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Rules and Regulations Federal Register

15597 

Vol. 78, No. 48 

Tuesday, March 12, 2013 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 33 

[Docket No. FAA–2012–0745; Special 

Condition No. 33–012–SC] 

Special Conditions: GE Aviation CT7– 

2E1 Turboshaft Engine Model 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These final special conditions 

are issued for the General Electric 

Aviation (GE) CT7–2E1 engine model. 

This engine model will have a novel or 

unusual design feature, which is a 

combination of two existing ratings into 

a new rating called ‘‘flat 30-second and 

2-minute OEI’’ rating. This rating is 

intended for the continuation of flight of 

a multi-engine rotorcraft after one 

engine becomes inoperative. The 

applicable airworthiness regulations do 

not contain adequate or appropriate 

safety standards for this design feature. 

These final special conditions contain 

the additional safety standards 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 April 11, 2013. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this rule, 

contact Dorina Mihail, ANE–111, 

Engine and Propeller Directorate, 

Aircraft Certification Service, 12 New 

England Executive Park, Burlington, 

Massachusetts 01803–5299; telephone 

(781) 238–7153; facsimile (781) 238– 

7199; email dorina.mihail@faa.gov. 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; email vincent.bennett@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

On September 10, 2009, GE applied 

for an amendment to type certificate 

E8NE to add the new CT7–2E1 

turboshaft engine model. The CT7–2E1 

engine model is a derivative of the CT7 

engine family certified between 1977 

and 2010. It is a free turbine turboshaft 

designed for a transport category twinengine helicopter. The CT7–2E1 engine 

model will incorporate a novel and 

unusual feature, which is the ‘‘flat 30- 

second and 2-minute OEI’’ rating. The 

applicant requested this rating to 

provide the increased power required 

for the rotorcraft performance. A special 

condition is necessary to apply 

additional requirements for the rating’s 

definition, overspeed, controls system, 

and endurance test, because the 

applicable airworthiness standards do 

not contain adequate or appropriate 

airworthiness standards to address this 

design feature. 

The ‘‘flat 30-second and 2-minute 

OEI’’ rating is equivalent in some 

regards with the 21⁄2-minute OEI rating, 

and in other regards with the 30-second 

OEI and the 2-minute OEI ratings. 

However, the new rating differs from the 

21⁄2-minute OEI rating because it limits 

the number of occurrences per flight 

and mandates post-flight inspection and 

maintenance actions. The new rating is 

similar with the combined or joined 30- 

second OEI and 2-minute OEI ratings 

when they are equal. However, the 

existing standards are not adequate for 

this combination. 

Similar to the ‘‘flat 30-second and 2- 

minute OEI’’ rating, the 30-second and 

2-minute OEI ratings were introduced to 

provide multi-engine rotorcraft with 

high power for short periods of time 

when an engine becomes inoperative 

during critical flight conditions. 

Existing airworthiness standards for the 

30-second OEI and 2-minute OEI ratings 

were established based on the 

assumption the two ratings will be 

selected together as a package, and that 

the 30-second OEI rating is higher than 

the 2-minute OEI rating. Because the 30- 

second OEI rating was assumed higher, 

specific requirements were established 

for only this rating and for the 30 

second time period. When the 30- 

second and 2-minute OEI ratings are 

equal, these requirements must be 

extended to a total period of 2.5 

minutes. 

These final special conditions for the 

‘‘flat 30-second and 2-minute OEI’’ 

rating are based on a combination of 

existing regulations for the 21⁄2-minute 

OEI rating, and the 30-second and 2- 

minute OEI ratings. Under the 

provisions of § 21.101(d), the special 

conditions must provide a level of safety 

equal to that established by the 

regulations in effect on the date of the 

application for the change. 

We determined that the type 

certification basis for the GE CT7–2E1 

engine model is up to and including 

Amendment 20 of part 33; refer to the 

section below titled ‘‘Type Certification 

Basis.’’ We also determined that the part 

33 standards, up to and including 

Amendment 25, contain part of the 

standards for the ‘‘flat 30-second and 2- 

minute OEI.’’ Therefore, we do not 

prescribe special conditions when the 

requirements exist in later amendments, 

instead we will apply these later 

amendments. These later requirements 

are: 

(1) Section A33.4, Airworthiness 

Limitations Section, paragraphs (b)(1) 

and (b)(2) of Amendments 1–25, and 

(2) Section 33.5, Instruction manual 

for installing and operating the engine, 

paragraph (b)(4) of Amendments 1–25. 

These final special conditions are in 

addition to the requirements of the 30- 

second and 2-minute OEI ratings that 

remain applicable to the ‘‘flat 30-second 

and 2-minute OEI’’ rating, as follows: 

(1) These final special conditions 

extend the standards applicable to the 

30-second or 2-minute OEI ratings for 

the 2.5 minute time duration of the ‘‘flat 

30-second and 2-minute OEI’’ rating. We 

developed these special conditions by 

revising the time dependent 

requirements of §§ 33.27, 33.87(a)(7), 

and 33.88(c). The 2.5 minute time 

duration for the rating would affect the 

structural and operational 

characteristics of the engine that are 

time dependent, such as the values for 

transients, time duration for 

stabilization to steady state, and part 

growth due to deformation. In addition, 

these special conditions are applied by 

extending the 30-second OEI rating 

requirements of § 33.67(d) for automatic 

availability and control of the engine 

power, from 30 seconds to 2.5 minutes. 


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15598 Federal Register / Vol. 78, No. 48 / Tuesday, March 12, 2013 / Rules and Regulations 

(2) These final special conditions are 

required to account for the proposed 

rating of a 2.5 minute time duration 

during the endurance test. For the 30- 

second and 2-minute OEI ratings, the 

test schedule of § 33.87(f) is divided 

among the two ratings. We applied these 

special conditions by revising the 

requirements of § 33.87(f) to ensure the 

test will run for a 2.5 minute duration 

with no interruption. 

Type Certification Basis 

Under the provisions of 14 CFR 

21.101(a), GE must show the CT7–2E1 

turboshaft engine model meets the 

provisions of the applicable regulations 

in effect on the date of application, 

except as detailed in § 21.101(b) and (c). 

We have determined the following 

certification basis for the CT7–2E1 

turboshaft engine model. 

(1) 14 CFR part 33, ‘‘Airworthiness 

Standards: Aircraft Engines,’’ dated 

February 1, 1965, with Amendments 1 

through 20, except §§ 33.5(b)(4), 

A33.4(b)(1), and A33.4(b)(2), 

Amendments 1–25 applicable to the 

‘‘flat 30-second and 2-minute OEI’’ 

rating. The applicant will voluntarily 

comply with § 33.28, Amendments 1–28 

for the EECU, FMU, and AISBV. 

(2) 14 CFR part 34, Amendments 1 

through 4, § 34.11 ‘‘Standard for Fuel 

Venting Emissions.’’ 

Under the provisions of 14 CFR 

21.101(d), if we find the regulations in 

effect, on the date of the application for 

the change, do not provide adequate 

standards with respect to the proposed 

change because of a novel or unusual 

design feature, the applicant must also 

comply with special conditions, and 

amendments to those special conditions 

prescribed under the provisions of 

§ 21.16 to provide a level of safety equal 

to that established by the regulations in 

effect on the date of the application for 

the change. 

We issue special conditions, as 

defined by 14 CFR 11.19, under 14 CFR 

11.38, which become part of the type 

certification basis as specified in 

§§ 21.17(a)(2) or 21.101(d). 

Special conditions are initially 

applicable to the engine model for 

which they are issued. If the type 

certificate for that model is amended 

later, to include another related model 

that incorporates the same or similar 

novel or unusual design feature, or if 

any other model already included on 

the same type certificate is modified to 

incorporate the same or similar novel or 

unusual design feature, these special 

conditions may also apply to the other 

model. 

Novel or Unusual Design Features 

The CT7–2E1 turboshaft engine model 

will incorporate a ‘‘flat 30-second and 2- 

minute OEI’’ rating for use after the 

failure or shutdown of one engine and 

for up to three periods of 2.5 minutes 

each on any one flight. These final 

special conditions, discussed below, for 

the ‘‘flat 30-second and 2-minute OEI’’ 

rating will address this novel and 

unusual design feature. 

Discussion of Comments 

A notice of proposed special 

conditions, No. 33–12–01–SC, for the 

CT7–2E1 turboshaft engine model was 

published on July 20, 2012 (77 FR 

42677). We received six comments from 

European Aviation Safety Agency 

(EASA) and two from Honeywell. One 

comment from EASA resulted in 

changes to the special conditions; the 

remaining comments resulted in 

clarifications. 

The EASA commented that the 

special conditions for the overspeed test 

of § 33.27 should not be the same as the 

requirements applicable to the 21⁄2- 

minute OEI rating. EASA considers that 

applying the overspeed test 

requirements associated with the 30- 

second and 2-minute OEI ratings would 

be more appropriate. 

We partially agree. We agree the 

requirements for the 30-second and 2- 

minute OEI ratings are more 

appropriate, except for the test time 

duration requirement. For the CT7 

engine model, the overspeed 

requirements for the 30-second and 2- 

minute OEI ratings reside in the special 

conditions 33–002–SC, published on 

May 28, 1999 (64 FR 28900). We are 

therefore adopting these requirements, 

except that the time duration of 

paragraph (a) of 33–002–SC is increased 

from 2.5 minutes to 5 minutes in these 

final special conditions. The rationale is 

that the test time duration should be 

representative of the rating duration, 

which is 2.5 minutes at the flat 30- 

second and 2-minute OEI rating versus 

30 seconds at the 30-second OEI. Also, 

the 5 minutes test time is the same as 

that applied to the 21⁄2-minute OEI 

rating, which is a rating of the same 

time duration. 

The EASA commented that 

amendments to §§ 33.67(d) and 33.28(k) 

are discussed, despite not being 

addressed under the part 33 

requirements section of the proposed 

special conditions. The EASA found 

this section unclear and suggested that 

additional clarification be provided. 

We agree. We eliminated the 

references to § 33.28(k) and assigned the 

special conditions to § 33.67(d), instead 

of § 33.28(k). This resulted in no change 

to the proposed special conditions 

themselves because § 33.28(k), 

Amendment 26 and § 33.67(d) 

Amendment 18, contain the same 

requirements. 

Honeywell and EASA provided 

comments related to the ‘‘Note’’ in the 

proposed special conditions paragraph 

(e)(1). The note addressed the intent for 

temperature stabilization. Honeywell 

recommended revising the note for 

clarity. The EASA stated that the note 

is confusing. 

We agree. We determined the note is 

not necessary and removed the note in 

the final special conditions. 

The EASA commented that for the 

overtemperature tests of § 33.88, the 

existing requirements are for a 4 minute 

demonstration at 35 degrees F, hotter 

than the maximum temperature limit for 

the 30 second OEI rating. The proposed 

special conditions, however, amend this 

requirement by increasing this 

demonstration to 5 minutes duration. 

The EASA does not see the technical 

grounds for this increase in severity. 

We do not agree. The 4 minute test 

duration applies to ratings of 2 minutes 

and shorter. The 5 minute test duration 

applies to ratings longer than 2 minutes. 

Since the flat 30-second and 2-minute 

OEI is a rating of 2.5 minutes length, the 

test time requirements should be a 5 

minute duration; the same as that for the 

21⁄2-minute OEI. 

The EASA commented on the 

applicability of Appendix A to part 33, 

A33.4 (b)(1) to the flat 30-second and 2- 

minute OEI rating. Specifically, that the 

flat 30-second and 2-minute OEI rating 

is a single rating, while the requirement 

of A33.4 (b)(1) applies to either 30- 

second OEI or 2-minute OEI ratings. 

EASA stated that the existing 

requirements are written for the existing 

ratings and not for the ‘new’ rating 

introduced by these special conditions, 

therefore, is not clear whether these 

requirements are relevant to the ‘new’ 

rating. 

We do not agree. The airworthiness 

standards of Appendix A to part 33, 

A33.4(b)(1) for the 30-second OEI and 2- 

minute OEI ratings were established 

based on the assumption that the two 

ratings will be selected together as a 

package. Paragraph A33.4(b)(1) does not 

prescribe specific requirements for the 

30-second OEI versus 2-minute OEI 

ratings and provides requirements for 

the use of both ratings. Therefore, 

A33.4(b)(1) requirements for 

maintenance actions associated with the 

use of the 30-second and 2-minute OEI 

ratings apply to the new rating. 

Honeywell provided a comment 

related to the naming of the rating, 


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Federal Register / Vol. 78, No. 48 / Tuesday, March 12, 2013 / Rules and Regulations 15599 

which, although recognizable, appears 

cumbersome. Honeywell suggested that, 

‘‘Rated limited use 21⁄2-minute OEI’’ 

could be a better definition that would 

still distinguish it from the existing 

unlimited use of the 30-second, 2- 

minute, and 21⁄2-minute OEI ratings. 

We do not agree. The applicant 

requested the new rating be named in 

closer relation with the 30-second and 

2-minute OEI ratings for consistency 

across existing engine models and to 

align the new rating with the 30-second 

and 2-minute-OEI ratings at the 

rotorcraft level. We agree with the 

applicant’s proposed name. We also do 

not agree with the commenter that the 

30-second and 2-minute OEI ratings are 

‘‘unlimited use.’’ These ratings are 

limited to a maximum use of 3 times per 

flight and require post-flight inspection, 

per 14 CFR 1.1, Definitions. 

Applicability 

These special conditions are 

applicable to the GE CT7–2E1 turboshaft 

engine model. If GE 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. This 

is true, provided the certification basis 

is the same or contains later 

amendments that satisfy the 

certification basis discussed in the 

section titled, ‘‘Type Certification 

Basis.’’ 

Conclusion 

We reviewed the available data and 

determined that air safety and the 

public interest require adopting these 

special conditions. This action affects 

certain novel or unusual design features 

on the CT7–2E1 turboshaft engine 

model. It is not a rule of general 

applicability and applies only to GE, 

whom requested FAA approval for this 

engine feature. 

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 FAA issues the 

following special conditions as part of 

the type certification basis for the GE 

CT7–2E1 turboshaft engine model. 

1. Part 1 Definitions 

Unless otherwise approved by the 

Administrator and documented in the 

appropriate manuals and certification 

documents, the following definition 

applies: ‘‘Rated Flat 30-second and 2- 

minute One Engine Inoperative (OEI) 

Power,’’ with respect to rotorcraft 

turbine engines, means: (1) A rating for 

which the shaft horsepower and 

associated operating limitations of the 

30-second OEI and 2-minute OEI ratings 

are equal, and (2) the shaft horsepower 

is that developed under static 

conditions at the altitude and 

temperature for the hot day, and within 

the operating limitations established 

under part 33. The rating is for 

continuation of one flight operation 

after the failure or shutdown of one 

engine in multiengine rotorcraft. The 

rating is for up to three periods of use 

no longer than 2.5 minutes each in any 

one flight, and followed by mandatory 

inspection and prescribed maintenance 

action. 

2. Part 33 Requirements 

(a) In addition to the airworthiness 

standards in the type certification basis 

applicable to the engine and the 30- 

second and 2-minute OEI ratings, the 

special conditions in this section apply. 

(b) Section 33.7 Engine ratings and 

operating limitations. Flat 30-second 

and 2-minute OEI rating and operating 

limitations are established by power, 

torque, rotational speed, gas 

temperature, and time duration. 

(c) Section 33.27 Turbine, 

compressor, fan, and turbosupercharger 

rotor overspeed. In addition to the 

requirements of § 33.27(b): 

(1) The turbine and compressor rotors 

must have sufficient strength to 

withstand the test conditions specified 

in paragraph (2) below. 

(2) The applicant must determine, by 

analysis or other acceptable means, the 

most critically stressed rotor component 

of each turbine and compressor, 

including integral drum rotors and 

centrifugal compressors. These 

components must be tested for the 

conditions in paragraphs (i) or (ii) 

below. The test selection from the 

following paragraphs (i) or (ii) below is 

determined by the speed defined in 

paragraph (i)(B) or (ii)(B), whichever is 

higher. 

(i) Test for a period of 5 minutes: 

(A) At its maximum operating 

temperature, except as provided in 

§ 33.27(c)(2)(iv); and 

(B) At the highest speed determined, 

in accordance with § 33.27(c)(2)(i) 

through (iv). 

(C) This test may be performed using 

a separate test vehicle as desired. 

(ii) Test for a period of 5 minutes: 

(A) At its maximum operating 

temperature, except as provided in 

paragraph (ii)(C) below; and 

(B) At 100 percent of the highest 

speed that would result from failure of 

the most critical component of each 

turbine and compressor, or system, in a 

representative installation of the engine 

when operating at the flat 30-second 

and 2-minute OEI rating conditions; and 

(C) The test speed must take into 

account minimum material properties, 

maximum operating temperature, if not 

tested at that temperature, and the most 

adverse dimensional tolerances. 

(D) This test may be performed using 

a separate test vehicle as desired. 

Following the test, rotor growth and 

distress beyond dimensional limits for 

an overspeed condition are permitted 

provided the structural integrity of the 

rotor is maintained, as shown by a 

procedure acceptable to the FAA. 

(d) Section 33.67(d) Fuel system. 

Engines must incorporate a means, or a 

provision for a means, for automatic 

availability and automatic control of the 

flat 30-second and 2-minute OEI power 

for the duration of 2.5 minutes and 

within the declared operating 

limitations. 

(e) Section 33.87 Endurance test. The 

requirements applicable to 30-second 

and 2-minute OEI ratings, except for: 

(1) The test of § 33.87(a)(7) as 

applicable to the 21⁄2-minute OEI rating. 

(2) The tests in § 33.87(f)(2) and (3) 

must be run continuously for the 

duration of 2.5 minutes, and 

(3) The tests in § 33.87(f)(6) and (7) 

must be run continuously for the 

duration of 2.5 minutes. 

(f) Section 33.88 Engine 

overtemperature test. The requirements 

of § 33.88(c), except that the test time is 

5 minutes instead of 4 minutes. 

Issued in Burlington, Massachusetts on 

March 4, 2013. 

Robert J. Ganley, 

Acting Manager, Engine and Propeller 

Directorate, Aircraft Certification Service. 

[FR Doc. 2013–05676 Filed 3–11–13; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2012–0689; Directorate 

Identifier 2009–SW–065–AD; Amendment 

39–17301; AD 2012–26–06] 

RIN 2120–AA64 

Airworthiness Directives; Sikorsky 

Aircraft-Manufactured Model S–64F 

Helicopters 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 


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