AD Amdt-39-11219

[Federal Register Volume 64, Number 133 (Tuesday, July 13, 1999)]
[Rules and Regulations]
[Pages 37667-37669]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 99-17427]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 92-ANE-23; Amendment 39-11219; AD 99-14-08]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D 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 (PW) JT9D series turbofan engines, 
that currently requires initial and repetitive inspections of the sixth 
stage low pressure turbine (LPT) inner airseal, and modification of the 
sixth stage LPT inner airseal to reduce the potential for two failure 
modes. This amendment requires additional repetitive borescope 
inspections for sixth stage LPT inner airseals found with cracks less 
than one inch in length. This amendment is prompted by the publication 
of a revision to a PW service bulletin that introduces the new 
borescope inspections. The actions specified by this AD are intended to 
prevent an uncontained failure of the sixth stage LPT inner airseal, 
which can result in damage to the aircraft.

DATES: Effective September 13, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 13, 1999.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; 
telephone (860) 565-8770, 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 01803-5299; 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) by superseding AD 94-10-09, 
Amendment 39-8916 (59 FR 36047, July 15, 1994), applicable to Pratt & 
Whitney (PW) JT9D series turbofan engines, was published in the Federal 
Register on September 9, 1998 (63 FR 48138). That action proposed to 
add, at intervals not to exceed 50 cycles in service (CIS) since last 
inspection, additional repetitive borescope inspections for sixth stage 
LPT inner airseals found with cracks less than one inch in length, in 
accordance with PW Service Bulletin (SB) No. 5978, Revision 4, dated 
May 6, 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.
    Two commenters state they are not affected by the proposed rule.
    One commenter states that it is not affected by the proposed 
changes to the current AD.
    The FAA has switched the placement of paragraphs (b) and (c) of the 
proposed rule in order to emphasize that rework of the 6th stage LPT 
inner airseal rear retaining wing must be performed prior to further 
flight, but that even after rework, the required ECI or borescope 
inspections must be performed until installation of an improved 6th 
stage inner airseal. Therefore, proposed paragraph (b) appears as 
paragraph (c) in the final rule, and proposed paragraph (c) as 
paragraph (b). 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 with this change. 
The FAA has determined that this change neither increases the economic 
burden on any operator nor increases the scope of the AD
    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 2.1 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 $19,782.

[[Page 37668]]

    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 removing Amendment 39-8916 (59 FR 
36047, July 15, 1994) and by adding a new airworthiness directive, 
Amendment 39-11219, to read as follows:

99-14-08  Pratt & Whitney: Amendment 39-11219. Docket No. 92-ANE-23. 
Supersedes AD 94-10-09, Amendment 39-8916.

    Applicability: Pratt & Whitney (PW) Model JT9D-59A, -70A, -7Q, 
and -7Q3 turbofan engines, 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 (e) 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 an uncontained failure of the sixth stage low 
pressure turbine (LPT) inner airseal, accomplish the following:
    (a) Prior to further flight, rework the sixth stage LPT inner 
airseal knife edge diameters in accordance with the Accomplishment 
Instructions of PW Service Bulletin (SB) 5847, Revision 2, dated 
October 31, 1990.
    (b) Prior to further flight, rework the sixth stage LPT inner 
airseal rear retaining wing in accordance with the Accomplishment 
Instructions of PW SB 5745, Revision 2, dated October 24, 1990.

    Note 2: Rework of the sixth stage LPT inner airseal rear 
retaining wing in accordance with paragraph (b) of this AD does not 
exempt sixth stage LPT inner airseals from initial and repetitive 
inspections in accordance with paragraphs (c)(1), (c)(2), (c)(3), 
and (c)(4) of this AD.

    (c) Eddy current inspect (ECI) or borescope inspect sixth stage 
LPT inner airseal rear retaining wings for cracks, as follows:
    (1) For sixth stage LPT inner airseals identified by part number 
(P/N) in PW SB No. 5978, Revision 4, dated May 6, 1998, or Revision 
3, dated May 20, 1992, with greater than 500 cycles since new (CSN) 
on the effective date of this AD, accomplish an initial ECI or 
borescope inspection prior to accumulating more than 250 cycles in 
service (CIS) after the effective date of this AD, or 500 CIS since 
the last in-shop fluorescent penetrant inspection (FPI), whichever 
occurs later, in accordance with the Accomplishment Instructions of 
PW SB No. 5978, Revision 4, dated May 6, 1998, or Revision 3, dated 
May 20, 1992.
    (2) For sixth stage LPT inner airseals identified by P/N in PW 
SB No. 5978, Revision 4, dated May 6, 1998, or Revision 3, dated May 
20, 1992, with less than or equal to 500 CSN on the effective date 
of this AD, accomplish an initial ECI or borescope inspection prior 
to accumulating 750 CSN, or 500 CIS since the last in-shop FPI, 
whichever occurs later, in accordance with the Accomplishment 
Instructions of PW SB No. 5978, Revision 4, dated May 6, 1998, or 
Revision 3, dated May 20, 1992.
    (3) For sixth stage LPT inner airseals that meet the continue in 
service criteria described in PW SB No. 5978, Revision 4, dated May 
6, 1998, thereafter, ECI or borescope inspect the sixth stage LPT 
inner airseal retaining wing for cracks at intervals specified in 
accordance with the Accomplishment Instructions of PW SB No. 5978, 
Revision 4, dated May 6, 1998.
    (4) Remove cracked sixth stage LPT inner airseals that do not 
meet the continue in service criteria described in PW SB No. 5978, 
Revision 4, dated May 6, 1998, and replace with a new, or 
serviceable sixth stage LPT inner airseal that has been reworked in 
accordance with paragraph (c) of this AD.
    (5) Thereafter, inspect initially, reinspect, and remove from 
service, if necessary, the replacement sixth stage LPT inner 
airseals in accordance with paragraphs (c)(1), (c)(2), (c)(3), and 
(c)(4) of this AD.
    (d) Installation of a new, improved 6th stage LPT inner airseal, 
in accordance with PW SB No. 6054, Revision 1, dated April 24, 1992, 
constitutes terminating action to the inspections and rework 
required by this AD.
    (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. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Engine Certification Office.

    Note 3: 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 PW SBs:

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          Document No.                 Pages                 Revision                          Date
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5847............................          1-4     2.............................  October 31, 1990.
                                            5     Original......................  April 11, 1989.
                                            6     2.............................  October 31, 1990.
                                            7     Original......................  April 11, 1989.
                                            8     2.............................  October 31, 1990.
                                            9     Original......................  April 11, 1989.
                                           10     2.............................  October 31, 1990.

[[Page 37669]]

 
    Total pages: 10.
5978............................            1     4.............................  May 6, 1998.
                                            2     Original......................  December 19, 1990.
                                          3,4     4.............................  May 6, 1998.
                                            5     1.............................  October 10, 1991.
                                            6     4.............................  May 6, 1998.
                                         7-11     1.............................  October 10, 1991.
                                           12     4.............................  May 6, 1998.
                                        13-18     1.............................  October 10, 1991.
                                           19     4.............................  May 6, 1998.
                                        20-33     1.............................  October 10, 1991.
                                           34     2.............................  April 28, 1992.
    Total pages: 34.
5978............................            1     3.............................  May 20, 1992.
                                            2     Original......................  December 19, 1990.
                                          3,4     2.............................  April 28, 1992.
                                            5     1.............................  October 10, 1991.
                                            6     4.............................  February 1998.
                                         7-11     1.............................  October 10, 1991.
                                           12     3.............................  May 20, 1992.
                                        13-18     1.............................  October 10, 1991.
                                           19     3.............................  May 20, 1992.
                                        20-33     1.............................  October 10, 1991.
                                           34     2.............................  April 28, 1992.
    Total pages: 34.
5745............................          1-9     2.............................  October 24, 1990.
    Total pages: 9.
6054............................          1-4     1.............................  April 24, 1992.
                                          5-7     Original......................  November 6, 1991.
                                            8     1.............................  April 24, 1992.
                                         9-16     Original......................  November 6, 1991.
    Total pages: 16.
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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, 400 Main St., 
East Hartford, CT 06108; telephone (860) 565-8770, 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.
    (h) This amendment becomes effective on September 13, 1999.

    Issued in Burlington, Massachusetts, on July 2, 1999.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 99-17427 Filed 7-12-99; 8:45 am]
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