Special Conditions: Airbus Model A350-900 Airplane; Transient Engine-Failure Loads, 46169-46170 [2014-18657]
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Federal Register / Vol. 79, No. 152 / Thursday, August 7, 2014 / Rules and Regulations
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA–2013–0897; Special
Conditions No. 25–523–SC]
Special Conditions: Airbus Model
A350–900 Airplane; Transient EngineFailure Loads
Federal Aviation
Administration (FAA), DOT.
ACTION: Final special conditions.
AGENCY:
These special conditions are
issued for Airbus Model A350–900
airplanes. These airplanes will have a
novel or unusual design feature
associated with the new generation of
high-bypass engines and the potential
loads resulting from extreme enginefailure conditions.
The applicable airworthiness
regulations do not contain adequate or
appropriate safety standards for this
design feature. These special conditions
contain the additional safety standards
that the Administrator considers
necessary to establish a level of safety
equivalent to that established by the
existing airworthiness standards.
DATES: Effective Date: September 8,
2014.
SUMMARY:
FOR FURTHER INFORMATION CONTACT:
Todd Martin, FAA, Airframe and Cabin
Safety Branch, ANM–115, Transport
Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue
SW., Renton, Washington 98057–3356;
telephone (425) 227–1178; facsimile
(425) 227–1320.
SUPPLEMENTARY INFORMATION:
emcdonald on DSK67QTVN1PROD with RULES
Background
On August 25, 2008, Airbus applied
for a type certificate for their new Model
A350–900 airplane. Later, Airbus
requested, and the FAA approved, an
extension to the application for FAA
type certification to November 15, 2009.
The Model A350–900 airplane has a
conventional layout with twin wingmounted Rolls-Royce Trent XWB
engines. It features a twin-aisle,
9-abreast, economy-class layout, and
accommodates side-by-side placement
of LD–3 containers in the cargo
compartment. The basic Model A350–
900 airplane configuration
accommodates 315 passengers in a
standard two-class arrangement. The
design cruise speed is Mach 0.85 with
a maximum take-off weight of 602,000
lbs.
The existing regulations are
inadequate because the new, large-
VerDate Mar<15>2010
16:00 Aug 06, 2014
Jkt 232001
bypass fan engines of the Model A350–
900 airplanes can cause more damage in
a failure event than could the previous
engines. To maintain the level of safety
envisioned by Title 14, Code of Federal
Regulations (14 CFR) 25.61(b), more
comprehensive criteria are needed for
the new generation of high-bypass
engines. The more severe events
resulting from extreme engine-failure
conditions would be treated as
dynamic-load conditions. The special
conditions would distinguish between
the more common engine-failure events
and those rare events resulting from
structural failures. The more common
events would continue to be treated as
static torque-limit load conditions. The
severe events would be considered
ultimate loads, and include all transient
loads associated with the event. An
additional safety factor would be
applied to the more critical airframe
supporting structure.
Type Certification Basis
Under 14 CFR 21.17, Airbus must
show that the Model A350–900 airplane
meets the applicable provisions of 14
CFR part 25, as amended by
Amendments 25–1 through 25–129.
If the Administrator finds that the
applicable airworthiness regulations
(i.e., 14 CFR part 25) do not contain
adequate or appropriate safety standards
for the Model A350–900 airplane
airplane because of a novel or unusual
design feature, special conditions are
prescribed under § 21.16.
Special conditions are initially
applicable to the model for which they
are issued. Should the type certificate
for that model be amended later to
include any other model that
incorporates the same or similar novel
or unusual design feature, the special
conditions would also apply to the other
model under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the Model A350–900
airplane must comply with the fuel-vent
and exhaust-emission requirements of
14 CFR part 34, and the noisecertification requirements of 14 CFR
part 36. The FAA must issue a finding
of regulatory adequacy under section
611 of Public Law 92–574, the ‘‘Noise
Control Act of 1972.’’
The FAA issues special conditions, as
defined in 14 CFR 11.19, under § 11.38,
and they become part of the typecertification basis under § 21.17(a)(2).
Novel or Unusual Design Features
The Model A350–900 airplane will
incorporate the following novel or
unusual design features: engines with
large-bypass fans capable of producing
PO 00000
Frm 00003
Fmt 4700
Sfmt 4700
46169
much higher failure loads than previous
engines. The Model A350–900 airplane
will therefore require additional
dynamic-load analyses to assess the
most severe engine-failure events. The
loads resulting from these conditions
would be considered as ultimate loads,
with an additional safety factor applied
to the airframe supporting structure.
Discussion
The size, configuration, and failure
modes of jet engines has changed
considerably from those envisioned by
14 CFR 25.361(b) when the engineseizure requirement was first adopted.
Engines have become larger and are now
designed with large-bypass fans capable
of producing much higher failure loads.
Relative to the engine configurations
that existed when the rule was
developed in 1957, the present
generation of engines are sufficiently
different and novel to justify special
conditions for Model A350–900
airplanes. Service history has shown
that the engine-failure events that tend
to cause the most severe loads are fanblade failures, and these events occur
much less frequently than the typical
‘‘limit’’ load condition.
The regulatory authorities and
industry developed a standardized
requirement in the Aviation Rulemaking
Advisory Committee (ARAC) forum.
The technical aspects of this
requirement have been agreed upon and
have been accepted by the ARAC Loads
and Dynamics Harmonization Working
Group. These special conditions reflect
the ARAC recommendation and are
essentially harmonized with the
corresponding European Aviation Safety
Agency (EASA) Certification
Specifications (CS) 25. In addition, the
ARAC recommendation includes
corresponding advisory material that is
incorporated in CS–25. This advisory
material is considered an acceptable
means of compliance to the special
conditions.
These special conditions contain the
additional safety standards that the
Administrator considers necessary to
establish a level of safety equivalent to
that established by the existing
airworthiness standards.
Discussion of Comments
Notice of proposed special conditions
no. 25–13–29–SC for Airbus Model
A350–900 airplanes was published in
the Federal Register on November 12,
2013 (78 FR 67323). No substantive
comments were received, and the
special conditions are adopted as
proposed.
E:\FR\FM\07AUR1.SGM
07AUR1
46170
Federal Register / Vol. 79, No. 152 / Thursday, August 7, 2014 / Rules and Regulations
Applicability
As discussed above, these special
conditions apply to the Airbus Model
A350–900 airplanes. Should Airbus
apply later for a change to the type
certificate to include another model
incorporating the same novel or unusual
design feature, the special conditions
would apply to that model as well.
Conclusion
This action affects only certain novel
or unusual design features on the Model
A350–900 airplanes. It is not a rule of
general applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting
and recordkeeping requirements.
The authority citation for these
special conditions is as follows:
4. The ultimate loads developed from
the conditions specified in special
conditions 3.a. and 3.b. are to be
multiplied by a factor of 1.0 when
applied to engine mounts and pylons,
and multiplied by a factor of 1.25 when
applied to adjacent supporting airframe
structure.
5. The airplane must be capable of
continued safe flight considering the
aerodynamic effects on controllability
due to any permanent deformation that
results from the conditions specified in
special condition 3.
Issued in Renton, Washington, on July 15,
2014.
John P. Piccola, Jr.,
Acting Manager, Transport Airplane
Directorate, Aircraft Certification Service.
[FR Doc. 2014–18657 Filed 8–6–14; 8:45 am]
Authority: 49 U.S.C. 106(g), 40113, 44701,
44702, 44704.
BILLING CODE 4910–13–P
The Special Conditions
DEPARTMENT OF TRANSPORTATION
Accordingly, pursuant to the authority
delegated to me by the Administrator,
the following special conditions are
issued as part of the type-certification
basis for Airbus Model A350–900
airplanes.
In lieu of § 25.361(b), the following
special conditions apply:
1. For turbine-engine installations, the
engine mounts, pylons, and adjacent
supporting airframe structure must be
designed to withstand 1g level flight
loads acting simultaneously with the
maximum limit torque loads imposed
by each of the following:
a. Sudden engine deceleration due to
a malfunction that could result in a
temporary loss of power or thrust, and
b. the maximum acceleration of the
engine.
2. For auxiliary power-unit
installations, the power-unit mounts
and adjacent supporting airframe
structure must be designed to withstand
1g level flight loads acting
simultaneously with the maximum limit
torque loads imposed by each of the
following:
a. Sudden auxiliary power-unit
deceleration due to malfunction or
structural failure, and
b. the maximum acceleration of the
power unit.
3. For engine-supporting structure, an
ultimate loading condition must be
considered that combines 1g flight loads
with the transient dynamic loads
resulting from:
a. The loss of any fan, compressor, or
turbine blade, and separately
b. where applicable to a specific
engine design, any other engine
structural failure that results in higher
loads.
Federal Aviation Administration
emcdonald on DSK67QTVN1PROD with RULES
■
VerDate Mar<15>2010
16:00 Aug 06, 2014
Jkt 232001
14 CFR Part 25
[Docket No. FAA–2013–0903; Special
Conditions No. 25–525–SC]
Special Conditions: Airbus Model
A350–900 Series Airplane; Side-Stick
Controllers
Federal Aviation
Administration (FAA), DOT.
ACTION: Final special conditions.
AGENCY:
These special conditions are
issued for Airbus Model A350–900
airplanes. These airplanes will have a
novel or unusual design feature
associated with side-stick controllers for
pitch and roll control, instead of
conventional wheels and columns. The
applicable airworthiness regulations do
not contain adequate or appropriate
safety standards for this design feature.
These special conditions contain the
additional safety standards that the
Administrator considers necessary to
establish a level of safety equivalent to
that established by the existing
airworthiness standards.
DATES: Effective Date: September 8,
2014.
SUMMARY:
FOR FURTHER INFORMATION CONTACT:
Loran Haworth, FAA, Airplane and
Flight Interface Branch, ANM–111,
Transport Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue
SW., Renton, Washington 98057–3356;
telephone (425) 227–1133; facsimile
(425) 227–1320.
SUPPLEMENTARY INFORMATION:
PO 00000
Frm 00004
Fmt 4700
Sfmt 4700
Background
On August 25, 2008, Airbus applied
for a type certificate for their new Model
A350–900 airplane. Later, Airbus
requested, and the FAA approved, an
extension to the application for FAA
type certification to November 15, 2009.
The Model A350–900 airplane has a
conventional layout with twin wingmounted Rolls-Royce Trent XWB
engines. It features a twin-aisle, 9abreast, economy-class layout, and
accommodates side-by-side placement
of LD–3 containers in the cargo
compartment. The basic Model A350–
900 airplane configuration
accommodates 315 passengers in a
standard two-class arrangement. The
design cruise speed is Mach 0.85 with
a maximum take-off weight of 602,000
lbs.
The Airbus Model A350–900 airplane,
like its predecessors the Model A320,
A330, A340 and A380 airplanes, will
use side-stick controllers for pitch and
roll control. Regulatory requirements
pertaining to conventional wheel and
column controls, such as pilot strength
and controllability, are not directly
applicable for the side stick. In addition,
pilot-control authority may be uncertain
because the side sticks are not
mechanically interconnected as with
conventional wheel and column
controls.
Type Certification Basis
Under Title 14, Code of Federal
Regulations (14 CFR) 21.17, Airbus must
show that the Model A350–900 airplane
meets the applicable provisions of 14
CFR part 25, as amended by
Amendments 25–1 through 25–129.
The FAA has determined that Airbus
Model A350–900 airplanes must comply
with §§ 25.143, 25.145(b), 25.175(b),
25.671, and 25.1329(a).
If the Administrator finds that the
applicable airworthiness regulations
(i.e., 14 CFR part 25) do not contain
adequate or appropriate safety standards
for the Airbus Model A350–900 airplane
because of a novel or unusual design
feature, special conditions are
prescribed under § 21.16.
Special conditions are initially
applicable to the model for which they
are issued. Should the type certificate
for that model be amended later to
include any other model that
incorporates the same or similar novel
or unusual design feature, the special
conditions would also apply to the other
model under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the Airbus Model A350–900
airplane must comply with the fuel-vent
E:\FR\FM\07AUR1.SGM
07AUR1
]]>Agencies
[Federal Register Volume 79, Number 152 (Thursday, August 7, 2014)]
[Rules and Regulations]
[Pages 46169-46170]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-18657]
[[Page 46169]]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2013-0897; Special Conditions No. 25-523-SC]
Special Conditions: Airbus Model A350-900 Airplane; Transient
Engine-Failure Loads
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
-----------------------------------------------------------------------
SUMMARY: These special conditions are issued for Airbus Model A350-900
airplanes. These airplanes will have a novel or unusual design feature
associated with the new generation of high-bypass engines and the
potential loads resulting from extreme engine-failure conditions.
The applicable airworthiness regulations do not contain adequate or
appropriate safety standards for this design feature. These special
conditions contain the additional safety standards that the
Administrator considers necessary to establish a level of safety
equivalent to that established by the existing airworthiness standards.
DATES: Effective Date: September 8, 2014.
FOR FURTHER INFORMATION CONTACT: Todd Martin, FAA, Airframe and Cabin
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057-
3356; telephone (425) 227-1178; facsimile (425) 227-1320.
SUPPLEMENTARY INFORMATION:
Background
On August 25, 2008, Airbus applied for a type certificate for their
new Model A350-900 airplane. Later, Airbus requested, and the FAA
approved, an extension to the application for FAA type certification to
November 15, 2009. The Model A350-900 airplane has a conventional
layout with twin wing-mounted Rolls-Royce Trent XWB engines. It
features a twin-aisle, 9-abreast, economy-class layout, and
accommodates side-by-side placement of LD-3 containers in the cargo
compartment. The basic Model A350-900 airplane configuration
accommodates 315 passengers in a standard two-class arrangement. The
design cruise speed is Mach 0.85 with a maximum take-off weight of
602,000 lbs.
The existing regulations are inadequate because the new, large-
bypass fan engines of the Model A350-900 airplanes can cause more
damage in a failure event than could the previous engines. To maintain
the level of safety envisioned by Title 14, Code of Federal Regulations
(14 CFR) 25.61(b), more comprehensive criteria are needed for the new
generation of high-bypass engines. The more severe events resulting
from extreme engine-failure conditions would be treated as dynamic-load
conditions. The special conditions would distinguish between the more
common engine-failure events and those rare events resulting from
structural failures. The more common events would continue to be
treated as static torque-limit load conditions. The severe events would
be considered ultimate loads, and include all transient loads
associated with the event. An additional safety factor would be applied
to the more critical airframe supporting structure.
Type Certification Basis
Under 14 CFR 21.17, Airbus must show that the Model A350-900
airplane meets the applicable provisions of 14 CFR part 25, as amended
by Amendments 25-1 through 25-129.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 25) do not contain adequate or
appropriate safety standards for the Model A350-900 airplane airplane
because of a novel or unusual design feature, special conditions are
prescribed under Sec. 21.16.
Special conditions are initially applicable to the model for which
they are issued. Should the type certificate for that model be amended
later to include any other model that incorporates the same or similar
novel or unusual design feature, the special conditions would also
apply to the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Model A350-900 airplane must comply with the fuel-vent
and exhaust-emission requirements of 14 CFR part 34, and the noise-
certification requirements of 14 CFR part 36. The FAA must issue a
finding of regulatory adequacy under section 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
The FAA issues special conditions, as defined in 14 CFR 11.19,
under Sec. 11.38, and they become part of the type-certification basis
under Sec. 21.17(a)(2).
Novel or Unusual Design Features
The Model A350-900 airplane will incorporate the following novel or
unusual design features: engines with large-bypass fans capable of
producing much higher failure loads than previous engines. The Model
A350-900 airplane will therefore require additional dynamic-load
analyses to assess the most severe engine-failure events. The loads
resulting from these conditions would be considered as ultimate loads,
with an additional safety factor applied to the airframe supporting
structure.
Discussion
The size, configuration, and failure modes of jet engines has
changed considerably from those envisioned by 14 CFR 25.361(b) when the
engine-seizure requirement was first adopted. Engines have become
larger and are now designed with large-bypass fans capable of producing
much higher failure loads. Relative to the engine configurations that
existed when the rule was developed in 1957, the present generation of
engines are sufficiently different and novel to justify special
conditions for Model A350-900 airplanes. Service history has shown that
the engine-failure events that tend to cause the most severe loads are
fan-blade failures, and these events occur much less frequently than
the typical ``limit'' load condition.
The regulatory authorities and industry developed a standardized
requirement in the Aviation Rulemaking Advisory Committee (ARAC) forum.
The technical aspects of this requirement have been agreed upon and
have been accepted by the ARAC Loads and Dynamics Harmonization Working
Group. These special conditions reflect the ARAC recommendation and are
essentially harmonized with the corresponding European Aviation Safety
Agency (EASA) Certification Specifications (CS) 25. In addition, the
ARAC recommendation includes corresponding advisory material that is
incorporated in CS-25. This advisory material is considered an
acceptable means of compliance to the special conditions.
These special conditions contain the additional safety standards
that the Administrator considers necessary to establish a level of
safety equivalent to that established by the existing airworthiness
standards.
Discussion of Comments
Notice of proposed special conditions no. 25-13-29-SC for Airbus
Model A350-900 airplanes was published in the Federal Register on
November 12, 2013 (78 FR 67323). No substantive comments were received,
and the special conditions are adopted as proposed.
[[Page 46170]]
Applicability
As discussed above, these special conditions apply to the Airbus
Model A350-900 airplanes. Should Airbus apply later for a change to the
type certificate to include another model incorporating the same novel
or unusual design feature, the special conditions would apply to that
model as well.
Conclusion
This action affects only certain novel or unusual design features
on the Model A350-900 airplanes. It is not a rule of general
applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Special Conditions
0
Accordingly, pursuant to the authority delegated to me by the
Administrator, the following special conditions are issued as part of
the type-certification basis for Airbus Model A350-900 airplanes.
In lieu of Sec. 25.361(b), the following special conditions apply:
1. For turbine-engine installations, the engine mounts, pylons, and
adjacent supporting airframe structure must be designed to withstand 1g
level flight loads acting simultaneously with the maximum limit torque
loads imposed by each of the following:
a. Sudden engine deceleration due to a malfunction that could
result in a temporary loss of power or thrust, and
b. the maximum acceleration of the engine.
2. For auxiliary power-unit installations, the power-unit mounts
and adjacent supporting airframe structure must be designed to
withstand 1g level flight loads acting simultaneously with the maximum
limit torque loads imposed by each of the following:
a. Sudden auxiliary power-unit deceleration due to malfunction or
structural failure, and
b. the maximum acceleration of the power unit.
3. For engine-supporting structure, an ultimate loading condition
must be considered that combines 1g flight loads with the transient
dynamic loads resulting from:
a. The loss of any fan, compressor, or turbine blade, and
separately
b. where applicable to a specific engine design, any other engine
structural failure that results in higher loads.
4. The ultimate loads developed from the conditions specified in
special conditions 3.a. and 3.b. are to be multiplied by a factor of
1.0 when applied to engine mounts and pylons, and multiplied by a
factor of 1.25 when applied to adjacent supporting airframe structure.
5. The airplane must be capable of continued safe flight
considering the aerodynamic effects on controllability due to any
permanent deformation that results from the conditions specified in
special condition 3.
Issued in Renton, Washington, on July 15, 2014.
John P. Piccola, Jr.,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2014-18657 Filed 8-6-14; 8:45 am]
BILLING CODE 4910-13-P
