[Federal Register Volume 69, Number 129 (Wednesday, July 7, 2004)]
[Proposed Rules]
[Pages 40819-40821]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-15391]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-27-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede 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 proposed AD would 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. This proposed AD results from 
the manufacturer introducing an improved design HPT second stage 
airseal and

[[Page 40820]]

modifications to increase cooling. We are proposing 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: We must receive any comments on this proposed AD by September 7, 
2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD:
     By mail: Federal Aviation Administration (FAA), New 
England Region, Office of the Regional Counsel, Attention: Rules Docket 
No. 2001-NE-27-AD, 12 New England Executive Park, Burlington, MA 01803-
5299.
     By fax: (781) 238-7055.
     By e-mail: [email protected].
    You can get the service information identified in this proposed 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 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: 

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. 2001-NE-27-AD'' in the 
subject line of your comments. If you want us to acknowledge receipt of 
your mailed comments, send us a self-addressed, stamped postcard with 
the docket number written on it; we will date-stamp your postcard and 
mail it back to you. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
AD. If a person contacts us verbally, and that contact relates to a 
substantive part of this proposed AD, we will summarize the contact and 
place the summary in the docket. We will consider all comments received 
by the closing date and may amend the proposed AD in light of those 
comments.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You may get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

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.

Discussion

    On May 10, 2002, the FAA issued AD 2002-10-07, Amendment 39-12753 
(67 FR 36092, May 23, 2002). That AD requires FPI of HPT second stage 
airseals, (P/Ns) 5002537-01, 788945, 753187, and 807410, knife-edges 
for cracks, each time the airseal is accessible. That AD was the result 
of reports of cracks found in the knife-edges of HPT second stage 
airseals during HPT disassembly. That condition, if not corrected, 
could result in 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.

Actions Since We Issued AD 2002-10-07

    Since we issued AD 2002-10-07, analysis by PW has revealed that 
thermal mechanical fatigue causes the cracks in the knife-edges and 
antirotation slots of HPT second stage airseals. Analysis has also 
revealed that material creep causes an excessive brace gap of the outer 
detail of HPT second stage airseals.

Relevant Service Information

    We have reviewed and approved the technical contents of PW Service 
Bulletin No. JT9D 6454, Revision 1, dated June 2, 2004, that describes 
procedures for addressing these conditions by:
     Introducing an improved design HPT second stage airseal 
that has a more efficient, 4 knife-edge design, to minimize leakage 
past the seal.
     Modifying the 2nd stage HPT vane cluster assembly and 1st 
stage retaining blade HPT plate assembly, to allow additional 13th and 
15th stage turbine cooling air into the 1-2 Cavity.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other engines of 
this same type design. We are proposing this AD, which would require 
introducing 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 are 
considered terminating action to the repetitive inspections required by 
AD 2002-10-07. The proposed AD would require that you do these actions 
using the service information described previously.

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 would be affected 
by this proposed AD. We also estimate that it would take approximately 
210 work hours per engine to perform the proposed actions, and that the 
average labor rate is $65 per work hour. Required parts would cost 
approximately $117,696 per engine. Based on these figures, we estimate 
the total cost of the proposed AD to U.S. operators to be $23,116,896.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Would 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 proposal 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-27-AD'' in your request.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

[[Page 40821]]

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by removing Amendment 39-12753 (67 FR 
36092, May 23, 2002) and by adding a new airworthiness directive to 
read as follows:

Pratt & Whitney: Docket No. 2001-NE-27-AD. Supersedes AD 2002-10-07, 
Amendment 39-12753.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by September 7, 
2004.

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 1, dated 
June 2, 2004, to do this.

Alternative Methods of Compliance

    (g) 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

    (h) None.

Related Information

    (i) None.


    Issued in Burlington, Massachusetts, on June 30, 2004.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 04-15391 Filed 7-6-04; 8:45 am]
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