[Federal Register Volume 76, Number 176 (Monday, September 12, 2011)]
[Rules and Regulations]
[Pages 56097-56099]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-23189]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. NE133; Special Condition No. 33-010-SC]


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued 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 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: The effective date of these special conditions is October 12, 
2011.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this 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 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: 

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

[[Page 56098]]

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 (0EI) rating and limits equal 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 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 turbo shaft 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. This design feature is considered to be novel and 
unusual relative to the part 33 airworthiness standards.

Discussion of Comments

    Notice of proposed special conditions, Notice 33-11-02-SC for the 
PT6C-67E engine model was published on July 7, 2011 (76 FR 39795). No 
comments were received.
    We added a statement to paragraph 2(c)(1) of the special conditions 
that clarifies the elements of the referenced test that cannot be taken 
credit for. The text change is for clarification only and does not 
change the requirement as proposed.
    Paragraph 2(c)(1) previously read:
    (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 then the 
30 minute AEO rating, may be credited toward this requirement.
    Paragraph 2(c)(1) now reads:
    (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 then the 
30 minute AEO rating, may be credited toward this requirement. Note 
that the test time required for the takeoff or other OEI ratings may 
not be counted toward the 25 hours of operation required at the 30-
minute AEO rating.

Applicability

    These special conditions are applicable to PWC model PT6C-67E turbo 
shaft 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, and would be made part of 
the certification basis for that model.

Conclusion

    We reviewed the available data and have determined that air safety 
and the public interest require adopting these special conditions as 
proposed. 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 
the applicant who applied to the FAA for approval of this feature on 
the engine product.

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 Special Conditions

    Accordingly, the FAA issues the following special conditions as 
part of the type certification basis for PWC model PT6C-67E turbo shaft 
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 these special conditions: ``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.

[[Page 56099]]

    (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 then the 
30 minute AEO rating, may be credited toward this requirement. Note 
that the test time required for the takeoff or other OEI ratings may 
not be counted toward the 25 hours of operation required at the 30-
minute AEO rating.

    Issued in Burlington, Massachusetts, on August 31, 2011.
Peter A. White,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-23189 Filed 9-9-11; 8:45 am]
BILLING CODE 4910-13-M