Document ID: FAA-2014-0376-0003
Agency: faa
Document Type: Rule
Title: Special Conditions: SNECMA, Silvercrest-2 SC-2D; Rated 10-Minute One Engine Inoperative Takeoff Thrust at High Ambient Temperature
Posted Date: 2014-10-31T04:00Z

[Federal Register Volume 79, Number 211 (Friday, October 31, 2014)]
[Rules and Regulations]
[Pages 64666-64669]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-25884]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. FAA-2014-0376; Notice No. 33-014-SC]

Special Conditions: SNECMA, Silvercrest-2 SC-2D; Rated 10-Minute 
One Engine Inoperative Takeoff Thrust at High Ambient Temperature

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These final special conditions are issued for the SNECMA, 
Silvercrest-2 SC-2D engine model. This engine will have a novel or 
unusual design feature--an additional takeoff rating that increases the 
exhaust gas temperature (EGT) limit to maintain takeoff thrust in 
certain high ambient temperature conditions with one engine inoperative 
(OEI) for a maximum of 10 minutes. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature. These final 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: The effective date of these special conditions is December 1, 
2014.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this rule, contact Tara Fitzgerald, ANE-111, Engine and Propeller 
Directorate, Aircraft Certification Service, 12 New England Executive 
Park, Burlington, Massachusetts 01803-5213; telephone (781) 238-7130; 
facsimile (781) 238-7199; email tara.fitzgerald@faa.gov. For legal 
questions concerning this rule, contact Vincent Bennett, ANE-7, Engine 
and Propeller Directorate, Aircraft Certification Service, 12 New 
England Executive Park, Burlington, Massachusetts 01803-5299; telephone 
(781) 238-7044; facsimile (781) 238-7055; email 
vincent.bennett@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

    On April 19, 2011, SNECMA applied for a new type certificate (TC) 
for the Silvercrest-2 SC-2D engine model. For

[[Page 64667]]

their Silvercrest-2 SC-2D engine model, SNECMA requested an additional 
takeoff rating to maintain takeoff thrust in certain high ambient 
temperature conditions with OEI. Therefore, the Silvercrest-2 SC-2D 
engine model will have two different takeoff ratings. The first rating 
corresponds with the rated takeoff thrust of the engine. The second 
takeoff rating maintains the takeoff thrust in certain high ambient 
temperature conditions for a maximum of 10 minutes when one engine is 
inoperative. This additional takeoff rating is named, ``Rated 10-Minute 
OEI Takeoff Thrust at High Ambient Temperature'' (Rated 10-minute OEI 
TOTHAT).
    These final special conditions are necessary because current part 
33 regulations do not contain airworthiness standards for airplane 
applications of OEI ratings. For an airplane application, the OEI 
rating is the same as the rated thrust of the engine. All OEI ratings 
in current part 33 regulations are only applicable to rotorcraft 
applications. These final special conditions were modeled based on the 
rotorcraft requirements for the 30-second and 2-minute OEI ratings, and 
modified to represent the airplane application. The Rated 10-minute OEI 
TOTHAT shares common features, such as the need to notify the pilot and 
maintenance personnel about the rating's use, provides data needed for 
power assurance check, and continued validation of the related 
maintenance procedures.
    The Rated 10-minute OEI TOTHAT is for use during OEI events that 
occur during takeoff in high ambient temperature conditions, up to 5 
degrees Celsius hotter than the rated takeoff thrust corner point. 
Under these unique conditions (extreme hot day and OEI), the Rated 10-
minute OEI TOTHAT leads to an increase in EGT to maintain the takeoff 
thrust of the engine. These final special conditions contain additional 
mandatory post-flight inspection and maintenance action requirements 
associated with any use of the Rated 10-minute OEI TOTHAT. These 
requirements add a rating definition in part 1.1; mandatory inspections 
in the ICA; instructions for installing and operating the engine; 
engine rating and operating limitations; instrument connection; and 
endurance testing.
    The current requirements of the endurance test under Sec.  33.87 
represent a typical airplane flight profile and the severity of the 
takeoff rating. Therefore, the endurance test under Sec.  33.87 covers 
normal, all-engines-operating takeoff conditions for which the engine 
control system limits the engine to the takeoff thrust rating. These 
final special conditions for the endurance testing requirements are 
intended to represent the airplane flight profile when an OEI event 
occurs during takeoff under specified ambient temperatures, and until 
the mandatory inspection and maintenance actions can be performed. 
These final special conditions require endurance testing that is not 
less than 135 minutes in duration and demonstrates the engine is 
capable of the additional Rated 10-minute OEI TOTHAT rating at the 
higher EGT limit following completion of the tests required by Sec.  
33.87(b), without disassembly or modification.
    The associated engine deterioration after use of the Rated 10-
minute OEI TOTHAT is not known without the intervening mandatory 
inspections in these special conditions. The mandatory inspections 
ensure the engine will continue to comply with its certification basis 
after any use of the Rated 10-minute OEI TOTHAT. The applicant is 
expected to assess the deterioration from use of the Rated 10-minute 
OEI TOTHAT. The Airworthiness Limitations section must prescribe the 
mandatory post-flight inspections and maintenance actions associated 
with any use of the Rated 10-minute OEI TOTHAT.
    These special conditions are necessary because the applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for the additional takeoff rating, and their requirements 
maintain a level of safety equivalent to the level intended by the 
applicable airworthiness standards in effect on the date of 
application.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.17, SNECMA must show that the Silvercrest-2 SC-2D meets the 
applicable provisions of the applicable regulations in effect on the 
date of application, except as detailed in paragraphs 21.101(b) and 
(c). The FAA has determined the following certification basis for the 
Silvercrest-2 SC-2D engine model:
    1. 14 CFR part 33, ``Airworthiness Standards Aircraft Engines,'' 
dated February 1, 1965, with Amendments 33-1 through 33-31, dated July 
18, 2011.
    If the FAA finds that the regulations in effect on the date of the 
application for the change do not provide adequate or appropriate 
safety standards for the Silvercrest-2 SC-2D 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 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, these special conditions would also 
apply to the other model under Sec.  21.101.
    In addition to complying with the applicable product airworthiness 
regulations and the requirements of these special conditions, the 
Silvercrest-2 SC-2D engine model must also 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, per 
Sec.  11.38, and they become part of the type certification basis under 
Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The SNECMA Silvercrest-2 SC-2D engine model will incorporate an 
additional takeoff rating to maintain takeoff thrust in certain high 
ambient temperature OEI takeoff conditions for a maximum of 10 minutes. 
The result will be two different takeoff ratings, one for the rated 
takeoff thrust of the engine and the other to maintain the takeoff 
thrust in certain high ambient temperature OEI takeoff conditions for a 
maximum of 10 minutes. The additional takeoff rating is referred to as 
``Rated 10-Minute OEI Takeoff Thrust at High Ambient Temperature'' 
(Rated 10-minute OEI TOTHAT).
    The Rated 10-minute OEI TOTHAT is a novel and unusual design 
feature that requires additional airworthiness standards for type 
certification of the SNECMA Silvercrest-2 SC-2D engine model.

Discussion of Comments

    A notice of proposed special conditions, No. 33-14-01-SC, for the 
Silvercrest-2 SC-2D engine model was published in the Federal Register 
on July 31, 2014 (79 FR 44321). We did not receive any public comments. 
We did, however, modify the proposed special conditions by removing 
requirement (b) under ``Sec.  33.28, Engine control systems.'' These 
requirements are addressed at the aircraft level.

Applicability

    As discussed above, these special conditions are applicable to the 
Silvercrest-2 SC-2D engine model. Should SNECMA apply at a later date 
for a change to the type certificate to include another engine model 
incorporating the same novel or unusual

[[Page 64668]]

design feature, these special conditions would apply to that model as 
well.

Conclusion

    We reviewed the available data and determined that air safety and 
the public interest require adopting these special conditions. This 
action affects only the Rated 10-minute OEI TOTHAT features on the 
Silvercrest-2 SC-2D engine model. It is not a rule of general 
applicability and applies only to SNECMA, who requested FAA approval of 
this engine feature.

List of Subjects in 14 CFR Part 33

    Air Transportation, Aircraft, Aviation, Aviation safety, Safety.

    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 the SNECMA Silvercrest-2 SC-2D engine 
model.

1. Part 1.1, Definitions

    ``Rated 10-Minute One Engine Inoperative Takeoff Thrust at High 
Ambient Temperature'' (Rated 10-minute OEI TOTHAT) means the approved 
engine thrust developed under specified altitudes and temperatures 
within the operating limitations established for the engine, and for 
continuation of flight operation after failure or shutdown of one 
engine in a multi-engine airplane during takeoff operation. Use is 
limited to two periods, no longer than 10 minutes each in any one 
flight, and followed by mandatory inspection and maintenance actions.

2. Part 33 Requirements

    In addition to the airworthiness standards in 14 CFR part 33, 
effective February 1, 1965, Amendments 33-1 through 33-31 applicable to 
the engine and the Rated 10-minute OEI TOTHAT, the following special 
conditions apply:

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 use of the Rated 10-minute OEI TOTHAT.
    (b) The applicant must validate the adequacy of the inspections and 
maintenance actions required under paragraph Sec.  33.4(a) of these 
special conditions.
    (c) The applicant must establish an in-service engine evaluation 
program to ensure the continued adequacy of the instructions for 
mandatory post-flight inspections and maintenance actions prescribed 
under paragraph Sec.  33.4(a) of these special conditions, and of the 
data for thrust assurance procedures required by Sec.  33.5(b)(1) of 
these special conditions. The program must include service engine tests 
or equivalent service engine test experience on engines of similar 
design and evaluations of service use of the Rated 10-minute OEI 
TOTHAT.

Sec.  33.5  Instruction manual for installing and operating the engine.

    (a) Installation instructions:
    (1) The applicant must identify the means, or provisions for means, 
provided in compliance with the requirements of Sec.  33.29 of these 
special conditions.
    (2) The applicant must specify that the engine thrust control 
system automatically resets the thrust on the operating engine to the 
Rated 10-minute OEI TOTHAT level when one engine fails during takeoff 
at specified altitudes and temperatures, and that the Rated 10-minute 
OEI TOTHAT is not available when all engines are operational.
    (b) Operating instructions:
    (1) The applicant must provide data on engine performance 
characteristics and variability to enable the airplane manufacturer to 
establish airplane thrust assurance procedures.

Sec.  33.7  Engine ratings and operating limitations.

    (a) The Rated 10-minute OEI TOTHAT and the associated operating 
limitations are established as follows:
    (1) The thrust is the same as the engine takeoff rated thrust with 
extended flat rating corner point,
    (2) The rotational speed limits are the same as those associated 
with the engine takeoff rated thrust,
    (3) The applicant must establish a gas temperature steady-state 
limit and, if necessary, a transient gas overtemperature limit for 
which the time duration is no longer than 30 seconds, and
    (4) The use is limited to two periods of no longer than 10 minutes 
each in any one flight, and followed by mandatory inspection and 
maintenance actions prescribed by Sec.  33.4(a) of these special 
conditions.
    (b) The applicant must propose language to include in the type 
certificate data sheet specified in Sec.  21.41 for the following:
    (1) The Rated 10-minute OEI TOTHAT and associated limitations.
    (2) As required by Sec.  33.5(b), Operating instructions, include a 
note stating that ``Rated 10-Minute One Engine Inoperative Takeoff 
Thrust at High Ambient Temperature'' (Rated 10-minute OEI TOTHAT) means 
the approved engine thrust developed under specified altitudes and 
temperatures within the operating limitations established for the 
engine, and for continuation of flight operation after failure or 
shutdown of one engine in a multi-engine airplane during takeoff 
operation. Use is limited to two periods, no longer than 10 minutes 
each in any one flight, and followed by mandatory inspection and 
maintenance actions.
    (3) As required by Sec.  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 10-minute OEI TOTHAT 
level when one engine fails during takeoff at specified altitudes and 
temperatures, and that the Rated 10-minute OEI TOTHAT is not available 
when all engines are operational.

Sec.  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 10-minute 
OEI TOTHAT.

Sec.  33.29  Instrument connection.

    (a) The engine must:
    (1) Have means, or provisions for means, to alert the pilot when 
the Rated 10-minute OEI 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 10-
minute OEI TOTHAT, and
    (ii) Alert maintenance personnel that the engine has been operated 
at the Rated 10-minute OEI TOTHAT, and permit retrieval of recorded 
data.
    (iii) Have means, or provision for means, to enable routine 
verification of the proper operation of the means in Sec.  33.29(a)(1) 
and (a)(2) of these special conditions.

Sec.  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 Sec.  33.87 of these special 
conditions.

Sec.  33.87  Endurance test.

    (a) Following completion of the tests required by Sec.  33.87(b), 
and without intervening disassembly, except as needed to replace those 
parts described as consumables in the ICA, the

[[Page 64669]]

applicant must conduct the following test sequence for a total time of 
not less than 135 minutes:
    (1) Ten minutes at Rated 10-minute OEI TOTHAT,
    (2) Sixty-five minutes at rated maximum continuous thrust,
    (3) One minute at 50 percent of rated takeoff thrust,
    (4) Ten minutes at Rated 10-minute OEI TOTHAT,
    (5) One minute at flight idle,
    (6) Ten minutes at Rated 10-minute OEI TOTHAT,
    (7) Five minutes at rated maximum continuous thrust,
    (8) One minute at 50 percent of rated takeoff thrust,
    (9) Five minutes at Rated 10-minute OEI TOTHAT,
    (10) One minute at flight idle,
    (11) Ten minutes at Rated 10-minute OEI TOTHAT,
    (12) Five minutes at rated maximum continuous thrust,
    (13) One minute at 50 percent of rated takeoff thrust,
    (14) Nine minutes at Rated 10-minute OEI TOTHAT, and
    (15) One minute at flight idle
    (b) The test sequence of Sec.  33.87(a)(1) through (a)(15) 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.
    (c) Where the engine characteristics are such that acceleration to 
the Rated 10-minute OEI TOTHAT results in a transient overtemperature 
in excess of the steady-state temperature limit identified in Sec.  
33.7(a)(3) of these special conditions, the transient gas 
overtemperature must be applied to each acceleration to the Rated 10-
minute OEI TOTHAT of the test sequence in Sec.  33.87(a) of these 
special conditions.

Sec.  33.93  Teardown inspection.

    The applicant must perform the teardown inspection required by 
Sec.  33.93(a) after completing the endurance test prescribed by Sec.  
33.87 of these special conditions.

Sec.  33.201  Design and test requirements for Early ETOPS eligibility.

    In addition to the requirements of Sec.  33.201(c)(1), the 
simulated ETOPS mission cyclic endurance test must include two cycles 
of 10 minute duration, each at the Rated 10-minute OEI TOTHAT; one 
before the last diversion cycle and one at the end of the ETOPS test.

    Issued in Burlington, Massachusetts, on October 23, 2014.
Colleen M. D'Alessandro,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-25884 Filed 10-30-14; 8:45 am]
BILLING CODE 4910-13-P