[Federal Register Volume 76, Number 130 (Thursday, July 7, 2011)]
[Proposed Rules]
[Pages 39795-39796]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-16814]



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 Proposed Rules

                                                 Federal Register

 ________________________________________________________________________

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 This section of the FEDERAL REGISTER contains notices to the public of 

 the proposed issuance of rules and regulations. The purpose of these 

 notices is to give interested persons an opportunity to participate in 

 the rule making prior to the adoption of the final rules.

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  Federal Register / Vol. 76, No. 130 / Thursday, July 7, 2011 / 

Proposed Rules  



[[Page 39795]]







DEPARTMENT OF TRANSPORTATION



Federal Aviation Administration



14 CFR Part 33



[Docket No. NE133; Notice No. 33-11-02-SC]




Special Conditions: Pratt and Whitney Canada Model PT6C-67E 

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 Pratt and Whitney 

Canada (PWC) model PT6C-67E engines. The engine model will have a novel 

or unusual design feature which is a 30-Minute All Engines Operating 

(AEO) power rating. This rating is primarily intended for high power 

hovering operations during 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 August 8, 2011.



ADDRESSES: You may mail two copies of your comments to: Federal 

Aviation Administration, Engine and Propeller Directorate, Attn: Marc 

Bouthillier, Rules Docket (ANE111), Docket No. NE133, 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 may send comments via e-mail to [email protected]. 

You must mark your comments: Docket No. NE133. 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 July 10, 2008, PWC applied for type certification for the model 

PT6C-67E turboshaft engine. The PT6C-67E engine is a derivative of the 

PT6C-67C engine which has been type certificated by the FAA. This 

engine incorporates a four-stage axial compressor and a centrifugal 

compressor driven by a single stage high pressure turbine (HPT) and a 

two-stage power turbine (PT) driving a helicopter rotor system via a 

direct drive to the engine output shaft. The control system includes a 

dual channel full authority digital electronic control.

    The engine will incorporate a novel or unusual design feature which 

is a 30-minute AEO power rating. This rating was requested by the 

applicant to support rotorcraft search and rescue missions that require 

extensive hover operations at high power. The use of 30-minute AEO 

power is limited to a cumulative total of 50 minutes for any given 

flight. However, the number of times the rating can be accessed on any 

given flight is not limited, as long as 50 minutes total time per 

flight is not exceeded.

    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 (ICA), and endurance testing. 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 Airworthiness 

Limitations section limits in accordance with those assumptions, such 

that engine deterioration is not excessive.

    The endurance test requirement of 25 hours operation at 30 minutes 

AEO is similar to several special conditions issued over the past 20 

years. Because the PT6C-67E model has a Continuous One-Engine-

Inoperative (OEI) rating and limits equal to or higher than the 30-

minute AEO rating, the test time performed at the Continuous OEI rating 

may be credited toward the 25-hour requirement. However, test time 

spent at other rating elements of the test, such as takeoff or other 

OEI ratings (that may be equal to or higher values), may not be counted 

toward the 25 hours of required running.

    These special conditions contain the additional airworthiness 

standards necessary to establish a level of safety equivalent to the 

level that would result



[[Page 39796]]



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 and 21.101(a), PWC must show 

that the model PT6C-67E turboshaft 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 

this model series is 14 CFR part 33 Amendment 20; however, PWC proposes 

to demonstrate compliance to later amendments of part 33 for this 

model. In accordance with 14 CFR 21.101(b), the FAA concurs with the 

PWC proposal. Therefore, the certification basis for the PT6C-67E model 

turboshaft engine will be part 33, effective February 1, 1965, as 

amended by Amendments 33-1 through 33-30.

    If the Administrator finds that the applicable airworthiness 

regulations in part 33, as amended, do not contain adequate or 

appropriate safety standards for the PWC model PT6C-67E 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 PWC model PT6C-67E turboshaft engine will incorporate a novel 

or unusual design feature which is a 30-Minute All Engine Operating 

(AEO) power rating, for use up to 30 minutes at any time between take-

off and landing. Special conditions for a 30-Minute AEO rating are 

proposed to address this novel and unusual design feature. The special 

conditions are discussed below.



Discussion



    The PWC model PT6C-67E turboshaft engine is a free turbine 

turboshaft designed for a transport category twin-engine helicopter. 

The helicopter manufacturer anticipates that for search and rescue 

extended hovering maneuvers may require more than maximum continuous 

power for up to 30 minutes. PWC has requested a 30-Minute All Engine 

Operating (AEO) rating for use up to 30 minutes at any time between the 

take-off and landing phases of a flight. PWC has indicated that the 

number of times this rating can be accessed in one flight is not 

limited; but total time is limited to a cumulative total of 50 minutes 

for any one flight.



Applicability



    As discussed above, these special conditions are applicable to PWC 

model PT6C-67E turboshaft engines. If Pratt and Whitney Canada 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.



Conclusion



    This action affects only certain novel or unusual design features 

on the Pratt and Whitney Canada Model PT6C-67E Turboshaft Engine. It is 

not a rule of general applicability, and it affects only Pratt and 

Whitney Canada 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 continues to 

read 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 PWC model PT6C-67E turboshaft 

engines.



1. PART 1--DEFINITIONS



    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 AEO 

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, and limited to a cumulative total of 

50 minutes use for any given flight.



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 AEO rating, 

limits and usage.

    (b) Section 33.4, Instructions for Continued Airworthiness (ICA). 

In addition to the requirements of Sec.  33.4, the ICA must:

    (1) Include instructions to ensure that in-service engine 

deterioration due to rated 30 minute AEO power usage will not be 

excessive, meaning that all other approved ratings, including One 

Engine Inoperative (OEI), are available (within associated limits and 

assumed usage) for each flight; and that deterioration will not exceed 

that assumed for declaring a Time Between Overhaul 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, any mandatory 

inspections and serviceability limits related to the use of the 30-

minute AEO rating.

    (c) Section 33.87, Endurance Test. In addition to the requirements 

of Sec. Sec.  33.87(a) and 33.87(d), the overall test run must include 

a minimum of 25 hours of operation at 30 minute AEO power and limits, 

divided into periods of 30 minutes AEO power with alternate periods at 

maximum continuous power or less.

    (1) Each Sec.  33.87(d) continuous OEI rating test period of 30 

minutes or longer, run at power and limits equal to or higher than the 

30 minute AEO rating, may be credited toward this requirement.



    Issued in Burlington, Massachusetts, on June 23, 2011.

Peter A. White,

Acting Manager, Engine and Propeller Directorate, Aircraft 

Certification Service.

[FR Doc. 2011-16814 Filed 7-6-11; 8:45 am]

BILLING CODE 4910-13-M