99-3038. Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines  

  • [Federal Register Volume 64, Number 28 (Thursday, February 11, 1999)]
    [Rules and Regulations]
    [Pages 6784-6786]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 99-3038]
    
    
    =======================================================================
    -----------------------------------------------------------------------
    
    DEPARTMENT OF TRANSPORTATION
    
    Federal Aviation Administration
    
    14 CFR Part 39
    
    [Docket No. 98-ANE-28-AD; Amendment 39-11029; AD 99-04-05]
    RIN 2120-AA64
    
    
    Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan 
    Engines
    
    AGENCY: Federal Aviation Administration, DOT.
    
    ACTION: Final rule.
    
    -----------------------------------------------------------------------
    
    SUMMARY: This amendment adopts a new airworthiness directive (AD), 
    applicable to certain Pratt & Whitney (PW) JT9D series turbofan 
    engines, that requires a fluorescent penetrant inspection (FPI) of the 
    rear skirt of the diffuser case for cracks, and, if necessary, blending 
    down to minimum wall thickness to remove cracks and subsequent FPI to 
    determine if cracks have been removed, polishing, and shotpeening. If 
    the cracks are shown by subsequent FPI not to have been removed, this 
    AD requires removing the diffuser case from service and replace with a 
    serviceable part. This amendment is prompted by a report of a diffuser 
    case rupture during takeoff roll that resulted in damage to the 
    aircraft. The actions specified by this AD are intended to prevent 
    diffuser case rupture due to cracks, which can result in an uncontained 
    engine failure and damage to the aircraft.
    
    DATES: Effective April 12, 1999.
        The incorporation by reference of certain publications listed in 
    the regulations is approved by the Director of the Federal Register as 
    of April 12, 1999.
    
    ADDRESSES: The service information referenced in this AD may be 
    obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; 
    telephone (860) 565-6600, fax (860) 565-4503. This information may be 
    examined at the Federal Aviation Administration (FAA), New England 
    Region, Office of the Regional 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: Tara Goodman, Aerospace Engineer, 
    Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
    New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
    238-7130, fax (781) 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)
    
    [[Page 6785]]
    
    that is applicable to certain Pratt & Whitney (PW) JT9D series turbofan 
    engines was published in the Federal Register on August 31, 1998 (63 FR 
    46200). That action proposed to require fluorescent penetrant 
    inspection (FPI) of the rear skirt of the diffuser case for cracks, 
    and, if necessary, blending down to minimum wall thickness, to remove 
    cracks, subsequent FPI to determine if cracks have been removed, and 
    polishing and shotpeening. If the cracks are shown by subsequent FPI 
    not to have been removed, the proposed AD would require removing the 
    diffuser case from service for possible weld repair or replacement with 
    serviceable parts. The actions would be required to be accomplished in 
    accordance with PW Service Bulletin (SB) No. JT9D-6329, dated May 20, 
    1998.
        Interested persons have been afforded an opportunity to participate 
    in the making of this amendment. Due consideration has been given to 
    the comments received.
        One commenter states that the proposed AD only requires blending 
    out if an indication of a crack is found. The AD should be amended to 
    require blending out of all tooling and other surface marks at piece-
    part exposure, whether or not cracks are found, in order to remove the 
    danger of them becoming crack initiation sites at a future date. The 
    FAA does not concur. The referenced SB explains that scratches and 
    toolmarks can lead to cracking. The criteria in the SB also state any 
    questionable indications be marked as a crack. Although surface tooling 
    mark conditions may exist in other locations on the diffuser case, 
    there has been no field experience to indicate that an unsafe condition 
    exists in other locations.
        The same commenter states the proposed AD concentrates solely on 
    the area around the dog bone bosses. With a highly stressed part such 
    as a diffuser casing, attention should be paid to the whole component 
    and the AD should be amended to reflect this. The FAA concurs in part. 
    Paragraph (a) of the AD has been changed to reflect the intent of the 
    SB to perform an FPI of the rear skirt of the diffuser case with 
    particular attention to the area around the dogbone location because it 
    is a high stress area. At this time, however, the FAA has determined 
    that it is not necessary to require an FPI of the entire diffuser case. 
    The JT9D Engine Manual (Part Number (P/N) 777210) Inspection -01 Task 
    72-41-03-22-000 contains a full diffuser case FPI as a prerequisite 
    procedure for visual and dimensional inspection per SPOP 82. That 
    inspection procedure also contains cautionary note to pay particular 
    attention to the rear rail.
        Two commenters have no objection to the proposed AD.
        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.
        There are approximately 566 engines of the affected design in the 
    worldwide fleet. The FAA estimates that 157 engines installed on 
    aircraft of U.S. registry will be affected by this AD, that it will 
    take approximately 68 work hours per engine to accomplish the required 
    actions, and that the average labor rate is $60 per work hour. Based on 
    these figures, the total cost impact of the AD on U.S. operators is 
    estimated to be $640,560.
        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.
    
    Adoption of the Amendment
    
        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. 106(g), 40113, 44701.
    
    
    Sec. 39.13  [Amended]
    
        2. Section 39.13 is amended by adding the following new 
    airworthiness directive:
    
    99-04-05  Pratt & Whitney: Amendment 39-11029 Docket 98-ANE-28-AD.
    
        Applicability: Pratt & Whitney (PW) Model JT9D-7Q, -7Q3, -59A, 
    and -70A turbofan engines, with diffuser cases, part numbers (P/Ns) 
    772173, 772173-001, 772173-002, 782222, 782222-001, and 782222-002, 
    installed. These engines are installed on but not limited to Boeing 
    747 series, McDonnell Douglas DC-10 series, and Airbus A300 series 
    aircraft.
    
        Note 1: This airworthiness directive (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 request 
    approval for an alternative method of compliance in accordance with 
    paragraph (c) of this AD. The request should include an assessment 
    of the effect of the modification, alteration, or repair on the 
    unsafe condition addressed by this AD; and, if the unsafe condition 
    has not been eliminated, the request should include specific 
    proposed actions to address it.
    
        Compliance: Required as indicated, unless accomplished 
    previously.
        To prevent diffuser case rupture due to cracks, which can result 
    in an uncontained engine failure and damage to the aircraft, 
    accomplish the following:
        (a) At the next piece-part exposure of the diffuser case after 
    the effective date of this AD, accomplish the following in 
    accordance with PW Service Bulletin (SB) No. JT9D-6329, dated May 
    20, 1998:
        (1) Perform a fluorescent penetrant inspection (FPI) for cracks 
    in accordance with the procedures and criteria stated in the SB of 
    the diffuser case rear skirt paying particular attention to areas 
    around the dog bone-shaped bosses identified in the SB.
        (2) If no indications of cracks are found in accordance with the 
    procedures and criteria stated in the SB, no further action is 
    required.
        (3) If indications of cracks are found in accordance with the 
    procedures and criteria stated in the SB, remove the diffuser case 
    from service, replace with a serviceable part, or blend the cracks 
    as needed down to the minimum wall thickness to remove cracks in 
    accordance with the procedures and criteria stated in the SB.
        (4) After blending down in accordance with the procedures and 
    criteria stated in the SB, perform a subsequent etch and FPI for 
    cracks, as follows:
        (i) If no indications of cracks are found in accordance with the 
    procedures and criteria stated in the SB, polish and shot-peen the 
    area around each dog bone boss in accordance with the procedures and 
    criteria stated in the SB.
        (ii) If indications of cracks are found in accordance with the 
    procedures and criteria
    
    [[Page 6786]]
    
    stated in the SB, remove the diffuser case from service and replace 
    with a serviceable part.
        (b) For the purpose of this AD, piece-part exposure is defined 
    as when the part is considered completely disassembled when done in 
    accordance with the disassembly instructions in the engine 
    manufacturer's manual, to give access to the dog bone-shaped bosses 
    in the diffuser case rear skirt.
        (c) 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. 
    Operators shall submit their request through an appropriate FAA 
    Principal Maintenance Inspector, who may add comments and then send 
    it to the Manager, Engine Certification Office.
    
        Note 2: Information concerning the existence of approved 
    alternative methods of compliance with this airworthiness directive, 
    if any, may be obtained from the Engine Certification Office.
    
        (d) 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.
        (e) The actions required by this AD shall be done in accordance 
    with the following PW SB:
    
    ------------------------------------------------------------------------
                Document No.               Pages              Date
    ------------------------------------------------------------------------
    JT9D 6329..........................       1-42  May 20, 1998.
        Total Pages: 42.
    ------------------------------------------------------------------------
    
        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 Pratt & Whitney, 400 Main St., East 
    Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-4503. 
    Copies may be inspected at the FAA, New England Region, Office of the 
    Regional 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.
        (f) This amendment becomes effective on April 12, 1999.
    
        Issued in Burlington, Massachusetts, on February 1, 1999.
    David A. Downey,
    Assistant Manager, Engine and Propeller Directorate, Aircraft 
    Certification Service.
    [FR Doc. 99-3038 Filed 2-10-99; 8:45 am]
    BILLING CODE 4910-13-P
    
    
    

Document Information

Effective Date:
4/12/1999
Published:
02/11/1999
Department:
Federal Aviation Administration
Entry Type:
Rule
Action:
Final rule.
Document Number:
99-3038
Dates:
Effective April 12, 1999.
Pages:
6784-6786 (3 pages)
Docket Numbers:
Docket No. 98-ANE-28-AD, Amendment 39-11029, AD 99-04-05
RINs:
2120-AA64: Airworthiness Directives
RIN Links:
https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives
PDF File:
99-3038.pdf
CFR: (1)
14 CFR 39.13