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Proposed Rule

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

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

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 Start Printed Page 40820modifications 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: 9-ane-adcomment@faa.gov.

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.

Start Further Info

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.

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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.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. The FAA amends § 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.

Start Signature

Issued in Burlington, Massachusetts, on June 30, 2004.

Mark C. Fulmer,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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[FR Doc. 04-15391 Filed 7-6-04; 8:45 am]

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