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[Federal Register Volume 76, Number 63 (Friday, April 1, 2011)]
[Proposed Rules]
[Pages 18130-18132]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-7598]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. NE132; Notice No. 33-11-01-SC]

Special Conditions: Turbomeca Arriel 2D Turboshaft Engine

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for Turbomeca SA model 
Arriel 2D engines. The engine model will have a novel or unusual design 
feature which is a 30-minute power rating. This rating is generally 
intended to be used for hovering at increased power for search and 
rescue missions. The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for this design 
feature. These proposed special conditions contain the added safety 
standards that the Administrator considers necessary to establish a 
level of safety equivalent to that established by the existing 
airworthiness standards.

DATES: We must receive your comments by May 2, 2011.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Engine and Propeller Directorate, Attn: Marc 
Bouthillier, Rules Docket (ANE 111), Docket No. NE132, 12 New England 
Executive Park, Burlington, Massachusetts 01803 5299. You may deliver 
two copies to the Engine and Propeller Directorate at the above 
address. You must mark your comments: Docket No. NE 132, You can 
inspect comments in the Rules Docket weekdays, except Federal holidays, 
between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this proposed rule contact Marc Bouthillier, ANE-111, Engine and 
Propeller Directorate, Aircraft Certification Service, 12 New England 
Executive Park, Burlington, Massachusetts 01803-5299; telephone (781) 
238-7120; facsimile (781) 238-7199; e-mail [email protected]. 
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; e-mail 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data. We ask 
that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
about these special conditions. You can inspect the docket before and 
after the comment closing date. If you wish to review the docket in 
person, go to the address in the ADDRESSES section of this preamble 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. We will consider all comments we receive by the closing date 
for comments.
    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.
    If you want us to let you know we received your comments on this 
proposal, send us a pre-addressed, stamped postcard on which the docket 
number appears. We will stamp the date on the postcard and mail it back 
to you.

Background

    On August 26, 2010, Turbomeca applied for type certification for a 
new model Arriel 2D turboshaft engine. This engine consists of an axial 
air intake, an axial compressor and a centrifugal compressor driven by 
a single-stage turbine, a direct-flow annular combustion chamber, and a 
single-stage free turbine which drives a reduction gear assembly 
located at the rear end. The accessory gearbox, located at the front 
end, is driven by the gas generator turbine.
    The engine will incorporate a novel or unusual design feature, 
which is a 30-minute power rating. This rating was requested by the 
applicant to support rotorcraft search and rescue missions that require 
extensive operations at high power. This type of rating is generally 
associated with multi-engine

[[Page 18131]]

applications and has usually been named an all-engine-operating (AEO) 
rating. However, this model will be installed on a single engine 
rotorcraft, and the rating name for the purpose of this special 
condition is now 30-minute power rating. The number of times this new 
rating can be used during a flight is not intended to be limited.
    The applicable airworthiness standards do not contain adequate or 
appropriate airworthiness standards to address this design feature. 
Therefore a special condition is necessary to apply additional 
requirements for rating definition, instructions for continued 
airworthiness (TCA) and endurance testing. The 30 minute time limit 
applies to each instance the rating is used, however there is no limit 
to the number of times the rating can be used during any one flight, 
and there is no cumulative time limitation. The ICA requirement is 
intended to address the unknown nature of actual rating usage and 
associated engine deterioration. The applicant is expected to make an 
assessment of the expected usage and publish ICA's and ALS limits in 
accordance with those assumptions, such that engine deterioration is 
not excessive. The endurance test requirement of 25 hours operation at 
30 minute rating is similar to several special conditions issued over 
the past 20 years addressing the same subject. It must be noted that 
test time required for the takeoff rating, may not be counted toward 
the 25 hours of operation required for the 30 minute rating.
    These special conditions contain the additional airworthiness 
standards necessary to establish a level of safety equivalent to the 
level that would result from compliance with the applicable standards 
of airworthiness in effect on the date of application.

Type Certification Basis

    Under the provisions of 14 CFR 21.17(a) and 21.101(a), Turbomeca 
must show that the model Arriel 2D turboshafi engine meets the 
provisions of the applicable regulations in effect on the date of 
application, unless otherwise specified by the FAA. The current 
certification basis for engines in this model series varies, being 
either 14 CFR part 33, Amendment 14 or Amendment 15. Turbomeca proposes 
a certification basis of 14 CFR part 33, Amendment 15. In accordance 
with Sec.  21.101(b), the FAA concurs with the Turbomeca proposal. 
Therefore, the certification basis for the Turbomeca Arriel 2D will be 
part 33, effective February 1, 1965, as amended by Amendments 33-1 
through 33-15 inclusive. If the Administrator finds that the applicable 
airworthiness regulations in part 33, as amended, do not contain 
adequate or appropriate safety standards for the model Arriel 2D 
turboshaft engine, because of a novel or unusual design feature, 
special conditions are prescribed under the provisions of Sec.  21.16.
    The FAA issues special conditions, as defined by 14 CFR 11.19, in 
accordance with 14 CFR 11.38, which become part of the type 
certification basis in accordance with Sec.  21.17(b)(2). 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 another related model that incorporates the same or similar 
novel or unusual design feature, or should any other model already 
included on the same type certificate be modified to incorporate the 
same or similar novel or unusual design feature, the special conditions 
would also apply to the other model.

Novel or Unusual Design Features

    The Turbomeca model Arriel 2D turboshaft engine will incorporate a 
novel or unusual design feature which is a 30-minute power rating, for 
use up to 30 minutes at any time between the take-off and landing 
phases of a flight. Special conditions for a 30-minute rating are 
proposed to address this novel and unusual design feature. The special 
conditions are discussed below.

Discussion

    The Turbomeca model Arriel 2D turboshaft engine is a free turbine 
turboshaft designed for a normal category, single engine helicopter. 
The helicopter manufacturer anticipates that for search and rescue, 
extended hovering maneuvers may require more than maximum continuous 
power for periods up to 30 minutes. Turbomeca has requested a 30-minute 
rating, for use up to 30 minutes at any time between the take-off and 
landing phases of a flight. Turbomeca has indicated that the number of 
times this rating can be used in one flight is not limited.

Applicability

    As discussed above, these special conditions are applicable to the 
Turbomeca model Arriel 2D turbo shaft engine. If Turbomeca applies 
later for a change to the type certificate to include another closely 
related model incorporating the same novel or unusual design feature, 
these special conditions would apply to that model as well, and would 
be made part of the certification basis for that model.

Conclusion

    This action affects only certain novel or unusual design features 
on one model of engine. It is not a rule of general applicability, and 
it affects only the applicant who applied to the FAA for approval of 
these features on the engine.

List of Subjects in 14 CFR Part 33

    Air transportation, Aircraft, 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 Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for the Turbomeca model Arriel 2D turbo shaft engine.
    1. PART 1 DEFINITION. Unless otherwise approved by the 
Administrator and documented in the appropriate manuals and 
certification documents, the following definition applies to this 
special condition: ``Rated 30 Minute Power'', means the approved shaft 
horsepower developed under static conditions at the specified altitude 
and temperature, and within the operating limitations established under 
part 33, and limited in use to periods not exceeding 30 minutes each.
    2. PART 33 REQUIREMENTS.
    (a) Sections 33.1 Applicability and 33.3 General: As applicable, 
all documentation, testing and analysis required to comply with the 
part 33 certification basis, must account for the 30 minute rating, 
limits and usage.
    (b) Section 33.4, instructions for continued airworthiness (ICA). 
In addition to the requirements of 33.4, the ICA must:
    (1) Include instructions to ensure that in-service engine 
deterioration due to rated 30 minute power usage will not be excessive, 
meaning that all other approved ratings are available within associated 
limits and assumed usage, for successive flights; and that 
deterioration will not exceed that assumed for declaring a time between 
overhaul (TBO) period.
    (i) The applicant must validate the adequacy of the maintenance 
actions required under paragraph (b)(1) above.
    (2) Include in the airworthiness limitations section (ALS), any 
mandatory inspections and serviceability limits related to the use of 
the 30-minute rating.
    (c) Section 33.87, Endurance Test. In addition to the requirements 
of 33.87(a) and 33.87(b), the overall test run must

[[Page 18132]]

include a minimum of 25 hours of operation at 30 minute power and 
limits, divided into periods of 30 minutes power with alternate periods 
at maximum continuous power or less.
    (1) Modification of the Sec.  33.87 test requirements to include 
the 25 hours of operation at 30 minute power rating, must be proposed 
by the Applicant and accepted by the FAA. Note that the test time 
required for the takeoff rating may not be counted toward the 25 hours 
of operation required for the 30-minute rating.

    Issued in Burlington, Massachusetts, on March 22, 2011.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2011-7598 Filed 3-31-11; 8:45 am]
BILLING CODE M
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