95-8712. Airworthiness Directives; General Electric Company CF6 Series Turbofan Engines  

  • [Federal Register Volume 60, Number 70 (Wednesday, April 12, 1995)]
    [Rules and Regulations]
    [Pages 18540-18542]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 95-8712]
    
    
    
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    DEPARTMENT OF TRANSPORTATION
    
    Federal Aviation Administration
    
    14 CFR Part 39
    
    [Docket No. 94-ANE-37; Amendment 39-9192; AD 95-08-03]
    
    
    Airworthiness Directives; General Electric Company CF6 Series 
    Turbofan Engines
    
    AGENCY: Federal Aviation Administration, DOT.
    
    ACTION: Final rule.
    
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    SUMMARY: This amendment adopts a new airworthiness directive (AD), 
    applicable to General Electric Company (GE) CF6-45/-50 series turbofan 
    engines, that requires reduction of the low cycle fatigue (LCF) 
    retirement lives for certain high pressure turbine rotor (HPTR) stage 2 
    disks, and would provide a drawdown schedule for those affected parts 
    with reduced LCF retirement lives. This amendment is prompted by the 
    results of a refined life analysis performed by the manufacturer which 
    revealed minimum calculated LCF lives significantly lower than 
    published LCF retirement lives. The actions specified by this AD are 
    intended to prevent a LCF failure of the HPTR stage 2 disk, which could 
    result in an uncontained engine failure and damage to the aircraft.
    
    DATES: Effective June 12, 1995.
    
        The incorporation by reference of certain publications listed in 
    the regulations is approved by the Director of the Federal Register as 
    of June 12, 1995.
    
    ADDRESSES: The service information referenced in this AD may be 
    obtained from General Electric Aircraft Engines, CF6 Distribution 
    Clerk, Room 132, 111 Merchant Street, Cincinnati, OH 45246. This 
    information may be examined at the Federal Aviation Administration 
    (FAA), New England Region, Office of the Assistant Chief Counsel, 12 
    New England Executive Park, Burlington, MA; or at the Office of the 
    Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
    DC.
    
    FOR FURTHER INFORMATION CONTACT: Robert J. Ganley, Aerospace Engineer, 
    Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
    New England Executive Park, Burlington, MA [[Page 18541]] 01803-5299; 
    telephone (617) 238-7138; fax (617) 238-7199.
    
    SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
    Aviation Regulations (14 CFR part 39) to include an airworthiness 
    directive (AD) that is applicable to General Electric Company (GE) CF6-
    45/-50 series turbofan engines was published in the Federal Register on 
    December 20, 1994 (59 FR 65513). That action proposed to require a 
    reduction of the published low cycle fatigue (LCF) retirement lives for 
    certain high pressure turbine rotor stage 2 disks, and would provide a 
    drawdown schedule for those affected disks with reduced LCF retirement 
    lives. If the Federal Aviation Administration (FAA) approved rework is 
    accomplished, the LCF retirement life may be increased to 8,750 or 
    9,700 cycles, depending on the cycles since new of the disk when the 
    rework is performed. The actions would be performed in accordance with 
    GE CF6-50 Service Bulletin No. 72-1069, dated September 12, 1994.
        Interested persons have been afforded an opportunity to participate 
    in the making of this amendment. Due consideration has been given to 
    the comments received.
        Two commenters support the rule as proposed.
        Since publication of the NPRM, the FAA has increased its estimate 
    of the average labor cost to $60 per work hour, and has revised the 
    economic analysis of this final rule accordingly.
        After careful review of the available data, including the comments 
    noted above, the FAA has determined that air safety and the public 
    interest require the adoption of the rule as proposed with the changes 
    described previously. The FAA has determined that these changes will 
    not increase the scope of the AD.
        The FAA estimates that 280 engines installed on aircraft of U.S. 
    registry will be affected by this AD, that it will take approximately 
    194 work hours per engine to accomplish the required actions, and that 
    the average labor rate is $60 per work hour. Required parts will cost 
    approximately $16,383 per engine. Based on these figures, the total 
    cost impact of the AD on U.S. operators is estimated to be $7,846,440.
        The regulations adopted herein will not have substantial direct 
    effects 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. Therefore, in 
    accordance with Executive Order 12612, it is determined that this final 
    rule does not have sufficient federalism implications to warrant the 
    preparation of a Federalism Assessment.
        For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action 
    and it is contained in the Rules Docket. A copy of it may be obtained 
    from the Rules Docket at the location provided under the caption 
    ADDRESSES.
    
    List of Subjects in 14 CFR Part 39
    
        Air Transportation, Aircraft, Aviation safety, Incorporation by 
    reference, Safety.
    
        Accordingly, pursuant to the authority delegated to me by the 
    Administrator, the Federal Aviation Administration amends part 39 of 
    the Federal Aviation Regulations (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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
    106(g); and 14 CFR 11.89.
    
    
    39.13  [Amended]
    
        2. Section 39.13 is amended by adding the following new 
    airworthiness directive:
    
    95-08-03   General Electric Company: Amendment 39-9192. Docket 94-
    ANE-37.
    
        Applicability: General Electric Company (GE) CF6-45/50 series 
    turbofan engines installed on but not limited to Airbus A300 series, 
    Boeing 747 series, and McDonnell Douglas DC-10 series aircraft.
    
        Note: This AD applies to each engine identified in the preceding 
    applicability provision, regardless of whether it has been modified, 
    altered, or repaired in the area subject to the requirements of this 
    AD. For engines that have been modified, altered, or repaired so 
    that the performance of the requirements of this AD is affected, the 
    owner/operator must use the authority provided in paragraph (e) to 
    request approval from the FAA. This approval may address either no 
    action, if the current configuration eliminates the unsafe 
    condition, or different actions necessary to address the unsafe 
    condition described in this AD. Such a request should include an 
    assessment of the effect of the changed configuration on the unsafe 
    condition addressed by this AD. In no case does the presence of any 
    modification, alteration, or repair remove any engine from the 
    applicability of this AD.
    
        Compliance: Required as indicated, unless accomplished 
    previously.
        To prevent a low cycle fatigue (LCF) failure of the high 
    pressure turbine rotor (HPTR) stage 2 disk, which could result in an 
    uncontained engine failure and damage to the aircraft, accomplish 
    the following:
        (a) Remove from service HPTR stage 2 disks Part Numbers (P/N) 
    1474M49P04, 1474M49P05, 1474M49P06, 9045M35P15, 9045M35P17, and 
    9045M35P18, in accordance with the following:
        (1) For disks that have accumulated less than 3,500 cycles since 
    new (CSN) on the effective date of this airworthiness directive 
    (AD), remove disk from service prior to accumulating 7,080 CSN.
        (2) For disks that have accumulated 3,500 CSN or more, but less 
    than 7,080 CSN on the effective date of this AD, remove disk from 
    service prior to accumulating 7,080 CSN, or prior to accumulating 
    3,100 cycles in service (CIS) after the effective date of this AD, 
    whichever occurs later, but not to exceed 9,700 CSN.
        (3) For disks which have accumulated 7,080 CSN or more on the 
    effective date of this AD, remove disk from service at the next 
    piece-part exposure, but not to exceed 9,700 CSN.
        (b) Remove from service HPTR stage 2 disks P/N 9264M58P01, 
    9264M58P02, and 9264M58P03 prior to accumulating 7,080 CSN.
        (c) This AD establishes the following new LCF retirement lives 
    which will be published in Chapter 5 of the CF6-50 Engine Task 
    Numbered Shop Manual, GEK 50481: 7,080 cycles for HPTR stage 2 disk 
    P/N 1474M49P04, 1474M49P05, 1474M49P06, 9045M35P15, 9045M35P17, 
    9045M35P18, 9264M58P01, 9264M58P02, and 9264M58P03.
        (d) GE CF6-50 Service Bulletin (SB) No. 72-1069, dated September 
    12, 1994, describes an FAA-approved rework procedure for the 
    affected disks. Accomplishment of this rework increases the FAA-
    approved LCF retirement life to 8,750 or 9,700 cycles, depending on 
    the CSN of the disk when the rework is performed.
        (e) An alternative method of compliance or adjustment of the 
    compliance time that provides an acceptable level of safety may be 
    used if approved by the Manager, Engine Certification Office. The 
    request should be forwarded through an appropriate FAA Principal 
    Maintenance Inspector, who may add comments and then send it to the 
    Manager, Engine Certification Office.
    
        Note: Information concerning the existence of approved 
    alternative methods of compliance with this airworthiness directive, 
    if any, may be obtained from the Engine Certification Office.
    
        (f) Special flight permits may be issued in accordance with 
    sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
    CFR 21.197 and 21.199) to operate the aircraft to a location where 
    the requirements of this AD can be accomplished.
        (g) The actions required by this AD shall be done in accordance 
    with the following service bulletin:
    
    [[Page 18542]]
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                  Document No.                 Pages            Date        
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    GE CF6-50 SB No. 72-1069................     1-18  Sept. 12, 1994.      
      Total Pages: 18                                                       
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    This incorporation by reference was approved by the Director of the 
    Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
    Copies may be obtained from General Electric Aircraft Engines, CF6 
    Distribution Clerk, Room 132, 111 Merchant Street, Cincinnati, OH 
    45246. Copies may be inspected at the FAA, New England Region, Office 
    of the Assistant Chief Counsel, 12 New England Executive Park, 
    Burlington, MA; or at the Office of the Federal Register, 800 North 
    Capitol Street NW., suite 700, Washington, DC.
        (g) This amendment becomes effective on June 12, 1995.
    
        Issued in Burlington, Massachusetts, on March 31, 1995.
    James C. Jones,
    Acting Manager, Engine and Propeller Directorate, Aircraft 
    Certification Service.
    [FR Doc. 95-8712 Filed 4-11-95; 8:45 am]
    BILLING CODE 4910-13-U
    
    

Document Information

Effective Date:
6/12/1995
Published:
04/12/1995
Department:
Federal Aviation Administration
Entry Type:
Rule
Action:
Final rule.
Document Number:
95-8712
Dates:
Effective June 12, 1995.
Pages:
18540-18542 (3 pages)
Docket Numbers:
Docket No. 94-ANE-37, Amendment 39-9192, AD 95-08-03
PDF File:
95-8712.pdf
CFR: (1)
14 CFR 39