[Federal Register Volume 61, Number 28 (Friday, February 9, 1996)]
[Rules and Regulations]
[Pages 5130-5138]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-2084]
[[Page 5129]]
_______________________________________________________________________
Part III
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
_______________________________________________________________________
14 CFR Part 23, et al.
Airworthiness Standards; Final Rules
Federal Register / Vol. 61, No. 28 / Friday, February 9, 1996 / Rules
and Regulations
[[Page 5130]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. 27804; Amendment No. 23-51]
RIN 2120-AE60
Airworthiness Standards; Powerplant Rules Based on European Joint
Aviation Requirements
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This final rule amends the powerplant airworthiness standards
for normal, utility, acrobatic, and commuter category airplanes. This
amendment completes a portion of the Federal Aviation Administration
(FAA) and the European Joint Aviation Authorities (JAA) effort to
harmonize the Federal Aviation Regulations and the Joint Aviation
Requirements (JAR) for airplanes certificated in these categories. This
amendment will provide nearly uniform powerplant airworthiness
standards for airplanes certificated in the United States under 14 CFR
part 23 and in the JAA countries under Joint Aviation Requirements 23,
simplifying international airworthiness approval.
EFFECTIVE DATE: March 11, 1996.
FOR FURTHER INFORMATION CONTACT:
Norman Vetter, ACE-111, Small Airplane Directorate, Aircraft
Certification Service, Federal Aviation Administration, 601 East 12th
Street, Kansas City, Missouri 64106; telephone (816) 426-5688.
SUPPLEMENTARY INFORMATION:
Background
This amendment is based on Notice of Proposed Rulemaking (NPRM) No.
94-19 (59 FR 33822). All comments received in response to Notice 94-19
have been considered in adopting this amendment.
This amendment completes part of an effort to harmonize the
requirements of part 23 and JAR 23. The revisions to part 23 in this
amendment pertain to powerplants. Three other final rules are being
issued in this Federal Register that pertain to airworthiness standards
for systems and equipment flight, and airframe. These related
rulemakings are also part of the harmonization effort. Interested
persons should review all four final rules to ensure that all revisions
to part 23 are recognized.
The harmonization effort was initiated at a meeting in June 1990 of
the JAA Council (consisting of JAA members from European countries) and
the FAA, during which the FAA Administrator committed the FAA to
support the harmonization of the U.S. regulations with the JAR that
were being developed. In response to the commitment, the FAA Small
Airplane Directorate established an FAA Harmonization Task Force to
work with the JAR 23 Study Group to harmonize part 23 with the proposed
JAR 23. The General Aviation Manufacturers Association (GAMA) also
established a JAR 23 and part 23 committee to provide technical
assistance.
The FAA, JAA, GAMA, and the Association Europeene des Constructeurs
de Material Aerospatial (AECMA), an organization of European airframe
manufacturers, met on several occasions in a continuing harmonization
effort.
Near the end of the effort to harmonize the normal, utility, and
acrobatic category airplane airworthiness standards, the JAA requested
and received recommendations from its member countries on proposed
airworthiness standards for commuter category airplanes. Subsequent JAA
and FAA meetings on this issue resulted in proposals that were
reflected in Notice 94-19 to revise portions of the part 23 commuter
category airworthiness standards. Accordingly, this final rule adopts
the powerplant airworthiness standards for all part 23 airplanes.
In January 1991, the FAA established the Aviation Rulemaking
Advisory Committee (ARAC) (56 FR 2190, January 22, 1991). At an FAA/JAA
Harmonization Conference in Canada in June 1992, the FAA announced that
it would consolidate the harmonization effort within the ARAC
structure. The FAA assigned to ARAC the rulemakings related to JAR and
part 23 harmonization, which ARAC assigned to the JAR 23/FAR 23
Harmonization Working Group. The proposals for powerplant airworthiness
standards contained in Notice No. 94-19 were a result of both the
working group's efforts and the efforts at harmonization that occurred
before the formation of the working group.
The JAA submitted comments to the FAA on January 20, 1994, in
response to the four draft proposals for harmonization of the part 23
airworthiness standards. The JAA submitted comments again during the
comment period of the NPRM. At the April 26, 1995, ARAC JAR/FAR 23
Harmonization Working Group meeting, the JAA noted that many of the
comments in the January 20 letter had been satisfied or were no longer
relevant. The few remaining items concern issues that are considered
beyond the scope of this rulemaking, and, therefore, will be dealt with
at future FAA/JAA Harmonization meetings.
Discussion of Comments
General
Interested persons were invited to participate in the development
of these final rules by submitting written data, views, or arguments to
the regulatory docket on or before October 28, 1994. Four commenters
responded to Notice 94-19. Two commenters (Transport Canada and the Air
Line Pilots Association) expressed overall support for the proposed
changes. The JAA stated its overall support while commenting on
specific proposed changes. The fourth commenter (Beechcraft) commented
on several specific sections. The specific comments of JAA and
Beechcraft are discussed in detail in this document and include an FAA
response and a description of any changes to the final rule language.
Other minor technical and editorial changes have been made to the
proposed rules based on relevant comments received, consultation with
the ARAC, and further review by the FAA.
Discussion of Amendments
Section 23.777 Cockpit Controls
The FAA proposed to revise Sec. 23.777(c)(2) so that for single-
engine airplanes designed for a single cockpit occupant, the powerplant
controls would be located in the same position as they are for
airplanes with tandem seats.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.779 Motion and Effect of Cockpit Controls
The FAA proposed to revise Sec. 23.779(b)(1) by adding a new item,
``fuel,'' to the ``motion and effect'' table to require that any fuel
shutoff control other than mixture must move forward to open.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.901 Installation
The FAA proposed to revise Sec. 23.901(d)(1), which concerns
turbine engine installation and vibration characteristics that do not
exceed those established during the type certification of the engine.
The FAA proposed to add the word ``carcass'' before vibration in this
paragraph in order to restrict analyses to those vibrations that are
caused by external excitation to the
[[Page 5131]]
main engine frame or ``carcass.'' While the word ``carcass'' has not
traditionally been used in this context in the United States, it is
used in Europe and was proposed in the interest of harmonization.
The FAA proposed to revise Sec. 23.901(d)(2) by deleting the last
sentence, which reads: ``The engine must accelerate and decelerate
safely following stabilized operations under these rain conditions.''
This requirement is already provided for in the first sentence of
paragraph (d)(2), which states that the turbine engine must be
constructed and arranged to provide ``continued safe operation.''
The FAA proposed to revise paragraph (e) of this section by adding
the word ``powerplant'' in front of ``installation'' to make clear that
it pertains to all powerplant installations. The FAA proposed to revise
paragraph (e)(1) by adding the word ``installation'' in front of
``instruction'' to make clear which instructions are applicable.
The FAA proposed that new paragraph (e)(1)(i) contain the
requirement for an engine type certificate currently set forth in
paragraph (e)(1). The FAA proposed that paragraph (e)(1)(ii) continue
the current requirement for a propeller type certificate, and to allow
an equivalency finding for certain propellers not type certificated in
the United States. This revision was proposed to be consistent with the
proposed revisions to Sec. 23.905, Propellers.
No comments were received on the proposals. However, as discussed
below, the FAA has determined that the proposed amendment to
Sec. 23.905(a) concerning propellers should be withdrawn. Consequently,
proposed revisions to Sec. 23.901(e) are no longer appropriate and are
being withdrawn.
The proposal is adopted with the above change.
Section 23.903 Engines
The FAA proposed to revise Sec. 23.903 (c) and (g) by adding the
headings ``Engine isolation'' and ``Restart capability,'' respectively,
in order to identify the subjects of these paragraphs as is done for
the other paragraphs in this section. The FAA also proposed to change
the heading of paragraph (f) from ``Restart capability'' to ``Restart
envelope'' since the paragraph addresses the altitude and airspeed
envelope for restarting the engines in flight.
No comments were received on the proposals, and they are adopted as
proposed.
Section 23.905 Propellers
The FAA proposed to revise Sec. 23.905(a) to permit approval, on
part 23 airplanes, of propellers by a means other than the currently
required type certificate.
Comment: Beechcraft objects to what it characterizes as ``an
unknown method of compliance.'' Beechcraft states that it appears that
the economic burden of certification would be placed on the end user of
the propeller without any guidance as to the means of compliance.
Beechcraft asserts that experience indicates that equivalent level of
safety findings are very subjective, that propellers would be
certificated to various standards, and that this creates a liability
for the aircraft manufacturer. Beechcraft believes that uniform
airworthiness standards should be maintained and that ``an aircraft
manufacturer could not, for economic and liability reasons, afford to
purchase a propeller without a type certificate, U.S. or foreign.''
FAA Response: The FAA re-evaluated the proposal and determined that
public interest would be best served if the proposal were withdrawn.
Therefore, the FAA is withdrawing the proposal and will consider it for
future rulemaking action.
Section 23.907 Propeller Vibration
The FAA proposed to revise Sec. 23.907(a) to require that
propellers ``other than a conventional fixed-pitch wooden propeller''
be evaluated for vibration. Fixed-pitch wooden propellers are not
highly stressed, as are all metal and most composite propeller blades.
No comments were received on this proposal and it is adopted as
proposed.
Section 23.925 Propeller Clearance
The FAA proposed to revise Sec. 23.925 to require that propeller
clearance must be evaluated with the airplane at the most adverse
combination of weight and center of gravity, and with the propeller in
the most adverse pitch position. This revision would make the
requirement consistent with current certification practice.
Comment: The JAA pointed out that, under the JAR, the clearances
provided in this section are intended to represent minimum values and
that it had previously rejected the introductory text language that
states ``Unless smaller clearances are substantiated * * *.''
FAA Response: The language quoted by the JAA is in present
Sec. 23.925 and would not be affected by the proposed change. The FAA
acknowledges that the introductory language cited by the JAA has been
previously identified as an area of known disharmony between the two
sets of regulations that would not be affected by the proposed
revisions.
No comments other than the JAA acknowledgment of disharmony were
received on the changes proposed for this section in Notice 94-19, and
the proposal is adopted as proposed.
Section 23.929 Engine Installation Ice Protection
The FAA proposed to replace the word ``power'' in Sec. 23.929 in
the phrase ``without appreciable loss of power'' with the word
``thrust'' because ``thrust'' is more descriptive of the loss
experienced when ice forms on a propeller.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.933 Reversing Systems
The FAA proposed to revise Sec. 23.933(a)(1) so that these
provisions correspond to the turbojet and turbofan reversing system
airworthiness standards of part 25.
The FAA also proposed to delete as unnecessary the word ``forward''
from paragraph (a)(3).
No comments were received on the proposals, and they are adopted as
proposed.
Section 23.955 Fuel Flow
The FAA proposed to revise Sec. 23.955(a) by deleting the word
``and'' where it occurs between the subparagraphs. Each of the four
paragraphs is independent and all of them apply under paragraph (a).
The FAA also proposed to revise Sec. 23.955(a)(3) by adding the
word ``probable'' so that the requirement would read as follows: ``If
there is a flow meter without a bypass, it must not have any probable
failure mode * * *.'' The addition of the word ``probable'' would
clarify the intent of the requirement that only probable failures need
be analyzed.
No comments were received on the proposals, and they are adopted as
proposed.
Section 23.959 Unusable Fuel Supply
The FAA proposed that the text of Sec. 23.959 be redesignated as
paragraph (a), and proposed the addition of a new paragraph (b) to
require that the effect of any fuel pump failure on the unusable fuel
supply be established. This change would not require any change in the
fuel quantity indicator marking required by Sec. 23.1553.
No comments were received on the proposals, and they are adopted as
proposed.
[[Page 5132]]
Section 23.963 Fuel Tanks: General
The FAA proposed to clarify Sec. 23.963(b), which concerns fuel
tank liners, by replacing the phrase ``must be of an acceptable kind''
with the phrase ``must be shown to be suitable for the particular
application.'' Also, the FAA proposed to revise the cross reference in
this section to coincide with the proposed revision of Sec. 23.959
discussed above.
No comments were received on the proposals, and they are adopted as
proposed.
Section 23.965 Fuel Tank Tests
The FAA proposed to revise Sec. 23.965(b)(3)(i) by changing the
phrase ``the test frequency of vibration cycles per minute is obtained
by * * *'' to ``the test frequency of vibration is the number of cycles
per minute obtained by * * *'' to clarify that it is the number of
cycles per minute that is to be used during testing of a fuel tank.
No comments were received on the proposal. After further review of
the proposal, however, the FAA determined that the second portion of
paragraph (b)(3)(i), which includes the test frequency vibration
cycles, should be redesignated as paragraphs (b)(3)(i) (A) and (B), and
that the phrase ``except that'' should be removed and the word ``and''
added in its place. This would not be a substantive revision.
The proposal is adopted with the above change.
Section 23.973 Fuel Tank Filler Connection
The FAA proposed to revise Sec. 23.973(f) by removing the language
that limits its applicability so that the regulation would apply to all
airplanes with turbine engines, including turbine engines that are
equipped with pressure fueling systems.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.975 Fuel Tank Vents and Carburetor Vents
The FAA proposed to revise the first sentence of Sec. 23.975(a)(5)
to clarify that there may be no point in any vent line where moisture
can accumulate unless drainage is provided. The FAA explained that the
intent of this requirement is to allow low spots in the fuel tank vent
system if a drain is provided for each low spot.
Comment: No comments were received concerning the proposed revision
of the first sentence of Sec. 23.975(a)(5). However, the JAA submitted
a comment on the second sentence, for which no change was proposed.
That sentence currently reads, ``Any drain valve installed in the vent
lines must discharge clear of the airplane and be accessible for
drainage.'' The JAA's comment is threefold. First, JAA states that, in
smaller, less complex part 23 airplanes, whether a vent will remain
clear in all phases of operation cannot be guaranteed. Second, JAA
states that, on more complex part 23 airplanes, ``considerations of
inaccessibility during operation of an aircraft when the need for a
drain valve has been considered essential, has very often resulted in
the acceptance of automatic valves that drain back into the fuel
tank.'' Finally, JAA states that drainage/discharge clear of the
airplane is not in accord with environmental concerns.
FAA Response: The FAA has concluded after reviewing the JAA comment
and after discussions within the ARAC working group that further
clarification of this drainage requirement is appropriate, since the
rule language was never intended to limit discharge to an external
drain valve. Therefore, the last sentence of Sec. 23.975(a)(5), as
adopted, reads ``Any drain valve installed must be accessible for
drainage.''
Section 23.979 Pressure Fueling Systems
The FAA proposed to revise Sec. 23.979(b) to require, for commuter
category airplanes, an indication at each fueling station of failure of
the automatic shutoff means. This revision would make the commuter
category automatic shutoff means requirements similar to the
requirements for transport category airplanes in Sec. 25.979.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1001 Fuel Jettisoning System
The FAA proposed to revise Sec. 23.1001(b)(2) to redefine the speed
at which the fuel jettisoning system tests should be conducted by
referencing Sec. 23.69(b). The JAA states that a comparable change will
be made to JAR 23.
No other comments were received, and this proposal is adopted as
proposed.
Section 23.1013 Oil Tanks
The FAA proposed to delete the word ``crankcase'' in
Sec. 23.1013(d)(1) to make this paragraph applicable to all engine
installations.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1041 General
The FAA proposed to revise Sec. 23.1041, under the ``Cooling''
heading, to require, for all airplanes regardless of engine type, a
demonstration of adequate cooling at one maximum ambient atmosphere
temperature for which approval is requested.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1043 Cooling Tests
The FAA stated in the preamble to Notice 94-19 that it proposed to
revise Sec. 23.1043(a)(3) to show that the minimum grade fuel
requirement applies to both turbine and reciprocating engines and that
the lean mixture requirement applies to reciprocating engines only.
The FAA proposed to simplify the introductory text of paragraph (a)
by deleting the requirement that compliance must be shown ``under
critical ground, water, and flight operating conditions to the maximum
altitude for which approval is requested'' since this requirement is
already contained in Sec. 23.1041.
The FAA proposed to improve the organization of the section by
moving to paragraph (a)(4) the requirement in the introductory text of
paragraph (a) that for turbocharged engines, each turbocharger must be
operated through the part of the climb profile for which turbocharger
operation is requested.
The FAA proposed a non-substantive change to paragraph (a)(1) to
make it consistent with proposed changes to Sec. 23.1041.
The FAA proposed to reword paragraph (a)(2) without substantive
change to make this language identical to the JAR.
The FAA proposed to revise paragraph (a)(3) to clarify that the
requirement for mixture settings applies to reciprocating engines and
that the mixture settings must be the leanest recommended for the
climb. The FAA pointed out that the ``leanest recommended for climb''
mixture setting is considered a normal operating condition.
The FAA proposed to remove paragraph (a)(5) because water taxi
tests are already required by Sec. 23.1041 as amended by Amendment 23-
43 (58 FR 18958, April 9, 1993).
The FAA proposed to revise paragraphs (c) and (d) by adding the
requirement that cooling correction factors be determined for the
appropriate altitude. This proposed change was intended to codify
current certification practice and increase safety by ensuring that the
proper correction factor is determined.
[[Page 5133]]
Comment: Beechcraft comments that the minimum fuel requirement of
present paragraph (a)(3) should be deleted for turbine engines since
there are not real measurable differences for turbine engine fuel as
there are for reciprocating engine fuel.
FAA Response: The proposed rule did not contain any change to the
minimum fuel grade requirements and the preamble statement may be
unclear. The FAA agrees with the Beechcraft statement that today,
turbine engine fuels are not graded. Since no change was proposed in
this wording in the NPRM and since the present wording has not effect
on the use of turbine engine fuels, no change is made for this final
rule. However, after discussion within the ARAC Working Group, the FAA
has determined that paragraph (a)(3) can be clarified by moving the
second part of the sentence concerning mixture settings for
reciprocating engines to a new paragraph (a)(5). This is not considered
a substantive change to the proposed language, but a clarification of a
current requirement.
The only comment received on the changes proposed for Sec. 23.1043
concerned paragraph (a)(3), and that paragraph is adopted as explained
above. The remaining changes are adopted as proposed.
Section 23.1045 Cooling Test Procedures for Turbine Engine Powered
Airplanes
The FAA proposed to clarify Sec. 23.1045(a) by stating more
generally that (1) compliance with Sec. 23.1041 must be shown for all
phases of operations, not only the four listed phases: takeoff, climb,
enroute, and landing; and that (2) the airplane must be flown in the
configuration, at the speeds, and following the procedures recommended
in the Airplane Flight Manual for the relative stage of flight that
corresponds to the applicable performance requirements critical to
cooling.
No comments were received on the proposals, and they are adopted as
proposed.
Section 23.1047 Cooling Test Procedures for Reciprocating Engine
Powered Airplanes
The FAA proposed to revise the cooling test procedures in
Sec. 23.1047 for reciprocating engine powered airplanes by deleting the
specific procedures because experience has shown that some of the
listed detailed procedures are not directly applicable to certain
engine configurations and certain operating conditions.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1091 Air Induction System
The FAA proposed to revise Sec. 23.1091(c)(2) to require that air
induction system design protect against foreign matter, from whatever
source, ``during takeoff, landing, and taxiing'' rather than be
limited, as is the present rule, to foreign material located on the
runway, taxiway, or other airport operating surfaces.
Comment: Beechcraft comments that increasing the scope of the
foreign material environment poses very difficult technical questions
and potentially costly solutions. Beechcraft states that it is
extremely difficult to compensate for and protect against airborne
debris and also states its concern that the proposed rule language
gives no guidance as to the levels of protection that are necessary.
FAA Response: As stated in the NPRM preamble, the proposed language
is consistent with current certification practice and, therefore, would
not be a significant new burden on aircraft manufacturers. However, it
was not the FAA's intent to create an opportunity for an extreme
interpretation of this rule, as suggested by Beechcraft. To clarify the
intent, and after discussion within the ARAC Working Group, the FAA has
added the words ``hazard of'' to the second sentence of
Sec. 23.1091(c)(2) to make it clear that the intent of the rule is to
minimize the hazard of ingestion of foreign matter rather than to
require zero ingestion.
This proposal is adopted with the change explained above.
Section 23.1093 Induction System Icing Protection
The FAA proposed to revise Sec. 23.1093(c) by adding the heading
``Reciprocating engines with superchargers'' so that this paragraph
would be consistent with paragraphs (a) and (b) of this section, which
have headings.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1105 Induction System Screens
The FAA proposed to revise Sec. 23.1105 to include fuel injection
systems, since some reciprocating engines incorporate a fuel injection
system and the same provisions required for a carburetor are necessary
for a fuel injection system.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1107 Induction System Filters
The FAA proposed to revise the introductory text of Sec. 23.1107 by
deleting the reference to reciprocating engine installations to make
the section applicable to airplanes with either reciprocating or
turbine engines.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1121 General
The FAA proposed to revise Sec. 23.1121(g) by adding standards for
APU exhaust systems because these standards were overlooked when APU
standards were introduced into part 23 by Amendment 23-43 (58 FR 18958,
April 9, 1993).
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1141 Powerplant Controls: General
The FAA proposed to clarify Sec. 23.1141(b), which concerns
flexible controls, by replacing the phrase ``must be of an acceptable
kind'' with the phrase ``must be shown to be suitable for the
particular application.''
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1143 Engine Controls
The FAA proposed to revise Sec. 23.1143(f) to add a requirement
that a fuel control (other than a mixture control) must have a means to
prevent the inadvertent movement of the control into the shutoff
position.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1153 Propeller Feathering Controls
The FAA proposed to revise Sec. 23.1153 to require that it be
possible to feather each propeller separately, in order to prevent
inadvertent operation.
After further review of the proposal, the FAA decided to remove the
phrase ``whether or not they are separate from the propeller speed and
pitch controls'' and add the word ``installed'' in its place. The
meaning is maintained without the deleted phrase, which would be
redundant.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1181 Designated Fire Zones; Regions Included
The FAA proposed new Sec. 23.1181(b)(3) to add as a designated fire
zone for turbine engines ``any complete powerplant compartment in which
there is no isolation between compressor, accessory, combustor, turbine
and tailpipe sections.''
No comments were received on the proposal, and it is adopted as
proposed.
[[Page 5134]]
Section 23.1183 Lines, Fittings, and Components
The FAA proposed to clarify the intent of Sec. 23.1183(a), which
concerns the approval of flexible hose assemblies, by replacing the
word ``approved'' with the words ``shown to be suitable for the
particular application.''
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1191 Firewalls
The FAA proposed to amend Sec. 23.1191(b) to require that each
``firewall or shroud must be constructed so that no hazardous quantity
of liquid, gas, or flame can pass from the compartment created by the
firewall or shroud to other parts of the airplane.'' The intent of the
proposed change was to clarify that the requirement applies to any
compartment created by a firewall or shroud.
Comment: The JAA states that the additional wording proposed to be
added to paragraph (b) is superfluous and will not be proposed for JAR
23.
FAA Response: The FAA has determined that the proposed change to
Sec. 23.1191(b) is needed to retain the intent of the rule and that it
will not create a technical disharmony between the two bodies of
regulation.
This proposal is adopted as proposed.
Section 23.1203 Fire Detector System
The FAA proposed to revise Sec. 23.1203(e), which concerns the
wiring and other components of each fire detector system in an engine
compartment, by replacing the words ``fire zone'' with ``designated
fire zone'' to make the wording consistent with Sec. 23.1181.
No comments were received on the proposal, and it is adopted as
proposed.
Section 23.1305 Powerplant Instruments
The FAA proposed to revise Sec. 23.1305(b)(3), concerning cylinder
head temperature indicators, by deleting paragraph (b)(3)(ii), which
refers to compliance with Sec. 23.1041 at a speed higher than VY,
to be consistent with a general deletion of the requirements for a
determination of the VY speed.
No comments were received on the proposal. However, after further
review, the FAA has determined that it would be simpler to remove the
text of paragraph (b)(3)(ii) and to reserve paragraph (b)(3)(ii) for
future use in order to avoid confusion that could come from
redesignation of paragraph (b)(3)(iii).
The proposal is adopted as explained above.
Section 23.1337 Powerplant Instruments
The FAA proposed to change the reference in Sec. 23.1337(b) to
``Sec. 23.959'' to ``Sec. 23.959(a)'' to conform the reference to a
revision of Sec. 23.959 made elsewhere in this document.
No comments were received on the proposal, and it is adopted as
proposed.
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 justify its costs. Second, the Regulatory
Flexibility Act of 1980 requires agencies to analyze the economic
impact of regulatory changes on small entities. Finally, the Office of
Management and Budget directs agencies to assess the effects of
regulatory changes on international trade. In conducting these
assessments, the FAA has determined that this rule: (1) Will generate
benefits exceeding its costs and is ``significant'' as defined in
Executive Order 12866; (2) is ``significant'' as defined in DOT's
Policies and Procedures; (3) will not have a significant impact on a
substantial number of small entities; and (4) will not constitute a
barrier to international trade. These analyses, available in the
docket, are summarized below.
Comments Related to the Economics of the Proposed Rule
Two comments were received regarding the economic impact of the
proposals; one concerning an existing regulation (Sec. 23.1043 Cooling
tests) and one concerning a new proposal (Sec. 23.1091 Air induction
systems). Both of these comments, as well as the FAA's responses, are
included above in the section ``Discussion of Amendments.''
Regulatory Evaluation Summary
The FAA has determined that the benefits of the final rule, though
not directly quantifiable, will exceed the expected costs. Minor costs,
ranging from $240 to $6,000 per certification, are projected for four
of the provisions. No costs are attributed to the other provisions. The
benefits of the final rule are considered below in four categories: (1)
Harmonization, (2) safety, (3) reduced need for special conditions, and
(4) clarification.
Harmonization
These changes, in concert with other rulemaking and policy actions,
will provide nearly uniform powerplant airworthiness standards for
airplanes certificated in the United States and the JAA member
countries. The resulting greater uniformity of standards simplifies
airworthiness approval for import and export purposes.
Safety
In addition to the harmonization benefits, five provisions of the
rule provide additional safety benefits. First, the final rule revises
Sec. 23.933(a)(1) to more closely agree with the corresponding turbojet
and turbofan reversing system airworthiness standards of part 25. The
FAA estimates that this provision will necessitate an additional 100
hours of failure mode and effects analysis at an assumed cost rate of
$60 per hour, including labor and overhead. The estimated $6,000 cost
applies to each certification. The FAA projects that no additional
production or operating costs will result from this provision.
The primary potential benefit of the provision is the additional
safety that could result from analyzing the feasible range of reverser
system failures, the effects of those failures, and the corresponding
capabilities necessary to correct the failure or circumvent its
effects. Such an analysis could reduce the possibility that an
unanticipated condition with catastrophic potential would remain in the
system. In addition to the safety benefit, it is expected that
operating benefits and manufacturing economies will result from the
uniformity of standards between parts 23 and 25. The FAA is not able to
quantify the potential benefits of this provision but has determined
that the benefits will exceed the expected minor costs.
Second, the final rule adds a new paragraph (b) to Sec. 23.959
requiring that the effect of any fuel pump failure on the unusable fuel
supply be determined. Though not previously required, it has been
industry practice to include this information in the Airplane Flight
Manual. The FAA estimates that the nominal cost of making this
determination will be $240 per certification (4 hours at $60 per hour).
In addition, an insignificant cost ($1) will be incurred in adding a
table entry to the manual for each airplane that is produced. The fact
that this requirement is already standard practice supports the FAA's
position that the potential benefit of the provision exceed the minor
costs. The safety benefits of this provision
[[Page 5135]]
derive from the assurance that this vital information will continue to
be provided for future airplane models.
Third, under Sec. 23.979, the final rule adds the requirement for
commuter category airplanes that an indication be provided at each
fueling station in the event of a failure of the shutoff means to stop
fuel flow at the maximum level. The FAA estimates that the required
device will necessitate an incremental design and development cost of
$3,000 per certification (50 hours at $60 per hour) and an additional
nominal manufacturing cost of $10 per airplane. The benefit of the
provision is the avoidance of a potentially catastrophic condition
whereby excess fuel could unknowingly be forced out of the contained
fuel system by the pressure fueling system. The FAA has determined that
these potential benefits will exceed the minor associated costs.
Fourth, Sec. 23.1041 establishes the requirement that the
powerplant cooling system must be able to maintain the temperature of
the powerplant components and fluids. The ambient temperature for
testing reciprocating engine airplanes is currently required to be
corrected to show the capacity of the cooling system at 100 deg.F.
Under the amendment, this temperature standard is revised to the
``maximum ambient temperature conditions for which approval is
requested.''
No costs are attributed to this provision. Reciprocating engine
airplane manufacturers will continue to have the option to request
approval for operations at the existing 100 deg.F temperature. A
decision to request approval for a higher temperature would necessitate
demonstration of the capability of the cooling system at that
temperature. That choice, however, will be made at the manufacturer's
discretion and will be based on its decision that any associated
incremental cooling system costs would be recovered in the marketplace
or offset by other considerations. The potential benefit of this
provision is the reduced likelihood that an inadequate cooling system
would be relied on during high temperature operations.
Finally, paragraph (a) of Sec. 23.1045 is revised to state more
generally that compliance with the cooling margin requirements of
Sec. 23.1041 must be shown for all phases of operation, as compared to
the four phases of flight currently listed. In effect, the amendment
adds the taxi phase.
The FAA estimates that the specific addition of the taxi phase will
necessitate an incremental 5 hours of engineering analysis valued at
$60 per hour, for a total of $300 per certification. The potential
benefit of this provision is the enhanced safety that could result from
evaluating the efficacy of the cooling system during the taxi phase of
operation. In the taxi phase of operation, engine power settings and
heat production may be generally lower than that experienced during
flight, but available air circulation might also be lower. The heat
mechanics of the two conditions are distinct and warrant separate
evaluation. The FAA has determined that the potential benefits of this
provision will exceed the nominal associated costs.
Reduced Need for Special Conditions
The final rule includes five provisions that will replace the need
for ``special conditions'' processing of certain parts or materials
that were previously considered as novel or unusual design features.
The subjects of these provisions include composite propellers, fuel
injection systems for reciprocating engines, induction filters on
turbine engines, fuel shutoff controls other than mixture controls, and
auxiliary power units. No additional costs are attributed to these
provisions. Formalization of the equivalent safety standards and
requirements for these subjects obviates the need for special
conditions actions and simplifies the certification process for
manufacturers.
Clarification
Several unclear provisions of part 23 were revealed during the
harmonization review. In response to this finding, the final rule
includes a number of no-cost, editorial revisions that clarify the
existing requirements. These changes benefit manufacturers by removing
potential confusion about the specific standards and requirements
necessary for certification.
In summary, the FAA has determined that each of the amendments, as
well as the final rule as a whole, will be cost beneficial.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily or
disproportionately burdened by Government regulations. The RFA requires
a Regulatory Flexibility Analysis if a rule would have a significant
economic impact, either detrimental or beneficial, on a substantial
number of small entities. Based on implementing FAA Order 2100.14A,
Regulatory Flexibility Criteria and Guidance, the FAA has determined
that this rule will not have a significant economic impact on a
substantial number of small entities.
Trade Impact Assessment
The final rule will 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 amended powerplant airworthiness standards have been harmonized
with foreign aviation authorities and will reduce restraints on trade.
Federalism Implications
The regulations herein will not have substantial direct effects on
the States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government. Therefore, in accordance with Executive
Order 12612, it is determined that this rule does not have sufficient
federalism implications to warrant the preparation of a Federalism
Assessment.
Conclusion
The FAA is revising the airworthiness standards to provide
propulsion standards for normal, utility, acrobatic, and commuter
category airplanes to harmonize them with the standards that have been
adopted for the same category airplanes by the Joint Aviation
Authorities in Europe. The revisions will reduce the regulatory burden
on the United States and European airplane manufacturers by relieving
them of the need to show compliance with different standards each time
they seek certification approval of an airplane in the United States or
in a country that is a member of the JAA.
For the reasons discussed in the preamble, and based on the
findings in the Regulatory Evaluation, the FAA has determined that this
rule is significant under Executive Order 12866. In addition, the FAA
certifies that this rule will not have a significant economic impact,
positive or negative, on a substantial number of small entities under
the criteria of the Regulatory Flexibility Act. This rule is considered
significant under DOT Regulatory Policies and Procedures (44 FR 11034,
February 26, 1979). A regulatory evaluation of the rule 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 23
Aircraft, Aviation safety, Signs and symbols.
[[Page 5136]]
The Amendments
In consideration of the foregoing, the Federal Aviation
Administration amends 14 CFR part 23 as follows:
PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND
COMMUTER CATEGORY AIRPLANES
1. The authority citation for part 23 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
Sec. 23.777 [Amended]
2. Section 23.777(c)(2) is amended by adding the words ``single
and'' between the words ``for'' and ``tandem''.
3. The table in Sec. 23.779(b)(1) is amended by adding a new item
between the items ``mixture'' and ``carburetor air heat or alternate
air'' to read as follows:
Sec. 23.779 Motion and effect of cockpit controls.
* * * * *
(b) * * *
Motion and effect
(1) Powerplant controls:
* * * * *
Fuel.............................. Forward for open.
* * * * *
4. Section 23.901 is amended by revising paragraphs (d)(1) and
(d)(2) to read as follows:
Sec. 23.901 Installation.
* * * * *
(d) * * *
(1) Result in carcass vibration characteristics that do not exceed
those established during the type certification of the engine.
(2) Provide continued safe operation without a hazardous loss of
power or thrust while being operated in rain for at least three minutes
with the rate of water ingestion being not less than four percent, by
weight, of the engine induction airflow rate at the maximum installed
power or thrust approved for takeoff and at flight idle.
* * * * *
5. Section 23.903 is amended by adding headings to paragraphs (c)
and (g), and by revising the heading of paragraph (f) to read as
follows:
Sec. 23.903 Engines.
* * * * *
(c) Engine isolation. * * *
* * * * *
(f) Restart envelope. * * *
(g) Restart capability. * * *
Sec. 23.907 [Amended]
6. Section 23.907(a) introductory text is amended by removing the
phrase ``with metal blades or highly stressed metal components'' and
adding the phrase ``other than a conventional fixed-pitch wooden
propeller'' in its place.
7. Section 23.925 introductory text is revised to read as follows:
Sec. 23.925 Propeller clearance.
Unless smaller clearances are substantiated, propeller clearances,
with the airplane at the most adverse combination of weight and center
of gravity, and with the propeller in the most adverse pitch position,
may not be less than the following:
* * * * *
Sec. 23.929 [Amended]
8. Section 23.929 is amended by removing the word ``power'' and
adding, in its place, the word ``thrust''.
9. Section 23.933 is amended by removing the word ``forward'' in
the two instances in which it is used in paragraph (a)(3); by removing
the reference in paragraph (b)(2) that reads ``(a)(1)'' and adding the
reference ``(b)(1)'' in its place; and by revising paragraph (a)(1) to
read as follows:
Sec. 23.933 Reversing systems.
(a) * * *
(1) Each system intended for ground operation only must be designed
so that, during any reversal in flight, the engine will produce no more
than flight idle thrust. In addition, it must be shown by analysis or
test, or both, that--
(i) Each operable reverser can be restored to the forward thrust
position; or
(ii) The airplane is capable of continued safe flight and landing
under any possible position of the thrust reverser.
* * * * *
10. Section 23.955 is amended by revising paragraphs (a)(1) through
(a)(4) to read as follows:
Sec. 23.955 Fuel flow.
(a) * * *
(1) The quantity of fuel in the tank may not exceed the amount
established as the unusable fuel supply for that tank under
Sec. 23.959(a) plus that quantity necessary to show compliance with
this section.
(2) If there is a fuel flowmeter, it must be blocked during the
flow test and the fuel must flow through the meter or its bypass.
(3) If there is a flowmeter without a bypass, it must not have any
probable failure mode that would restrict fuel flow below the level
required for this fuel demonstration.
(4) The fuel flow must include that flow necessary for vapor return
flow, jet pump drive flow, and for all other purposes for which fuel is
used.
* * * * *
11. Section 23.959 is amended by designating the current text of
the section as paragraph (a) and by adding a new paragraph (b) to read
as follows:
Sec. 23.959 Unusable fuel supply.
* * * * *
(b) The effect on the usable fuel quantity as a result of a failure
of any pump shall be determined.
12. Section 23.963 is amended by removing the reference in
paragraph (e) that reads ``Sec. 23.959'' and adding the reference
``Sec. 23.959(a)'' in its place, and by revising paragraph (b) to read
as follows:
Sec. 23.963 Fuel tanks: general.
* * * * *
(b) Each flexible fuel tank liner must be shown to be suitable for
the particular application.
* * * * *
13. Section 23.965 is amended by revising paragraph (b)(3)(i) to
read as follows:
Sec. 23.965 Fuel tank tests.
* * * * *
(b) * * *
(3) * * *
(i) If no frequency of vibration resulting from any rpm within the
normal operating range of engine or propeller speeds is critical, the
test frequency of vibration is:
(A) The number of cycles per minute obtained by multiplying the
maximum continuous propeller speed in rpm by 0.9 for propeller-driven
airplanes, and
(B) For non-propeller driven airplanes the test frequency of
vibration is 2,000 cycles per minute.
* * * * *
14. Section 23.973(f) is revised to read as follows:
Sec. 23.973 Fuel tank filler connection.
* * * * *
(f) For airplanes with turbine engines, the inside diameter of the
fuel filler opening must be no smaller than 2.95 inches.
15. Section 23.975(a)(5) is revised to read as follows:
Sec. 23.975 Fuel tank vents and carburetor vapor vents.
(a) * * *
(5) There may be no point in any vent line where moisture can
accumulate with the airplane in either the ground or level flight
attitudes, unless drainage is
[[Page 5137]]
provided. Any drain valve installed must be accessible for drainage;
* * * * *
16. Section 23.979(b) is revised to read as follows:
Sec. 23.979 Pressure fueling systems.
* * * * *
(b) An automatic shutoff means must be provided to prevent the
quantity of fuel in each tank from exceeding the maximum quantity
approved for that tank. This means must--
(1) Allow checking for proper shutoff operation before each fueling
of the tank; and
(2) For commuter category airplanes, indicate at each fueling
station, a failure of the shutoff means to stop the fuel flow at the
maximum quantity approved for that tank.
* * * * *
17. Section 23.1001(b)(2) is revised to read as follows:
Sec. 23.1001 Fuel jettisoning system.
* * * * *
(b) * * *
(2) A climb, at the speed at which the one-engine-inoperative
enroute climb data have been established in accordance with
Sec. 23.69(b), with the critical engine inoperative and the remaining
engines at maximum continuous power; and
* * * * *
Sec. 23.1013 [Amended]
18. Section 13.1013(d)(1) is amended by removing the word
``crankcase''.
Sec. 23.1041 [Amended]
19. Section 23.1041 is amended by adding the phrase ``and maximum
ambient atmospheric temperature conditions'' between the phrases
``maximum altitude'' and ``for which approval''.
20. Section 23.1043 is amended by revising paragraphs (a), (c), and
(d) to read as follows:
Sec. 23.1043 Cooling tests.
(a) General. Compliance with Sec. 23.1041 must be shown on the
basis of tests, for which the following apply:
(1) If the tests are conducted under ambient atmospheric
temperature conditions deviating from the maximum for which approval is
requested, the recorded powerplant temperatures must be corrected under
paragraphs (c) and (d) of this section, unless a more rational
correction method is applicable.
(2) No corrected temperature determined under paragraph (a)(1) of
this section may exceed established limits.
(3) The fuel used during the cooling tests must be of the minimum
grade approved for the engine.
(4) For turbocharged engines, each turbocharger must be operated
through that part of the climb profile for which operation with the
turbocharger is requested.
(5) For a reciprocating engine, the mixture settings must be the
leanest recommended for climb.
* * * * *
(c) Correction factor (except cylinder barrels). Temperatures of
engine fluids and powerplant components (except cylinder barrels) for
which temperature limits are established, must be corrected by adding
to them the difference between the maximum ambient atmospheric
temperature for the relevant altitude for which approval has been
requested and the temperature of the ambient air at the time of the
first occurrence of the maximum fluid or component temperature recorded
during the cooling test.
(d) Correction factor for cylinder barrel temperatures. Cylinder
barrel temperatures must be corrected by adding to them 0.7 times the
difference between the maximum ambient atmospheric temperature for the
relevant altitude for which approval has been requested and the
temperature of the ambient air at the time of the first occurrence of
the maximum cylinder barrel temperature recorded during the cooling
test.
21. Section 23.1045(a) is revised to read as follows:
Sec. 23.1045 Cooling test procedures for turbine engine powered
airplanes.
(a) Compliance with Sec. 23.1041 must be shown for all phases of
operation. The airplane must be flown in the configurations, at the
speeds, and following the procedures recommended in the Airplane Flight
Manual for the relevant stage of flight, that correspond to the
applicable performance requirements that are critical to cooling.
* * * * *
22. Section 23.1047 is revised to read as follows:
Sec. 23.1047 Cooling test procedures for reciprocating engine powered
airplanes.
Compliance with Sec. 23.1041 must be shown for the climb (or, for
multiengine airplanes with negative one-engine-inoperative rates of
climb, the descent) stage of flight. The airplane must be flown in the
configurations, at the speeds and following the procedures recommended
in the Airplane Flight Manual, that correspond to the applicable
performance requirements that are critical to cooling.
23. Section 23.1091(c)(2) is revised to read as follows:
Sec. 23.1091 Air induction system.
* * * * *
(c) * * *
(2) The airplane must be designed to prevent water or slush on the
runway, taxiway, or other airport operating surfaces from being
directed into the engine or auxiliary power unit air intake ducts in
hazardous quantities. The air intake ducts must be located or protected
so as to minimize the hazard of ingestion of foreign matter during
takeoff, landing, and taxiing.
Sec. 23.1093 [Amended]
24. Section 23.1093 is amended by adding the heading
``Reciprocating engines with Superchargers'' to paragraph (c).
25. Section 23.1105(a) is revised to read as follows:
Sec. 23.1105 Induction system screens.
* * * * *
(a) Each screen must be upstream of the carburetor or fuel
injection system.
* * * * *
26. Section 23.1107 introductory text is revised to read as
follows:
Sec. 23.1107 Induction system filters.
If an air filter is used to protect the engine against foreign
material particles in the induction air supply--
* * * * *
27. Section 23.1121(g) is revised to read as follows:
Sec. 23.1121 General.
* * * * *
(g) If significant traps exist, each turbine engine and auxiliary
power unit exhaust system must have drains discharging clear of the
airplane, in any normal ground and flight attitude, to prevent fuel
accumulation after the failure of an attempted engine or auxiliary
power unit start.
* * * * *
28. Section 23.1141(b) is revised to read as follows:
Sec. 23.1141 Powerplant controls: general.
* * * * *
(b) Each flexible control must be shown to be suitable for the
particular application.
* * * * *
29. Section 23.1143(f) is amended by revising the introductory text
to read as follows:
Sec. 23.1143 Engine controls.
* * * * *
(f) If a power, thrust, or a fuel control (other than a mixture
control)
[[Page 5138]]
incorporates a fuel shutoff feature, the control must have a means to
prevent the inadvertent movement of the control into the off position.
The means must--
* * * * *
30. Section 23.1153 is revised to read as follows:
Sec. 23.1153 Propeller feathering controls.
If there are propeller feathering controls installed, it must be
possible to feather each propeller separately. Each control must have a
means to prevent inadvertent operation.
31. Section 23.1181 is amended by adding a new paragraph (b)(3) to
read as follows:
Sec. 23.1181 Designated fire zones; regions included.
* * * * *
(b) * * *
(3) Any complete powerplant compartment in which there is no
isolation between compressor, accessory, combustor, turbine, and
tailpipe sections.
* * * * *
Sec. 23.1183 [Amended]
32. Section 23.1183(a) is amended by removing the word ``approved''
in the next to the last sentence, and adding the phrase ``shown to be
suitable for the particular application'' in its place.
33. Section 23.1191(b) is revised to read as follows:
Sec. 23.1191 Firewalls.
* * * * *
(b) Each firewall or shroud must be constructed so that no
hazardous quantity of liquid, gas, or flame can pass from the
compartment created by the firewall or shroud to other parts of the
airplane.
* * * * *
34. Section 23.1203(e) is revised to read as follows:
Sec. 23.1203 Fire detector system.
* * * * *
(e) Wiring and other components of each fire detector system in a
designated fire zone must be at least fire resistant.
* * * * *
Sec. 23.1305 [Amended]
35. Section 23.1305(b)(3)(ii) is removed and reserved.
Sec. 23.1337 [Amended]
36. Section 23.1337(b)(1) is amended by removing the reference
``Sec. 23.959'' and adding the reference ``Sec. 23.959(a)'' in its
place.
Issued in Washington, DC, on January 29, 1996.
David R. Hinson,
Administrator.
[FR Doc. 96-2084 Filed 2-8-96; 8:45 am]
BILLING CODE 4910-13-M