[Federal Register Volume 60, Number 154 (Thursday, August 10, 1995)]
[Rules and Regulations]
[Pages 40754-40756]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-19232]



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[[Page 40755]]



DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 81-ANE-03; Amendment 39-9327; AD 95-16-07]


Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Pratt & Whitney JT8D series turbofan engines, that 
currently requires initial and repetitive inspections of 9th through 
12th stage high pressure compressor (HPC) disks at the tierod holes. 
This amendment eliminates an optional on-wing ultrasonic inspection of 
the 10th stage high pressure compressor (HPC) disk. This amendment is 
prompted by a report of an uncontained failure of a 10th stage HPC disk 
that was previously inspected using the on-wing ultrasonic inspection 
method. The actions specified by this AD are intended to prevent 
uncontained fractures of 9th through 12th stage HPC disks and engine 
failure.

DATES: Effective September 11, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 11, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, Technical Publications Department, M/S 
132-30, 400 Main Street, East Hartford, CT 06108. 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 01803-5299; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mark A. Rumizen, Aerospace Engineer 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7137; fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: On February 7, 1984, the Federal Aviation 
Administration (FAA) issued airworthiness directive (AD) 81-08-02 R2, 
Amendment No. 39-4817 (49 FR 7361; February 29, 1984), to require 
initial and repetitive inspections of 9th through 12th stage high 
pressure compressor (HPC) disks at the tierod holes in Pratt & Whitney 
(PW) JT8D series turbofan engines. That action was prompted by cracks 
in the tierod holes in HPC disks that resulted in engine failures. That 
condition, if not corrected, can result in uncontained fractures of 9th 
through 12th stage HPC disks and engine failure.
    On August 30, 1984, the FAA issued a correction to AD 81-08-02 R2, 
Amendment 39-4817 (49 FR 35618; September 11, 1984), to include an 
engine model that had been inadvertently omitted from the AD.
    Since issuance of AD 81-08-02 R2, the FAA received a report of an 
uncontained fracture of a 10th stage HPC disk. This disk had been 
subjected to three previous on-wing ultrasonic inspections prior to 
fracture. This method has since been determined as inadequate for 
detecting tierod hole cracking.
    On May 8, 1989, the FAA issued a notice of proposed rulemaking 
(NPRM) that was published in the Federal Register (54 FR 22306; May 23, 
1989), that would have amended the existing AD by eliminating the 
optional on-wing ultrasonic inspection of the 10th stage HPC disk, and 
by including an engine model inadvertently omitted.
    Since the issuance of that NPRM, the FAA has determined that the 
reference to the inadvertently omitted engine model was unnecessary, as 
the FAA had remedied this discrepancy in the August 30, 1984, 
correction. Also, the FAA now utilizes a revised format that supersedes 
existing AD's by publishing a complete document rather than only 
amending applicable paragraphs of the compliance section. Since the FAA 
changed the format of the proposed rule, the FAA determined that it was 
desirable to reopen the comment period to provide additional 
opportunity for public comment.
    A Supplementary NPRM was published in the Federal Register on 
December 19, 1994 (59 FR 65281). That action reprints the corrected AD 
compliance section text in its entirety for clarity.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comment received.
    The commenter states no objection to adoption of the proposed rule.
    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 200 engines that are affected by this AD, 
and the FAA has determined that eliminating the optional on-wing 
ultrasonic inspection will have negligible economic impact, since most 
operators use uninstalled tenth stage disk inspections.
    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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-4817 (49 FR 
35618, September 11, 1984) and by adding a new airworthiness directive, 
Amendment 39-9327, to read as follows:

95-16-07  Pratt & Whitney: Amendment 39-9327. Docket 81-ANE-03. 
Supersedes AD 81-08-02 R2, Amendment 39-4817.

    Applicability: Pratt & Whitney (PW) JT8D-1, -1A, -7, -7A, -7B, -
9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines 
with 9th through 12th stage high pressure compressor (HPC) disks 
specified in 

[[Page 40756]]
Tables I through V and Table VIII of PW Alert Service Bulletin (ASB) 
No. 4723, Revision 12, dated March 8, 1990, installed. These engines 
are installed on but not limited to Boeing 727 series and 737 
series, and McDonnell Douglas DC-9 series aircraft.

    Note: 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 use the 
authority provided in paragraph (e) to request approval from the 
Federal Aviation Administration (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 in accordance with PW ASB No. 4723, Revision 9, dated 
July 13, 1983; Revision 10, dated September 15, 1986; or Revision 
11, dated October 30, 1987. All inspections subsequent to the 
effective date of this AD must be accomplished in accordance with 
the methods and intervals identified in PW ASB No. 4723, Revision 
12, dated March 8, 1990, except as is specified in paragraph (d) of 
this AD.
    To prevent uncontained fractures of 9th through 12th stage HPC 
disks and engine failure, accomplish the following:
    (a) Initially inspect 9th through 12th stage HPC disks at the 
tierod holes in accordance with Tables I through V and Table VIII of 
PW ASB No. 4273, Revision 12, dated March 8, 1990.
    (b) Thereafter, inspect 9th through 12th stage HPC disks at the 
tierod holes in accordance with Tables I through V and Table VIII of 
PW ASB No. 4723, Revision 12, dated March 8, 1990. Disks initially 
inspected prior to the first inspection limit must be reinspected 
before reaching the specified reinspection interval, or before 
reaching the first inspection limit, whichever is later. In no case 
shall the established life limits of the disks be exceeded.
    (c) Remove cracked disks from service prior to further flight, 
and replace with a serviceable part. Disks may be returned to 
service if repaired in accordance with Paragraph 7 of PW ASB No. 
4723, Revision 12, dated March 8, 1990.
    (d) For 10th stage HPC disks that were last inspected in 
accordance with the on-wing ultrasonic inspection procedure 
specified in AD 81-08-02 R2 prior to the effective date of this AD, 
inspect as follows:
    (1) Perform a magnetic particle inspection or eddy current 
inspection in accordance with the procedure defined in Paragraph 6 
and Appendix B of PW ASB No. 4723, Revision 12, dated March 8, 1990, 
no later than 750 cycles in service (CIS) since the last on-wing 
inspection.
    (2) Accomplish all subsequent inspections in accordance with the 
methods and intervals specified in PW ASB No. 4723, Revision 12, 
dated March 8, 1990.
    (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 method of compliance with this AD, 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 ASB:

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                  Document No.                               Pages             Rev.              Date           
----------------------------------------------------------------------------------------------------------------
PW ASB No. 4723.................................  1.........................      12  Mar. 8, 1990.             
                                                  2-8.......................      10  Sept. 15, 1986.           
                                                  9-10......................      11  Oct. 30, 1987.            
                                                  11-25.....................      10  Sept. 15, 1986.           
Appendix A......................................  A-1.......................      10  Sept. 15, 1986.           
                                                  A-2.......................                                    
Appendix B......................................  B-1--B-9..................       7  Feb. 16, 1981.            
                                                  B-10......................       8  July 9, 1982.             
                                                  B-11--B-12................       7  Feb. 16, 1981.            
Total pages: 38.                                                                                                
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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 Pratt & Whitney, Technical 
Publications Department, M/S 132-30, 400 Main Street, East Hartford, 
CT 06108. 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.
    (h) This amendment becomes effective on September 11, 1995.

    Issued in Burlington, Massachusetts, on July 26, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-19232 Filed 8-9-95; 8:45 am]
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