Rules and Regulations. Final rule

Agency: Federal Aviation Administration (FAA), DOT
Action: Final rule
Citation: FR Doc. 05-3190 · RIN 2120-AA64 · Docket No. 2003-NE-59-AD; Amendment 39-13982; AD 2005-04-10 · 14 CFR 39

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.

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