Airworthiness Directives; Pratt & Whitney JT9D-59A, -70A, -7Q, and -7Q3 Turbofan Engines

[Federal Register Volume 70, Number 46 (Thursday, March 10, 2005)]
[Rules and Regulations]
[Pages 11844-11846]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-4562]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-27-AD; Amendment 39-14002; AD 2005-05-13]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D-59A, -70A, -7Q, 
and -7Q3 Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD) for Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, and -7Q3 turbofan 
engines. That AD currently requires fluorescent penetrant inspection 
(FPI) of high pressure turbine (HPT) second stage airseals, part 
numbers (P/Ns) 5002537-01, 788945, 753187, and 807410, knife-edges for 
cracks, each time the engine's HPT second stage airseal is accessible. 
This AD requires replacing each existing HPT second stage airseal with 
an improved design HPT second stage airseal and modifying the 2nd stage 
HPT vane cluster assembly and 1st stage retaining blade HPT plate 
assembly at next piece-part exposure, but no later than five years 
after the effective date of this AD. These actions are considered 
terminating action to the repetitive inspections required by AD 2002-
10-07. This AD results from the manufacturer introducing an improved 
design HPT second stage airseal and modifications to increase cooling. 
We are issuing this AD to prevent failure of the HPT second stage 
airseal due to cracks in the knife-edges, which if not detected, could 
result in uncontained engine failure and damage to the airplane.

DATES: This AD becomes effective April 14, 2005. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in the regulations as of April 14, 2005.

ADDRESSES: You can get the service information identified in this AD 
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 
(860) 565-8770; fax (860) 565-4503.
    You may examine the AD docket and the service information at the 
FAA, New England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Kevin Donovan, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01887-5299; telephone (781) 
238-7743; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR Part 39 
with a proposed AD. The proposed AD applies to PW JT9D-59A, -70A, -7Q, 
and -7Q3 turbofan engines. We published the proposed AD in the Federal 
Register on July 7, 2004 (69 FR 40819). That action proposed to require 
replacing each existing HPT second stage airseal with an improved 
design HPT second stage airseal and modifying the 2nd stage HPT vane 
cluster assembly and 1st stage retaining blade HPT plate assembly at 
next piece-part exposure, but no later than five years after the 
effective date of the proposed AD. These actions would be considered 
terminating action to the repetitive inspections required by AD 2002-
10-07.

Examining the AD Docket

    You may examine the AD Docket (including any comments and service 
information), by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. See ADDRESSES for the 
location.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Request To Keep AD 2002-10-07 as an Alternative Means of Compliance

    One commenter requests that the existing AD, which is AD 2002-10-
07, be kept as an alternative means of compliance. The commenter states 
that the compliance of the proposed AD, as per the Accomplishment 
Instructions of PW Service Bulletin (SB) No. JT9D 6454, Revision 1, not 
only requires replacement of the HPT second stage turbine airseal, but 
also requires replacement and modification of many other parts. Since 
all of the parts of the HPT module are required to be exposed to piece-
parts during overhaul, and not at any other time, the compliance 
statement which states ``At the next piece-part exposure'' should be 
amended to ``At the next HPT Module overhaul'', as also stated in SB 
No. JT9D 6454, Revision 1.
    We do not agree. AD 2002-10-07 was introduced solely as an interim 
action, with the intent of the redesign being the final solution. We 
are issuing this AD to prevent failure of the HPT second stage airseal 
due to cracks in the knife-edges, which if not detected, could result 
in uncontained engine failure and damage to the airplane. Therefore we 
do not feel that the AD 2002-10-07 interim action provides an 
equivalent level of safety. In addition, there are times such as an 
unscheduled maintenance event, in which the HPT module hardware will be 
exposed. It is our intention to incorporate this AD at the next piece-
part exposure.

Proposal for an Alternative Management Plan

    One commenter proposes an alternative management plan to the 
compliance section in the proposed AD, subject to the provisions in the 
proposed AD. The commenter provided the details of the proposed 
management plan to us in a separate document. The background to the 
proposed plan is as follows:
    HPT second stage airseals, P/Ns 5002537-01, 788945, 753187, and 
807410, have very high scrap rates. About 75% of airseals are scrapped 
after

[[Page 11845]]

fluorescent penetrant inspection (FPI). Only those airseals passing FPI 
which are reinstalled, will continue to have a risk of knife-edge 
cracking. Limiting those airseals to 2,000 cycles-in-service, maximum, 
before a repeat FPI is required, will increase the detection rate when 
compared to AD 2002-10-07.
    We do not agree. The purpose of AD 2002-10-07 was to serve as an 
interim action until PW provided a new design part. Since the new 
design part is available, we feel it is in the interest of public 
safety to replace the part at the earliest opportunity and prevent any 
failure of the HPT second stage airseal, which if not detected, could 
result in uncontained engine failure and damage to the airplane.

Request To Clarify Piece-Part Exposure

    One commenter requests clarification of the term ``piece-part 
exposure'' and suggests changing the term to ``piece-part level''.
    We agree to clarify the term ``piece-part exposure''. We have added 
a definition that states that for the purposes of this AD, piece-part 
exposure means the HPT second stage airseal disk is considered 
completely disassembled, when done in accordance with the disassembly 
instructions in the engine manufacturer's, or other FAA-approved engine 
manual.

Request for AD To Reflect the Latest Service Bulletin Compliance, and 
To Clarify That New Parts Can Also Be Installed

    One commenter, PW, states the following:
    ``The compliance requirements specified in the proposed AD are more 
stringent than what is recommended in the compliance section of SB No. 
JT9D 6454. Compliance with the proposed AD would require operators to 
incorporate the SB coincidental with module repair (piece-part 
exposure), which could occur well in advance of HPT module overhaul as 
defined in the SB. Although the proposed AD compliance requirement may 
seem prudent with regards to added conservatism, the SB recommendation 
is based on an industry-accepted methodology for the assessment of risk 
for future uncontained failures. A key variable in performing the risk 
analysis is the incorporation rate. The rate applied that satisfies 
PW's risk criteria, was in fact based on a typical HPT overhaul 
interval range. No consideration was given for piece-part exposure 
during a premature module repair or a specific ``hard-time'' 
incorporation date. Recognizing the FAA's desire to mandate a 
compliance date, PW reviewed the incorporation rate as it relates to a 
five-year compliance period and estimates 95% incorporation based on a 
typical overhaul interval, while incorporation at a six-year threshold 
captures 98.4% of the population.
    In summary:
    The AD should reflect compliance as defined in PW SB No. 6454, 
having a compliance date of 6 years as imposed by the FAA.
    Service Bulletin No. JT9D -6454 has been revised since the proposed 
AD was issued, adding additional airflow data to the turbine rotor 
nozzle and ring assembly airflow test procedure. The AD should reflect 
SB No. JT9D 6454, Revision 2.
    Wording throughout the proposed AD implies that compliance can only 
be achieved through modification of existing second stage vane 
clusters, and first stage blade retaining plates. The proposed AD 
should recognize that all parts required to accomplish the intent of SB 
No. JT9D 6454 are also available as new, from PW and modification of 
serviceable parts may be optional as specified in the SB.''
    We summarize the comment as follows:
    It is PW's technical opinion that the incorporation of SB No. JT9D 
6454 before HPT module overhaul, would create an unnecessary burden on 
operators. It is also PW's technical opinion that the compliance period 
should be extended to six years to capture a greater percentage of the 
population so not to create unnecessary financial burden on lower 
utilization operators.
    We partially agree. The purpose of AD 2002-10-07 was to serve as an 
interim action until PW provided a new design part. Since the new 
design for this part is now available, we feel it is an item of public 
safety to replace the part as a closing action for this AD and prevent 
an uncontained engine failure and damage to the airplane. We are 
referencing the latest revision of the SB, which is Revision 3, in the 
AD.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 564 PW JT9D-59A, -70A, -7Q, and -7Q3 turbofan 
engines of the affected design in the worldwide fleet. We estimate that 
176 engines installed on airplanes of U.S. registry will be affected by 
this AD. We also estimate that it will take approximately 210 work 
hours per engine to perform the actions, and that the average labor 
rate is $65 per work hour. Required parts will cost approximately 
$117,696 per engine. Based on these figures, we estimate the total cost 
of the AD to U.S. operators to be $23,116,896.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect 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.
    For the reasons discussed above, I certify that this AD:
    (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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary by 
sending a request to us at the address listed under ADDRESSES. Include 
``AD Docket No. 2001-NE-17-AD'' in your request.

[[Page 11846]]

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by removing Amendment 39-12753 (67 FR 
12753, May 23, 2002) and by adding a new airworthiness directive, 
Amendment 39-14002, to read as follows:

2005-05-13 Pratt & Whitney: Amendment 39-14002. Docket No. 2001-NE-
27-AD.

Effective Date

    (a) This AD becomes effective April 14, 2005.

Affected ADs

    (b) This AD supersedes AD 2002-10-07, Amendment 39-12753.

Applicability

    (c) This AD applies to Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, 
and -7Q3 turbofan engines with high pressure turbine (HPT) second 
stage airseal, part number (P/N) 5002537-01, 788945, 753187, or 
807410, installed. These engines are installed on, but not limited 
to, Airbus Industrie A300 series, Boeing 747 series, and McDonnell 
Douglas DC-10 series airplanes.

Unsafe Condition

    (d) This AD results from the manufacturer introducing an 
improved design HPT second stage airseal and modifications to 
increase cooling. We are issuing this AD to prevent failure of the 
HPT second stage airseal due to cracks in the knife-edges, which if 
not detected, could result in uncontained engine failure and damage 
to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.

Replacement of HPT Second Stage Airseal

    (f) At the next piece-part exposure, but no later than five 
years after the effective date of this AD, replace the HPT second 
stage airseal with a P/N HPT second stage airseal that is not listed 
in this AD, and modify the 2nd stage HPT vane cluster assembly and 
1st stage retaining blade HPT plate assembly. Use the Accomplishment 
Instructions of PW Service Bulletin No. JT9D 6454, Revision 3, dated 
November 9, 2004, to do this.

Definition

    (g) For the purposes of this AD, piece-part exposure means the 
HPT second stage airseal disk is considered completely disassembled, 
when done in accordance with the disassembly instructions in the 
engine manufacturer's, or other FAA-approved engine manual.

Alternative Methods of Compliance

    (h) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

    (i) You must use Pratt & Whitney Service Bulletin No. JT9D 6454, 
Revision 3, dated November 9, 2004, to perform the replacement and 
modification required by this AD. The Director of the Federal 
Register approved the incorporation by reference of this service 
bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You 
can get a copy from Pratt & Whitney, 400 Main St., East Hartford, CT 
06108; telephone (860) 565-8770; fax (860) 565-4503. You can review 
copies at the FAA, New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA; or at the 
National Archives and Records Administration (NARA). For information 
on the availability of this material at NARA, call 202-741-6030, or 
go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Related Information

    (j) None.

    Issued in Burlington, Massachusetts, on March 2, 2005.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 05-4562 Filed 3-9-05; 8:45 am]
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