AD Amdt-39-9721

[Federal Register Volume 61, Number 181 (Tuesday, September 17, 1996)]
[Rules and Regulations]
[Pages 48818-48820]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 96-22771]



[[Page 48818]]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-51; Amendment 39-9721; AD 96-17-11]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Pratt & Whitney (PW) JT9D-7R4 series turbofan engines, 
that requires replacement of 3rd, 4th, and 5th stage low pressure 
turbine (LPT) vane retention bolts and nuts, the removal of the 5th 
stage vane configuration which includes an electro-discharge machined 
(EDM) slot and replacement with a cast slot configuration, and 
prohibits the use of uncured anti-gallant compound on vane retention 
hardware. This amendment is prompted by reports of LPT failures that 
resulted in uncontained engine failures. The actions specified by this 
AD are intended to prevent LPT vane failures, which can result in 
uncontained engine failure, fire, and possible damage to the aircraft.

DATES: Effective November 18, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 18, 1996.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, Publications Department, Supervisor 
Technical Publications Distribution, M/S 132-30,400 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 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: John Fisher, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7149, 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 Pratt & Whitney (PW) JT9D-7R4 
series turbofan engines was published in the Federal Register on 
October 16, 1995 (60 FR 53556). That action proposed to require 
replacement of 3rd, 4th, and 5th stage low pressure turbine (LPT) vane 
retention bolts and nuts and the removal of the 5th stage vane 
configuration which includes an electro-discharge machined (EDM) slot, 
and replacement with a 5th stage vane featuring a cast slot 
configuration. In addition, the proposed AD would prohibit use of 
uncured anti-gallant compound on the bolts or nuts, as uncured anti-
gallant compound was a contributor to the unsafe condition. The actions 
would be required to be accomplished in accordance with PW Service 
Bulletin (SB) No. JT9D-7R4-72-473, Revision 2, dated February 8, 1993; 
PW Alert Service Bulletin (ASB) No. JT9D-7R4-72-480, dated April 20, 
1993; PW ASB No. JT9D-7R4-72-481, dated April 20, 1993; and PW SB No. 
JT9D-7R4-72-484, Revision 1, dated October 9, 1993.
    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 basically concur with the intent of the AD, but 
recommend a change in the accomplishment time, from the next shop visit 
to the next LPT module disassembly. The commenters believe 
accomplishment at the next shop visit causes an undue scheduling burden 
and increases cost by an estimated $558,900. The FAA does not concur. 
The FAA has reviewed the risk analysis, which predicts that if the 
accomplishment time is extended, the risk would quadruple, which the 
FAA considers unacceptable.
    Two commenters recommend a change to the acceptable configurations. 
They state that paragraph (b)(2) of the compliance section should be 
revised to reference PW SB No. JT9D-7R4-72-488, Revision 1, dated 
November 20, 1993, as an additional approved and acceptable 
configuration, as the configuration defined by that SB became available 
after the criteria for the NPRM was established. The FAA concurs in 
part. Pratt & Whitney SB No. JT9D-7R4-72-488, Revision 1, dated 
November 20, 1993, which describes modifying the vane retention stops, 
is not an alternative to PW SB No. JT9D-7R4-72-484, Revision 1, dated 
October 9, 1993, but can be added as a compliance option for an 
additional acceptable configuration. The FAA has therefore revised this 
final rule to include the following configurations as acceptable: (1) 
PW ASB No. JT9D-7R4-72-481, dated April 20, 1993; (2) PW SB No. JT9D-
7R4-72-484, Revision 1, dated October 9, 1993; or (3) PW SB No. JT9D-
7R4-72-484, Revision 1, dated October 9, 1993, and PW SB No. JT9D-7R4-
72-488, Revision 1, dated November 20, 1993.
    One commenter states that the reference to not using uncured anti-
gallant compound on the bolt threads in the compliance section should 
be deleted, and that the issue should only be addressed in the 
discussion section. The commenter believes that the prohibition against 
using anti-gallant compound in the compliance section is not 
appropriate as a maintenance action within an AD, and would result in 
no terminating action being available to the airlines. The FAA does not 
concur. The primary cause of the LPT vane retention hardware failures 
was the use of uncured anti-gallant compound. Therefore, the FAA has 
determined that the prohibition against using uncured anti-gallant 
compound is a key element of the AD, and must be an integral part of 
the compliance section.
    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 the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    The FAA estimates that 600 engines installed on aircraft of U.S. 
registry will be affected by this AD, that it will take approximately 
22 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 
$792,000.
    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

[[Page 48819]]

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), 40113, 44701.


Sec. 39.13  [AMENDED]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

    96-17-11 Pratt & Whitney: Amendment 39-9721. Docket 94-ANE-51.

    Applicability: Pratt & Whitney (PW) JT9D-7R4 series turbofan 
engines, installed on but not limited to Airbus A300 and A310 
series, and Boeing 747 and 767 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 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 low pressure turbine (LPT) vane failures, which can 
result in uncontained engine failure, fire, and possible damage to 
the aircraft, accomplish the following, accomplish the following:
    (a) Remove 5th stage LPT vane cluster segments that incorporate 
electro-discharge machined (EDM) slots, Part Numbers (P/N) 787885 or 
787885-001, and replace with the cast pocket vane configuration, P/N 
796985, 795175, 796985-001, 808875, 811985, or 811985-001, at the 
next shop visit, but not later than 5,000 cycles in service (CIS) 
after the effective date of this AD, in accordance with PW Alert 
Service Bulletin (ASB) No. JT9D-7R4-72-480, dated April 20, 1993.

    Note: Pratt & Whitney SB No. JT9D-7R4-72-473, Revision 2, dated 
February 8, 1993, may be used to segregate EDM slot from cast pocket 
5th stage LPT vane clusters sharing the same P/N 787885 and 787885-
001.

    (b) For LPT modules that previously have had the 3rd, 4th, or 
5th stage vane retention hardware disassembled for any reason 
perform paragraph (b)(1), (b)(2), or (b)(3) of this AD at the next 
shop visit, but not later than 5,000 CIS after the effective date of 
this AD, accomplish one of the following. Do not use uncured anti-
gallant compound on the bolts or nuts:
    (1) Install new 3rd, 4th, and 5th stage LPT vane bolts and nuts, 
in accordance with PW ASB No. JT9D-7R4-72-481, dated April 20, 1993; 
or
    (2) Install new 3rd, 4th, and 5th stage LPT vane bolts and nuts, 
and install heat shield assemblies and air sealing ring stop 
assemblies in accordance with PW SB No. JT9D-7R4-72-484, Revision 1, 
dated October 9, 1993; or
    (3) Install new 3rd, 4th, and 5th stage LPT vane bolts and nuts, 
and install heat shield assemblies and air sealing ring stop 
assemblies in accordance with PW SB No. JT9D-7R4-72-484, Revision 1, 
dated October 9, 1993, and PW SB No. JT9D-7R4-72-488, Revision 1, 
dated November 20, 1993.
    (c) For LPT modules that have never had the 3rd, 4th, or 5th 
stage vane retention hardware disassembled, perform paragraph 
(b)(1), (b)(2), or (b)(3) of this AD at the first LPT module 
disassembly. Do not use uncured anti-gallant compound on the bolts 
or nuts.
    (d) For the purpose of this AD, a shop visit is defined as the 
induction of an engine into a maintenance facility for the purpose 
of either:
    (1) Separation of pairs of major mating engine flanges; or
    (2) The removal of an engine disk, hub, or spool.
    (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 PW service documents:

----------------------------------------------------------------------------------------------------------------
          Document No.                   Pages               Revision                       Date                
----------------------------------------------------------------------------------------------------------------
SB No. JT9D-7R4 -72-473.........  1..................  2..................  February 8, 1993.                   
                                  2-5................  Original...........  November 11, 1992.                  
                                  6, 7...............  2..................  February 8, 1993.                   
                                  8..................  Original...........  November 11, 1992.                  
                                  9..................  1..................  December 16, 1992.                  
                                  10, 11.............  2..................  February 8, 1993.                   
      Total Pages: 11...........                                                                                
ASB No. JT9D-7R4-72-480.........  1-13...............  Original...........  April 20, 1993.                     
      Total Pages: 13...........                                                                                
ASB No. JT9D-7R4-72-481           1-11...............  Original...........  April 20, 1993.                     
      Total Pages: 11...........                                                                                
SB No. JT9D-7R4-72-484..........  1..................  1..................  October 9, 1993.                    
                                  2-8................  Original...........  August 2, 1993.                     
                                  9..................  1..................  October 9, 1993.                    
                                  10-16..............  Original...........  August 2, 1993.                     
                                  17.................  1..................  October 9, 1993.                    
                                  18-44..............  Original...........  August 2, 1993.                     
      Total Pages: 44...........                                                                                
SB No. JT9D-7R4-72-488..........  1..................  1..................  November 20, 1993                   
                                  2..................  Original...........  October 7, 1993.                    
                                  3..................  1..................  November 20, 1993.                  
                                  4-17...............  Original...........  October 7, 1993.                    

[[Page 48820]]

                                                                                                                
                                  18.................  1..................  November 20, 1993.                  
      Total Pages: 18...........                                                                                
----------------------------------------------------------------------------------------------------------------

    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, Publications 
Department, Supervisor Technical Publications Distribution, M/S 132-
30,400 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 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 November 18, 1996.

    Issued in Burlington, Massachusetts, on August 15, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 96-22771 Filed 9-16-96; 8:45 am]
BILLING CODE 4910-13-U