[Federal Register Volume 76, Number 112 (Friday, June 10, 2011)]
[Rules and Regulations]
[Pages 33981-33982]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-14113]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. NE130; Special Conditions No. 33-008-SCI]


Special Conditions: Pratt and Whitney Canada Model PW210S 
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 PW210S engines. The engine model will have a novel 
or unusual design feature which is engine operation in auxiliary power 
unit (APU) mode. 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 July 11, 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 December 5, 2005, PWC applied for type certification for a new 
model PW210S turboshaft engine. This engine consists of a two stage 
compressor driven by a single stage uncooled turbine, and a two stage 
free power turbine driving a two stage reduction gearbox. The control 
system includes a dual channel full authority digital electronic 
control.
    The engine will incorporate a novel or unusual design feature, 
which is engine operation in auxiliary power unit (APU) mode.
    The applicable airworthiness standards do not contain adequate or 
appropriate airworthiness standards to address this design feature.
    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), PWC must 
show that the model PW210S turboshaft engine meets the provisions of 
the applicable regulations in effect on the date of application, unless 
otherwise specified by the FAA. The application date is December 5, 
2005, which corresponds to 14 CFR part 33 Amendment 20. However, PWC 
has elected to demonstrate compliance to later amendments of part 33 
for this model. Therefore, the certification basis for the PW210S model 
turboshaft engine will be part 33, effective February 1, 1965, amended 
by Amendments 33-1 through 33-24.
    The FAA has determined that the applicable airworthiness 
regulations in part 33, Amendments 1-24 inclusive, do not contain 
adequate or appropriate safety standards for the model PW210 turboshaft 
engine, because of a novel or unusual rating. Therefore, special 
conditions are prescribed under the provisions of 14 CFR 11.19 and 14 
CFR 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 PW210S turbo shaft engine will incorporate a novel or 
unusual design feature which is engine operation in auxiliary power 
unit (APU) mode. 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 No. 33-10-01-SC for 
the PW210S engine model was published on February 14, 2011 (76 FR 
8321). One comment letter was received.
    The commenter stated that the part 1 definition included in the 
special condition may not be necessary, or may require clarification. 
The FAA does not agree. The definition is necessary to explain the 
engine function to which these special conditions apply, and the term 
is used within the rule itself. However, to improve clarity, each of 
the special condition subsections now includes a reference to APU mode 
operation.
    The commenter stated that the 400 cycle dynamic braking test is 
inappropriate for this engine certification program, that engine 
dynamics will be difficult to simulate in a test stand, and that an 
engine test of this type would be better addressed as part of part 29 
rotorcraft certification testing. The FAA does not agree. This test is 
the same as conducted for turbopropeller engines under Sec.  33.96 and 
is applicable to turboshaft engines as well. We do not believe it is 
impractical to reasonably simulate the braking action input into the 
engine

[[Page 33982]]

type design, and that the effects of dynamic braking need to be 
demonstrated on the complete engine prior to issuing a type 
certificate. Lastly, a need for installation limitations or special 
instructions for continued airworthiness requirements could be 
identified based on the results from this test, making it impractical 
to wait for part 29 certification testing.
    The commenter stated that the locked rotor portion of the special 
condition tests needs to be conducted on a single engine, but the 
dynamic requirements can be addressed separately. The FAA concurs in 
part. We have concluded that an engine test is required to demonstrate 
the complete engine response to dynamic braking, however we do agree 
that the two elements of required testing (locked rotor and dynamic) 
can be conducted on separate test engines. The FAA has therefore 
revised paragraph (d) to eliminate the reference to paragraph (b) (400 
cycle dynamic braking test), and therefore allows separate engine tests 
at the applicant's discretion. The FAA has also deleted proposed 
paragraph (0, which is a safety analysis requirement specific to 
dynamic responses. In this regard, existing Sec.  33.75 Safety Analysis 
is considered adequate when an engine test for dynamic braking is 
conducted per this special condition.

Applicability

    These special conditions are applicable to the PWC PW210S turbo 
shaft engine. If PWC 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 may also apply to 
that model as well, and would be made part of the certification basis 
for that model.

Conclusion

    We reviewed the available data, including the comment received, and 
have determined that air safety and the public interest require 
adopting this special condition with the changes described above. 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 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 is as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701-44702, 44704.

The Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) issues the 
following special conditions as part of the type certification basis 
for the PWC PW210S 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: ``Auxiliary Power Unit Mode''--Engine operation with 
the main output shaft and power turbine locked and stationary, while 
the gas generator portion of the engine continues to operate, for the 
purpose of supplying the rotorcraft with electric/hydraulic/pneumatic 
power (as applicable) while on the ground.
    2. PART 33 ENGINE TEST REQUIREMENTS:
    (a) Ground locking: A total of 45 hours with the engine output 
shaft locked to simulate rotor brake engagement, in a manner which 
clearly demonstrates the complete engine's ability to function without 
adverse affect while operating in the APU mode under the maximum 
conditions of engine rotor speed, torque, temperature, air bleed and 
power extraction as specified by the applicant.
    (b) Dynamic braking: A total of 400 application-release cycles of 
simulated brake engagements must be made in a manner which clearly 
demonstrates the complete engine's ability to function without adverse 
affect while operating in the APU mode under the maximum conditions of 
engine acceleration and deceleration rate, rotor speed, torque and 
temperature as specified by the applicant. The engine output shaft must 
be stopped prior to brake-release.
    (c) One hundred engine starts and stops with the output shaft 
locked in a manner simulating rotor brake engagement during APU mode 
operation.
    (d) The tests required by paragraphs (a) and (c) of this section 
must be performed on the same engine.
    (e) The tests required by paragraphs (a), (b) and (c) above must be 
followed by engine disassembly to the extent necessary to show that 
each engine part conforms to the type design and is eligible for 
incorporation into an engine for continued operation in accordance with 
information submitted in compliance with Sec.  33.4 Instructions for 
Continued Airworthiness.

    Issued in Burlington, Massachusetts, on May 25, 2011.
Colleen M. D'Alessandro,
Acting Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2011-14113 Filed 6-9-11; 8:45 am]
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