14 CFR Part 39 

[Docket No. FAA-2008-0808; Directorate Identifier 2008-NE-18-AD; Amendment 

39-18288; AD 2015-20-09] 

RIN 2120-AA64 

Airworthiness Directives; General Electric Company Turboshaft Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are superseding airworthiness directives (AD) 2001-18-06 and AD 

2008-22-16, for all General Electric Company (GE) CT58 turboshaft engines. AD 2001-

18-06 and AD 2008-22-16 required recalculating the lives oflife-limited rotating parts 

using a repetitive heavy-lift (RHL) multiplying factor and removal from service of parts 

that exceed the recalculated cyclic or hourly life limit. This new AD would consolidate 

AD 2001-18-06 and AD 2008-22-16, and furfber reduce the life capability of certain 

parts. This AD was prompted by recalculation of life for parts installed on engines used 

in Utility operations, and a reduced life for compressor spools in all operations. We are 

issuing this AD to prevent failure of life-limited rotating parts, uncontained part release, 

damage to the engine, and damage to the aircraft. 

DATES: This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

The Director of the Federal Register approved the incorporation by reference of a 

certain publication listed in this AD as of[INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 
Park, Burlington, MA For information on the availability of this material at the FAA, 

call 781-238-7125. 

Examining the AD Docket 

You may examine the AD docket on the Internet at http://www.regulations.gov by 

searching for and locating Docket No. F AA-2008-0808; or in person at the Docket 

Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal 

holidays. The AD docket contains this AD, the regulatory evaluation, any comments 

received, and other information. The address for the Docket Office (phone: 

800-647-5527) is Document Management Facility, U.S. Department of Transportation, 

Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 

Jersey Avenue SE., Washington, DC 20590. 

FOR FURTHER INFORMATION CONTACT: Christopher McGuire, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 01803; phone: 781-238-7120; fax: 781-238-

7199; email: chris.mcguire@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to 

supersede AD 2001-18-06, Amendment 39-12432 (66 FR 47575, September 13,2001, 

("AD 2001-18-06") and AD 2008-22-16, Amendment 39-15712 (73 FR 63629, October 

27, 2008, ("AD 2008-22-16"). AD 2001-18-06 and AD 2008-22-16 applied to certain GE 

CT58 turboshaft engines. The NPRM published in the Federal Register on May 1, 2015 

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Utility operations. The NPRM proposed to consolidate AD 2001-18-06 and AD 2008-22-

16, and further reduce the life capability of certain parts. We are issuing this AD to 

prevent failure of life-limited rotating parts, uncontained part release, damage to the 

engine, and damage to the aircraft. 

Related Service Information under 1 CFR Part 51 

We reviewed GE CT58 Alert Service Bulletin (ASB) No. SB 72-A0162, Revision 

16, dated January 7, 2015. The service information describes procedures for calculating 

life limits for the affected life-limited rotating parts. This service information is 

reasonably available because the interested parties have access to it through their normal 

course of business or see ADDRESSES for other ways to access this service information. 

Comments 

We gave the public the opportunity to participate in developing this AD. The 

following presents the comments received on the NPRM and the FAA's response to each 

comment. 

Request New Method for Determining Reduced Life Limits 

AAR Airlift Group (AAR) requested replacement of the current method for 

determining reduced life limits because current limits do not agree with operators field 

experience. AAR independent testing revealed that expired critical rotating parts showed 

no fatigue cracks. 

We disagree. FAA -approved life limits for rotating parts are specified to prevent 

fatigue crack initiation, using conservative analytical margins. The number of parts that 

AAR had inspected would not be sufficient to show a likelihood of part cracking 

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that their cost per flight would increase and company revenue would be reduced. 

We agree that this AD will impose an economic impact to operators. How an 

operator absorbs or passes on the cost is left to the operator to determine. We did not 

change this AD. 

Clarification Requirements 

Since we issued the proposed AD, we discovered that ASB formatting 

discrepancies exist due to documentation changes implemented by GE. We changed 

paragraphs (e)(2), (e)(3), and (e)( 4) to reflect the correct SB paragraph numbers. 

Conclusion 

We reviewed the relevant data and determined that air safety and the public 

interest require adopting this AD as proposed. 

Costs of Compliance 

We estimate that this AD will affect about 60 engines installed on aircraft of U.S. 

registry. The average pro-rated cost of the life-limited rotating parts is $20,000. The 

average labor rate is $85 per hour. Based on these figures, we estimate the cost ofthis 

AD on U.S. operators to be $8,715,000. Authority for this Rulemaking 

Title 49 of the United States Code specifies the FAA's authority to issue rules on 

aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. 

Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's 

authority. 

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necessary for safety in air commerce. This regulation is within the scope of that authority 

because it addresses an unsafe condition that is likely to exist or develop on products 

identified in this rulemaking action. 

Regulatory Findings 

We have determined that this AD will not have federalism implications under 

Executive Order 13132. This AD will not have a substantial direct effect on the States, on 

the relationship between the national government and the States, or on the distribution of 

power and responsibilities among the various levels of government. 

For the reasons discussed above, I certify that this AD: 

(1) Is not a "significant regulatory action" under Executive Order 12866, 

(2) Is not a "significant rule" under DOT Regulatory Policies and Procedures 

(44 FR 11034, February 26, 1979), 

(3) Will not affect intrastate aviation in Alaska to the extent that it justifies 

making a regulatory distinction, and 

( 4) Will not have a significant economic impact, positive or negative, on a 

substantial number of small entities under the criteria of the Regulatory Flexibility Act. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation .safety, Incorporation by reference, Safety. 

Adoption of the Amendment 

Accordingly, under the authority delegated to me by the Administrator, the FAA 

amends 14 CFR part 39 as follows: 

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2. The FAA amends§ 39.13 by: 

a. Removing airworthiness directives (AD) 2001-18-06, Amendment 39-12432 

(66 FR 47575, September 13, 2001) ("AD 2001-18-06"): and AD 2008-22-16, 

Amendment 39-15712 (73 FR 63629, October 27, 2008) ("AD 2008-22-16"), and 

b. Adding the following new AD: 

2015-xx-xx General Electric Company: Amendment 39-18xxx; Docket 

No. F AA-2008-0808; Directorate Identifier 2008-NE-18-AD. 

(a) Effective Date 

This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

This AD replaces AD 2001-18-06 and AD 2008-22-16. 

(c) Applicability 

This AD applies to all General Electric Company (GE) CT58-100-2, CT58-110-l, 

CT58-110-2, CT58-140-l, and CT58-140-2 turboshaft engines. 

(d) Unsafe Condition 

This AD was prompted by recalculation of life for parts installed on engines used 

in Utility operations, and a reduced life for compressor spools in all operations. We are 

issuing this AD to prevent failure of life-limited rotating parts, uncontained part release, 

damage to the engine, and damage to the aircraft. 

(e) Compliance 

Do the actions required by this AD, unless already done. 

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Bulletin (ASB) No. SB 72-A0162, Revision 16, dated January 7, 2015, to perform the 

calculations. 

(2) Removal of Compressor Spools 

After the effective date of this AD, remove compressor spools, part numbers 

(PINs) 5124T94G02, 6010T57G04, 6010T57G07, and 6010T57G08 from service, before 

reaching the life limits specified in paragraph 4.A., Appendix A, in GE CT58 ASB No. 

SB 72-A0162, Revision 16, dated January 7, 2015, as re-calculated per paragraph (e)(!) 

of this AD. 

(3) Removal of Rotating Parts used in Utility Operations other than Compressor 

Spools 

After the effective date of this AD, remove from service any life-limited rotating 

part used in Utility operations, other than the compressor spools with PINs listed in 

paragraph (e )(2) of this AD, that exceeds its life limit as re-calculated per paragraph 

(e)(!) of this AD. Use Tables I, II, III, and IV in paragraphs 3.D. through 3.G. in the 

Accomplishment Instructions in GE CT58 ASB No. SB 72-A0162, Revision 16, dated 

January 7, 2015, and paragraph 4.D., Appendix A of this GE CT58 ASB, to determine 

when to remove these parts. 

(4) Removal of Rotating Parts not used in Utility Operations other than Compressor 

Spools 

After the effective date of this AD, remove from service any life-limited rotating 

part not used in Utility operations, other than the compressor spools with PINs listed in 

paragraph (e)(2) of this AD, that exceeds its life limit. Use Tables I, II, III, and IV in 

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The Manager, Engine Certification Office, FAA, may approve AMOCs for this 

AD. Use the procedures found in 14 CFR 39.19 to make your request. You may email 

your request to: ANE-AD-AMOC@faa.gov. 

(g) Related Information 

For more information about this AD, contact Christopher McGuire, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 01803; phone: 781-238-7120; fax: 781-238-

7199; email: chris.mcguire@faa.gov. 

(h) Material Incorporated by Reference 

(1) The Director of the Federal Register approved the incorporation by reference 

(IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and I CFR 

part 51. 

(2) You must use this service information as applicable to do the actions required 

by this AD, unless the AD specifies otherwise. 

(i) General Electric Company (GE) CT58 Alert Service Bulletin No. SB 72-

A0162, Revision 16, dated January 7, 2015. 

(ii) Reserved. 

(3) ForGE service information identified in this AD, contact General Electric 

Company, GE Aviation, Room 285, One Neumann Way, Cincinnati, OH 45215; phone: 

513-552-3272; email: aviation.fleetsupport@ge.com. 

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Administration (NARA). For information on the availability of this material at NARA, 

call202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibrlocations.html. 

Issued in Burlington, Massachusetts, on September 30,2015. 

ColleenM. D'Alessandro, 

Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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