Skip to Content

Proposed Rule

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

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble Start Printed Page 8875

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for General Electric Company (GE) CT58-140-1, CT58-140-2, and T58-GE-5, -10, -100, and -402 series turboshaft engines with certain serial numbers (SNs) of stage 1 compressor disks, part number (P/N) 5001T20P01, installed. This proposed AD would require removing certain stage 1 compressor disks from service before reaching a reduced low-cycle-fatigue (LCF) life limit. This proposed AD results from two reports of low blade tip clearances in the compressor. We are proposing this AD to prevent LCF cracking and failure of the stage 1 compressor disk, an uncontained engine failure, and damage to the helicopter.

DATES:

We must receive any comments on this proposed AD by April 26, 2004.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

  • By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-NE-59-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
  • By fax: (781) 238-7055.
  • By e-mail: 9-ane-adcomment@faa.gov

You can get the service information identified in this proposed AD from GE Aircraft Engines Customer Support Center, M/D 285, 1 Neumann Way, Evendale, OH 45215, telephone (513) 552-3272; fax (513) 552-3329, email GEAE.csc@ae.ge.com.

You may examine the AD docket, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Norman Brown, Senior Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park; telephone (781) 238-7181; fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2003-NE-59-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. If a person contacts us verbally, and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

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.

Discussion

On May 1, 2003, GE informed the FAA that 320 stage 1 compressor disks, P/N 5001T20P01, have high-peak stresses. GE has identified the affected stage 1 compressor disks by SN. An investigation by GE revealed that the tangential positioning of the blade dovetail slot resulted in the high-peak stresses. This proposed AD would require removing those stage 1 compressor disks, PN 5001T20P01, from service before reaching a reduced LCF life limit of 2,100 hours time-since-new (TSN) or by December 31, 2008, whichever occurs first. This condition, if not corrected, could result in LCF cracking and failure of the stage 1 compressor disk, an uncontained engine failure, and damage to the helicopter.

Relevant Service Information

We have reviewed and approved the technical contents of GE Alert Service Bulletin (ASB) No. CT58 S/B 72-A0196, dated July 24, 2003, that describes the procedures for replacing the stage 1 compressor disk.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. Therefore, 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 TSN or by December 31, 2008, whichever occurs first.

Changes to 14 CFR Part 39—Effect on the Proposed AD

On July 10, 2002, we issued a new version of 14 CFR part 39 (67 FR 47998, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Interim Action

These actions are interim actions and we may take further rulemaking actions in the future.

Costs of Compliance

There are about 320 GE CT58-140-1, CT58-140-2, and T58-GE-5, -10, -100, and -402 series turboshaft engines of Start Printed Page 8876the affected design in the worldwide fleet. We estimate that 45 engines installed on helicopters of U.S. registry would be affected by this proposed AD. The proposed 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 would be about $4,181 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $188,172.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

3. Would 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 proposal 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

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

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

General Electric Company: Docket No. 2003-NE-59-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by April 26, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to General Electric Company (GE) CT58-140-1, CT58-140-2, and T58-GE-5, -10, -100, and -402 series 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
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
Start Printed Page 8877
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
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. Start Printed Page 8878

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 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 (ASB) No. CT58 S/B 72-A0196, dated July 24, 2003, pertains to the subject of this AD.

Start Signature

Issued in Burlington, Massachusetts, on February 17, 2004.

Francis A. Favara,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 04-4101 Filed 2-25-04; 8:45 am]

BILLING CODE 4910-13-U