Special Conditions: General Electric Company, GE9X Engine Models; Endurance Test Special Conditions, 28790-28793 [2017-13210]
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Federal Register / Vol. 82, No. 121 / Monday, June 26, 2017 / Proposed Rules
takeoff at specified altitudes and
temperatures.
(iii) The applicant must specify that
the Rated TOTHAT is available by
manual crew selection at specified
altitudes and temperatures in AEO
conditions.
(2) Operating Instructions: The
applicant must provide data on engine
performance characteristics and
variability to enable the airplane
manufacturer to establish airplane
thrust assurance procedures.
(c) Section 33.7, Engine ratings and
operating limitations.
(1) Rated TOTHAT and the associated
operating limitations are established as
follows:
(i) The thrust is the same as the
engine takeoff rated thrust with
extended flat rating corner point.
(ii) The rotational speed limits are the
same as those associated with the
engine takeoff rated thrust.
(iii) The applicant must establish a
gas temperature steady-state limit and, if
necessary, a transient gas over
temperature limit for which the
duration is no longer than 30 seconds.
(iv) The use is limited to two periods
of no longer than 10 minutes each under
OEI conditions or 5 minutes each under
AEO conditions in any one flight, for a
maximum accumulated usage of 20
minutes in any one flight. Each flight
where the Rated TOTHAT is used must
be followed by mandatory inspections
and maintenance actions prescribed by
paragraph 2(a)(1) of these special
conditions.
(2) The applicant must propose
language to include in the type
certificate data sheet specified in § 21.41
for the following:
(i) Rated TOTHAT and associated
limitations.
(ii) As required by § 33.5(b), Operating
instructions, include a note stating that
‘‘Rated Takeoff Thrust at High Ambient
Temperature (Rated TOTHAT) means
the approved engine thrust developed
under specified altitudes and
temperatures within the operating
limitations established for the engine.
Use is limited to two periods, no longer
than 10 minutes each under OEI
conditions or 5 minutes each under
AEO conditions in any one flight, for a
maximum accumulated usage of 20
minutes in any one flight. Each flight
where the Rated TOTHAT is used must
be followed by mandatory inspection
and maintenance actions.’’
(iii) As required by § 33.5(b),
Operating instructions, include a note
stating that the engine thrust control
system automatically resets the thrust
on the operating engine to the Rated
TOTHAT level when one engine fails
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during takeoff at specified altitudes and
temperatures, and the Rated TOTHAT is
available by manual selection when all
engines are operational during takeoff at
specified altitudes and temperatures.
(d) Section 33.28, Engine Control
Systems.
The engine must incorporate a means,
or a provision for a means, for automatic
availability and automatic control of the
Rated TOTHAT under OEI conditions
and must permit manual activation of
the Rated TOTHAT under AEO
conditions.
(e) Section 33.29, Instrument
connection.
The engine must:
(1) Have means, or provisions for
means, to alert the pilot when the Rated
TOTHAT is in use, when the event
begins and when the time interval
expires.
(2) Have means, or provision for
means, which cannot be reset in flight,
to:
(i) Automatically record each use and
duration of the Rated TOTHAT, and
(ii) Alert maintenance personnel that
the engine has been operated at the
Rated TOTHAT and permit retrieval of
recorded data.
(3) Have means, or provision for
means, to enable routine verification of
the proper operation of the means in
paragraph 2(e)(1) and (e)(2) of these
special conditions.
(f) Section 33.85(b), Calibration tests.
The applicant must base the
calibration test on the thrust check at
the end of the endurance test required
by § 33.87 of these special conditions.
(g) Section 33.87, Endurance test.
(1) In addition to the applicable
requirements of § 33.87(a):
(i) The § 33.87 endurance test must be
modified as follows:
(A) Modify the thirty minute test
cycle at the rated takeoff thrust in
§ 33.87(b)(2)(ii) to run one minute at
rated takeoff thrust, followed by five
minutes at the Rated TOTHAT, followed
by the rated takeoff thrust for the
remaining twenty-four minutes.
(B) The modified thirty minute period
described above in paragraph
2(g)(1)(i)(A) must be repeated ten times
in cycles 16 through 25 of the § 33.87
endurance test.
(2) After completion of the tests
required by § 33.87(b), as modified in
paragraph 2(g)(1)(i) above, and without
intervening disassembly, except as
needed to replace those parts described
as consumables in the ICA, the
applicant must conduct the following
test sequence for a total time of not less
than 120 minutes:
(i) Ten minutes at Rated TOTHAT.
(ii) Eighty-eight minutes at rated
maximum continuous thrust.
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(iii) One minute at 50 percent of rated
takeoff thrust.
(iv) Ten minutes at Rated TOTHAT.
(v) Ten minutes at rated maximum
continuous thrust.
(vi) One minute at flight idle.
(3) The test sequence of §§ 33.87(b)(1)
through (b)(6) of these special
conditions must be run continuously. If
a stop occurs during these tests, the
interrupted sequence must be repeated
unless the applicant shows that the
severity of the test would not be
reduced if the current tests were
continued.
(4) Where the engine characteristics
are such that acceleration to the Rated
TOTHAT results in a transient over
temperature in excess of the steady-state
temperature limit identified in
paragraph 2(c)(1)(iii) of these special
conditions, the transient gas
overtemperature must be applied to
each acceleration to the Rated TOTHAT
of the test sequence in paragraph 2(g)(2)
of these special conditions.
(h) Section 33.93, Teardown
inspection.
The applicant must perform the
teardown inspection required by
§ 33.93(a), after completing the
endurance test prescribed by § 33.87 of
these special conditions.
(i) Section 33.201, Design and test
requirements for Early ETOPS
eligibility.
In addition to the requirements of
§ 33.201(c)(1), the simulated ETOPS
mission cyclic endurance test must
include two cycles of 10 minute
duration, each at the Rated TOTHAT;
one before the last diversion cycle and
one at the end of the ETOPS test.
Issued in Burlington, Massachusetts, on
June 14, 2017.
Carlos A. Pestana,
Acting Assistant Manager, Engine and
Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 2017–13305 Filed 6–23–17; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 33
[Docket No. FAA–2017–0537; Notice No. 33–
17–02–SC]
Special Conditions: General Electric
Company, GE9X Engine Models;
Endurance Test Special Conditions
Federal Aviation
Administration (FAA), DOT.
ACTION: Notice of proposed special
conditions.
AGENCY:
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Federal Register / Vol. 82, No. 121 / Monday, June 26, 2017 / Proposed Rules
This action proposes special
conditions for the General Electric
turbofan engine models GE9X–105B1A,
–105B1A1, –105B1A2, –105B1A3,
–102B1A, –102B1A1, –102B1A2,
–102B1A3, and –93B1A. These engine
models will be referred to as ‘‘GE9X’’ in
these special conditions. The engines
will have a novel or unusual design
features associated with the engine
design. The applicable airworthiness
regulations do not contain adequate or
appropriate safety standards for this
design feature. These proposed 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: Send your comments on or
before August 10, 2017.
ADDRESSES: Send comments identified
by docket number FAA–2017–0537
using any of the following methods:
• Federal eRegulations Portal: Go to
https://www.regulations.gov and follow
the online instructions for sending your
comments electronically.
• Mail: Send comments to Docket
Operations, M–30, U.S. Department of
Transportation (DOT), 1200 New Jersey
Avenue SE., Room W12–140, West
Building Ground Floor, Washington,
DC, 20590–0001.
• Hand Delivery or Courier: Take
comments to Docket Operations in
Room W12–140 of the West Building
Ground Floor at 1200 New Jersey
Avenue SE., Washington, DC, between 9
a.m. and 5 p.m., Monday through
Friday, except Federal holidays.
• Fax: Fax comments to Docket
Operations at 202–493–2251.
Privacy: In accordance with 5 U.S.C.
553(c), DOT solicits comments from the
public to better inform its rulemaking
process. DOT posts these comments,
without edit, including any personal
information the commenter provides, to
www.regulations.gov, as described in
the system of records notice (DOT/ALL–
14 FDMS), which can be reviewed at
www.dot.gov/privacy.
Docket: Background documents or
comments received may be read at
https://www.regulations.gov at any time.
Follow the online instructions for
accessing the docket or go to the Docket
Operations in Room W12–140 of the
West Building Ground Floor at 1200
New Jersey Avenue SE., Washington,
DC, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT:
Dorina Mihail, ANE–111, Engine and
Propeller Directorate, Aircraft
Certification Service, 1200 District
Avenue, Burlington, Massachusetts,
sradovich on DSK3GMQ082PROD with PROPOSALS
SUMMARY:
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01803–5213; telephone (781) 238–7153;
facsimile (781) 238–7199; email
Dorina.Mihail@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite interested people to
participate in this rulemaking by
sending written comments, data, or
views. The agency also invites
comments relating to the economic,
environmental, energy, or federalism
impacts that might result from adopting
the proposals in this document. The
most helpful comments reference a
specific portion of the proposed special
conditions, explain the reason for any
recommended change, and include
supporting data. To ensure the docket
does not contain duplicate comments,
commenters should send only one copy
of written comments, or if comments are
filed electronically, commenters should
submit only one time.
We will file in the docket all
comments we receive, as well as a
report summarizing each substantive
public contact with FAA personnel
concerning this proposed rulemaking.
Before acting on this proposal, we will
consider all comments we receive on or
before the closing date for comments.
We will consider comments filed after
the comment period has closed if it is
possible to do so without incurring
expense or delay. We may change these
special conditions based on the
comments we receive.
Proprietary or Confidential Business
Information: Commenters should not
file proprietary or confidential business
information in the docket. Such
information must be sent or delivered
directly to the person identified in the
FOR FURTHER INFORMATION CONTACT
section of this document, and marked as
proprietary or confidential. If submitting
information on a disk or CD–ROM, mark
the outside of the disk or CD–ROM, and
identify electronically within the disk or
CD–ROM the specific information that
is proprietary or confidential.
Under 14 CFR 11.35(b), if the FAA is
aware of proprietary information filed
with a comment, the agency does not
place it in the docket. It is held in a
separate file to which the public does
not have access, and the FAA places a
note in the docket that it has received
it. If the FAA receives a request to
examine or copy this information, it
treats it as any other request under the
Freedom of Information Act (5 U.S.C.
552). The FAA processes such a request
under Department of Transportation
procedures found in 49 CFR part 7.
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Background
On January 29, 2016, General Electric
Company (GE) applied for type
certificate application for GE’s GE9X
turbofan engine models. The GE9X
engine models are high-bypass-ratio
engines that incorporate novel and
unusual design features. The GE9X
engine models incorporate new
technologies such that it cannot run the
endurance test conditions prescribed in
§ 33.87 without significant test-enabling
modifications, making the test vehicle
non-representative of the proposed type
design. An alternative endurance test
cycle has been developed that provides
a level of safety equivalent with that
intended by § 33.87. The proposed
alternate endurance test provides the
test conditions that allow the engine to
be run in type design configuration and
demonstrate engine operability and
durability as well as systems
functionality to a level intended by the
current § 33.87 rule.
Type Certification Basis
Under the provisions of Title 14, Code
of Federal Regulations (14 CFR) 21.17,
GE must show that the GE9X engine
models meet the applicable provisions
of part 33, as amended by Amendments
33–1 through 33–34.
If the FAA finds that the applicable
airworthiness regulations do not contain
adequate or appropriate safety standards
for the GE9X engine models because of
a novel or unusual design feature,
special conditions are prescribed under
the provisions of § 21.16.
Special conditions are initially
applicable to the engine model for
which they are issued. Should the type
certificate for that engine model be
amended later to include any other
engine models that incorporate the same
or similar novel or unusual design
features, the special conditions would
also apply to the other engine models
under § 21.101.
In addition to complying with the
applicable product airworthiness
regulations and special conditions, the
GE9X engine models must comply with
the fuel venting and exhaust emission
requirements of 14 CFR part 34.
The FAA issues special conditions, as
defined in 14 CFR 11.19, in accordance
with § 11.38, and they become part of
the type-certification basis under
§ 21.17(a)(2).
Novel or Unusual Design Features
The GE9X engine models will
incorporate the following novel or
unusual design features: Technological
advances that reduce noise and
emissions while improving fuel
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efficiency and increasing thrust, when
compared to previous similar
certificated GE engine models.
The GE9X series engine type design
incorporates new technologies such that
it cannot run the endurance test
conditions prescribed in § 33.87 without
significant test-enabling modifications,
making the test vehicle nonrepresentative of the proposed type
design. The modifications needed to run
the § 33.87 endurance test have become
increasingly complex over time, and
reconciling the test results to the
proposed type design has also become
increasingly difficult.
For past certifications, GE has shown
that the proposed engine design, as
modified, still represented the
durability and operating characteristics
of the intended type design but the
modifications needed to the GE9X
engine model to run the § 33.87
endurance test cannot be reconciled and
would affect the test outcome.
Discussion
These proposed special conditions
provide the necessary conditions for
verification of engine-level and
component-level effects as intended by
the current § 33.87 endurance test. The
special conditions include a
demonstration for the oil, fuel, air bleed,
and accessory drive systems as required
in the current § 33.87 endurance test.
The level of severity is provided by an
engine test demonstration at the gas
path limiting temperature and at shaft
speed redlines and at the most extreme
shaft speeds as determined through a
critical point analysis (CPA). In
addition, times on condition and cycle
counts were developed to allow
additional challenges to the new and
novel features that would not have been
as challenged by the current § 33.87 test
schedule. The alternate test
demonstrates no potential safety issue
will develop while operating in service.
The proposed cycles dwell time
duration reflect that GE9X does not have
a 10-minute OEI extension for the
takeoff rating.
The special conditions for § 33.4 and
§ 33.29 are added to support an
equivalent compliance by means of
mandatory inspections prescribed in
paragraph (b)(3) of the § 33.87 special
conditions.
These special condition requirements
maintain a level of safety equivalent to
the level intended by the applicable
airworthiness standards in effect on the
date of application.
Applicability
As discussed above, the proposed
special conditions are applicable to the
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GE9X engine model(s). Should GE apply
at a later date for a change to the type
certificate to include another model on
the same type certificate 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 GE9X
turbofan engine models. It is not a rule
of general applicability and applies only
to GE, who requested FAA approval of
this engine feature.
List of Subjects in 14 CFR Part 33
Aircraft, Engines, 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 Proposed Special Conditions
Accordingly, the FAA proposes the
following special conditions as part of
the type certification basis for the GE9X
engine models: GE9X–105B1A,
–105B1A1, –105B1A2, –105B1A3,
–102B1A, –102B1A1, –102B1A2,
–102B1A3, and –93B1A.
■
PART 33—REQUIREMENTS
§ 33.4 Instructions for Continued
Airworthiness.
(a) The Airworthiness Limitations
section must prescribe the mandatory
post-flight inspections and maintenance
actions associated with any exceedance
required by § 33.87, paragraph (b)(3), of
these special conditions.
§ 33.29
Instrument connection.
(a) The engine must have means, or
provisions for means, to automatically
record and alert maintenance personnel
for each occurrence of any exceedance
required by § 33.87 paragraph (b)(3), of
these special conditions.
§ 33.87
Endurance Test.
(a) General: The applicant must show
that the endurance test schedule in
combination with any prescribed
mandatory actions provide an
equivalent level of severity and
demonstration of durability and
operability as that intended by
§ 33.87(a) and (b) for a turbofan engine.
When showing that the level of
durability is equivalent with that
intended by the rule, the applicant must
consider the damage accumulated
during the test for the limiting damage
mechanisms for components and engine
systems, up to and including the
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applicable limitations declared in the
Type Certificate Data Sheets (TCDS).
The test cycle content must create
conditions in the engine for a sufficient
amount of time to demonstrate no
potential safety issue will develop from
the limiting damage mechanisms while
operating in service. The following
minimum requirements apply:
(1) The tests in paragraphs (b), (c), and
(d) of these special conditions, for total
cumulative and dwell time duration
between ground idle and the takeoff
thrust prescribed in these special
conditions. The test cycle durations
must include all maximums allowed in
the TCDS and expected service
operation.
(2) Requirements of § 33.87(a)(1), (2),
(4), and (6) applicable to turbofan
engines.
(3) Requirements of § 33.87(a)(3)
applicable to the temperature of external
surfaces of the engine, if limited.
(4) Testing for maximum air bleed
must be at least equal with the
prescribed test required in § 33.87(a)(5).
However, for these cycles, the thrust or
the rotor shaft rotational speed may be
less than 100 percent of the value
associated with the particular operation
being tested if the FAA finds that the
validity of the endurance test is not
compromised.
(5) Testing for engine fuel, oil, and
hydraulic fluid pressure and oil
temperature must be at least equal with
the prescribed test required in
§ 33.87(a)(7).
(6) If the number of occurrences of
either transient rotor shaft overspeed or
transient gas over temperature is not
limited, at least 155 accelerations must
be made at the limiting overspeed or
over temperature. If the number of
occurrences is limited, that number of
accelerations must be made at the
limiting overspeed or over temperature.
(7) One hundred starts must be made,
of which 25 starts must be preceded by
at least a two-hour engine shutdown.
There must be at least 10 false engine
starts, pausing for the applicant’s
specified minimum fuel drainage time,
before attempting a normal start. There
must be at least 10 normal restarts with
not longer than 15 minutes since engine
shutdown. The remaining starts may be
made after completing the endurance
testing prescribed by these special
conditions.
(8) Unless otherwise specified (i.e.
(d)(2)), for accelerations from ground
idle to takeoff, the throttle must be
moved in not more than one second,
except that, if different regimes of
control operations are incorporated
necessitating scheduling of the thrustcontrol lever motion in going from one
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extreme position to the other, a longer
period of time is acceptable, but not
more than two seconds.
(i) When operating with max oil
temperatures the throttle movement
may be ‘stair-stepped’ to allow for oil
temperature stabilization for durations
greater than two seconds.
(9) The applicant must validate any
analytical methods used for compliance
with these special conditions.
Validation includes the ability to
accurately predict an outcome
applicable to the engine being tested.
(10) The applicant must perform the
endurance test on an engine that
substantially conforms to its type
design. Modifications may be made as
needed to achieve test conditions and/
or engine operating conditions
representative of the type design.
(b) Conduct the endurance test at or
above the declared shaft speeds and gas
temperatures limits, and at or above
conditions representative of critical
points (speeds, temperatures, rated
thrust) in the operating envelope.
(1) Conduct the endurance test at or
above the rated takeoff thrust and rated
maximum continuous thrust and with
the associated limits for rotor speeds
and gas temperature (redlines), as
follows:
(i) Either rotor speed or gas
temperature, or concurrent rotor speed
and gas temperature if analysis indicates
a combination of redline operational
conditions is possible to occur in
service, must be at least 100 percent of
the values associated with the engine
rating being tested.
(ii) The cumulative test time duration
and number of cycles must be
representative of the rotor speed and gas
temperature excursions to redlines that
can be expected to occur in between
overhauls.
(iii) The time durations for each
takeoff or maximum continuous
segment must include all maximums
allowed in the TCDS and expected
service operation and must include the
following cycles:
(A) At least one (1) takeoff cycle of 5
minutes time duration at the low
pressure rotor speed limit and gas
temperature limit (redlines).
(B) At least one (1) takeoff cycle of 5
minutes time duration at the high
pressure rotor speed limit and gas
temperature limit (redlines).
(C) In lieu of the separate cycles
specified in paragraphs (A) and (B) of
this section, the applicant may run the
low pressure and high pressure rotor
speeds and gas temperature limits
(redlines) in the same cycle. However in
this case, the applicant must run at least
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2 cycles of 5 minutes time duration
each.
(2) Conduct the endurance test at or
above the rated takeoff thrust and the
rated maximum continuous thrust with
rotor speeds at or above those
determined by a critical point analysis
(CPA) and with gas temperature redline
conditions as follows:
(i) The applicant must determine
through a CPA the highest rotor shaft
rotational speeds (CPA speeds) expected
to occur for each rotor shaft system
within the declared operating envelope.
The CPA must be conducted for the
takeoff and maximum continuous rated
thrust and must consider the declared
operating envelope, engine
deterioration, engine-to-engine
variability, and any other applicable
variables that can cause the engine to
operate at the extremes of its
performance ratings.
(ii) Except as provided in paragraph
(b)(3)(ii) of these special conditions,
conduct a cyclic test between ground
idle and combined takeoff and
maximum continuous thrust ratings, as
follows:
(A) Eighteen hours and forty five
minutes (18.75 hours) cumulated time
duration at or above the rated takeoff
thrust, the gas temperature limit for
takeoff (redline), and the CPA rotor
speeds for takeoff determined per
paragraph (b)(2)(i) of these special
conditions.
(B) Forty five (45) hours cumulated
time duration at or above the rated
maximum continuous thrust, the gas
temperature limit for maximum
continuous (redline), and the CPA rotor
speeds for maximum continuous
determined per paragraph (b)(2)(i) of
these special conditions.
(C) The time durations for each
takeoff or maximum continuous
segments must include all maximums
allowed in the TCDS and expected
service operation, and must include at
least one maximum continuous cycle of
30 minutes run continuously.
(3) If the cyclic shaft speed excursions
specified in paragraphs (b)(1) or (b)(2) of
these special conditions cannot be
demonstrated in the test, then an
alternative equivalent with the rule
intent must be provided. Alternatives
may include alternate means of test
demonstration, mandatory actions, or
other means found acceptable to the
FAA. The applicant must prescribe a
mandatory action plan for engine
operation between the shaft speeds
demonstrated for a minimum of
cumulated 18.75 hours at or above rated
takeoff and 45 hours at or above rated
maximum continuous, respectively, and
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28793
the declared speed limits (redlines), as
follows:
(i) Prescribe post-event actions or
operating limitations acceptable to the
FAA for operation below the declared
speed limits (redlines) and above the
CPA speeds.
(ii) If the test required by (b)(2)(ii) of
these special conditions can only be
accomplished at a rotor shaft speed
lower than the CPA speed, prescribe
post-event actions or operating
limitations acceptable to the FAA for
operation below that CPA speed and
above the value demonstrated during
the test.
(c) Conduct the endurance test at the
incremental cruise thrust that must be at
least equal with the prescribed test
required in § 33.87(b)(4). The 25
incremental test cycles must be
uniformly distributed throughout the
entire endurance test.
(d) Conduct at least 300 cycles
between ground idle and combined
takeoff and maximum continuous
thrust, as follows:
(1) Each cycle to include acceleration
to or above rated takeoff thrust,
deceleration from takeoff to ground idle,
followed by 5 to 15 seconds at ground
idle, acceleration to or above rated
maximum continuous thrust, and
deceleration to ground idle.
(2) The throttle movement from
ground idle to rated takeoff or maximum
continuous thrust and from rated takeoff
thrust to ground idle should be not more
than one (1) second, except that, if
different regimes of control operations
are incorporated necessitating
scheduling of the thrust-control lever
motion in going from one extreme
position to the other, a longer period of
time is acceptable, but not more than
two seconds. The throttle move from
rated maximum continuous thrust to
ground idle should not be more than
five (5) seconds.
(3) The time durations for each cycle
associated with either takeoff or
maximum continuous thrust segments
must include all maximums allowed in
the TCDS and expected service
operation, and must include the
following cycles:
(i) Three (3) cycles of 5 minutes each
and one (1) cycle of 10 minutes at the
takeoff thrust.
(ii) Three (3) cycles of 30 minutes
each at the maximum continuous thrust.
Issued in Burlington, Massachusetts, on
June 1, 2017.
Carlos A. Pestana,
Acting Assistant Manager, Engine and
Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 2017–13210 Filed 6–23–17; 8:45 am]
BILLING CODE 4910–13–P
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]]>Agencies
[Federal Register Volume 82, Number 121 (Monday, June 26, 2017)]
[Proposed Rules]
[Pages 28790-28793]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-13210]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 33
[Docket No. FAA-2017-0537; Notice No. 33-17-02-SC]
Special Conditions: General Electric Company, GE9X Engine Models;
Endurance Test Special Conditions
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This action proposes special conditions for the General
Electric turbofan engine models GE9X-105B1A, -105B1A1, -105B1A2, -
105B1A3, -102B1A, -102B1A1, -102B1A2, -102B1A3, and -93B1A. These
engine models will be referred to as ``GE9X'' in these special
conditions. The engines will have a novel or unusual design features
associated with the engine design. The applicable airworthiness
regulations do not contain adequate or appropriate safety standards for
this design feature. These proposed 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: Send your comments on or before August 10, 2017.
ADDRESSES: Send comments identified by docket number FAA-2017-0537
using any of the following methods:
Federal eRegulations Portal: Go to https://www.regulations.gov and follow the online instructions for sending your
comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room
W12-140, West Building Ground Floor, Washington, DC, 20590-0001.
Hand Delivery or Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: In accordance with 5 U.S.C. 553(c), DOT solicits comments
from the public to better inform its rulemaking process. DOT posts
these comments, without edit, including any personal information the
commenter provides, to www.regulations.gov, as described in the system
of records notice (DOT/ALL-14 FDMS), which can be reviewed at
www.dot.gov/privacy.
Docket: Background documents or comments received may be read at
https://www.regulations.gov at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE.,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Dorina Mihail, ANE-111, Engine and
Propeller Directorate, Aircraft Certification Service, 1200 District
Avenue, Burlington, Massachusetts, 01803-5213; telephone (781) 238-
7153; facsimile (781) 238-7199; email Dorina.Mihail@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite interested people to participate in this rulemaking by
sending written comments, data, or views. The agency also invites
comments relating to the economic, environmental, energy, or federalism
impacts that might result from adopting the proposals in this document.
The most helpful comments reference a specific portion of the proposed
special conditions, explain the reason for any recommended change, and
include supporting data. To ensure the docket does not contain
duplicate comments, commenters should send only one copy of written
comments, or if comments are filed electronically, commenters should
submit only one time.
We will file in the docket all comments we receive, as well as a
report summarizing each substantive public contact with FAA personnel
concerning this proposed rulemaking. Before acting on this proposal, we
will consider all comments we receive on or before the closing date for
comments. We will consider comments filed after the comment period has
closed if it is possible to do so without incurring expense or delay.
We may change these special conditions based on the comments we
receive.
Proprietary or Confidential Business Information: Commenters should
not file proprietary or confidential business information in the
docket. Such information must be sent or delivered directly to the
person identified in the FOR FURTHER INFORMATION CONTACT section of
this document, and marked as proprietary or confidential. If submitting
information on a disk or CD-ROM, mark the outside of the disk or CD-
ROM, and identify electronically within the disk or CD-ROM the specific
information that is proprietary or confidential.
Under 14 CFR 11.35(b), if the FAA is aware of proprietary
information filed with a comment, the agency does not place it in the
docket. It is held in a separate file to which the public does not have
access, and the FAA places a note in the docket that it has received
it. If the FAA receives a request to examine or copy this information,
it treats it as any other request under the Freedom of Information Act
(5 U.S.C. 552). The FAA processes such a request under Department of
Transportation procedures found in 49 CFR part 7.
Background
On January 29, 2016, General Electric Company (GE) applied for type
certificate application for GE's GE9X turbofan engine models. The GE9X
engine models are high-bypass-ratio engines that incorporate novel and
unusual design features. The GE9X engine models incorporate new
technologies such that it cannot run the endurance test conditions
prescribed in Sec. 33.87 without significant test-enabling
modifications, making the test vehicle non-representative of the
proposed type design. An alternative endurance test cycle has been
developed that provides a level of safety equivalent with that intended
by Sec. 33.87. The proposed alternate endurance test provides the test
conditions that allow the engine to be run in type design configuration
and demonstrate engine operability and durability as well as systems
functionality to a level intended by the current Sec. 33.87 rule.
Type Certification Basis
Under the provisions of Title 14, Code of Federal Regulations (14
CFR) 21.17, GE must show that the GE9X engine models meet the
applicable provisions of part 33, as amended by Amendments 33-1 through
33-34.
If the FAA finds that the applicable airworthiness regulations do
not contain adequate or appropriate safety standards for the GE9X
engine models because of a novel or unusual design feature, special
conditions are prescribed under the provisions of Sec. 21.16.
Special conditions are initially applicable to the engine model for
which they are issued. Should the type certificate for that engine
model be amended later to include any other engine models that
incorporate the same or similar novel or unusual design features, the
special conditions would also apply to the other engine models under
Sec. 21.101.
In addition to complying with the applicable product airworthiness
regulations and special conditions, the GE9X engine models must comply
with the fuel venting and exhaust emission requirements of 14 CFR part
34.
The FAA issues special conditions, as defined in 14 CFR 11.19, in
accordance with Sec. 11.38, and they become part of the type-
certification basis under Sec. 21.17(a)(2).
Novel or Unusual Design Features
The GE9X engine models will incorporate the following novel or
unusual design features: Technological advances that reduce noise and
emissions while improving fuel
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efficiency and increasing thrust, when compared to previous similar
certificated GE engine models.
The GE9X series engine type design incorporates new technologies
such that it cannot run the endurance test conditions prescribed in
Sec. 33.87 without significant test-enabling modifications, making the
test vehicle non-representative of the proposed type design. The
modifications needed to run the Sec. 33.87 endurance test have become
increasingly complex over time, and reconciling the test results to the
proposed type design has also become increasingly difficult.
For past certifications, GE has shown that the proposed engine
design, as modified, still represented the durability and operating
characteristics of the intended type design but the modifications
needed to the GE9X engine model to run the Sec. 33.87 endurance test
cannot be reconciled and would affect the test outcome.
Discussion
These proposed special conditions provide the necessary conditions
for verification of engine-level and component-level effects as
intended by the current Sec. 33.87 endurance test. The special
conditions include a demonstration for the oil, fuel, air bleed, and
accessory drive systems as required in the current Sec. 33.87
endurance test.
The level of severity is provided by an engine test demonstration
at the gas path limiting temperature and at shaft speed redlines and at
the most extreme shaft speeds as determined through a critical point
analysis (CPA). In addition, times on condition and cycle counts were
developed to allow additional challenges to the new and novel features
that would not have been as challenged by the current Sec. 33.87 test
schedule. The alternate test demonstrates no potential safety issue
will develop while operating in service.
The proposed cycles dwell time duration reflect that GE9X does not
have a 10-minute OEI extension for the takeoff rating.
The special conditions for Sec. 33.4 and Sec. 33.29 are added to
support an equivalent compliance by means of mandatory inspections
prescribed in paragraph (b)(3) of the Sec. 33.87 special conditions.
These special condition requirements maintain a level of safety
equivalent to the level intended by the applicable airworthiness
standards in effect on the date of application.
Applicability
As discussed above, the proposed special conditions are applicable
to the GE9X engine model(s). Should GE apply at a later date for a
change to the type certificate to include another model on the same
type certificate 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 GE9X turbofan engine models. It is not a rule of general
applicability and applies only to GE, who requested FAA approval of
this engine feature.
List of Subjects in 14 CFR Part 33
Aircraft, Engines, 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 Proposed Special Conditions
0
Accordingly, the FAA proposes the following special conditions as part
of the type certification basis for the GE9X engine models: GE9X-
105B1A, -105B1A1, -105B1A2, -105B1A3, -102B1A, -102B1A1, -102B1A2, -
102B1A3, and -93B1A.
PART 33--REQUIREMENTS
Sec. 33.4 Instructions for Continued Airworthiness.
(a) The Airworthiness Limitations section must prescribe the
mandatory post-flight inspections and maintenance actions associated
with any exceedance required by Sec. 33.87, paragraph (b)(3), of these
special conditions.
Sec. 33.29 Instrument connection.
(a) The engine must have means, or provisions for means, to
automatically record and alert maintenance personnel for each
occurrence of any exceedance required by Sec. 33.87 paragraph (b)(3),
of these special conditions.
Sec. 33.87 Endurance Test.
(a) General: The applicant must show that the endurance test
schedule in combination with any prescribed mandatory actions provide
an equivalent level of severity and demonstration of durability and
operability as that intended by Sec. 33.87(a) and (b) for a turbofan
engine. When showing that the level of durability is equivalent with
that intended by the rule, the applicant must consider the damage
accumulated during the test for the limiting damage mechanisms for
components and engine systems, up to and including the applicable
limitations declared in the Type Certificate Data Sheets (TCDS). The
test cycle content must create conditions in the engine for a
sufficient amount of time to demonstrate no potential safety issue will
develop from the limiting damage mechanisms while operating in service.
The following minimum requirements apply:
(1) The tests in paragraphs (b), (c), and (d) of these special
conditions, for total cumulative and dwell time duration between ground
idle and the takeoff thrust prescribed in these special conditions. The
test cycle durations must include all maximums allowed in the TCDS and
expected service operation.
(2) Requirements of Sec. 33.87(a)(1), (2), (4), and (6) applicable
to turbofan engines.
(3) Requirements of Sec. 33.87(a)(3) applicable to the temperature
of external surfaces of the engine, if limited.
(4) Testing for maximum air bleed must be at least equal with the
prescribed test required in Sec. 33.87(a)(5). However, for these
cycles, the thrust or the rotor shaft rotational speed may be less than
100 percent of the value associated with the particular operation being
tested if the FAA finds that the validity of the endurance test is not
compromised.
(5) Testing for engine fuel, oil, and hydraulic fluid pressure and
oil temperature must be at least equal with the prescribed test
required in Sec. 33.87(a)(7).
(6) If the number of occurrences of either transient rotor shaft
overspeed or transient gas over temperature is not limited, at least
155 accelerations must be made at the limiting overspeed or over
temperature. If the number of occurrences is limited, that number of
accelerations must be made at the limiting overspeed or over
temperature.
(7) One hundred starts must be made, of which 25 starts must be
preceded by at least a two-hour engine shutdown. There must be at least
10 false engine starts, pausing for the applicant's specified minimum
fuel drainage time, before attempting a normal start. There must be at
least 10 normal restarts with not longer than 15 minutes since engine
shutdown. The remaining starts may be made after completing the
endurance testing prescribed by these special conditions.
(8) Unless otherwise specified (i.e. (d)(2)), for accelerations
from ground idle to takeoff, the throttle must be moved in not more
than one second, except that, if different regimes of control
operations are incorporated necessitating scheduling of the thrust-
control lever motion in going from one
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extreme position to the other, a longer period of time is acceptable,
but not more than two seconds.
(i) When operating with max oil temperatures the throttle movement
may be `stair-stepped' to allow for oil temperature stabilization for
durations greater than two seconds.
(9) The applicant must validate any analytical methods used for
compliance with these special conditions. Validation includes the
ability to accurately predict an outcome applicable to the engine being
tested.
(10) The applicant must perform the endurance test on an engine
that substantially conforms to its type design. Modifications may be
made as needed to achieve test conditions and/or engine operating
conditions representative of the type design.
(b) Conduct the endurance test at or above the declared shaft
speeds and gas temperatures limits, and at or above conditions
representative of critical points (speeds, temperatures, rated thrust)
in the operating envelope.
(1) Conduct the endurance test at or above the rated takeoff thrust
and rated maximum continuous thrust and with the associated limits for
rotor speeds and gas temperature (redlines), as follows:
(i) Either rotor speed or gas temperature, or concurrent rotor
speed and gas temperature if analysis indicates a combination of
redline operational conditions is possible to occur in service, must be
at least 100 percent of the values associated with the engine rating
being tested.
(ii) The cumulative test time duration and number of cycles must be
representative of the rotor speed and gas temperature excursions to
redlines that can be expected to occur in between overhauls.
(iii) The time durations for each takeoff or maximum continuous
segment must include all maximums allowed in the TCDS and expected
service operation and must include the following cycles:
(A) At least one (1) takeoff cycle of 5 minutes time duration at
the low pressure rotor speed limit and gas temperature limit
(redlines).
(B) At least one (1) takeoff cycle of 5 minutes time duration at
the high pressure rotor speed limit and gas temperature limit
(redlines).
(C) In lieu of the separate cycles specified in paragraphs (A) and
(B) of this section, the applicant may run the low pressure and high
pressure rotor speeds and gas temperature limits (redlines) in the same
cycle. However in this case, the applicant must run at least 2 cycles
of 5 minutes time duration each.
(2) Conduct the endurance test at or above the rated takeoff thrust
and the rated maximum continuous thrust with rotor speeds at or above
those determined by a critical point analysis (CPA) and with gas
temperature redline conditions as follows:
(i) The applicant must determine through a CPA the highest rotor
shaft rotational speeds (CPA speeds) expected to occur for each rotor
shaft system within the declared operating envelope. The CPA must be
conducted for the takeoff and maximum continuous rated thrust and must
consider the declared operating envelope, engine deterioration, engine-
to-engine variability, and any other applicable variables that can
cause the engine to operate at the extremes of its performance ratings.
(ii) Except as provided in paragraph (b)(3)(ii) of these special
conditions, conduct a cyclic test between ground idle and combined
takeoff and maximum continuous thrust ratings, as follows:
(A) Eighteen hours and forty five minutes (18.75 hours) cumulated
time duration at or above the rated takeoff thrust, the gas temperature
limit for takeoff (redline), and the CPA rotor speeds for takeoff
determined per paragraph (b)(2)(i) of these special conditions.
(B) Forty five (45) hours cumulated time duration at or above the
rated maximum continuous thrust, the gas temperature limit for maximum
continuous (redline), and the CPA rotor speeds for maximum continuous
determined per paragraph (b)(2)(i) of these special conditions.
(C) The time durations for each takeoff or maximum continuous
segments must include all maximums allowed in the TCDS and expected
service operation, and must include at least one maximum continuous
cycle of 30 minutes run continuously.
(3) If the cyclic shaft speed excursions specified in paragraphs
(b)(1) or (b)(2) of these special conditions cannot be demonstrated in
the test, then an alternative equivalent with the rule intent must be
provided. Alternatives may include alternate means of test
demonstration, mandatory actions, or other means found acceptable to
the FAA. The applicant must prescribe a mandatory action plan for
engine operation between the shaft speeds demonstrated for a minimum of
cumulated 18.75 hours at or above rated takeoff and 45 hours at or
above rated maximum continuous, respectively, and the declared speed
limits (redlines), as follows:
(i) Prescribe post-event actions or operating limitations
acceptable to the FAA for operation below the declared speed limits
(redlines) and above the CPA speeds.
(ii) If the test required by (b)(2)(ii) of these special conditions
can only be accomplished at a rotor shaft speed lower than the CPA
speed, prescribe post-event actions or operating limitations acceptable
to the FAA for operation below that CPA speed and above the value
demonstrated during the test.
(c) Conduct the endurance test at the incremental cruise thrust
that must be at least equal with the prescribed test required in Sec.
33.87(b)(4). The 25 incremental test cycles must be uniformly
distributed throughout the entire endurance test.
(d) Conduct at least 300 cycles between ground idle and combined
takeoff and maximum continuous thrust, as follows:
(1) Each cycle to include acceleration to or above rated takeoff
thrust, deceleration from takeoff to ground idle, followed by 5 to 15
seconds at ground idle, acceleration to or above rated maximum
continuous thrust, and deceleration to ground idle.
(2) The throttle movement from ground idle to rated takeoff or
maximum continuous thrust and from rated takeoff thrust to ground idle
should be not more than one (1) second, except that, if different
regimes of control operations are incorporated necessitating scheduling
of the thrust-control lever motion in going from one extreme position
to the other, a longer period of time is acceptable, but not more than
two seconds. The throttle move from rated maximum continuous thrust to
ground idle should not be more than five (5) seconds.
(3) The time durations for each cycle associated with either
takeoff or maximum continuous thrust segments must include all maximums
allowed in the TCDS and expected service operation, and must include
the following cycles:
(i) Three (3) cycles of 5 minutes each and one (1) cycle of 10
minutes at the takeoff thrust.
(ii) Three (3) cycles of 30 minutes each at the maximum continuous
thrust.
Issued in Burlington, Massachusetts, on June 1, 2017.
Carlos A. Pestana,
Acting Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 2017-13210 Filed 6-23-17; 8:45 am]
BILLING CODE 4910-13-P
