[Federal Register Volume 61, Number 129 (Wednesday, July 3, 1996)]
[Proposed Rules]
[Pages 35056-35061]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17034]
[[Page 35055]]
_______________________________________________________________________
Part VII
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
_______________________________________________________________________
14 CFR Part 25
Revision of Hydraulic Systems Airworthiness Standards To Harmonize With
European Airworthiness Standards for Transportation Category Airplanes,
and Proposed Advisory Circular for Hydraulic System Certification Tests
and Analysis; Proposed Rule and Notice
Federal Register / Vol. 61, No. 129 / Wednesday, July 3, 1996 /
Proposed Rules
[[Page 35056]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. 28617; Notice 96-6]
RIN 2120-AF79
Revision of Hydraulic Systems Airworthiness Standards To
Harmonize With European Airworthiness Standards for Transport Category
Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking.
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SUMMARY: This document proposes to amend the airworthiness standards
for transport category airplanes to harmonize hydraulic systems design
and test requirements with standards proposed for the European Joint
Aviation Requirements (JAR). These proposals were developed in
cooperation with the Joint Aviation Authorities (JAA) of Europe and the
U.S. and European aviation industry through the Aviation Rulemaking
Advisory Committee (ARAC). These changes are intended to benefit the
public interest by standardizing certain requirements, concepts, and
procedures contained in the airworthiness standards without reducing,
but potentially enhancing, the current level of safety.
DATES: Comments must be received on or before October 1, 1996.
ADDRESSES: Comments on this notice may be mailed in triplicate to:
Federal Aviation Administration, Office of the Chief Counsel,
Attention: Rules Docket (AGC-200), Docket No. 28617, 800 Independence
Avenue SW., Washington, DC 20591; or delivered in triplicate to: Room
915G, 800 Independence Avenue SW., Washington, DC 20591.
Comments delivered must be marked Docket No. 28617. Comments may
also be sent electronically to the following internet address:
[email protected]. Comments may be examined in Room 915G
weekdays, except Federal holidays, between 8:30 a.m. and 5:00 p.m. In
addition, the FAA is in maintaining an information docket of comments
in the Transport Airplane Directorate (ANM-100), Federal Aviation
Administration, Northwest Mountain Region, 1601 Lind Avenue SW.,
Renton, WA 98055-4056. Comments in the information docket may be
examined weekdays, except Federal holidays, between 7:30 a.m. and 4:00
p.m.
FOR FURTHER INFORMATION CONTACT:
Mahinder K. Wahi, Flight Test and Systems Branch, ANM-111, Transport
Airplane Directorate, Aircraft Certification Service, FAA, 1601 Lind
Avenue SW., Renton, WA 98055-4056; telephone (206) 227-2142; facsimile
(206) 227-1320.
SUPPLEMENTARY INFORMATION:
Comment Invited
Interested persons are invited to participate in this proposed
rulemaking by submitting such written data, views, or arguments as they
may desire. Comments relating to any environmental, energy, or economic
impact that might result from adopting the proposals contained in this
notice are invited. Substantive comments should be accompanied by cost
estimates. Commenters should identify the regulatory docket or notice
number and submit comments in triplicate to the Rules Docket address
above. All comments received on or before the closing date for comments
will be considered by the Administrator before taking action on this
proposed rulemaking. The proposals contained in this notice may be
changed in light of comments received. All comments received will be
available in the Rules Docket, both before and after the comment period
closing date, for examination by interested persons. A report
summarizing each substantive public contact with FAA personnel
concerning this rulemaking will be filed in the docket. Persons wishing
the FAA to acknowledge receipt of their comments must submit with those
comments a self-addressed, stamped postcard on which is stated:
``Comments to Docket No. 28617.'' The postcard will be date stamped and
returned to the commenter.
Availability of the NPRM
An electronic copy of this document may be downloaded using a modem
and suitable communications software from the FAA regulations section
of the Fedworld electronic bulletin board service (telephone: 703-321-
3339), the Federal Register's electronic bulletin board service
(telephone 202-512-1661), or the FAA's Aviation Rulemaking Advisory
Committee Bulletin Board service (telephone: 202-267-5948).
Internet users may reach the FAA's web page at http://www.faa.gov
or the Federal Register's web page at http://www.access.gpo/su-docs for
access to recently published rulemaking documents.
Any person may obtain a copy of this notice of submitting a request
to the Federal Aviation Administration (FAA), Office of Rulemaking,
ARM-1, 800 Independence Avenue, S.W., Washington, D.C. 20591 or by
calling (202) 267-9680. Communications must identify the notice number
or docket number of this notice.
Persons interested in being placed on a mailing list for future
rulemaking documents should also request a copy of Advisory Circular
No. 11-2A, Notice of Proposed Rulemaking Distribution System, which
describes the application procedure.
Background
The airworthiness standards for transport category airplanes are
contained in 14 CFR part 25. Manufacturers of transport category
airplanes must show that each airplane they produce of a different type
design complies with the relevant standards of part 25. These standards
apply to airplanes manufactured within the U.S. for use by U.S.
registered operators and to airplanes manufactured in other countries
and imported under a bilateral airworthiness agreement.
In Europe, the Joint Aviation Requirements (JAR) were developed by
the Joint Aviation Authorities (JAA) to provide a common set of
airworthiness standards for use within the European aviation community.
The airworthiness standards for European type certification of
transport category airplanes, JAR-25, are based on part 25 of Title 14.
Airplanes certificated to the JAR-25 standards, including airplanes
manufactured in the U.S. for export to Europe, receive type
certificates that are accepted by the aircraft certification
authorities of 23 European countries.
Although part 25 and JAR-25 are very similar, they are not
identical. Differences between the FAR and the JAR can result in
substantial additional costs when airplanes are type certificated to
both standards. These additional costs, however, frequently do not
bring about an increase in safety. For example, part 25 and JAR-25 may
use different means to accomplish the same safety intent. In this case,
the manufacturer is usually burdened with meeting both requirements,
although the level of safety is not increased correspondingly.
Recognizing that a common set of standards would not only economically
benefit the aviation industry, but would also maintain the necessary
high level of safety, the FAA and JAA consider harmonization to be a
high priority.
In 1988, the FAA, in cooperation with the JAA and other
organizations representing the American and European aerospace
industries, began a
[[Page 35057]]
process to harmonize the airworthiness requirements of the United
States and the airworthiness requirements of Europe, especially in the
areas of Flight Test and Structures.
In 1992, the FAA harmonization effort was undertaken by the ARAC. A
working group of industry and government hydraulic systems specialists
of Europe and the United States was chartered by notice in the Federal
Register (57 FR 58843, December 12, 1992). The working group was tasked
to develop a draft notice of proposed rulemaking (NPRM) and any
collateral documents, such as advisory circulars, concerning new or
revised requirements for hydraulic systems, and the associated test
conditions for hydraulic systems, installed in transport category
airplanes (Sec. 25.1435). The JAA is to develop a similar proposal to
amend JAR-25, as necessary, to achieve harmonization.
The rulemaking proposal contained in this notice is based on a
recommendation developed by the Hydraulic Systems Harmonization Working
Group, and was presented to the FAA by the ARAC as a recommendation.
The Aviation Rulemaking Advisory Committee
The ARAC was formally established by the FAA on January 22, 1991
(56 FR 2190) to provide advice and recommendations concerning the full
range of the FAA's safety-related rulemaking activity. This advice was
sought to develop better rules in less overall time using fewer FAA
resources than are currently needed. The committee provides the
opportunity for the FAA to obtain firsthand information and insight
from interested parties regarding proposed new rules or revisions of
existing rules.
There are 64 member organizations on the committee, representing a
wide range of interests within the aviation community. Meetings of the
committee are open to the public, except as authorized by section 10(d)
of the Federal Advisory Committee Act.
The ARAC establishes working groups to develop proposals to
recommend to the FAA for resolving specific issues. Tasks assigned to
working groups are published in the Federal Register. Although working
group meetings are not generally open to the public, all interested
parties are invited to participate as working group members. Working
groups report directly to the ARAC, and the ARAC must accept a working
group proposal before that proposal can be presented to the FAA as an
advisory committee recommendation.
The activities of the ARAC will not, however, circumvent the public
rulemaking procedures. After an ARAC recommendation is received and
found acceptable by the FAA, the agency proceeds with the normal public
rulemaking procedures. Any ARAC participation in a rulemaking package
will be fully disclosed in the public docket.
Discussion of the Proposals
The FAA proposes to amend Sec. 25.1435 to harmonize this section
with JAR-25. The JAA intend to publish a Notice of Proposed Amendment
(NPA), also developed by the Hydraulic Systems Harmonization Working
Group, to revise JAR-25 as necessary to ensure harmonization in those
areas for which the proposed amendments differ from the current JAR-25,
Change 14. When it is published, the NPA will be placed in the docket
for this rulemaking.
Generally, the FAA proposes to: (1) Add appropriate existing-JAR
requirements to achieve harmonization; (2) Move some of the existing
regulatory text to an advisory circular; (3) Consolidate and/or
separate requirement subparagraphs for clarity; and (4) Revise airplane
static proof pressure test requirements to require a complete
functional (dynamic) airplane test at a lower pressure. A new proposed
Advisory Circular (AC) 25.1435-1 has been developed by the ARAC to
ensure consistent application of these proposed revised standards.
Public comments concerning the AC 25.1435-1 are invited by separate
notice published elsewhere in this issue of the Federal Register. The
JAA intend to publish an Advisory Material Joint (AMJ), also developed
by the Harmonization Working Group, to accompany their NPA. The
proposed AC and the proposed AMJ contain harmonized advisory
information. The following is a discussion of the specific proposals
prescribed in this NPRM.
Proposal 1. The FAA proposes to replace current Sec. 25.1435(a)(1)
to add the existing requirements of JAR 25.1435(a)(10) and associated
Appendix K requirements regarding design load factors for proof and
ultimate pressure conditions for elements of the hydraulic system (see
proposal 2 below regarding current Sec. 25.1435(a)(1)). The proof and
ultimate pressure conditions would be defined as the design operating
pressure times the factors of safety. This would be done to address
unusually high pressures which may be seen in service, material defects
and differences, manufacturing/construction tolerances and the
consequences of failures (e.g. pressure vessel failure). The proposed
load factors, ranging between 1.5 and 4.0, relate to the design
operating pressure (DOP) and would apply to tubes, fittings, pressure
vessels containing gas at high pressure (e.g., accumulators) and at low
pressure (e.g. hydraulic reservoirs), hoses, and all other elements.
By adopting these JAR minimum factors of safety standards which
currently are not specifically stated in the FAR, the FAA intends to
maintain an existing level of safety because normal U.S. Industry
practices meet or exceed these standards.
DOP is the normal maximum steady pressure. Excluded are reasonable
tolerances and transient pressure effects such as may arise from
acceptable pump ripple or reaction to system functioning or flow
demands that may affect fatigue. In localized areas of systems and
system elements the DOP may be different from the DOP for the system as
a whole due to the range or normally anticipated airplane operational,
dynamic and environmental conditions. Such differences would be
required to be taken into account. The term ``design operating
pressure'' would be discussed in AC 25.1435-1.
Proposal 2. The FAA proposes to redesignate the current
Sec. 25.1435(a)(1) as Sec. 25.1435(a)(2), delete the word ``loads''
from ``pressure loads'' (``loads'' is redundant) and edit some text to
avoid repetition. The term ``limit structural load'', and a recommended
minimum time to hold pressure would be discussed in AC 25.1435-1.
Proposal 3. The FAA proposes to redesignate the current
Sec. 25.1435(a)(2) as a new Sec. 25.1435(a)(3), delete the word
``loads'' from ``pressure loads'' (``loads'' is redundant) and edit
some text to avoid repetition. The term ``ultimate structural load''
and a minimum time to hold pressure would be discussed in AC 25.1435-1.
Proposal 4. The FAA proposes to add a new Sec. 25.1435(a)(4) that
would contain the current requirements of Sec. 25.1435(b)(2)(i) and
(b)(2)(ii) regarding induced loads, pressure transients, and fatigue as
well as the current JAR 25.1435(a)(11) requirements regarding fatigue
design considerations accounting for fluctuating or repeated external
or internal loads and pressure transients. These loads could be
structurally or environmentally induced. By delineating these
requirements, the FAA intends to ensure that each element is designed
to provide fatigue resistance capability consistent with anticipated
element usage, thus maintaining the current
[[Page 35058]]
level of safety. The terms ``fatigue'', and ``externally induced
loads'' would be discussed in AC 25.1435-1.
Proposal 5. The FAA proposes to add a new Sec. 25.1435(a)(5) that
would contain the current requirements of Sec. 25.1435(b)(2)(i) through
(b)(2)(v), except those addressed under proposal 4 above, as well as
parts of the current JAR 25.1435 (a)(5) and (a)(6) requirements
addressing excessive vibration, abrasion, corrosion, mechanical damage,
and the ability to withstand inertia loads. These requirements would be
consolidated and simplified by stating that each element must be
designed to perform as intended under all environmental conditions for
which the airplane is certificated. An acceptable means of compliance
would be included in AC 25.1435-1.
Proposal 6. The FAA proposes to add a modified version of the
existing JAR 25.1435(a)(2) as Sec. 25.1435(a)(1), requiring means to
indicate appropriate system parameters at a flight crewmember station
if (1) the system performs a function necessary for continued safe
flight and landing, or (2) in the event of hydraulic system
malfunction, corrective action by the crew is required to ensure
continued safe flight and landing. The existing JAR 25.1435(a)(2)
requires fluid quantity and pressure indication under specified
circumstances; prior to Amendment 25-72, Sec. 25.2435 contained an
identical requirement. It was considered at the time that this
requirement is covered by Sec. 25.1309(c), which requires that warning
information must be provided to alert the crew to unsafe system
operating conditions, and to enable them to take appropriate corrective
action, and the Sec. 25.1435 requirement was therefore deleted. It is,
however, now recognized that there is value in defining indication
requirements for hydraulic systems and implications of their loss. The
existing level of safety would not be impacted since the FAA is
proposing the adopt an existing industry practice. The term
``appropriate system parameters'' would be discussed in AC 25.1435-1.
(Note: see proposal 12 below with respect to status of current
Sec. 25.1435(b)(1) requirements).
Proposal 7. The FAA proposes to replace the current
Sec. 25.1435(b)(2) by adding a modified version of the current JAR
25.1435 (a)(4) and (a)(7) to require that each system have means to
ensure that system pressures remain within the design capabilities of
each element. Prior to Amendment 25-72, Sec. 25.1435 contained a
requirement that was identical to the current JAR requirement, but it
was characterized as both containing arbitrary pressure transient
limits and unnecessary because the intent is covered under
Sec. 25.1309. The requirement was therefore deleted from Sec. 25.1435.
The proposed version deletes the arbitrary limits but would require
that the intent be specifically addressed by Sec. 25.1435(b)(2) to
ensure consideration of the pressure and volume related transients that
are unique to the hydraulic systems. There would be no impact on level
of safety since an existing industry practice is being adopted. An
acceptable means of compliance with Sec. 25.1435(b)(2) would be
included in AC 25.1435-1.
Proposal 8. The FAA proposes to add a new Sec. 25.1435(b)(3) which
would contain a modified version of the existing JAR 25.1435(a)(5)
requirements regarding the means to minimize harmful or hazardous
concentrations of the hydraulic fluid or vapors, if liberated in any
form, into the crew and passenger compartments during flight. Prior to
Amendment 25-72, Sec. 25.1435 contained an identical requirement. It
was considered at the time that Sec. 25.831(b) covers this requirement
under a general statement that the ventilation air must be free of
hazardous or harmful gases or vapors. However, Sec. 25.831(b) specifies
allowable limits for carbon monoxide and carbon dioxide, but no other
products. It could be construed that those two gases are the only
hazardous products. Section 25.1435 would therefore be revised to state
the specific requirement with respect to the hydraulic fluid or vapors.
The JAR requirement currently states, in relevant part, that
``there must be a means to prevent harmful or hazardous concentration
of fluid. * * *'' In recognition of the fact that absolute prevention
of such concentrations is not an achievable objective, the FAA proposes
that the hydraulic system must have ``means to minimize the release of
harmful or hazardous concentrations * * *'' To show compliance with
this requirement, an applicant would have to show, both that the
likelihood of releases has been minimized, and that, if there is such a
release, the concentrations from the release would also be minimized.
The level of safety would remain unaffected because it's an existing
industry practice to address this issue. An acceptable means of
compliance with Sec. 25.1435(b)(3) and a discussion of the terms
``harmful'' and ``hazardous'' would be included in AC 25.1435-1.
Proposal 9. The FAA proposes to redesignate the existing
Sec. 25.1435(c) as Sec. 25.1435(b)(4); this is identical to the
existing JAR 25.1435(c) requirements regarding use of flammable
hydraulic fluid and fire protection. A discussion of the term
``flammable hydraulic fluid'' would be included in AC 25.1435-1.
Proposal 10. The FAA proposes to add a new Sec. 25.1435(b)(5),
containing the current JAR 25.1435(d) requirements that the airplane
manufacturer must specify the approved hydraulic fluid(s) suitable to
be used in the system(s) and ensure that the system(s) meet the
applicable placarding requirements of the current Sec. 25.1541.
Although it is a standard U.S. industry practice to identify the
compatible hydraulic fluid on each component's name plate, the practice
may not be universal. In order to minimize the potential use of
incompatible fluids, seals, etc. in any system, it is necessary to
include this requirement. A discussion of mixability of hydraulic
fluids would be included in AC 25.1435-1.
Proposal 11. Current Sec. 25.1435(b)(2) requirements for hydraulic
system compliance by test and analysis would be separated into
Secs. 25.1435 (c), (c)(1) and (c)(2); the list of environmental factors
[current Sec. 25.1435 (b)(2)(ii) through (b)(2)(v)] would be moved to
AC 25.1435-1; and, text in the aforementioned sections would be
clarified. In addition, analysis would be permitted in place of or to
supplement testing, where shown to be reliable and appropriate. A
discussion on endurance and fatigue testing, and simulated failures
would be included in AC 25.1435-1.
Proposal 12. Current Sec. 25.1435(b)(1) requirements for static
testing of a complete hydraulic system to 1.5 times the design
operating pressure (without deformation of any part of the system that
would prevent performance of intended function) would be replaced with
a new Sec. 25.1435(c)(3) requirement that ``the complete hydraulic
system must be functionally tested on the airplane over the range of
motion of all associated user systems.'' Also, the section would
require that ``the test must be conducted at the system relief pressure
or 1.25 times the DOP if a system pressure relief device is not part of
the system design.'' This proposal reflected the recently granted
petition for exemption to the Boeing Company, Regulatory Docket No.
27384. The petition, any comments received, and a copy of the final
disposition are filed in the assigned regulatory docket and are
available for examination in the Rules Docket (AGC 200), room 915G, FAA
Headquarters Building (FOB 10A), 800 Independence Avenue SW.,
Washington, DC 20591; telephone (202) 267-3132. A discussion on relief
[[Page 35059]]
pressure settings and an acceptable means of compliance with
Sec. 25.1435(c)(3) would be included in AC 25.1435-1.
The FAA considers that the proposed functional (i.e., dynamic) test
more closely approximates actual operating conditions than the existing
static test. This is because for the static test, several parts of the
system and associated relief valves (including return lines) may need
to be disabled to allow system pressurization at 1.5 times the design
operating pressure because the relief valves are designed to open at a
pressure lower than 1.5 times the design operating pressure. Although
the proposed test pressure would be lower than 1.5 times the design
operating pressure, all elements would still be required to be able to
withstand at least 1.5 times the design operating pressure per current
Sec. 25.1435(a)(2) (proposed Sec. 25.1435(a)(3)), at least retaining
and potentially enhancing the current level of safety by identification
of additional dynamic interference problems.
Regulatory Evaluation Summary
Regulatory Evaluation, Regulatory Flexibility Determination, and Trade
Impact Assessment
Changes to federal regulations must undergo several economic
analyses. First, Executive Order 12866 directs Federal agencies to
promulgate new regulations or modify existing regulations only if the
potential benefits to society outweigh the potential costs. Second, the
Regulatory Flexibility Act of 1980 requires agencies to analyze the
economic impact of regulatory changes on small entities. Finally, the
Office of Management and Budget directs agencies to assess the effect
of regulatory changes on international trade. In conducting these
assessments, the FAA has determined that this proposed rule: (1) Would
generate benefits exceeding its costs and is not ``significant'' as
defined in Executive Order 12866; (2) Is not ``significant'' as defined
in DOT's Policies and Procedures; (3) would not have a significant
impact on a substantial number of small entities; and (4) would lessen
restraints on international trade. These analyses, available in the
docket, are summarized below.
Although several revisions would be made to Sec. 25.1435, only
three of them would impose additional costs (see below--proposals 1, 4,
and 12, with the latter having potential cost savings for some
manufacturers). Most of the changes codify current industry practice or
conform Sec. 25.1435 to corresponding sections of the JAR. Adoption of
the proposed changes would increase harmonization and commonality
between American and European airworthiness standards. Harmonization
would eliminate unnecessary duplication of airworthiness requirements,
thus reducing manufacturers' certification costs. One manufacturer of
part 25 large airplanes estimated such cost-savings could range between
$60,000 and 600,000 per type certification (pertaining to hydraulic
systems only); a manufacturer of part 25 small airplanes estimated such
savings at $30,000 to $90,000 per type certification; Potential safety
benefits resulting from specification of minimum accepted standards
would supplement these cost-savings.
Proposal 1. These changes codify existing industry standards. As
such, they would not result in additional costs for most manufacturers,
However, one manufacturer of small transport category airplanes
estimated increased testing costs of approximately $25,000 per type
certification Codification of the proposed standards would ensure that
current safety levels are retained.
Proposals 2, 3, and 9. There would be no additional costs
associated with these minor changes.
Proposal 4. Although some of the changes described are new
requirements in the FAR, most American manufacturers of large transport
category airplanes are already in compliance with the similar current
European standards, which had to be met in order to market airplanes in
JAA member countries. The modified testing and analysis regime is
already in place. Initial first-time costs have already been incurred;
such costs have diminished in recent certifications. Consequently,
actual incremental costs would be negligible. One manufacturer,
however, indicated that additional testing and analysis costs, ranging
between $100,000 and $200,000 per type certification, would be incurred
for the first one or two type certifications. Learning curve
efficiencies would likely reduce these costs thereafter. Manufacturers
of small transport category airplanes, on the other hand, expect no or
negligible additional costs attributable to the new fatigue-related
proposals. Codification of the proposed standards would ensure that
minimum acceptable fatigue requirements are specified with potential
for safety enhancement.
Proposals 5, 6, 7, 8, and 10. These changes codify existing
industry standards and would not result in additional certification/
production costs. Codification of the proposed standards would ensure
that current safety levels are retained.
Proposal 11. There would be no additional costs associated with
these revisions. The use of analysis in lieu of or supplemental to
testing may reduce certification costs in some cases.
Proposal 12. Most manufacturers of part 25 airplanes would not
experience additional costs associated with dynamic testing of
hydraulic systems. In fact, testing time and associated costs could be
reduced to some small extent since, unlike static testing, the proposed
dynamic testing would not entail disabling any system(s) or otherwise
reconfiguring the airplane. One manufacturer of part 25 large airplanes
estimated potential savings between $100,000 and $200,000 per type
certification in this regard (another estimated such savings at only
$25,000). However, a manufacturer of part 25 small transport category
airplanes estimates $25,000 in additional testing, analysis, and report
preparation costs per type certification attributable to this proposal.
The proposed requirements would at least retain, and potentially
enhance, the current level of safety by identification of additional
dynamic interference problems.
Summary of Costs and Benefits
Manufacturers of part 25 small airplanes could experience
additional costs totalling approximately $50,000 per type certification
resulting from proposals 1 (design load factors) and 12 (dynamic
testing). The estimated $30,000-$90,000 harmonization cost savings,
coupled with potential safety benefits from proposals 4 and 12, would
exceed these costs.
For manufacturers of part 25 large airplanes, the cost differential
could range from a $25,000-$200,000 reduction (resulting from proposal
12) to a $100,000-$200,000 increase (resulting from proposal 4). The
proposal 12 cost savings coupled with the estimated $60,000-$600,000
harmonization cost savings would exceed the additional costs of
proposal 4; potential safety benefits from proposals 4 and 12 would
supplement the cost-savings.
The FAA finds the proposed rule, therefore, to be cost-beneficial
for both part 25 small and large transport manufacturers.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily or
disproportionately burdened by government regulations. The RFA requires
a Regulatory
[[Page 35060]]
Flexibility Analysis if a rule would have a significant economic
impact, either detrimental or beneficial, on a substantial number of
small entities. FAA Order 2100.14A, Regulatory Flexibility Criteria and
Guidance, prescribes standards for complying with RFA review
requirements in FAA rulemaking actions. The order defines ``small
entities'' in terms of size thresholds, ``significant economic impact''
in terms of annualized cost threshold, and ``substantial number'' as a
number which is not less than eleven and which is more than one-third
of the small entities subject to the proposed or final rule.
The proposed rule would affect manufacturers of transport category
airplanes produced under future new airplane type certifications. For
manufacturers, Order 2100.14A specifies a size threshold for
classification as a small entity as 75 or fewer employees. Since no
transport category airplane manufacturer has 75 or fewer employees, the
proposed rule would not have a significant economic impact on a
substantial number of small manufacturers.
International Trade Impact Assessment
The proposed rule would not constitute a barrier to international
trade, including the export of American airplanes to foreign countries,
and the import of foreign airplanes into the United States. Instead,
the proposed changes to the FAR would harmonize with corresponding
existing or proposed standards in the JAR, thereby lessening restraints
on trade.
Federalism Implications
The amended regulations proposed in this rulemaking would not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government. Therefore,
in accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
preparing a Federalism Assessment.
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
determined that this rule does not conflict with any international
agreement of the United States.
Paperwork Reduction Act
In accordance with the Paperwork Reduction Act of 1980 (Pub. L. 96-
511), there are no requirements for information collection associated
with this proposed rule.
Conclusion
Because the proposed changes to standardize specific hydraulic
systems test requirements of part 25 are not expected to result in
substantial economic cost, the FAA has determined that this proposed
regulation would not be significant under Executive Order 12866.
Because this is an issue which has not prompted a great deal of public
concern, the FAA has determined that this action is not significant
under DOT Regulatory Policies and Procedures (44 FR 11034, February 25,
1979). In addition since there are no small entities affected by this
proposed rulemaking, the FAA certifies, under the criteria of the
Regulatory Flexibility Act, that this rule, if adopted, will not have a
significant economic impact, positive or negative, on a substantial
number of small entities. An initial regulatory evaluation of the
proposal, including a Regulatory Flexibility Determination and Trade
Impact Analysis, has been placed in the docket. A copy may be obtained
by contacting the person identified under for further information
contact.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The Proposed Amendments
Accordingly, the Federal Aviation Administration proposes to amend
14 CFR part 25 as follows:
PART 25--AIRWORTHINESS STANDARDS--TRANSPORT CATEGORY AIRPLANES
1. The authority citation for part 25 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
2. Section 25.1435 is revised to read as follows:
Sec. 25.1435 Hydraulic systems.
(a) Element design. Each element of the hydraulic system must be
designed to:
(1) Withstand the proof pressure without leakage or permanent
deformation that prevents it from performing its intended function, and
the ultimate pressure without rupture. The proof and ultimate pressures
are defined in terms of the design operating pressure (DOP) as follows:
------------------------------------------------------------------------
Proof Ultimate
Element (xDOP) (xDOP)
------------------------------------------------------------------------
1. Tubes & fittings................................. 1.5 3.0
2. Pressure vessels containing gas:
High pressure (e.g., accumulators)................ 3.0 4.0
Low pressure (e.g., reservoirs)................... 1.5 3.0
3. Hoses............................................ 2.0 4.0
4. All other elements............................... 1.5 2.0
------------------------------------------------------------------------
(2) Withstand, without deformation that would prevent it from
performing its intended function, the design operating pressure in
combination with limit structural loads that may be imposed;
(3) Withstand, without rupture, the design operating pressure
multiplied by a factor of 1.5 in combination with ultimate structural
load that can reasonably occur simultaneously;
(4) Withstand the fatigue effects of all cyclic pressures,
including transients, and associated externally induced loads, taking
into account the consequences of element failure; and
(5) Perform as intended under all environmental conditions for
which the airplane is certificated.
(b) System design. Each hydraulic system must:
(1) Have means located at a flightcrew station to indicate
appropriate system parameters.
(i) It performs a function necessary for continued safe flight and
landing; or
(ii) In the event of hydraulic system malfunction, corrective
action by the crew to ensure continued safe flight and landing is
necessary;
(2) Have means to ensure that system pressures, including transient
pressures and pressures from fluid volumetric changes in elements that
are likely to remain closed long enough for such changes to occur, are
within the design capabilities of each element, such that they meet the
requirements defined in Sec. 25.1435(a)(1) through (a)(5);
(3) Have means to minimize the release of harmful of hazardous
concentrations of hydraulic fluid or vapors into the crew and passenger
compartments during flight;
(4) Meet the applicable requirements of Secs. 25.863, 25.1183,
25.1185, and 25.1189 if a flammable hydraulic fluid is used; and
(5) Be designed to use any suitable hydraulic fluid specified by
the airplane manufacturer, which must be identified by appropriate
markings as required by Sec. 25.1541.
(c) Tests. To demonstrate compliance with Sec. 25.1435 and support
compliance with Sec. 25.1309, tests must be conducted on the hydraulic
system(s), and/or
[[Page 35061]]
subsystem(s) and elements, except that analysis may be used in place of
or to supplement testing, where the analysis is shown to be reliable
and appropriate. All internal and external influences must be taken
into account to an extent necessary to evaluate their effects, and to
assure reliable system and element functioning and integration. Failure
or unacceptable deficiency of an element or system must be corrected
and be sufficiently retested, where necessary.
(1) The system(s), subsystem(s), or element(s) must be subjected to
performance, fatigue, and endurance tests representative of airplane
ground flight operations.
(2) The complete system must be tested to determine proper
functional performance and relation to the other systems, including
simulation of relevant failure conditions, and to support or validate
element design.
(3) The complete hydraulic system(s) must be functionally tested on
the airplane in normal operation over the range of motion of all
associated user systems. The test must be conducted at the system
relief pressure 1.25 times the DOP if a system pressure relief device
is not part of the system design. Clearances between hydraulic system
elements and other systems or structural elements must remain adequate
and there must be no detrimental effects.
Issued in Washington, DC, on June 26, 1996.
Ava L. Robinson,
Acting Director, Aircraft Certification Service.
[FR Doc. 96-17034 Filed 7-2-96; 8:45 am]
BILLING CODE 4910-13-M