[Federal Register Volume 76, Number 132 (Monday, July 11, 2011)]
[Rules and Regulations]
[Pages 40594-40596]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-17298]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. NE131; Special Conditions No. 33-009-SC]


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 a 30- minute all engine operating 
(AEO) 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

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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 August 10, 
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, ANF-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 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 a 30-minute AEO power rating. This rating was requested by the 
applicant to support rotorcraft search and rescue missions that require 
extensive operations at high power.
    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 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 airworthiness 
limitations section (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 AEO rating is similar to 
several special conditions issued over the past 20 years addressing the 
same subject. Because the PWC model PW210S turboshaft engine has a 
continuous OEI rating and limits equal to or higher then 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(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 (14 CFR 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 turboshaft engine will incorporate a novel or 
unusual design feature which is a 30-minute AEO power rating, for use 
up to 30-minutes at any time between the takeoff and landing phases of 
a flight. 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. 33-10-02-SC for 
the PW210S engine model was published on March 1, 2011 (76 FR 11172). 
One comment letter was received. The commenter stated disagreement with 
the special condition requirement of incorporating 25 hours of 
operation at the 30-minutes AEO rating into the Sec.  33.87 test 
profile. The commenter proposing taking credit for the 30-minute 
periods run at takeoff rating that is part of the normal test profile 
required by Sec.  33.87(b), thereby reducing the amount of test time at 
the new 30-minute AEO rating. The FAA does not concur. The takeoff 
rating and other normal use ratings are defined within 14 CFR part 1 
and the associated requirements can be found in 14 CFR part 33 Takeoff 
rating is limited in use to a continuous period of not more then 5 
minutes during takeoff operations, which occurs each flight. The 
existing Sec.  33.87 requirements are designed to demonstrate engine 
durability for the takeoff rating which is considered a normal every 
flight operation, and is independent of any other ratings The proposed 
30-minute rating is not defined within 14 CFR, but has been 
specifically requested by PWC. This new rating can be used for periods 
of up to 30-minutes at any time during a flight for a variety of normal 
mission purposes. Also, the number of usages during a single flight is 
not limited; and its use does not require special maintenance actions. 
So this rating is intended for normal mission use, similar to takeoff 
and other normal use ratings, and is different than limited turboshaft 
one-engine-inoperative (OEI) ratings. The OEI ratings for turboshafts, 
with the exception of continuous OEI, are for limited use during a 
flight and in some cases limited cumulative use. Therefore engine 
durability using the 30-minute AEO rating must be demonstrated over and 
above the takeoff rating and other normal use ratings included in the 
rating structure. So the baseline for endurance testing will be Sec.  
33.87(b) (no OEI rating). The FAA also

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finds that the test time associated with the continuous OEI rating is 
an appropriate baseline to define additional requirements for this new 
normal use 30- minute AEO rating. Therefore, engine durability using 
this rating must be demonstrated over and above the takeoff rating and 
other normal use ratings included in the rating structure. No changes 
to the special conditions have been made in this regard.
    The commenter also states that the 25 hour requirement is 
inconsistent with Sec.  33.87 philosophies, stating that time at any 
rating validates any lower rating. This statement is incorrect. The 
test requirements are established to demonstrate engine durability at 
all normal and emergency ratings and associated limits. The test 
profiles incorporate specific elements to this end. The normal ratings 
all have individual elements that must be performed. The 30-minutes AEO 
rating is a normal use rating that is expected to be used with a 
frequency of occurrence similar to the takeoff or maximum continuous 
ratings, and must have a specific and independent element as part of 
the overall test. Also, the expectation is that 30-minute AEO will be 
used far more frequently than any emergency 0E1 rating. These emergency 
ratings must also be demonstrated (when applicable) however due to 
their limited use, these elements of the test may overlap certain 
normal rating elements found in the various test profiles. The practice 
mentioned by the commenter is applied to OEI ratings only, because they 
are rarely used and only in emergency situations. Therefore, the 
frequency of occurrence for normal use ratings dictate that specific 
test time be allocated to each rating, and that time can't be combined 
because a rating is higher than another. No changes to the special 
conditions have been made in this regard.
    The commenter also states that the basis for 25 hours of required 
run time was not described in the special condition. The 25 hours was 
selected to be between the basic cumulative run time for takeoff rating 
(18.75 hours) and maximum continuous rating (45 hours). This 
requirement is weighted more heavily toward the takeoff time due to the 
severe nature of the rating and intended operation. Therefore, no 
changes to the special conditions have been made in this regard.

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 Proposed 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: ``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 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 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 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 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) Modification of the Sec.  33.87 test requirements to include 
the 25 hours of operation at 30- minute AEO power rating must be 
proposed by the Applicant and accepted by the FAA.
    (2) Each Sec.  33.87(d) continuous one-engine-inoperative (0EI) 
rating test period of 30-minutes or longer, run at power and limits 
equal to or higher then the 30-minutes AEO raring, 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 June 29, 2011.
Robert J. Ganley,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2011-17298 Filed 7-8-11; 8:45 am]
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