Airworthiness Directives; General Electric Company CT58 Series and Surplus Military T58 Series Turboshaft Engines, 8504-8507 [05-3190]

Download as PDF 8504 Federal Register / Vol. 70, No. 34 / Tuesday, February 22, 2005 / Rules and Regulations Dated: February 14, 2005. Gilbert Gonzales, Acting Under Secretary, Rural Development. [FR Doc. 05–3226 Filed 2–18–05; 8:45 am] federal_register/ code_of_federal_regulations/ ibr_locations.html. BILLING CODE 3410–XV–P Norman Brown, Senior Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803–5299; telephone 781–238–7181; fax 781–238–7199. SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to GE CT58–140–1, CT58–140– 2, and surplus military T58–GE–5, –10, –100, and –402 series turboshaft engines with certain SNs of stage 1 compressor disks, P/N 5001T20P01, installed. We published the proposed AD in the Federal Register on February 26, 2004 (69 FR 8875). That action proposed to require removing certain stage 1 compressor disks from service before reaching a reduced LCF life limit for those affected disks of 2,100 hours TSN or by December 31, 2008, whichever occurs first. DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 2003–NE–59–AD; Amendment 39–13982; AD 2005–04–10] RIN 2120–AA64 Airworthiness Directives; General Electric Company CT58 Series and Surplus Military T58 Series Turboshaft Engines Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: SUMMARY: The FAA is adopting a new airworthiness directive (AD) for General Electric Company (GE) CT58–140–1, CT58–140–2, and surplus military T58– GE–5, –10, –100, and –402 turboshaft engines with certain serial numbers (SNs) of stage 1 compressor disks, part number (P/N) 5001T20P01, installed. This AD requires removing certain stage 1 compressor disks from service before reaching a reduced low-cycle-fatigue (LCF) life limit for those affected disks of 2,100 hours time-since-new (TSN) or by December 31, 2008, whichever occurs first. This AD results from two reports of low blade tip clearances in the compressor. We are issuing this AD to prevent LCF cracking and failure of the stage 1 compressor disk, an uncontained engine failure, and damage to the helicopter. DATES: This AD becomes effective March 29, 2005. ADDRESSES: Contact GE Aircraft Engines Customer Support Center, M/D 285, 1 Neumann Way, Evendale, OH 45215, telephone (513) 552–3272; fax (513) 552–3329, e-mail GEAE.csc@ae.ge.com, for the service information identified in this AD. You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA. You may examine the service information, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: https://www.archives.gov/ VerDate jul<14>2003 12:43 Feb 18, 2005 Jkt 205001 includes surplus military models T58– GE–5, T58–GE–10, –100, and –402. FOR FURTHER INFORMATION CONTACT: Examining the AD Docket You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location. Comments We provided the public the opportunity to participate in the development of this AD. We have considered the comments received, which are all from GE. Request To Change the Number of U.S. Engines Affected One commenter, GE, requests that we change the estimated number of affected engines installed on helicopters of U.S. registry from 45 to 30. The commenter states that this number is a more accurate estimate of engines in the U.S. and affects the total cost of disk replacement by one third. GE bases this quantity change on their engine tracking system. We agree, and have changed that number in the final rule based on GE’s estimate of the number of affected engines. Request To Add ‘‘Surplus Military’’ Before References to T58 GE requests that we add ‘‘surplus military’’ before all references to ‘‘T58– GE–5’’, to differentiate those engines from the commercially-designated CT58 engines. We agree, and have made these changes in the final rule, which PO 00000 Frm 00004 Fmt 4700 Sfmt 4700 Request To Change the Unsafe Condition Description GE requests that we change the unsafe condition description of ‘‘We are issuing this AD to prevent low cycle fatigue (LCF) cracking and failure of the stage 1 compressor disk, an uncontained engine failure, and damage to the helicopter’’ to ‘‘We are issuing this AD to prevent low-cycle-fatigue (LCF) cracking of the stage 1 compressor disk.’’ GE states that they do not consider the condition to be unsafe based on their investigation and analysis of this condition. We do not agree. We reviewed GE’s investigation and engineering analysis data with GE, and concluded there is an unsafe condition that requires an AD. The basis for the unsafe condition description in the proposed AD completes the potential scenario leading to the unsafe condition, should the disk cracking continue to an uncontained disk failure, resulting in damage to the helicopter. Further, our statement of the unsafe condition does not change the compliance requirements of GE Alert Service Bulletin No. 72–A0196. We have made no changes to the AD based on this comment. Request To Change Wording in the Discussion of the Proposed AD GE requests that we change some wording in the discussion of the proposed AD from ‘‘An investigation by GE revealed that the tangential positioning of the blade dovetail slot resulted in the high-peak stresses.’’ to ‘‘An investigation conducted by GE determined that a defined population of stage 1 compressor disks had nonconforming tangential positioning of the blade dovetail slots, which resulted in high-peak stresses at the disk dovetail slot aft acute corner’’. GE did not indicate any justification or reason for the proposed change. We evaluated the change and determined it does offer a more detailed description and points out a nonconformance. However, this discussion information only appears in the proposed AD and not in the final rule, so we have made no change to the AD based on this comment. Request To Change Requirements Statement GE requests that we change the requirements statement from ‘‘We are proposing this AD which would require removing certain stage 1 compressor disks from service at or before reaching a reduced LCF life limit of 2,100 hours E:\FR\FM\22FER1.SGM 22FER1 Federal Register / Vol. 70, No. 34 / Tuesday, February 22, 2005 / Rules and Regulations TSN or by December 31, 2008, whichever occurs first’’ to ‘‘We are proposing this AD which would require removing certain stage 1 compressor disks from service at or before reaching 2,100 hours TSN or by December 31, 2008, whichever occurs first’’. GE states that they recommend compliance with GE Alert Service Bulletin No. 72– A0196. GE also reminds the FAA that the published FAA—approved life limit for P/N 5001T20P01 is 4,000 hours or 9,900 cycles. We partially agree. GE points out that the published FAA-approved life limit for compressor disks, P/N 5001T20P01, is 4,000 hours or 9,900 cycles, for most of the SN disks with this P/N, while the affected SN population of disks has a reduced life limit of 2,100 hours or December 31, 2008, whichever occurs first. The intent of this AD is to require removing the affected disks that need the reduced life limit because of the nonconformity of those disks. We have changed the requirements statement of this AD to state ‘‘This AD requires removing certain stage 1 compressor disks from service at or before reaching a reduced LCF life limit for those affected disks of 2,100 hours TSN or by December 31, 2008, whichever occurs first’’. Conclusion We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. Costs of Compliance There are about 320 GE CT58–140–1, CT58–140–2, and surplus military T58– GE–5, –10, –100, and –402 series turboshaft engines of the affected design in the worldwide fleet. We estimate that 30 engines installed on helicopters of U.S. registry will be affected by this AD. The action does not impose any additional labor costs. A new disk would cost about $7,965 per engine. We estimate that the prorated cost of the life reduction will be about $4,181 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $125,430. 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 VerDate jul<14>2003 12:43 Feb 18, 2005 Jkt 205001 8505 detail the scope of the Agency’s authority. We are 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. 2005–04–10 General Electric Company: Amendment 39–13982. Docket No. 2003–NE–59–AD. Regulatory Findings Table 1–Stage 1 Compressor Disk SNs Affected By This AD 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); and (3) 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. We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include ‘‘AD Docket No. 2003–NE–59– AD’’ in your request. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 as follows: I PART 39—AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: I Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: I PO 00000 Frm 00005 Fmt 4700 Sfmt 4700 Effective Date (a) This airworthiness directive (AD) becomes effective March 29, 2005. Affected ADs (b) None. Applicability (c) This AD applies to General Electric Company (GE) CT58–140–1, CT58–140–2, and surplus military T58–GE–5, –10, –100, and ‘‘402 turboshaft engines with stage 1 compressor disks, part number (P/N) 5001T20P01, that have a serial number (SN) listed in the following Table 1: GATD0PD2 GATH6RWW GATH7PR0 GATH86K2 GATH8K0P GATD0PD3 GATH6T00 GATH7PR1 GATH86K3 GATH8K0R GATD0PD5 GATH6T01 GATH7PR2 GATH86K4 GATH8K0T GATD0PD6 GATH6T02 GATH7PR3 GATH86K5 GATH8K0W GATD0PD7 GATH6T03 GATH7PR4 GATH8A5G GATH8K12 GATD0PD8 GATH6T04 GATH7PR5 GATH8A5H GATH8K13 GATD0PD9 GATH6T05 GATH7PR6 GATH8A5J GATH8K14 GATD0PDA GATH7K4K GATH7PR7 GATH8A5K GATH8K15 GATD0PDC GATH7K4L GATH7PR8 GATH8A5L GATH8K16 GATH53GC GATH7K4M GATH7PR9 GATH8A5M E:\FR\FM\22FER1.SGM 22FER1 8506 Federal Register / Vol. 70, No. 34 / Tuesday, February 22, 2005 / Rules and Regulations GATH8K17 GATH53GD GATH7K4N GATH7PRA GATH8A5N GATH8K18 GATH53GE GATH7K4P GATH7PRC GATH8A5P GATH8K19 GATH53GF GATH7K4R GATH7PRD GATH8A5T GATH8W7H GATH53GH GATH7K4T GATH7PRE GATH8A5W GATH8W7J GATH53GJ GATH7K5G GATH7PRF GATH8A60 GATH8W7L GATH53GK GATH7KGH GATH7PRG GATH8A61 GATH8W7M GATH5T70 GATH7KGK GATH7PRH GATH8A62 GATH8W7N GATH5T71 GATH7KGL GATH7PRJ GATH8A63 GATH8W7P GATH5T72 GATH7KGM GATH7PRK GATH8A64 GATH8W7R GATH5T73 GATH7KGN GATH7PRL GATH8A66 GATH8W7T GATH5T74 GATH7KGP GATH7PRM GATH8A67 GATH8WD4 GATH5T75 GATH7KGR GATH7PRN GATH8A68 GATH8WD5 GATH5T76 GATH7KGT GATH7PRP GATH8GRG GATH8WD6 GATH5T77 GATH7KGW GATH7PRR VerDate jul<14>2003 12:43 Feb 18, 2005 GATH8GRH GATH8WD7 GATH5T78 GATH7KH0 GATH7PRT GATH8GRK GATH8WD8 GATH5T79 GATH7KH1 GATH7PRW GATH8GRL GATH8WD9 GATH5T7A GATH7KH2 GATH7PT0 GATH8GRM GATH8WDA GATH5T7C GATH7LAL GATH7RTP GATH8GRN GATH8WDC GATH5T7D GATH7LAM GATH7RTR GATH8GRP GATH8WDD GATH5T7E GATH7LAN GATH7RTT GATH8GRR GATH8WDE GATH5T7F GATH7LAP GATH82R8 GATH8GRT GATH8WDF GATH5T7G GATH7LAR GATH82R9 GATH8GRW GATH8WDG GATH5T7H GATH7LAT GATH82RA GATH8GT0 GATH8WDH GATH6CDL GATH7LAW GATH82RD GATH8GT1 GATH8WDJ GATH6CDM GATH7LC0 GATH82RE GATH8GT3 GATH8WDK GATH6CDN GATH7LC1 GATH82RF GATH8GT5 GATH8WDL GATH6CDP GATH7LC2 GATH82RG GATH8GT7 GATH94R3 GATH6CDR GATH7LC3 Jkt 205001 PO 00000 Frm 00006 Fmt 4700 GATH82RH GATH8GT8 GATH94R4 GATH6CDT GATH7LC4 GATH82RJ GATH8HGF GATH94R6 GATH6CE0 GATH7LC5 GATH82RK GATH8HGG GATH94R7 GATH6CE1 GATH7LC6 GATH82RL GATH8HGH GATH94R8 GATH6CE2 GATH7LC7 GATH82RM GATH8HGJ GATH94R9 GATH6CE3 GATH7LC8 GATH82RN GATH8HGK GATH94RA GATH6CE4 GATH7M8G GATH82RP GATH8HGL GATH94RC GATH6CE5 GATH7M8H GATH82RR GATH8HGM GATH94RD GATH6CE6 GATH7M8J GATH82RT GATH8HGN GATH94RE GATH6CE7 GATH7M8K GATH82RW GATH8HGP GATH94RF GATH6CE8 GATH7M8L GATH82T0 GATH8HGR GATH94RG GATH6CE9 GATH7M8M GATH82T1 GATH8HGT GATH94RJ GATH6CEA GATH7M8N GATH86JD GATH8HGW GATH94RK GATH6CEC GATH7MLK GATH86JE GATH8HH0 GATH94RN GATH6CED Sfmt 4700 E:\FR\FM\22FER1.SGM 22FER1 Federal Register / Vol. 70, No. 34 / Tuesday, February 22, 2005 / Rules and Regulations GATH7MLL GATH86JF GATH8HH1 GATH94RP GATH6CEE GATH7MLM GATH86JG GATH8HH2 GATH94RR GATH6CEF GATH7MLN GATH86JH GATH8HH3 GATH94RT GATH6RH8 GATH7MLP GATH86JJ GATH8HH4 GATH96HF GATH6RH9 GATH7MLR GATH86JK GATH8HH5 GATH96HG GATH6RHC GATH7MLT GATH86JL GATH8HH6 GATH96HK GATH6RHD GATH7MLW GATH86JM GATH8HH7 GATH96HL GATH6RHE GATH7MM0 GATH86JN GATH8K0H GATH96HM GATH6RHF GATH7MM1 GATH86JP GATH8K0J GATH96HN GATH6RHG GATH7MM2 GATH86JR GATH8K0K GATH96HR GATH6RHH GATH7MM3 GATH86JT GATH8K0L GATH96HT GATH6RHJ GATH7PPT GATH86JW GATH8K0M GATH96HW GATH6RWT GATH7PPW GATH86K0 GATH8K0N GATH96J0 These engines are installed on, but not limited to, Agusta S.p.A AS–61N, AS–61N1, Sikorsky S–61L, S–61N, S– 61R, and S–61NM helicopters, and the following surplus military helicopters VerDate jul<14>2003 12:43 Feb 18, 2005 Jkt 205001 that have been certified in accordance with sections 21.25 or 21.27 of the Federal Aviation Regulations (14 CFR 21.25 or 21.27): Sikorsky S–61D and S– 61V, Glacier CH–3E, Siller CH–3E and SH–3A, and Robinson Crane CH–3C, CH–3E, HH–3C, HH–3E, and Carson S– 61L helicopters. Unsafe Condition (d) This AD results from two reports of low blade tip clearances in the compressor. We are issuing this AD to prevent low-cycle-fatigue (LCF) cracking and failure of the stage 1 compressor disk, an uncontained engine failure, and damage to the helicopter. Compliance (e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. Replacement of Stage 1 Compressor Disks (f) If you have a stage 1 compressor disk, P/N 5001T20P01, with a SN listed in Table 1 of this AD, replace that stage 1 compressor disk at or before reaching a reduced LCF life limit for those affected disks of 2,100 hours time-sincenew (TSN) or by December 31, 2008, whichever occurs first. GE Alert Service Bulletin (ASB) No. CT58 S/B 72–A0196, dated July 24, 2003, contains information on replacing the stage 1 compressor disk. (g) After the effective date of this AD, do not install any stage 1 compressor disk, P/N 5001T20P01, that has a SN listed in Table 1 of this AD and has 2,100 hours TSN or more, into any engine. Alternative Methods of Compliance (h) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Material Incorporated by Reference (i) None. Related Information (j) GE Alert Service Bulletin No. CT58 S/B 72–A0196, dated July 24, 2003, pertains to the subject of this AD. Issued in Burlington, Massachusetts, on February 10, 2005. Francis A. Favara, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 05–3190 Filed 2–18–05; 8:45 am] BILLING CODE 4910–13–P PO 00000 Frm 00007 Fmt 4700 Sfmt 4700 8507 DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 2003–NE–50–AD; Amendment 39–13980; AD 2005–04–08] RIN 2120–AA64 Airworthiness Directives; Hartzell Propeller Inc. Model HC–B3TN–5( )/ T10282( ) Propellers Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: SUMMARY: The FAA is superseding an existing Priority Letter Airworthiness Directive (AD) for Hartzell Propeller Inc. model HC–B3TN–5( )/T10282( ) propellers. That AD currently requires initial and repetitive inspections of the blade pilot tube bore area. This ad requires the same inspections. This AD results from a review of all currently effective ADs. That review determined that Priority Letter AD 88–24–15 was not published in the Federal Register to make it effective to all operators, as opposed to just the operators who received actual notice of the original Priority Letter AD. This AD also results from the discovery that the original AD omitted an airplane model with a certain Supplemental Type Certificate (STC) from the applicability. We are issuing this AD to prevent possible blade failure near the hub which can result in blade separation, engine separation, damage to the airplane, and possible loss of the airplane. DATES: This AD becomes effective March 29, 2005. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of March 29, 2005. ADDRESSES: Contact Hartzell Propeller Inc. Technical Publications Department, One Propeller Place, Piqua, OH 45356; telephone (937) 778–4200; fax (937) 778–4391, for the service information identified in this AD. You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA. You may examine the service information, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: https://www.archives.gov/ federal_register/ E:\FR\FM\22FER1.SGM 22FER1

Agencies

[Federal Register Volume 70, Number 34 (Tuesday, February 22, 2005)]
[Rules and Regulations]
[Pages 8504-8507]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-3190]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NE-59-AD; Amendment 39-13982; AD 2005-04-10]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CT58 Series 
and Surplus Military T58 Series Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
General Electric Company (GE) CT58-140-1, CT58-140-2, and surplus 
military T58-GE-5, -10, -100, and -402 turboshaft engines with certain 
serial numbers (SNs) of stage 1 compressor disks, part number (P/N) 
5001T20P01, installed. This AD requires removing certain stage 1 
compressor disks from service before reaching a reduced low-cycle-
fatigue (LCF) life limit for those affected disks of 2,100 hours time-
since-new (TSN) or by December 31, 2008, whichever occurs first. This 
AD results from two reports of low blade tip clearances in the 
compressor. We are issuing this AD to prevent LCF cracking and failure 
of the stage 1 compressor disk, an uncontained engine failure, and 
damage to the helicopter.

DATES: This AD becomes effective March 29, 2005.

ADDRESSES: Contact GE Aircraft Engines Customer Support Center, M/D 
285, 1 Neumann Way, Evendale, OH 45215, telephone (513) 552-3272; fax 
(513) 552-3329, e-mail GEAE.csc@ae.ge.com, for the service information 
identified in this AD.
    You may examine the AD docket at the FAA, New England Region, 
Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA. You may examine the service information, at the FAA, 
New England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA; or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: https://www.archives.gov/
federal_register/code_of_federal_regulations/ibr_locations.html.

FOR FURTHER INFORMATION CONTACT: Norman Brown, Senior Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone 781-238-7181; fax 781-238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to GE CT58-140-1, CT58-140-
2, and surplus military T58-GE-5, -10, -100, and -402 series turboshaft 
engines with certain SNs of stage 1 compressor disks, P/N 5001T20P01, 
installed. We published the proposed AD in the Federal Register on 
February 26, 2004 (69 FR 8875). That action proposed to require 
removing certain stage 1 compressor disks from service before reaching 
a reduced LCF life limit for those affected disks of 2,100 hours TSN or 
by December 31, 2008, whichever occurs first.

Examining the AD Docket

    You may examine the AD Docket (including any comments and service 
information), by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. See ADDRESSES for the 
location.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received, which 
are all from GE.

Request To Change the Number of U.S. Engines Affected

    One commenter, GE, requests that we change the estimated number of 
affected engines installed on helicopters of U.S. registry from 45 to 
30. The commenter states that this number is a more accurate estimate 
of engines in the U.S. and affects the total cost of disk replacement 
by one third. GE bases this quantity change on their engine tracking 
system.
    We agree, and have changed that number in the final rule based on 
GE's estimate of the number of affected engines.

Request To Add ``Surplus Military'' Before References to T58

    GE requests that we add ``surplus military'' before all references 
to ``T58-GE-5'', to differentiate those engines from the commercially-
designated CT58 engines.
    We agree, and have made these changes in the final rule, which 
includes surplus military models T58-GE-5, T58-GE-10, -100, and -402.

Request To Change the Unsafe Condition Description

    GE requests that we change the unsafe condition description of ``We 
are issuing this AD to prevent low cycle fatigue (LCF) cracking and 
failure of the stage 1 compressor disk, an uncontained engine failure, 
and damage to the helicopter'' to ``We are issuing this AD to prevent 
low-cycle-fatigue (LCF) cracking of the stage 1 compressor disk.'' GE 
states that they do not consider the condition to be unsafe based on 
their investigation and analysis of this condition.
    We do not agree. We reviewed GE's investigation and engineering 
analysis data with GE, and concluded there is an unsafe condition that 
requires an AD. The basis for the unsafe condition description in the 
proposed AD completes the potential scenario leading to the unsafe 
condition, should the disk cracking continue to an uncontained disk 
failure, resulting in damage to the helicopter. Further, our statement 
of the unsafe condition does not change the compliance requirements of 
GE Alert Service Bulletin No. 72-A0196. We have made no changes to the 
AD based on this comment.

Request To Change Wording in the Discussion of the Proposed AD

    GE requests that we change some wording in the discussion of the 
proposed AD from ``An investigation by GE revealed that the tangential 
positioning of the blade dovetail slot resulted in the high-peak 
stresses.'' to ``An investigation conducted by GE determined that a 
defined population of stage 1 compressor disks had non-conforming 
tangential positioning of the blade dovetail slots, which resulted in 
high-peak stresses at the disk dovetail slot aft acute corner''. GE did 
not indicate any justification or reason for the proposed change.
    We evaluated the change and determined it does offer a more 
detailed description and points out a nonconformance. However, this 
discussion information only appears in the proposed AD and not in the 
final rule, so we have made no change to the AD based on this comment.

Request To Change Requirements Statement

    GE requests that we change the requirements statement from ``We are 
proposing this AD which would require removing certain stage 1 
compressor disks from service at or before reaching a reduced LCF life 
limit of 2,100 hours

[[Page 8505]]

TSN or by December 31, 2008, whichever occurs first'' to ``We are 
proposing this AD which would require removing certain stage 1 
compressor disks from service at or before reaching 2,100 hours TSN or 
by December 31, 2008, whichever occurs first''. GE states that they 
recommend compliance with GE Alert Service Bulletin No. 72-A0196. GE 
also reminds the FAA that the published FAA--approved life limit for P/
N 5001T20P01 is 4,000 hours or 9,900 cycles.
    We partially agree. GE points out that the published FAA-approved 
life limit for compressor disks, P/N 5001T20P01, is 4,000 hours or 
9,900 cycles, for most of the SN disks with this P/N, while the 
affected SN population of disks has a reduced life limit of 2,100 hours 
or December 31, 2008, whichever occurs first. The intent of this AD is 
to require removing the affected disks that need the reduced life limit 
because of the nonconformity of those disks. We have changed the 
requirements statement of this AD to state ``This AD requires removing 
certain stage 1 compressor disks from service at or before reaching a 
reduced LCF life limit for those affected disks of 2,100 hours TSN or 
by December 31, 2008, whichever occurs first''.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 320 GE CT58-140-1, CT58-140-2, and surplus military 
T58-GE-5, -10, -100, and -402 series turboshaft engines of the affected 
design in the worldwide fleet. We estimate that 30 engines installed on 
helicopters of U.S. registry will be affected by this AD. The action 
does not impose any additional labor costs. A new disk would cost about 
$7,965 per engine. We estimate that the prorated cost of the life 
reduction will be about $4,181 per engine. Based on these figures, we 
estimate the total cost of the AD to U.S. operators to be $125,430.

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.
    We are 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 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); and
    (3) 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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary by 
sending a request to us at the address listed under ADDRESSES. Include 
``AD Docket No. 2003-NE-59-AD'' in your request.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:
2005-04-10 General Electric Company: Amendment 39-13982. Docket No. 
2003-NE-59-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective March 
29, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CT58-140-1, 
CT58-140-2, and surplus military T58-GE-5, -10, -100, and ``402 
turboshaft engines with stage 1 compressor disks, part number (P/N) 
5001T20P01, that have a serial number (SN) listed in the following 
Table 1:

Table 1-Stage 1 Compressor Disk SNs Affected By This AD

GATD0PD2
GATH6RWW
GATH7PR0
GATH86K2
GATH8K0P
GATD0PD3
GATH6T00
GATH7PR1
GATH86K3
GATH8K0R
GATD0PD5
GATH6T01
GATH7PR2
GATH86K4
GATH8K0T
GATD0PD6
GATH6T02
GATH7PR3
GATH86K5
GATH8K0W
GATD0PD7
GATH6T03
GATH7PR4
GATH8A5G
GATH8K12
GATD0PD8
GATH6T04
GATH7PR5
GATH8A5H
GATH8K13
GATD0PD9
GATH6T05
GATH7PR6
GATH8A5J
GATH8K14
GATD0PDA
GATH7K4K
GATH7PR7
GATH8A5K
GATH8K15
GATD0PDC
GATH7K4L
GATH7PR8
GATH8A5L
GATH8K16
GATH53GC
GATH7K4M
GATH7PR9
GATH8A5M

[[Page 8506]]

GATH8K17
GATH53GD
GATH7K4N
GATH7PRA
GATH8A5N
GATH8K18
GATH53GE
GATH7K4P
GATH7PRC
GATH8A5P
GATH8K19
GATH53GF
GATH7K4R
GATH7PRD
GATH8A5T
GATH8W7H
GATH53GH
GATH7K4T
GATH7PRE
GATH8A5W
GATH8W7J
GATH53GJ
GATH7K5G
GATH7PRF
GATH8A60
GATH8W7L
GATH53GK
GATH7KGH
GATH7PRG
GATH8A61
GATH8W7M
GATH5T70
GATH7KGK
GATH7PRH
GATH8A62
GATH8W7N
GATH5T71
GATH7KGL
GATH7PRJ
GATH8A63
GATH8W7P
GATH5T72
GATH7KGM
GATH7PRK
GATH8A64
GATH8W7R
GATH5T73
GATH7KGN
GATH7PRL
GATH8A66
GATH8W7T
GATH5T74
GATH7KGP
GATH7PRM
GATH8A67
GATH8WD4
GATH5T75
GATH7KGR
GATH7PRN
GATH8A68
GATH8WD5
GATH5T76
GATH7KGT
GATH7PRP
GATH8GRG
GATH8WD6
GATH5T77
GATH7KGW
GATH7PRR
GATH8GRH
GATH8WD7
GATH5T78
GATH7KH0
GATH7PRT
GATH8GRK
GATH8WD8
GATH5T79
GATH7KH1
GATH7PRW
GATH8GRL
GATH8WD9
GATH5T7A
GATH7KH2
GATH7PT0
GATH8GRM
GATH8WDA
GATH5T7C
GATH7LAL
GATH7RTP
GATH8GRN
GATH8WDC
GATH5T7D
GATH7LAM
GATH7RTR
GATH8GRP
GATH8WDD
GATH5T7E
GATH7LAN
GATH7RTT
GATH8GRR
GATH8WDE
GATH5T7F
GATH7LAP
GATH82R8
GATH8GRT
GATH8WDF
GATH5T7G
GATH7LAR
GATH82R9
GATH8GRW
GATH8WDG
GATH5T7H
GATH7LAT
GATH82RA
GATH8GT0
GATH8WDH
GATH6CDL
GATH7LAW
GATH82RD
GATH8GT1
GATH8WDJ
GATH6CDM
GATH7LC0
GATH82RE
GATH8GT3
GATH8WDK
GATH6CDN
GATH7LC1
GATH82RF
GATH8GT5
GATH8WDL
GATH6CDP
GATH7LC2
GATH82RG
GATH8GT7
GATH94R3
GATH6CDR
GATH7LC3
GATH82RH
GATH8GT8
GATH94R4
GATH6CDT
GATH7LC4
GATH82RJ
GATH8HGF
GATH94R6
GATH6CE0
GATH7LC5
GATH82RK
GATH8HGG
GATH94R7
GATH6CE1
GATH7LC6
GATH82RL
GATH8HGH
GATH94R8
GATH6CE2
GATH7LC7
GATH82RM
GATH8HGJ
GATH94R9
GATH6CE3
GATH7LC8
GATH82RN
GATH8HGK
GATH94RA
GATH6CE4
GATH7M8G
GATH82RP
GATH8HGL
GATH94RC
GATH6CE5
GATH7M8H
GATH82RR
GATH8HGM
GATH94RD
GATH6CE6
GATH7M8J
GATH82RT
GATH8HGN
GATH94RE
GATH6CE7
GATH7M8K
GATH82RW
GATH8HGP
GATH94RF
GATH6CE8
GATH7M8L
GATH82T0
GATH8HGR
GATH94RG
GATH6CE9
GATH7M8M
GATH82T1
GATH8HGT
GATH94RJ
GATH6CEA
GATH7M8N
GATH86JD
GATH8HGW
GATH94RK
GATH6CEC
GATH7MLK
GATH86JE
GATH8HH0
GATH94RN
GATH6CED

[[Page 8507]]

GATH7MLL
GATH86JF
GATH8HH1
GATH94RP
GATH6CEE
GATH7MLM
GATH86JG
GATH8HH2
GATH94RR
GATH6CEF
GATH7MLN
GATH86JH
GATH8HH3
GATH94RT
GATH6RH8
GATH7MLP
GATH86JJ
GATH8HH4
GATH96HF
GATH6RH9
GATH7MLR
GATH86JK
GATH8HH5
GATH96HG
GATH6RHC
GATH7MLT
GATH86JL
GATH8HH6
GATH96HK
GATH6RHD
GATH7MLW
GATH86JM
GATH8HH7
GATH96HL
GATH6RHE
GATH7MM0
GATH86JN
GATH8K0H
GATH96HM
GATH6RHF
GATH7MM1
GATH86JP
GATH8K0J
GATH96HN
GATH6RHG
GATH7MM2
GATH86JR
GATH8K0K
GATH96HR
GATH6RHH
GATH7MM3
GATH86JT
GATH8K0L
GATH96HT
GATH6RHJ
GATH7PPT
GATH86JW
GATH8K0M
GATH96HW
GATH6RWT
GATH7PPW
GATH86K0
GATH8K0N
GATH96J0
    These engines are installed on, but not limited to, Agusta S.p.A 
AS-61N, AS-61N1, Sikorsky S-61L, S-61N, S-61R, and S-61NM helicopters, 
and the following surplus military helicopters that have been certified 
in accordance with sections 21.25 or 21.27 of the Federal Aviation 
Regulations (14 CFR 21.25 or 21.27): Sikorsky S-61D and S-61V, Glacier 
CH-3E, Siller CH-3E and SH-3A, and Robinson Crane CH-3C, CH-3E, HH-3C, 
HH-3E, and Carson S-61L helicopters.

Unsafe Condition

    (d) This AD results from two reports of low blade tip clearances in 
the compressor. We are issuing this AD to prevent low-cycle-fatigue 
(LCF) cracking and failure of the stage 1 compressor disk, an 
uncontained engine failure, and damage to the helicopter.

Compliance

    (e) You are responsible for having the actions required by this AD 
performed within the compliance times specified unless the actions have 
already been done.

Replacement of Stage 1 Compressor Disks

    (f) If you have a stage 1 compressor disk, P/N 5001T20P01, with a 
SN listed in Table 1 of this AD, replace that stage 1 compressor disk 
at or before reaching a reduced LCF life limit for those affected disks 
of 2,100 hours time-since-new (TSN) or by December 31, 2008, whichever 
occurs first. GE Alert Service Bulletin (ASB) No. CT58 S/B 72-A0196, 
dated July 24, 2003, contains information on replacing the stage 1 
compressor disk.
    (g) After the effective date of this AD, do not install any stage 1 
compressor disk, P/N 5001T20P01, that has a SN listed in Table 1 of 
this AD and has 2,100 hours TSN or more, into any engine.

Alternative Methods of Compliance

    (h) The Manager, Engine Certification Office, has the authority to 
approve alternative methods of compliance for this AD if requested 
using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

    (i) None.

Related Information

    (j) GE Alert Service Bulletin No. CT58 S/B 72-A0196, dated July 24, 
2003, pertains to the subject of this AD.

    Issued in Burlington, Massachusetts, on February 10, 2005.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 05-3190 Filed 2-18-05; 8:45 am]
BILLING CODE 4910-13-P

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