[Federal Register Volume 62, Number 182 (Friday, September 19, 1997)]
[Rules and Regulations]
[Pages 49133-49135]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24796]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-ANE-32; Amendment 39-10133; AD 97-19-12]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT8D 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 Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, 
-11, -15, -17, and -17R series turbofan engines, that requires initial 
and repetitive fluorescent penetrant and eddy current inspections of 
4th stage low pressure turbine (LPT) hubs for cracks, and, if 
necessary, replacement with serviceable parts. This amendment

[[Page 49134]]

is prompted by a report of an uncontained 4th stage LPT blade release. 
The actions specified by this AD are intended to prevent a 4th stage 
LPT blade release due to hub cracking, which can result in an 
uncontained engine failure and damage to the aircraft.

DATES: Effective November 18, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 18, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, Publication Department, Supervisor 
Technical Publications Distribution, M/S 132-30, 400 Main St., East 
Hartford, CT 06108; telephone (860) 565-7700, fax (860) 565-4503. 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: Christopher Spinney, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (781) 238-7175, 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) that is applicable to Pratt & Whitney JT8D-1, -1A, -1B, 
-7, -7A, -7B, -9, -9A, -11, -15, -17, and -17R series turbofan engines 
was published in the Federal Register on January 9, 1997 (62 FR 1299). 
That action proposed to require initial and repetitive fluorescent 
penetrant inspections (FPI) and eddy current inspections (ECI) of 
affected 4th stage low pressure turbine (LPT) hubs for cracks, and, if 
necessary, replacement with serviceable parts.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Four commenters support the rule as proposed.
    One commenter states that the inspection should be performed in 
less than 5,900 cycles in service (CIS), as that was the number of CIS 
between the last FPI and the uncontained event that prompted this AD. 
The FAA does not concur. The FAA has evaluated the data and risk 
management plan supplied by PW that includes risk analysis, crack 
growth analysis, and field experience for the 4th stage LPT hubs. That 
data supports the FAA conclusion that the unsafe condition is an 
uncontained release of an LPT blade. The FAA concludes the loads 
introduced by the cracking of the 4th stage hub are not sufficient to 
result in an uncontained release of the entire 4th stage hub. Further, 
the analyses support the risk management plan, which includes a 
focused, ultra high sensitivity FPI and ECI at the next piece part 
exposure. The FAA has also concluded that the unsafe condition 
resulting from an uncontained blade failure can be mitigated by a 
reduced compliance time for installing LPT containment hardware on 
engines in which certain 4th stage LPT hubs are installed. The revised 
compliance requirement is described in AD 97-19-14.
    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.
    The FAA estimates that 381 engines installed on aircraft of U.S. 
registry will be affected by this AD, that it will take approximately 6 
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 
$137,160.
    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:

97-19-12 Pratt & Whitney: Amendment 39-10133. Docket 96-ANE-32.

    Applicability: Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7, 
-7A, -7B, 9, -9A, -11, -15, -17, and -17R turbofan engines, with 4th 
stage low pressure turbine (LPT) hubs identified by serial number 
(S/N) in Table A of PW Alert Service Bulletin (ASB) No. A6274, 
Revision 1, dated December 9, 1996. These engines are installed on 
but not limited to Boeing 727 and 737 series, and McDonnell Douglas 
DC-9 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 (b) 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 4th stage LPT blade failure due to hub cracking, 
which can result in an uncontained engine failure and damage to the 
aircraft, accomplish the following:
    (a) Perform fluorescent penetrant inspection (FPI) and eddy 
current inspection (ECI) of affected 4th stage LPT hubs for cracks, 
in accordance with Paragraph 2A of PW ASB No. A6274, Revision 1, 
dated December 9, 1996, as follows:
    (1) Inspect at the next time after the effective date of this AD 
that the hub is removed from the module and has been debladed.
    (2) Thereafter, inspect each time the hub is removed from the 
module and has been debladed.

[[Page 49135]]

    (3) Remove from service any cracked 4th stage LPT hub and 
replace with a serviceable part.
    (b) 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 forward their requests 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.

    (c) 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.
    (d) The actions required by this AD shall be done in accordance 
with the following PW ASB:

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         Document No.           Pages   Revision           Date         
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A6274........................    1-23          1  December 9, 1996.     
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    Total Pages: 23.
    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, Publication Department, 
Supervisor Technical Publications Distribution,
M/S 132-30, 400 Main St., East Hartford, CT 06108; telephone (860) 565-
7700, fax (860) 565-4503. 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.
    (e) This amendment becomes effective on November 18, 1997.

    Issued in Burlington, Massachusetts, on September 10, 1997.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-24796 Filed 9-18-97; 8:45 am]
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