with 
either Sec.  23.907 or Sec.  25.907 of this chapter, as applicable, or 
compliance is not required for installation on that airplane.
    (d) For the purposes of this part, the propeller consists of those 
components listed in the propeller type design, and the propeller 
system consists of the propeller and all the components necessary for 
its functioning, but not necessarily included in the propeller type 
design.

0
12. Add Sec.  35.2 to read as follows:


Sec.  35.2  Propeller configuration.

    The applicant must provide a list of all the components, including 
references to the relevant drawings and software design data, that 
define the type design of the propeller to be approved under Sec.  
21.31 of this chapter.

0
13. Revise Sec.  35.3 to read as follows:


Sec.  35.3  Instructions for propeller installation and operation.

    The applicant must provide instructions that are approved by the 
Administrator. Those approved instructions must contain:
    (a) Instructions for installing the propeller, which:
    (1) Include a description of the operational modes of the propeller 
control system and functional interface of the control system with the 
airplane and engine systems;
    (2) Specify the physical and functional interfaces with the 
airplane, airplane equipment and engine;
    (3) Define the limiting conditions on the interfaces from paragraph 
(a)(2) of this section;
    (4) List the limitations established under Sec.  35.5;
    (5) Define the hydraulic fluids approved for use with the 
propeller, including grade and specification, related operating 
pressure, and filtration levels; and
    (6) State the assumptions made to comply with the requirements of 
this part.
    (b) Instructions for operating the propeller which must specify all 
procedures necessary for operating the propeller within the limitations 
of the propeller type design.

0
14. Revise Sec.  35.5 to read as follows:


Sec.  35.5  Propeller ratings and operating limitations.

    (a) Propeller ratings and operating limitations must:
    (1) Be established by the applicant and approved by the 
Administrator.
    (2) Be included directly or by reference in the propeller type 
certificate data sheet, as specified in Sec.  21.41 of this chapter.
    (3) Be based on the operating conditions demonstrated during the 
tests required by this part as well as any other information the 
Administrator requires as necessary for the safe operation of the 
propeller.
    (b) Propeller ratings and operating limitations must be established 
for the following, as applicable:
    (1) Power and rotational speed:
    (i) For takeoff.
    (ii) For maximum continuous.
    (iii) If requested by the applicant, other ratings may also be 
established.
    (2) Overspeed and overtorque limits.

0
15. Add Sec.  35.7 to read as follows:


Sec.  35.7  Features and characteristics.

    (a) The propeller may not have features or characteristics, 
revealed by any test or analysis or known to the applicant, that make 
it unsafe for the uses for which certification is requested.
    (b) If a failure occurs during a certification test, the applicant 
must determine the cause and assess the effect on the airworthiness of 
the propeller. The applicant must make changes to the design and 
conduct additional tests that the Administrator finds necessary to 
establish the airworthiness of the propeller.

Subpart B--Design and Construction


Sec.  35.11  [Removed and Reserved.]

0
16. Remove and reserve Sec.  35.11.


Sec.  35.13  [Removed and Reserved.]

0
17. Remove and reserve Sec.  35.13.
0
18. Revise Sec.  35.15 to read as follows:


Sec.  35.15  Safety analysis.

    (a)(1) The applicant must analyze the propeller system to assess 
the likely consequences of all failures that can reasonably be expected 
to occur. This analysis will take into account, if applicable:
    (i) The propeller system in a typical installation. When the 
analysis depends on representative components, assumed interfaces, or 
assumed installed conditions, the assumptions must be stated in the 
analysis.
    (ii) Consequential secondary failures and dormant failures.
    (iii) Multiple failures referred to in paragraph (d) of this 
section, or that result in the hazardous propeller effects defined in 
paragraph (g)(1) of this section.
    (2) The applicant must summarize those failures that could result 
in major propeller effects or hazardous propeller effects defined in 
paragraph (g) of this section, and estimate the probability of 
occurrence of those effects.
    (3) The applicant must show that hazardous propeller effects are 
not predicted to occur at a rate in excess of that defined as extremely 
remote (probability of 10-7 or less per propeller flight 
hour). Since the estimated probability for individual failures may be 
insufficiently precise to enable the applicant to assess the total rate 
for hazardous propeller effects, compliance may be shown by 
demonstrating that the probability of a hazardous propeller effect 
arising from an individual failure can be predicted to be not greater 
than 10-8 per propeller flight hour. In dealing with 
probabilities of this low order of magnitude, absolute proof is not 
possible and reliance must be placed on engineering judgment and 
previous experience combined with sound design and test philosophies.
    (b) If significant doubt exists as to the effects of failures or 
likely combination of failures, the Administrator may require 
assumptions used in the analysis to be verified by test.
    (c) The primary failures of certain single elements (for example, 
blades) cannot be sensibly estimated in numerical terms. If the failure 
of such elements is likely to result in hazardous propeller effects, 
then compliance may be shown by reliance on the prescribed integrity 
requirements of this part.

[[Page 63347]]

These instances must be stated in the safety analysis.
    (d) If reliance is placed on a safety system to prevent a failure 
progressing to hazardous propeller effects, the possibility of a safety 
system failure in combination with a basic propeller failure must be 
included in the analysis. Such a safety system may include safety 
devices, instrumentation, early warning devices, maintenance checks, 
and other similar equipment or procedures. If items of the safety 
system are outside the control of the propeller manufacturer, the 
assumptions of the safety analysis with respect to the reliability of 
these parts must be clearly stated in the analysis and identified in 
the propeller installation and operation instructions required under 
Sec.  35.3.
    (e) If the safety analysis depends on one or more of the following 
items, those items must be identified in the analysis and appropriately 
substantiated.
    (1) Maintenance actions being carried out at stated intervals. This 
includes verifying that items that could fail in a latent manner are 
functioning properly. When necessary to prevent hazardous propeller 
effects, these maintenance actions and intervals must be published in 
the instructions for continued airworthiness required under Sec.  35.4. 
Additionally, if errors in maintenance of the propeller system could 
lead to hazardous propeller effects, the appropriate maintenance 
procedures must be included in the relevant propeller manuals.
    (2) Verification of the satisfactory functioning of safety or other 
devices at pre-flight or other stated periods. The details of this 
satisfactory functioning must be published in the appropriate manual.
    (3) The provision of specific instrumentation not otherwise 
required. Such instrumentation must be published in the appropriate 
documentation.
    (4) A fatigue assessment.
    (f) If applicable, the safety analysis must include, but not be 
limited to, assessment of indicating equipment, manual and automatic 
controls, governors and propeller control systems, synchrophasers, 
synchronizers, and propeller thrust reversal systems.
    (g) Unless otherwise approved by the Administrator and stated in 
the safety analysis, the following failure definitions apply to 
compliance with this part.
    (1) The following are regarded as hazardous propeller effects:
    (i) The development of excessive drag.
    (ii) A significant thrust in the opposite direction to that 
commanded by the pilot.
    (iii) The release of the propeller or any major portion of the 
propeller.
    (iv) A failure that results in excessive unbalance.
    (2) The following are regarded as major propeller effects for 
variable pitch propellers:
    (i) An inability to feather the propeller for feathering 
propellers.
    (ii) An inability to change propeller pitch when commanded.
    (iii) A significant uncommanded change in pitch.
    (iv) A significant uncontrollable torque or speed fluctuation.

0
19. Revise Sec.  35.17 to read as follows:


Sec.  35.17  Materials and manufacturing methods.

    (a) The suitability and durability of materials used in the 
propeller must:
    (1) Be established on the basis of experience, tests, or both.
    (2) Account for environmental conditions expected in service.
    (b) All materials and manufacturing methods must conform to 
specifications acceptable to the Administrator.
    (c) The design values of properties of materials must be suitably 
related to the most adverse properties stated in the material 
specification for applicable conditions expected in service.

0
20. Revise Sec.  35.21 to read as follows:


Sec.  35.21  Variable and reversible pitch propellers.

    (a) No single failure or malfunction in the propeller system will 
result in unintended travel of the propeller blades to a position below 
the in-flight low-pitch position. The extent of any intended travel 
below the in-flight low-pitch position must be documented by the 
applicant in the appropriate manuals. Failure of structural elements 
need not be considered if the occurrence of such a failure is shown to 
be extremely remote under Sec.  35.15.
    (b) For propellers incorporating a method to select blade pitch 
below the in-flight low pitch position, provisions must be made to 
sense and indicate to the flight crew that the propeller blades are 
below that position by an amount defined in the installation manual. 
The method for sensing and indicating the propeller blade pitch 
position must be such that its failure does not affect the control of 
the propeller.

0
21. Add Sec.  35.22 to read as follows:


Sec.  35.22  Feathering propellers.

    (a) Feathering propellers are intended to feather from all flight 
conditions, taking into account expected wear and leakage. Any 
feathering and unfeathering limitations must be documented in the 
appropriate manuals.
    (b) Propeller pitch control systems that use engine oil to feather 
must incorporate a method to allow the propeller to feather if the 
engine oil system fails.
    (c) Feathering propellers must be designed to be capable of 
unfeathering after the propeller system has stabilized to the minimum 
declared outside air temperature.

0
22. Revise Sec.  35.23 to read as follows:


Sec.  35.23  Propeller control system.

    The requirements of this section apply to any system or component 
that controls, limits or monitors propeller functions.
    (a) The propeller control system must be designed, constructed and 
validated to show that:
    (1) The propeller control system, operating in normal and 
alternative operating modes and in transition between operating modes, 
performs the functions defined by the applicant throughout the declared 
operating conditions and flight envelope.
    (2) The propeller control system functionality is not adversely 
affected by the declared environmental conditions, including 
temperature, electromagnetic interference (EMI), high intensity 
radiated fields (HIRF) and lightning. The environmental limits to which 
the system has been satisfactorily validated must be documented in the 
appropriate propeller manuals.
    (3) A method is provided to indicate that an operating mode change 
has occurred if flight crew action is required. In such an event, 
operating instructions must be provided in the appropriate manuals.
    (b) The propeller control system must be designed and constructed 
so that, in addition to compliance with Sec.  35.15:
    (1) No single failure or malfunction of electrical or electronic 
components in the control system results in a hazardous propeller 
effect.
    (2) Failures or malfunctions directly affecting the propeller 
control system in a typical airplane, such as structural failures of 
attachments to the control, fire, or overheat, do not lead to a 
hazardous propeller effect.
    (3) The loss of normal propeller pitch control does not cause a 
hazardous propeller effect under the intended operating conditions.
    (4) The failure or corruption of data or signals shared across 
propellers does not cause a hazardous propeller effect.
    (c) Electronic propeller control system imbedded software must be 
designed

[[Page 63348]]

and implemented by a method approved by the Administrator that is 
consistent with the criticality of the performed functions and that 
minimizes the existence of software errors.
    (d) The propeller control system must be designed and constructed 
so that the failure or corruption of airplane-supplied data does not 
result in hazardous propeller effects.
    (e) The propeller control system must be designed and constructed 
so that the loss, interruption or abnormal characteristic of airplane-
supplied electrical power does not result in hazardous propeller 
effects. The power quality requirements must be described in the 
appropriate manuals.


0
23. Add Sec.  35.24 to read as follows:


Sec.  35.24  Strength.

    The maximum stresses developed in the propeller may not exceed 
values acceptable to the Administrator considering the particular form 
of construction and the most severe operating conditions.

Subpart C--Type Substantiation


Sec.  35.31  [Removed and Reserved.]

0
24. Remove and reserve Sec.  35.31.


0
25. Revise Sec.  35.33 to read as follows:


Sec.  35.33  General.

    (a) Each applicant must furnish test article(s) and suitable 
testing facilities, including equipment and competent personnel, and 
conduct the required tests in accordance with part 21 of this chapter.
    (b) All automatic controls and safety systems must be in operation 
unless it is accepted by the Administrator as impossible or not 
required because of the nature of the test. If needed for 
substantiation, the applicant may test a different propeller 
configuration if this does not constitute a less severe test.
    (c) Any systems or components that cannot be adequately 
substantiated by the applicant to the requirements of this part are 
required to undergo additional tests or analysis to demonstrate that 
the systems or components are able to perform their intended functions 
in all declared environmental and operating conditions.


0
26. Add Sec.  35.34 to read as follows:


Sec.  35.34  Inspections, adjustments and repairs.

    (a) Before and after conducting the tests prescribed in this part, 
the test article must be subjected to an inspection, and a record must 
be made of all the relevant parameters, calibrations and settings.
    (b) During all tests, only servicing and minor repairs are 
permitted. If major repairs or part replacement is required, the 
Administrator must approve the repair or part replacement prior to 
implementation and may require additional testing. Any unscheduled 
repair or action on the test article must be recorded and reported.


0
27. Revise Sec.  35.35 to read as follows:


Sec.  35.35  Centrifugal load tests.

    The applicant must demonstrate that a propeller complies with 
paragraphs (a), (b) and (c) of this section without evidence of 
failure, malfunction, or permanent deformation that would result in a 
major or hazardous propeller effect. When the propeller could be 
sensitive to environmental degradation in service, this must be 
considered. This section does not apply to fixed-pitch wood or fixed-
pitch metal propellers of conventional design.