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###### Department of Transportation

###### Federal Aviation Administration

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

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed special conditions.

# 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                         *marc.bouthillier@faa.gov.*                         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                         *vincent.bennett@faa.gov.*

# 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                           ( print 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 § 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 § 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 § 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                           ( print 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 § 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