Document ID: FAA-2007-27311-0010
Agency: faa
Document Type: Rule
Title: Airworthiness Standards; Engine Control System Requirements
Posted Date: 2008-08-19T04:00Z

[Federal Register: August 19, 2008 (Volume 73, Number 161)]
[Rules and Regulations]               
[Page 48279-48286]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19au08-1]                         

========================================================================
Rules and Regulations
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains regulatory documents 
having general applicability and legal effect, most of which are keyed 
to and codified in the Code of Federal Regulations, which is published 
under 50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by the Superintendent of Documents. 
Prices of new books are listed in the first FEDERAL REGISTER issue of each 
week.

========================================================================

[[Page 48279]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. FAA-2007-27311, Amendment No. 33-26]
RIN 2120-AI94

 
Airworthiness Standards; Engine Control System Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is amending type certification standards for aircraft 
engine control systems. These changes reflect current industry 
practices and harmonize FAA standards with those recently adopted by 
the European Aviation Safety Agency (EASA). These changes establish 
uniform standards for all engine control systems for aircraft engines 
certificated by both U.S. and European countries and will simplify 
airworthiness approvals for import and export.

DATES: This amendment becomes effective October 20, 2008.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this final rule contact Gary Horan, Engine and Propeller Directorate 
Standards Staff, ANE-111, Federal Aviation Administration, 12 New 
England Executive Park, Burlington, Massachusetts 01803-5299; telephone 
(781) 238-7164, fax (781) 238-7199, e-mail gary.horan@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 engines. This proposed rule is within the scope 
of that authority because it updates existing regulations for aircraft 
engine control systems.

Background

    U.S. and European aircraft engine regulations differ in several 
areas including engine controls. Certifying to a common set of 
requirements (harmonization) benefits industry and regulators because 
of the lower costs associated with a single set of regulations.
    The FAA, in cooperation with the Joint Aviation Authorities (JAA), 
the European rulemaking authority before EASA, established an 
international engine certification study group to compare part 33 with 
the Joint Aviation Requirements--Engines (JAR-E), the European 
requirements for engines. As a follow-on, the Aviation Rulemaking 
Advisory Committee, through its Engine Harmonization Working Group 
(EHWG), looked at harmonizing the engine control requirements of part 
33 and the JAR-E. This final rule reflects the agreed harmonization 
between the FAA and the JAA that was subsequently adopted by EASA as 
CS-E (Certification Specifications for Engines) 50.

Summary of the NPRM

    A Notice of Proposed Rulemaking (NPRM) was published on April 11, 
2007 (72 FR 18148) that proposed changes to Sec. Sec.  33.5, 33.7, 
33.27, 33.28, 33.29, 33.53, and 33.91. The comment period for the NPRM 
closed on July 10, 2007. These proposed changes would harmonize FAA and 
EASA regulations for the referenced sections.

Summary of the Final Rule

    This final rule on Engine Control System requirements contains no 
significant changes from the NPRM published on April 11, 2007. We made 
minor changes to several sections to ensure clarity and better 
harmonization with EASA regulations. This rule harmonizes FAA and EASA 
regulations for portions of Sec. Sec.  33.5, 33.7, 33.27, 33.28, 33.29, 
33.53, and 33.91.

Summary of Comments

    Five commenters, including an aircraft engine manufacturer and a 
manufacturer of light business jets, responded to the NPRM request for 
comments. The commenters supported the proposed rule while suggesting 
minor changes.
    The FAA received comments on the following general areas of the 
proposal:
     Instructions for installing the engine control transitions
     Engine control system failures
     Overspeed protection
     System Safety Assessment (SSA) interfaces between engine 
and aircraft
     Programmable logic devices
     Instrument connection

Discussion of the Final Rule

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

Instructions for Installing and Operating the Engine

    We revised Sec.  33.5, Instruction manual for installing and 
operating the engine, to require applicants to list in the installation 
instructions the instruments necessary for satisfactory control of the 
engine. The new Sec.  33.5 also requires that the limits of accuracy 
and transient response required for satisfactory engine operation be 
identified so the suitability of the instruments as installed can be 
assessed.
    General Electric (GE) indicated the definition of the reliability, 
accuracy, and transient response requirements should not be required in 
part 33 and would be more appropriate for evaluation as part of 
compliance with part 25.
    During the design, development and certification of an engine, the 
engine manufacturer must determine the specific information the pilot 
needs to control the engine. The engine manufacturer must convey this 
information, which includes necessary measurement data, to the 
installer. In addition, the FAA notes that the engine manufacturer, 
rather than the installer, should know the transient capability needed 
by the display to accurately represent the engine behavior. We did

[[Page 48280]]

not change the final rule due to this comment.
    In the final rule, we are adding a paragraph (b)(5) that was 
originally proposed in the NPRM as paragraph (b)(4). We are doing this 
because another final rule, ``Rotorcraft Turbine Engines One-Engine-
Inoperative (OEI) Ratings, Type Certification Standards'' has already 
added paragraph (b)(4) to this section.

Engine Ratings and Operating Limitations

    The revised Sec.  33.7 requires that the overall limits of accuracy 
of the engine control system and the necessary instruments, as defined 
in Sec.  33.5(a)(6), be considered when determining engine performance 
and operating limitations.
    Sino Swearingen, a business jet manufacturer, suggested any 
assumptions made relative to the accuracy of installer-supplied 
instruments should be stated as assumptions in the installation manual. 
The FAA believes this level of detail is excessive for a regulatory 
requirement. Therefore, we did not change the final rule due to this 
comment.
    GE asserted that defining the accuracy limits for the aircraft-
provided instruments should be a task for the airframe manufacturer and 
should be part of compliance with part 25 not part 33.
    We find the engine manufacturer needs to determine the accuracy 
limits for aircraft-provided instruments and provide this information 
to the installer. Without this information, it is unclear if it is 
critical that a given parameter must be measured and displayed with an 
accuracy of 1% or as much as 20%, which is a significant difference to 
the installer. We did not change the final rule due to this comment.
    None of the above comments to the proposed Sec.  33.7 reflect the 
complexity of integration encountered during installation of an engine 
on an aircraft. Sections 33.7 and 33.5(a)(6) require that the engine 
manufacturer and the installer account for the accuracies and the 
documentation of these accuracies for the overall system as installed. 
This is to ensure the engine, as installed, can be operated within its 
limitations.

Engine Control Systems

    We revised the title and contents of Sec.  33.28 to apply to all 
types of engine control systems, including hydromechanical and 
reciprocating engine controls. Formerly, Sec.  33.28 applied only to 
electrical and electronic engine control systems.

Engine Control Systems Validation

    The revised Sec.  33.28(b) prescribes requirements for engine 
control system validation. Section 33.28(b)(1) requires that applicants 
demonstrate their engine control system performs its intended function 
in the declared operating conditions, including the environmental 
conditions and flight envelope. Section 33.28(b)(1)(ii) also requires 
that the engine control system comply with Sec. Sec.  33.51, 33.65, and 
33.73, as appropriate, under all likely system inputs and allowable 
engine power or thrust demands.
    GE found proposed Sec.  33.28(b)(1)(ii) difficult to understand. GE 
suggested Sec.  33.28(b)(1)(ii) be revised to read: ``Complies with the 
operability requirements of Sec. Sec.  33.51, 33.65 and 33.73, as 
appropriate, under all likely system inputs and allowable engine power 
or thrust demands, unless it can be demonstrated that failure of the 
control function results in a non-dispatchable condition in the 
intended application.'' The FAA agrees and has revised the final rule 
to read as the commenter suggested.

Control Transitions

    We revised Sec.  33.28(c) to clarify the requirements for control 
transitions, including crew notification, when fault accommodation is 
implemented through alternate modes, channel changes, or changes from 
primary to back-up systems.
    GE suggested that revised Sec.  33.28(c)(1)(iii) requires the 
action of the flight crew be described in the engine operating 
instructions if the crew must respond to changes in control modes. GE 
claimed the indication of the mode change to the cockpit crew should be 
included in the compliance with part 33 but the action required by the 
crew should be reserved for compliance with part 25. GE also noted 
Sec.  33.28(c)(2) requires the magnitude of a thrust change associated 
with a control mode change be described in the engine installation 
manual. GE believes it is only necessary for this information to be 
included in the engine installation manual if the flight crew is 
required to initiate, respond, or be aware of this mode change.
    We note the intent of these changes to Sec.  33.28(c) is to ensure 
the installer is aware of any engine or engine control operational 
differences and the recommended differences in procedures. We have 
observed this problem in some previous engine installations. The 
inclusion of these actions in the operating instructions draws the 
attention of the installer to this condition so that the crew action 
must be evaluated--and be found acceptable--under aircraft 
certification. This recommended crew action in the engine installation 
manual is a guideline for the installer and does not replace 
requirements for crew action that are normally included in the aircraft 
operations manual. We did not change the final rule due to this 
comment.

Engine Control System Failures

    Revised Sec.  33.28(d) consists of control system failure 
requirements formerly located in Sec.  33.28(c). Section 33.28(d)(1) 
addresses integrity requirements, such as Loss of Thrust Control 
(LOTC)/Loss of Power Control (LOPC) requirements consistent with the 
intended application.
    Section 33.28(d)(2) requires the engine control system be designed 
and constructed so that in its full-up configuration it is single fault 
tolerant, as determined by the Administrator, for electrical or 
electronic failures with respect to LOTC/LOPC events. We received no 
comments on proposed Sec.  33.28(d)(2).
    Sino Swearingen pointed out Sec.  33.28(d)(1) requires the 
applicant to design a system that will achieve an LOTC rate compatible 
with intended application. However, Sino Swearingen notes that 
different aircraft categories (normal, commuter, transport, rotorcraft) 
have different levels of safety, associated reliability requirements, 
and software verification and validation requirements. Sino Swearingen 
asserted the ``intended application'' should, therefore, be specified 
in the engine installation instructions.
    We do not believe this level of specificity is appropriate for a 
regulation, but we will provide appropriate LOTC/LOPC rates and levels 
of reliability in the advisory material that accompanies the rule.

System Safety Assessment

    The revised Sec.  33.28(e) requires a System Safety Assessment 
(SSA) for the engine control system. The SSA must identify faults or 
failures that would have harmful effects on the engine.
    GE expressed concern that the conditions to be analyzed for 
compliance with Sec.  33.28(e) are not clearly related to safety, as 
would be implied by the requirement that an SSA be done. The commenter 
believes the listed conditions would have a minor effect for a typical 
installation.
    We note that under the SSA, in complying with Sec. Sec.  33.28 and 
33.75, applicants are required to identify faults or failures that 
would cause major,

[[Page 48281]]

hazardous and catastrophic engine effects. These types of faults would 
require an SSA and a reliability assessment. For example, faults that 
can lead to an LOTC and subsequent high thrust or an uncontrolled 
overspeed can cause a hazardous engine effect. Faults such as thrust in 
the wrong direction or excessive drag (propeller airplanes) or `thrust 
failed high and not controllable' can produce a catastrophic aircraft 
effect. We find, therefore, that the conditions to be analyzed for an 
SSA under Sec.  33.28(e) are clearly related to safety. We did not 
change the final rule due to this comment.
    GE also claimed the phrase ``an effect on engine operability'' in 
Sec.  33.28(e) is not ``bounded.'' The commenter felt this phrase 
should be modified to ``an effect on engine operability producing a 
surge or stall * * *''
    The suggested phrasing is clearer and places the appropriate 
boundaries on the statement. We, therefore, revised Sec.  33.28(e) in 
the final rule to include the suggested phrase.
    GE commented that requiring an SSA addressing every single data 
element would impose additional costs to applicants. This final rule 
requires an aggregate SSA, not a separate analysis on every single data 
element. The SSA must identify faults or failures that would have 
harmful effects on the engine. It has been used in the certification 
process for the last several years and is already an existing 
requirement in Europe. Recent examples include certification of Pratt & 
Whitney's PW6000, Rolls-Royce's Model 250, and General Electric GEnx 
engines. We find that this manufacturer will not face additional cost 
from complying with this requirement because it already meets the 
existing European requirements.

Protection Systems

    The new Sec.  33.28(f) requires protective functions, such as 
overspeed protection systems, that preserve rotor integrity. Section 
33.28(f)(2) adds a requirement that the design of electronic overspeed 
protection systems include a means for testing at least once per engine 
start/stop cycle to establish the availability of the system's 
function.
    GE commented that the frequency at which the overspeed protection 
must be tested should be determined based on the application, the 
possible failure modes, and the potential of those failure modes.
    We have found the requirement to test overspeed protection at least 
once per engine start/stop cycle is appropriate based on safety 
considerations. We note that if overspeed protection is not available, 
then exposure of an engine to a single failure could result in 
uncontrolled overspeed. We made no changes to the final rule due to 
this comment. We will, however, clarify in the advisory material that 
will accompany this rule that testing the overspeed system depends on a 
number of design and architecture factors. For example, the system 
architecture may implement a number of protection paths that have to be 
individually tested to confirm the system's functionality. Thus, while 
the test frequency is one flight cycle, it may take more than one 
flight cycle to complete the test of the overspeed protection system.

Aircraft-Supplied Data

    The new Sec.  33.28(h) prescribes requirements for single failures 
leading to loss, interruption, or corruption of aircraft-supplied data 
or data shared between engines. We modified the former fault 
accommodation requirement for loss of all aircraft-supplied data to 
require detection and accommodation for single failures leading to 
loss, interruption, or corruption of aircraft-supplied data. This 
accommodation must not result in an unacceptable change in thrust or 
power or an unacceptable change in engine operating and starting 
characteristics.
    GE suggested the phrase ``as part of certification documentation'' 
be added to Sec.  33.28(h)(2) to avoid confusion since other parts of 
this rule define what needs to be documented in the installation 
manual. FAA experience with previous engine programs has been that 
information on the effects of failures on engine power or thrust, 
engine operability, and starting characteristics is needed in the 
engine installation instructions to ensure that it is clearly 
communicated by the applicant to the installer. As a result of this 
comment, we modified the final rule to clarify that this information 
must be documented in the engine installation instructions.
    Also, Sino Swearingen expressed concern that Sec.  33.28(h)(2) does 
not define the unacceptable change in thrust or power or ``allowable 
degradation'' in engine operating and starting characteristics. We find 
that including this information in the rule would be overly 
prescriptive. Unacceptable changes or allowable degradation often 
depend on the installation. We find, therefore, that it is more 
appropriate to explain unacceptable changes in thrust, power, or engine 
operating and starting characteristics in the advisory material that 
accompanies this rule. We did not change the final rule due to this 
comment.

Aircraft-Supplied Electrical Power

    The new Sec.  33.28(i) establishes requirements for the response of 
the engine control system to the loss or interruption of electrical 
power supplied from the aircraft. Section 33.28(i) applies to all 
electrical power supplied to the engine control system, including that 
supplied from the aircraft power system and from the dedicated power 
source, if required.
    GE commented the applicant should be able to identify the 
characteristics of any electrical power supplied from the aircraft to 
the engine control system for starting and operating the engine in any 
document that is part of the certification process rather than in the 
engine instructions for installation, as required by the proposed rule.
    The FAA has observed a significant number of problems caused by 
inadequate communication between the applicant and the installer 
regarding aircraft-supplied electrical power. We have found it is 
critical that this level of detail be clearly communicated by the 
applicant to the installer. The FAA notes also that at the time of 
engine certification, it is not always clear who the ultimate 
installer(s) will be. Providing these details, therefore, in the engine 
instructions for installation will help to ensure the installer has the 
needed information. We did not change the final rule due to this 
comment.

Programmable Logic Devices

    The new Sec.  33.28(m) establishes safety requirements for 
programmable logic devices (PLDs) that include application-specific 
integrated circuits and programmable gate arrays. The rule requires 
that development of the devices and associated encoded logic used in 
their design and implementation be at a level equal to the hazard level 
of the functions performed via the devices.
    EASA suggested that the FAA should clarify the rule to ensure it is 
not the FAA's intent to mandate that the type certificate (TC) holder 
design and implement PLD logic. EASA argued the TC holder should only 
be required to provide evidence that these devices have been developed 
using a method, for example DO-254, that is acceptable to the FAA.
    We agree with EASA that the proposed language might be 
misinterpreted. We, therefore, have revised Sec.  33.28(m) in the final 
rule to indicate the applicant must provide evidence that PLDs have 
been developed in accordance with a method approved by the FAA.

[[Page 48282]]

Instrument Connection

    We revised Sec.  33.29 by adding new paragraphs (e) through (h). 
The new Sec.  33.29(e) requires that applicants provide instrumentation 
necessary to ensure engine operation in compliance with the engine 
operating limitations. The new Sec.  33.29(f) requires that applicants 
provide a means to minimize the possibility of incorrect fitting of 
instruments, sensors and connectors. The new Sec.  33.29(g) reduces the 
probability of faults propagating from the instrumentation and 
monitoring functions to the control functions, or vice versa, by 
prescribing that the probability of propagation of faults be consistent 
with the criticality of the function performed. The new Sec.  33.29(h) 
adds requirements for instrumentation that enables the flight crew to 
monitor the functioning of the turbine case cooling system.
    Sino Swearingen agreed it is appropriate in Sec.  33.29(f) to 
specify that the engine design should include means to prevent improper 
installation or ``fit'' of instruments, sensors and connectors. Sino 
Swearingen commented, however, that it is virtually impossible to 
consider the effects of multiple possible incorrect assembly and 
installation scenarios within the engine control system's SSA 
especially since it must consider airplane-installed instruments to be 
comprehensive.
    The FAA notes the intent of this rule is to achieve an engine 
design where the fit of the installation will prevent an accidental 
incorrect assembly. When incorrect fit cannot be ensured, the SSA needs 
to address the effects of the incorrect assembly. The FAA is not 
intending to include aircraft-installed instruments in this assessment. 
We did not change the final rule due to this comment.

Engine Overtemperature Test

    We did not propose changes to this section in the NPRM. We are, 
however, changing a reference in this section in the final rule from 
Sec.  33.67(d) to Sec.  33.28(k) because this rule eliminates Sec.  
33.67(d) and moves its contents to Sec.  33.28(k). We did not make any 
other changes to Sec.  33.88 by this rule.

Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
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.
    An agency may not collect or sponsor the collection of information, 
nor may it impose an information collection requirement unless it 
displays a currently valid Office of Management and Budget (OMB) 
control number.

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 each Federal agency 
propose or adopt a regulation only upon a 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 developing U.S. standards, this Trade 
Act also requires agencies to consider international standards and, 
where appropriate, use them as 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 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.
    Presently, engine manufacturers must satisfy both United States and 
European requirements to certify and market part 33 engines in both the 
United States and in Europe. Meeting two sets of certification 
requirements raises the cost of developing a new engine often with no 
increase in safety. In the interest of fostering international trade, 
lowering the cost of engine development, and making the certification 
process more efficient, the FAA, EASA, and manufacturers have worked to 
create to the maximum extent possible a single set of certification 
requirements accepted in both the United States and Europe. These 
efforts are referred to as harmonization.
    This final rule codifies current industry practices and harmonizes 
FAA requirements for aircraft engine control systems with similar 
requirements recently adopted by EASA, thereby simplifying 
airworthiness approvals for import and export. Similar international 
requirements reduce duplicative testing which will reduce certification 
costs. The FAA has not attempted to quantify the cost savings that may 
accrue due to this specific rule, beyond noting that while they may be 
minimal they contribute to harmonization savings. In addition, a 
potential for increased safety lies in having clearer and more explicit 
regulations. The agency concludes that there is consensus among 
potentially impacted manufacturers that savings will result, and 
further analysis is not required. The benefits of this final rule 
justify the costs and the existing level of safety will be preserved.

Economic Summary

    The FAA has determined that the benefits of this final rule justify 
the costs. It 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.

Final 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 businesses, 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,

[[Page 48283]]

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 agency determines 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.
    During the comment period, one individual questioned our 
determination that the rule would not affect a substantial number of 
small entities. In the Initial Regulatory Flexibility Determination, we 
found there would not be a significant economic impact on a substantial 
number of small entities and used the broadest category, ``more than 
just a few,'' in determining if a substantial number of small entities 
were impacted. There were no other comments on the potential effect on 
small businesses.
    Although there are engine manufacturers who qualify as small 
businesses based on Small Business Administration Size Standards, this 
rule reduces cost. Our final regulatory flexibility determination is 
that this final rule will not have a significant economic impact on a 
substantial number of small entities.
    Therefore, as the Acting FAA Administrator, I certify that this 
final 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.
    This final rule considers and incorporates an international 
standard as the basis of an FAA regulation. Thus this final rule 
complies with The Trade Agreements Act of 1979 and does not create 
unnecessary obstacles to international trade.

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 
(adjusted annually for inflation with the base year 1995) 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 level equivalent of $100 million in CY 1995, 
adjusted for inflation to CY 2007 levels by the Consumer Price Index 
for all Urban Consumers (CPI-U) as published by the Bureau of Labor 
Statistics, is $136.1 million.
    This final rule does not contain such a mandate. The requirements 
of Title II 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 have 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 (http://
www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://
www.faa.gov/regulations_policies/; or
    3. Accessing the Government Printing Office's Web page at http://
www.gpoaccess.gov/fr/index.html.
    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 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 
http://docketsinfo.dot.gov.

Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires the 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 http://www.faa.gov/regulations_
policies/rulemaking/sbre_act/.

List of Subjects in 14 CFR Part 33

    Aircraft, Aviation safety, Life-limited parts, Reporting and 
recordkeeping requirements.

The Amendment

0
In consideration of the foregoing, the Federal Aviation Administration 
amends Chapter I of Title 14, Code of Federal Regulations as follows:

[[Page 48284]]

PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES

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

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

0
2. Amend Sec.  33.5 by adding new paragraphs (a)(4), (a)(5), (a)(6), 
and (b)(5), to read as follows:

Sec.  33.5  Instruction manual for installing and operating the engine.

* * * * *
    (a) * * *
    (4) A definition of the physical and functional interfaces with the 
aircraft and aircraft equipment, including the propeller when 
applicable.
    (5) Where an engine system relies on components that are not part 
of the engine type design, the interface conditions and reliability 
requirements for those components upon which engine type certification 
is based must be specified in the engine installation instructions 
directly or by reference to appropriate documentation.
    (6) A list of the instruments necessary for control of the engine, 
including the overall limits of accuracy and transient response 
required of such instruments for control of the operation of the 
engine, must also be stated so that the suitability of the instruments 
as installed may be assessed.
    (b) * * *
    (5) A description of the primary and all alternate modes, and any 
back-up system, together with any associated limitations, of the engine 
control system and its interface with the aircraft systems, including 
the propeller when applicable.
* * * * *

0
3. Amend Sec.  33.7 by adding new paragraph (d) to read as follows:

Sec.  33.7  Engine ratings and operating limitations.

* * * * *
    (d) In determining the engine performance and operating 
limitations, the overall limits of accuracy of the engine control 
system and of the necessary instrumentation as defined in Sec.  
33.5(a)(6) must be taken into account.

0
4. Amend Sec.  33.27 by revising paragraph (b) to read as follows:

Sec.  33.27  Turbine, compressor, fan, and turbosupercharger rotors.

* * * * *
    (b) The design and functioning of engine systems, instruments, and 
other methods, not covered under Sec.  33.28 must give reasonable 
assurance that those engine operating limitations that affect turbine, 
compressor, fan, and turbosupercharger rotor structural integrity will 
not be exceeded in service.
* * * * *

0
5. Revise Sec.  33.28 to read as follows:

Sec.  33.28  Engine control systems.

    (a) Applicability. These requirements are applicable to any system 
or device that is part of engine type design, that controls, limits, or 
monitors engine operation, and is necessary for the continued 
airworthiness of the engine.
    (b) Validation.
    (1) Functional aspects. The applicant must substantiate by tests, 
analysis, or a combination thereof, that the engine control system 
performs the intended functions in a manner which:
    (i) Enables selected values of relevant control parameters to be 
maintained and the engine kept within the approved operating limits 
over changing atmospheric conditions in the declared flight envelope;
    (ii) Complies with the operability requirements of Sec. Sec.  
33.51, 33.65 and 33.73, as appropriate, under all likely system inputs 
and allowable engine power or thrust demands, unless it can be 
demonstrated that failure of the control function results in a non-
dispatchable condition in the intended application;
    (iii) Allows modulation of engine power or thrust with adequate 
sensitivity over the declared range of engine operating conditions; and
    (iv) Does not create unacceptable power or thrust oscillations.
    (2) Environmental limits. The applicant must demonstrate, when 
complying with Sec. Sec.  33.53 or 33.91, that the engine control 
system functionality will not be adversely affected by declared 
environmental conditions, including electromagnetic interference (EMI), 
High Intensity Radiated Fields (HIRF), and lightning. The limits to 
which the system has been qualified must be documented in the engine 
installation instructions.
    (c) Control transitions.
    (1) The applicant must demonstrate that, when fault or failure 
results in a change from one control mode to another, from one channel 
to another, or from the primary system to the back-up system, the 
change occurs so that:
    (i) The engine does not exceed any of its operating limitations;
    (ii) The engine does not surge, stall, or experience unacceptable 
thrust or power changes or oscillations or other unacceptable 
characteristics; and
    (iii) There is a means to alert the flight crew if the crew is 
required to initiate, respond to, or be aware of the control mode 
change. The means to alert the crew must be described in the engine 
installation instructions, and the crew action must be described in the 
engine operating instructions;
    (2) The magnitude of any change in thrust or power and the 
associated transition time must be identified and described in the 
engine installation instructions and the engine operating instructions.
    (d) Engine control system failures. The applicant must design and 
construct the engine control system so that:
    (1) The rate for Loss of Thrust (or Power) Control (LOTC/LOPC) 
events, consistent with the safety objective associated with the 
intended application can be achieved;
    (2) In the full-up configuration, the system is single fault 
tolerant, as determined by the Administrator, for electrical or 
electronic failures with respect to LOTC/LOPC events;
    (3) Single failures of engine control system components do not 
result in a hazardous engine effect; and
    (4) Foreseeable failures or malfunctions leading to local events in 
the intended aircraft installation, such as fire, overheat, or failures 
leading to damage to engine control system components, do not result in 
a hazardous engine effect due to engine control system failures or 
malfunctions.
    (e) System safety assessment. When complying with this section and 
Sec.  33.75, the applicant must complete a System Safety Assessment for 
the engine control system. This assessment must identify faults or 
failures that result in a change in thrust or power, transmission of 
erroneous data, or an effect on engine operability producing a surge or 
stall together with the predicted frequency of occurrence of these 
faults or failures.
    (f) Protection systems.
    (1) The design and functioning of engine control devices and 
systems, together with engine instruments and operating and maintenance 
instructions, must provide reasonable assurance that those engine 
operating limitations that affect turbine, compressor, fan, and 
turbosupercharger rotor structural integrity will not be exceeded in 
service.
    (2) When electronic overspeed protection systems are provided, the 
design must include a means for testing, at least once per engine 
start/stop cycle, to establish the availability of the protection 
function. The means must be such that a complete test of the system can 
be achieved in the minimum number of cycles. If the test is not fully 
automatic, the requirement for a manual test must be contained in the 
engine instructions for operation.

[[Page 48285]]

    (3) When overspeed protection is provided through hydromechanical 
or mechanical means, the applicant must demonstrate by test or other 
acceptable means that the overspeed function remains available between 
inspection and maintenance periods.
    (g) Software. The applicant must design, implement, and verify all 
associated software to minimize the existence of errors by using a 
method, approved by the FAA, consistent with the criticality of the 
performed functions.
    (h) Aircraft-supplied data. Single failures leading to loss, 
interruption or corruption of aircraft-supplied data (other than thrust 
or power command signals from the aircraft), or data shared between 
engines must:
    (1) Not result in a hazardous engine effect for any engine; and
    (2) Be detected and accommodated. The accommodation strategy must 
not result in an unacceptable change in thrust or power or an 
unacceptable change in engine operating and starting characteristics. 
The applicant must evaluate and document in the engine installation 
instructions the effects of these failures on engine power or thrust, 
engine operability, and starting characteristics throughout the flight 
envelope.
    (i) Aircraft-supplied electrical power.
    (1) The applicant must design the engine control system so that the 
loss, malfunction, or interruption of electrical power supplied from 
the aircraft to the engine control system will not result in any of the 
following:
    (i) A hazardous engine effect, or
    (ii) The unacceptable transmission of erroneous data.
    (2) When an engine dedicated power source is required for 
compliance with paragraph (i)(1) of this section, its capacity should 
provide sufficient margin to account for engine operation below idle 
where the engine control system is designed and expected to recover 
engine operation automatically.
    (3) The applicant must identify and declare the need for, and the 
characteristics of, any electrical power supplied from the aircraft to 
the engine control system for starting and operating the engine, 
including transient and steady state voltage limits, in the engine 
instructions for installation.
    (4) Low voltage transients outside the power supply voltage 
limitations declared in paragraph (i)(3) of this section must meet the 
requirements of paragraph (i)(1) of this section. The engine control 
system must be capable of resuming normal operation when aircraft-
supplied power returns to within the declared limits.
    (j) Air pressure signal. The applicant must consider the effects of 
blockage or leakage of the signal lines on the engine control system as 
part of the System Safety Assessment of paragraph (e) of this section 
and must adopt the appropriate design precautions.
    (k) Automatic availability and control of engine power for 30-
second OEI rating. Rotorcraft engines having a 30-second OEI rating 
must incorporate a means, or a provision for a means, for automatic 
availability and automatic control of the 30-second OEI power within 
its operating limitations.
    (l) Engine shut down means. Means must be provided for shutting 
down the engine rapidly.
    (m) Programmable logic devices. The development of programmable 
logic devices using digital logic or other complex design technologies 
must provide a level of assurance for the encoded logic commensurate 
with the hazard associated with the failure or malfunction of the 
systems in which the devices are located. The applicant must provide 
evidence that the development of these devices has been done by using a 
method, approved by the FAA, that is consistent with the criticality of 
the performed function.

0
6. Amend Sec.  33.29 by adding new paragraphs (e) through (h) to read 
as follows:

Sec.  33.29  Instrument connection.

* * * * *
    (e) The applicant must make provision for the installation of 
instrumentation necessary to ensure operation in compliance with engine 
operating limitations. Where, in presenting the safety analysis, or 
complying with any other requirement, dependence is placed on 
instrumentation that is not otherwise mandatory in the assumed aircraft 
installation, then the applicant must specify this instrumentation in 
the engine installation instructions and declare it mandatory in the 
engine approval documentation.
    (f) As part of the System Safety Assessment of Sec.  33.28(e), the 
applicant must assess the possibility and subsequent effect of 
incorrect fit of instruments, sensors, or connectors. Where necessary, 
the applicant must take design precautions to prevent incorrect 
configuration of the system.
    (g) The sensors, together with associated wiring and signal 
conditioning, must be segregated, electrically and physically, to the 
extent necessary to ensure that the probability of a fault propagating 
from instrumentation and monitoring functions to control functions, or 
vice versa, is consistent with the failure effect of the fault.
    (h) The applicant must provide instrumentation enabling the flight 
crew to monitor the functioning of the turbine cooling system unless 
appropriate inspections are published in the relevant manuals and 
evidence shows that:
    (1) Other existing instrumentation provides adequate warning of 
failure or impending failure;
    (2) Failure of the cooling system would not lead to hazardous 
engine effects before detection; or
    (3) The probability of failure of the cooling system is extremely 
remote.

0
7. Amend Sec.  33.53 by revising the section heading and paragraph (a) 
to read as follows:

Sec.  33.53  Engine system and component tests.

    (a) For those systems and components that cannot be adequately 
substantiated in accordance with endurance testing of Sec.  33.49, the 
applicant must conduct additional tests to demonstrate that systems or 
components are able to perform the intended functions in all declared 
environmental and operating conditions.
* * * * *

Sec.  33.67  [Amended]

0
8. Remove paragraph (d) from Sec.  33.67.
0
9. Amend Sec.  33.88 by revising paragraph (b) to read as follows:

Sec.  33.88  Engine overtemperature test.

* * * * *
    (b) In addition to the test requirements in paragraph (a) of this 
section, each engine for which 30-second OEI and 2-minute OEI ratings 
are desired, that incorporates a means for automatic temperature 
control within its operating limitations in accordance with Sec.  
33.28(k), must run for a period of 4 minutes at the maximum power-on 
rpm with the gas temperature at least 35 [deg]F (19 [deg]C) higher than 
the maximum operating limit at 30-second OEI rating. Following this 
run, the turbine assembly may exhibit distress beyond the limits for an 
overtemperature condition provided the engine is shown by analysis or 
test, as found necessary by the FAA, to maintain the integrity of the 
turbine assembly.
* * * * *

0
10. Amend Sec.  33.91 by revising the section heading and paragraph (a) 
to read as follows:

[[Page 48286]]

Sec.  33.91  Engine system and component tests.

    (a) For those systems or components that cannot be adequately 
substantiated in accordance with endurance testing of Sec.  33.87, the 
applicant must conduct additional tests to demonstrate that the systems 
or components are able to perform the intended functions in all 
declared environmental and operating conditions.
* * * * *

    Issued in Washington, DC, on July 2, 2008.
Robert A. Sturgell,
Acting Administrator.
[FR Doc. E8-19048 Filed 8-18-08; 8:45 am]

BILLING CODE 4910-13-P