[Federal Register Volume 72, Number 69 (Wednesday, April 11, 2007)]
[Proposed Rules]
[Pages 18148-18155]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-6535]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 33
[Docket No. FAA-2007-27311; Notice No. 07-03]
RIN 2120-AI94
Airworthiness Standards; Engine Control System Requirements
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The Federal Aviation Administration (FAA) is proposing to
revise type certification standards for aircraft engine control
systems. These proposed changes reflect current practices and harmonize
FAA standards with those recently adopted by the European Aviation
Safety Agency (EASA). These proposed changes would establish uniform
standards for all engine control systems for aircraft engines
certificated by both U.S. and European countries and would simplify
airworthiness approvals for import and export.
DATES: Send your comments on or before July 10, 2007.
ADDRESSES: You may send comments identified by Docket Number [FAA-2007-
27311] using any of the following methods:
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
[[Page 18149]]
Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your
comments electronically.
Mail: Docket Management Facility; U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401,
Washington, DC 20590-0001.
Fax: 1-202-493-2251.
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For more information on the rulemaking process, see the
SUPPLEMENTARY INFORMATION section of this document.
Privacy: We will post all comments we receive, without change, to
http://dms.dot.gov, including any personal information you provide. For
more information, see the Privacy Act discussion in the SUPPLEMENTARY
INFORMATION section of this document.
Docket: To read background documents or comments received, go to
http://dms.dot.gov at any time or to Room PL-401 on the plaza level of
the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION 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
[email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites interested persons to participate in this
rulemaking by submitting written comments, data, or views. We also
invite comments relating to the economic, environmental, energy, or
federalism impacts that might result from adopting the proposals in
this document. The most helpful comments reference a specific portion
of the proposal, explain the reason for any recommended change, and
include supporting data. We ask that you send us two copies of written
comments.
We will file in the docket all comments we receive, as well as a
report summarizing each substantive public contact with FAA personnel
concerning this proposed rulemaking. The docket is available for public
inspection before and after the comment closing date. If you wish to
review the docket in person, go to the address in the ADDRESSES section
of this preamble between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays. You may also review the docket using the
Internet at the Web address in the ADDRESSES section.
Privacy Act: Using the search function of our docket Web site,
anyone can find and read the comments received into any of our dockets,
including the name of the individual sending the comment (or signing
the comment 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 (65 FR 19477-78) or you may visit
http://dms.dot.gov.
Before acting on this proposal, we will consider all comments we
receive on or before the closing date for comments. We will consider
comments filed late if it is possible to do so without incurring
expense or delay. We may change this proposal in light of the comments
we receive.
If you want the FAA to acknowledge receipt of your comments on this
proposal, include with your comments a pre-addressed, stamped postcard
on which the docket number appears. We will stamp the date on the
postcard and mail it to you.
Availability of Rulemaking Documents
You can get an electronic copy using the Internet by:
(1) Searching the Department of Transportation's electronic Docket
Management System (DMS) Web page (http://dms.dot.gov/search);
(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 docket number, notice number, or amendment number
of this rulemaking.
Background
U.S. and European aircraft engine regulations differ in several
areas including engine controls. Harmonization of these differences
benefits industry and regulators because of the lower costs associated
with one set of engine control 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.
In response to EHWG recommendations, the JAA published a Notice of
Proposed Amendment (NPA), NPA-E-33 Rev 0, on April 20, 2001. JAA's
proposed amendment contained rules and advisory material almost
identical to FAA's proposed part 33 changes. Some commenters to this
NPA objected that the reliability of aircraft-supplied electrical power
should be considered when determining the required degree of protection
against failure. Because of these comments, the JAA updated its
rulemaking in NPA-E-33 Rev 1. The FAA and the JAA subsequently agreed
that the reliability and quality of aircraft-supplied power should be a
factor in considering the approval of the engine design. This NPRM
reflects this agreement between FAA and the JAA. EASA has adopted this
agreement as CS-E (Certification Specifications for Engines) 50(h).
Section-by-Section Discussion of the Proposals
Section 33.5
We propose adding new paragraphs (a)(4), (a)(5), (a)(6) and (b)(4)
to Sec. 33.5 to require applicants to include additional installation
information in their instructions for installation. The requirements in
proposed paragraphs (a)(4), (a)(5) and (b)(4) are currently prescribed
under Sec. 33.28(a) as part of the control system description. This
proposal places these requirements in sections consistent with their
intended purpose.
Our proposed Sec. 33.5(a)(6) would require that installation
instructions list the instruments necessary for satisfactory control of
the engine. It would also require that the limits of accuracy and
transient response required for satisfactory engine operation be
identified so that the suitability of the instruments as installed can
be assessed. Part 33 does not require similar installation information.
We would harmonize Sec. Sec. 33.5(a)(4), (a)(5) and (b)(4) with CS-E
20(d), CS-E 30(b), and CS-E 20(d), respectively. Adding Sec.
33.5(a)(6) would harmonize with CS-E 60(b).
Section 33.7
We propose adding a new paragraph (d) to this section. This
paragraph
[[Page 18150]]
would require 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. Paragraph (d) would harmonize with CS-E 40(g).
Section 33.27
We propose a new Sec. 33.27(b) that prescribes requirements for
methods, other than engine control methods, for protecting rotor
structural integrity during overspeed conditions. These methods would
include protection methods, such as blade shedding, currently regulated
under the CS-E but not identified under part 33.
Section 33.28
We propose changing the title of Sec. 33.28 and the content of its
paragraphs. The title would be changed from ``Electrical and electronic
engine control systems'' to ``Engine control systems.'' Currently,
Sec. 33.28 applies only to electrical and electronic engine control
systems, while CS-E 50 and associated requirements apply to all types
of engine control systems, including hydromechanical and reciprocating
engine controls. The new title reflects the proposed revisions to the
section which, to harmonize with EASA specifications, would change the
scope of the proposed rule to include all types of engine control
systems and devices under Sec. 33.28.
Section 33.28(a)
Our proposed Sec. 33.28(a) would be titled ``Applicability'' and
would clarify the systems or devices that are subject to Sec. 33.28
requirements.
Section 33.28(b)
We propose replacing existing Sec. 33.28(b) with new Sec.
33.28(b), ``Validation,'' which prescribes requirements for engine
control system validation. The new Sec. 33.28(b) consists of new
paragraphs (b)(1) and (b)(2).
Our proposed Sec. 33.28(b)(1) requires that applicants demonstrate
that their engine control system performs its intended function in the
declared operating conditions, including environmental conditions and
flight envelope. Part 33 generally requires this showing, but does so
nonspecifically. This new specific requirement will clarify the
regulation.
The proposed Sec. 33.28(b)(1) 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. It also requires that the engine control system allow engine
power and thrust modulation with adequate sensitivity over the declared
range of engine operating conditions. The engine control system also
must not create unacceptable power or thrust oscillations.
Proposed Sec. 33.28(b)(1) would harmonize the sections in part 33
that address engine performance and operability requirements with
similar requirements in CS-E 50.
Our proposed Sec. 33.28(b)(2) revises requirements located in the
existing Sec. 33.28(d). Proposed Sec. 33.28(b)(2) would clarify
environmental testing requirements, including those for High Intensity
Radiated Fields (HIRF), lightning, and electromagnetic interference
(EMI) for the engine control system.
The environmental testing requirements that are part of the
proposed Sec. 33.28(b) set the installation limitations. Those
limitations are incorporated into the instructions in accordance with
Sec. 33.5(b)(4).
Section 33.28(c)
We propose to revise Sec. 33.28(c) to clarify the requirements for
control transitions when fault accommodation is implemented through
alternate modes, channel changes, or changes from primary to back-up
systems. Proposed Sec. 33.28(c), titled ``Control transitions,'' will
clarify the need for crew notification if crew action is required as
part of fault accommodation.
Section 33.28(d)
Our proposed Sec. 33.28(d) would consist of revised control system
failure requirements formerly located in Sec. 33.28(c). Proposed Sec.
33.28(d), titled ``Engine control system failures,'' would consist of
four paragraphs: Sec. 33.28(d)(1) would address integrity
requirements, such as Loss of Thrust Control (LOTC) requirements
consistent with the intended application; Sec. 33.28(d)(2) would
require accommodation of single failures with respect to LOTC/LOPC
(Loss of Power Control) events; Sec. 33.28(d)(3) would clarify
requirements for single failures of electrical or electronic
components; and Sec. 33.28(d)(4) would add requirements for
foreseeable failures or malfunctions in the intended aircraft
installation such as fire and overheat (i.e., local events).
We considered using the phrase ``essentially single fault
tolerant'' in proposed paragraph (d)(2) as the standard for measuring
the compliance of an applicant's engine control system. We have had
extensive discussions with industry about the meaning of ``essentially
single fault tolerant.'' However, in reviewing the meaning of
``essentially,'' we decided that this term introduces sufficient
ambiguity so that the phrase could not serve as the basis for an
enforceable standard. We chose, therefore, to remove ``essentially''
and to reserve to the Administrator the right to define what is meant
by ``single fault tolerant.'' We are preparing an advisory circular to
offer guidance regarding what we mean by ``single fault tolerant'' as
used in the regulation.
Section 33.28(e)
Our proposed Sec. 33.28(e), titled ``System safety assessment,''
would require a System Safety Assessment (SSA) for the engine control
system. The SSA would identify faults or failures that would have
harmful effects on the engine. Proposed Sec. 33.28(e) harmonizes with
CS-E 50(d).
Section 33.28(f)
Our proposed Sec. 33.28(f), titled ``Protection systems,''
requires protective functions that preserve rotor integrity. Proposed
Sec. 33.28(f)(1) would include the protection requirements of the
existing Sec. 33.27(b). Proposed Sec. 33.28(f)(2) adds requirements
for testing the protection function for availability. Proposed Sec.
33.28(f)(3) establishes requirements for overspeed protection systems
implemented through hydromechanical or mechanical means. Proposed Sec.
33.28(f) harmonizes with CS-E 50(e).
Section 33.28(g)
Our proposed Sec. 32.28(g), titled ``Software,'' would consist of
the software requirements for the engine control system currently
prescribed under Sec. 33.28(e). We are proposing to revise Sec.
33.28(g) to require that software be consistent with the criticality of
performed functions. Proposed Sec. 33.28(g) harmonizes with CS-E
50(f).
Section 33.28(h)
Our proposed Sec. 33.28(h), titled ``Aircraft-supplied data,''
clarifies requirements related to failure of aircraft-supplied data.
The revision consists of two new paragraphs that prescribe requirements
for single failures leading to loss, interruption, or corruption of
aircraft-supplied data or data shared between engines. We propose to
modify the current FAA requirement for fault accommodation 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
[[Page 18151]]
operating and starting characteristics. Proposed Sec. 33.28(h)
harmonizes with CS-E 50(g).
Section 33.28(i)
Our proposed Sec. 33.28(i), titled ``Aircraft-supplied electrical
power,'' clarifies requirements for the response of the engine control
system to loss or interruption of electrical power supplied from the
aircraft. Proposed Sec. 33.28(i) would apply 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.
We propose to add requirements to Sec. 33.28(i) that represent
current industry standard practices but are not in part 33. These
include a requirement that the applicant define in the instructions for
installation:
1. The power characteristics of any power supplied from the
aircraft to the engine control system; and
2. The engine control and engine responses to low voltage
transients outside the declared power supply voltage limitations.
This action proposes an additional requirement for a dedicated
power source for the control system to provide sufficient capacity to
power the functions provided by the control system below idle, such as
for the auto-relight function.
With the change in scope of this proposal from electronic engine
controls to engine controls, it is not our intent that all electrically
powered engine functions be under the Sec. 33.28(i) requirement for a
dedicated power source. The loss of some control functions
traditionally dependent on aircraft-supplied power continues to be
acceptable. The use of conventional aircraft-supplied power for these
traditional functions has been acceptable as they, in general, do not
affect the safe operation of the engine. Examples include:
Functions without safety significance that are primarily
performance enhancement functions
Engine start and ignition
Thrust reverser deployment
Anti-icing (engine probe heat)
Fuel shut-off
Our proposed Sec. 33.28(i) harmonizes with CS-E 50(h).
Section 33.28(j)
We propose adding a new Sec. 33.28(j), titled ``Air pressure
signal,'' that would add safety requirements for air pressure signals
in the engine control system. It will require that applicants take
design precautions to minimize system malfunction from ingress of
foreign matter or blockage of the signal lines by foreign matter or
ice. Our proposed Sec. 33.28(j) harmonizes with CS-E 50(i).
Section 33.28(k)
Our proposed Sec. 33.28(k), ``Automatic availability and control
of engine power for 30-second OEI rating,'' prescribes requirements for
engines with One-Engine-Inoperative (OEI) capability. This proposal,
formerly located in Sec. 33.67(d), prescribes a control function that
more properly is located in the ``Engine control systems'' section. We
propose moving the contents of Sec. 33.67(d) to 33.28(k). Our proposed
Sec. 33.28(k) harmonizes with CS-E 50(j).
Section 33.28(l)
Our proposed Sec. 33.28(l), titled ``Engine shutdown means,''
requires that the engine control system provide a rapid means of
shutting down the engine. Proposed Sec. 33.28(l) harmonizes with CS-E
50(k).
Section 33.28(m)
Our proposed Sec. 33.28(m), titled ``Programmable logic devices,''
adds safety requirements for programmable logic devices (PLD) that
include Application-Specific Integrated Circuits and programmable gate
arrays. We decided to propose new PLD requirements separate from
software requirements, although the requirements are similar, because
PLD's combine software and complex hardware. The proposed rule would
require 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. Proposed Sec.
33.28(m) harmonizes with CS-E 50(f).
Section 33.29
We propose revising Sec. 33.29 by adding new paragraphs (e)
through (h) to harmonize with CS-E 60, Provision for Instruments.
The new Sec. 33.29(e) would require that applicants provide
instrumentation necessary to ensure engine operation in compliance with
the engine operating limitations. When instrumentation is necessary for
compliance with the engine requirements, applicants must specify the
instrumentation in the instructions for installation and include the
instrumentation as part of the engine type design. The proposed Sec.
33.29(e) harmonizes with CS-E 60(a).
The existing Sec. 33.29(a) requirement addresses the prevention of
incorrect connections of instruments only. Proposed Sec. 33.29(f)
would require that applicants provide a means to minimize the
possibility of incorrect fitting of instruments, sensors and
connectors. Proposed Sec. 33.29(f) harmonizes with CS-E 110(e).
Currently, part 33 does not address requirements for sensors and
associated wiring and signal conditioning segregation. Proposed Sec.
33.29(g) would reduce 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.
Proposed Sec. 33.29(g) harmonizes with CS-E 60(c).
Our proposed Sec. 33.29(h) would add new requirements for
instrumentation that enables the flight crew to monitor the functioning
of the turbine case cooling system. Proposed Sec. 33.29(h) harmonizes
with CS-E 60(e).
Section 33.53
We propose revising the title of Sec. 33.53 from ``Engine
component tests,'' to ``Engine system and component tests.'' The
revised title would better identify reciprocating engine control system
tests that may be conducted under this paragraph. Proposed Sec.
33.53(a) provides for systems tests if required.
Section 33.91
We propose changing the title of Sec. 33.91 from ``Engine
component tests'' to ``Engine system and component tests.'' The revised
title would better identify engine control system tests, for example,
system validation testing, that may be required under this paragraph.
Our proposed Sec. 33.91(a) would provide for systems tests if
required.
Rulemaking Analyses and Notices
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. 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.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by 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
[[Page 18152]]
updates existing regulations for aircraft engine control systems.
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 determined that this
proposed rule does not impose any new information collection
requirements.
International Compatibility
In keeping with U.S. obligations under the Convention on
International Civil Aviation, we comply with International Civil
Aviation Organization (ICAO) Standards and Recommended Practices to the
maximum extent practicable. We determined that ICAO has no Standards or
Recommended Practices that correspond to these proposed regulations.
Economic Assessment, Regulatory Flexibility Determination, 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
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 proposed 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 proposed rule. The
reasoning for this determination follows.
The proposed rule reflects current practices and harmonizes FAA
airworthiness standards for aircraft engine control systems with
similar requirements recently adopted by EASA. These proposed changes
to engine control system requirements would establish uniform standards
for all engine control systems for aircraft engines certificated by
both U.S. and European countries and would simplify airworthiness
approvals for import and export. Similar international requirements
would reduce duplicative testing which would reduce certification
costs.
An engine control system is any system or device that controls,
limits, or monitors engine operation and is necessary for the continued
airworthiness of the engine. This implies consideration of all control
system components including the electronic control unit(s), fuel
metering unit(s), variable-geometry actuators, cables, wires, and
sensors.
An engine control system may be composed of several subsystems
which can include: (1) Fuel control, (2) spark control, (3)
turbocharger wastegate control, (4) throttle control, and (5) propeller
governor. A turbine FADEC (Full Authority Digital Engine Control)
system typically controls the fuel, the variable pitch vanes, the
engine operability bleeds, the temperature management system and, most
recently, the ignition and other starting elements. A reciprocating
engine could be considered to have a FADEC system if any of the
subsystems are controlled electronically over their full range of
operation.
The proposed regulation covers the main engine control system as
well as the protection systems, for example, overspeed, over-torque, or
over-temperature. Engine monitoring systems are covered by this
proposed regulation when they are physically or functionally integrated
with the control system and they perform functions that affect engine
safety or are used to effect continued-operation or return-to-service
decisions.
The purpose of Sec. 33.28 is to set objectives for the general
design and functioning of the engine control system. These requirements
are not intended to replace or supersede other requirements, such as
Sec. 33.67 for the fuel system. Therefore, individual components of
the control system, such as alternators, sensors, actuators, should be
covered, in addition, under other part 33 paragraphs such as Sec.
33.53 and Sec. 33.91 as appropriate.
Although the proposed rule would cover all types of engine control
systems (including hydromechanical and reciprocating engine controls),
it would not cover one particular simple electro-mechanical device--the
conventional magneto--because that device is not a true control
component. On the other hand, the proposed rule would cover subsystems
controlled by a FADEC because this is considered part of the engine
control system. FADECs are standard on virtually all new turbine
engines, and are now being put on some new reciprocating engines also.
This proposal would lower costs by establishing uniform
certification standards for all engine control systems certified in the
United States under part 33 and in European countries under EASA
regulations, simplifying airworthiness approvals for import and export.
In addition, a potential for increased safety lies in having more clear
and explicit regulations, but the FAA was unable to quantify this
benefit. The FAA concludes that the benefits of this rule justify the
costs. The FAA requests comments with supporting justification about
the FAA determination of minimal impact.
The FAA has, therefore, determined that this proposed 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 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,
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
[[Page 18153]]
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.
The FAA believes that this proposed rule would not have a
significant economic impact on a substantial number of small entities
because only one U.S. engine manufacturer meets the definition of small
business contained in the Small Business Administration's small
business size standard regulations. Therefore, the FAA certifies that
this proposed rule would not have a significant economic impact on a
substantial number of small entities. The FAA solicits comments
regarding this determination.
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 rulemaking and determined that it uses
European standards as the basis for U.S. regulations.
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) 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 $128.1 million in lieu of
$100 million.
This proposed rule does not contain such a mandate. The
requirements of Title II do not apply.
Executive Order 13132, Federalism
The FAA has analyzed this proposed rule under the principles and
criteria of Executive Order 13132, Federalism. We determined that this
action would not have a substantial direct effect on the States, on the
relationship between the national Government and the States, or on the
distribution of power and responsibilities among the various levels of
government, and therefore would 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. We determined that
this proposed rulemaking action qualifies for the categorical exclusion
identified in Chapter 3, paragraph 312d and involves no extraordinary
circumstances.
Regulations that Significantly Affect Energy Supply, Distribution, or
Use
The FAA has analyzed this NPRM under Executive Order 13211, Actions
Concerning Regulations that Significantly Affect Energy Supply,
Distribution, or Use (May 18, 2001). We 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.
List of Subjects in 14 CFR Part 33
Aircraft, Air transportation, Aviation safety, Safety.
The Proposed Amendment
In consideration of the foregoing, the Federal Aviation
Administration proposes to amend chapter I of Title 14, Code of Federal
Regulations, as follows:
PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES
1. The authority citation for part 33 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44704.
2. Amend Sec. 33.5 by adding new paragraphs (a)(4), (a)(5),
(a)(6), and (b)(4), 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) * * *
(4) 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.
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.
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 of this part 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.
* * * * *
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:
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(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 this is not required for non-dispatchable specific
control modes in the intended application, in which case the engine
would be approved;
(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 Sec. Sec. 33.28
and 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 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.
(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 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 Sec. 33.28(i)(1), 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 Sec. 33.28(i)(3) must meet the requirements of
Sec. 33.28(i)(1). 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 Sec. 33.28(e) 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
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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 design, implement,
and verify all associated logic to minimize the existence of errors by
using a method, approved by the FAA, that is consistent with the
criticality of the performed function.
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.
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]
8. Remove paragraph (d) from Sec. 33.67.
9. Amend Sec. 33.91 by revising the section heading and paragraph
(a) to read as follows:
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 March 26, 2007.
John J. Hickey,
Director, Aircraft Certification Service.
[FR Doc. E7-6535 Filed 4-10-07; 8:45 am]
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