Document ID: FAA-2014-0376-0001
Agency: faa
Document Type: Proposed Rule
Title: Special Conditions: SNECMA, Silvercrest-2 SC-2D; Rated 10-Minute One Engine Inoperative Takeoff Thrust at High Ambient Temperature
Posted Date: 2014-07-31T04:00Z

[Federal Register Volume 79, Number 147 (Thursday, July 31, 2014)]
[Proposed Rules]
[Pages 44321-44324]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-18074]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No.FAA-2014-0376; Notice No. 33-14-01-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: Notice of proposed special conditions.

-----------------------------------------------------------------------

SUMMARY: This action proposes special conditions 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. The 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 September 2, 2014.

ADDRESSES: Send comments identified by docket number [FAA-2014-0376] 
using any of the following methods:
     Federal eRegulations Portal: Go to http://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 of 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 8 a.m., and 5 p.m., 
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: Docket Operations will post all comments it receives, 
without change, to http://regulations.gov, including any personal 
information the commenter provides. Using the search function of the 
docket Web site, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478), as well as at http://DocketsInfo.dot.gov.
    Docket: You may read background documents or comments received at 
http://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: For technical questions concerning 
this proposed 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. For legal questions concerning this 
proposed 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: 

Comments Invited

    We invite interested persons to participate in this rulemaking by 
submitting 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 proposal, 
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 it receives, 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 comments filed late if it is possible to do so without 
incurring expense or delay. We may change these special conditions 
based on the comments we receive.

Background

    On April 19, 2011, SNECMA applied for a new type certificate (TC) 
for the Silvercrest-2 SC-2D engine model. On April 30, 2014, SNECMA 
requested an extension to their original TC application, which the FAA 
granted through June 30, 2015.
    For their Silvercrest-2 SC-2D engine model, SNECMA requests an 
additional takeoff rating to maintain takeoff thrust in certain high 
ambient temperature conditions with OEI. Therefore, the Silvercrest-2 
SC-2D engine model would 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. This 
additional takeoff rating is named, ``Rated 10-Minute OEI Takeoff 
Thrust at High Ambient Temperature'' (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.

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

[[Page 44322]]

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, the 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 vent 
and exhaust emission requirements of 14 CFR part 34 and the noise 
certification requirements of 14 CFR part 36 in accordance with the 
``Noise Control Act of 1972.''
    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 Silvercrest-2 SC-2D engine model will incorporate the following 
novel or unusual design feature:
    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

    These proposed 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 proposed 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 is similar to the 30-second and 2-minute OEI ratings available 
in part 33 for rotorcraft engines. 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 proposed 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 and mandates 
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. The 
proposed 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 proposed 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 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, 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 design feature, these special 
conditions would apply to that model as well.

Conclusion

    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 Proposed Special Conditions

    Accordingly, the FAA proposes the following special conditions 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 Take-off 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

[[Page 44323]]

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 Take-off 
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 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.

    (a) 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.
    (b) The engine controls managing the OEI takeoff thrust for all 
ambient conditions must assure that:
    (1) The approved rated takeoff thrust is available to the pilot at 
all times by throttle selection, and
    (2) The Rated 10-minute OEI TOTHAT is only available in an OEI 
condition at specified altitudes and temperatures.

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. Sec.  
33.29(1) and (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 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 maximum continuous thrust,
    (3) One minute at 50 percent of 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 maximum continuous thrust,
    (8) One minute at 50 percent of 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 maximum continuous thrust,
    (13) One minute at 50 percent of takeoff thrust,
    (14) Nine minutes at Rated 10-minute OEI TOTHAT, and
    (15) One minute at flight idle
    (b) The test sequence of Sec. 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

[[Page 44324]]

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 July 11, 2014.
Kimberly K. Smith,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-18074 Filed 7-30-14; 8:45 am]
BILLING CODE 4910-13-P