DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

!Docket No. FAA-2008-0808; Directorate Identifier 2008-NE-18-ADI 

RIN 2120-AA64 

[4910-13-P] 

Ainvorthincss Directives; General Electric Company CT58 Turboshaft Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking (NPRM). 

SUMMARY: We propose to supersede airworthiness directives (ADs) 2001-18-06 and 

2008-22-16, which apply to certain General Electric Company (GE) CT58 turboshaft 

engines. ADs 200 1-18-06 and 2008-22-16 require recalculating the lives of life-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 proposed AD 

would consolidate ADs 2001-18-06 and 2008-22-16, and further reduce the life capability 

of certain parts. We are proposing this AD to prevent failure of life-limited rotating parts, 

uncontained part release, damage to the engine, and damage to the aircraft. 

DATES: We must receive comments on this proposed AD by [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43 

and 11.45, by any of the following methods: 

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: 202-493-2251. 
• Mail: U.S. Department ofTransportation, Docket Operations, M-30, West 

Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 

20590. 

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal holidays. 

For service information identified in this proposed AD, contact General Electric 

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

5 13- 552-3272; emai l: aviation.fleetsupport@ge.com. You may view this service 

infom1ation at the FAA, Engine & Propeller Directorate, 12 New England Executive 

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 proposed AD, the regulatory evaluation, any 

comments received, and other information. The street address for the Docket Office 

(phone: 800-647-5527) is in the ADDRESSES section. Comments will be available in the 

AD docket shortly after receipt. 

FOR FURTHER INFORMATION CONTACT: Sanjana Murthy, Aerospace 

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

England Executive Park, Burlington, MA 01803; phone: 781-238-7750; fax: 781-238-

7199; email: sanjana.murthy@faa.gov. 

2 
SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to send any written relevant data, views, or arguments about this 

proposed AD. Send your comments to an address listed under the ADDRESSES section. 

Include "Docket No. F AA-2008-0808; Directorate Identifier 2008-NE-1 8-AD" at the 

beginning of your comments. We spec ifica ll y invite comments on the overall regulatory, 

economic, environmental, and energy aspects of this proposed AD. We will consider all 

comments rece ived by the closing date and may amend this proposed AD because of 

those comments. 

We will post all comments we receive, without change, to 

http://www.regulations.gov, including any personal information you provide. We will 

also post a report summarizing each substantive verbal contact we receive about this 

proposed AD. 

Discussion 

On August 24, 200 I, we issued AD 2001-18-06, Amendment 39- 12432 (66 FR 

4 7575, September 13, 2001 ), ("AD 200 1-18-06"), and on October 20, 2008, we issued 

AD 2008-22-1 6, Amendment 39-1571 2 (73 FR 63629, October 27, 2008), ("AD 2008-

22-16"), for CT58 turboshaft engines. AD 200 1- 18-06 requires the use of an RHL 

multiplying factor in calculating the lives of life-limited rotating parts used in RHL 

missions. AD 2008-22-1 6 addressed a shortfall in the life capability of compressor spools 

used in RHL operations. We issued ADs 2001-18-06 and 2008-22- 16 to prevent cracks in 

rotating parts that could result in an uncontained engine failure, damage to the engine, 

and damage to the aircraft. 

Actions Since ADs 2001-18-06 and 2008-22-16 Were Issued 

Since we issued ADs 200 1-18-06 and 2008-22-1 6, GE updated the life limits of 

compressor spools. GE also updated how to calculate the life consumption of compressor 

3 
spools and ofli fe-limited rotating parts flown in Utility operations. This update resulted 

in generally reduced li ves for compressor spools and all other life-limited parts used in 

Utility operations. GE published their updated life calculations for all life-limited parts in 

GE Alert Service Bulletin (ASB) No. CT58 SIB 72-A0 162, Revision 16, dated January 7, 

2015. 

Relevant Service T nformation 

We reviewed GE ASB No. CT58 SIB 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. 

FAA's Determination 

We are proposing this AD because we evaluated all the relevant info1mation and 

determined the unsafe condition described previously is likely to exist or develop in other 

products of the same type design. 

Proposed AD Requirements 

This proposed AD would reduce the life limits of certain compressor spools used 

in all operations and, through imposition of a new lifing methodology, increase the life 

consumption of all rotating parts used in Utility operations. 

Costs of Compliance 

We estimate that this proposed AD would 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 fi gures, we estimate the 

cost ofthe proposed AD on U.S. operators to be $8,715,000. 

4 
Authority for this Rulemaking 

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

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

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

authority. 

We arc issuing this rulemaking under the authority described in Subtitle VII, 

Part A, Subpart III, Section 44701 , "General requirements." Under that section, Congress 

charges the FAA with promoting safe flight of civil aircraft in air commerce by 

prescribing regulations for practices, methods, and procedures the Administrator finds 

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 proposed AD would not have federalism 

implications under Executive Order 13 132. This proposed AD would not have a 

substantial direct e ffect 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 or government. 

For the reasons discussed above, I certify that the proposed regulation: 

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

(2) ls not a '·significant rule" under the DOT Regulatory Policies and Procedures 

(44 FR 11034, February 26, 1979), 

(3) Will not affect intrastate avi ation 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. 

5 
List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, i\ viation safety, Incorporation by reference, Safety. 

The Proposed Amendment 

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

proposes to amend 14 CFR part 39 as follows: 

PART 39- AIRWORTHINESS DIRECTIVES 

I. The authority citation for part 39 continues to read as fo llows: 

Authority: 49 U.S.C. 1 06(g), 401 13, 4470 I. 

§ 39.13 [Amended] 

2. The FAA amends§ 39.13 by: 

a. Removing airworthiness directives (AD) 200 1-18-06; Amendment 39-12432 

(66 FR47575, September 13, 2001); and AD 2008-22-16, Amendment 39-15712 (73 FR 

63629, October 27, 2008), and 

b. Adding the following new AD: 

General Electric Company: Docket No. F AA-2008-0808; Directorate Identifier 2008-

NE-18-AD. 

(a) Comments Due Date 

The FAA must receive comments on this AD action by [INSERT DATE 60 

DAYS AFTER DATE OF PUBLlCA TION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

This AD replaces AD 2001-18-06, Amendment 39-12432 (66 FR 47575, 

September 13, 200 I) and AD 2008-22-16, Amendment 39-15712 (73 FR 63629, October 

27,2008. 

(c) Applicability 

This AD applies to all General Electric Company (GE) CT58-I 00-2, CT58-1l 0-l, 

CT58-11 0-2, CT58-140-1 , and CT58-140-2 turboshaft engines. 

6 
(d) Unsafe Condition 

This AD was prompted by reca lculation of life for parts insta lled on engines used 

in Uti li ty 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. 

(1) Calculating Cyclic Life Consumption 

Re-calculate the cycles-since-new for all compressor spools, and for life-limited 

rotating parts other than compressor spools used in Utility operations. Use paragraphs 

3.A.(l) and 3.8.( 1) in the Accomplishment Instructions ofGE Alert Service Bulletin 

(ASB) No. CT58 SIB 72-A0 162, Revision 16, dated January 7, 20 15, to perform the 

calculations. 

(2) Removal of Compressor Spools 

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

(PINs) 5 124T94G02, 6010T57G04, 6010T57G07, and 6010T57G08 from service, before 

reaching the life limits specified in paragraph 4.( 1 }, Appendix A, in GE ASB No. CT58 

SIB 72-AO 162, Revision 16, dated January 7, 20 I 5, as re-calculated per paragraph (e)( I) 

in this AD. 

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

Spools 

After the effecti ve 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)(l) in this AD. Use Tables I, II, III, and IV in paragraphs 3.D. through 3.0. in the 

Accomplishment Instructions in GE ASB No. CT58 SIB 72-AO 162, Revision 16, dated 

7 
January 7, 2015, and paragraph 4.(4), Appendix A, ofthis GE ASB, to determi ne 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 limits. Use Tables I, II, Ill, and IV in 

paragraphs 3.D. through 3.G. in the Accomplishment Instructions in GE ASB No. CT58 

S/8 72-A0 162, Revision 16, dated January 7, 2015, and paragraph 4.(3), Appendix A of 

this GE ASB to determine when to remove these parts. 

(f) Alternative Methods of Compliance (AMOCs) 

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 

( 1) For more infom1ation about this AD, contact Sanjana Murthy, Aerospace 

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

England Executive Park, Burlington, MA 0 1803; phone: 781 -238-7750; fax: 781 -238-

7199; email: sanjana.murthy@faa.gov. 

(2) GE ASB No. CT58 S/B 72-A0162, Revision 16, dated January 7, 2015, which 

is not incorporated by reference in this proposed AD, can be obtained from GE using the 

contact information in paragraph (g)(3) of this proposed AD. 

(3) For service information identifi ed in this AD, contact General Electric 

Company, GE Aviation, Room 285, One Neumann Way, Cincinnati, OH 452 15; phone: 

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

8 
(4) You may view this service information at the FAA, Engine & Propeller 

Directorate, 12 New England Executive Park, Burlinf,rton, MA. For information on the 

availabi I ity of this material at the FAA, call 78 1-238-7 125. 

Issued in Burlington, Massachusetts, on April 17, 2015. 

Acting 

ThomasAMan

~ ager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

9