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Proposed Rule

Airworthiness Directives; Pratt & Whitney (PW) Models PW2037, PW2037(M), and PW2040 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), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for PW models PW2037, PW2037(M), and PW2040 turbofan engines. This proposed AD would require inspecting all high-pressure turbine (HPT) 2nd stage hubs at the next HPT overhaul after the effective date of the proposed AD. The inspections of the hubs include fluorescent penetrant inspection (FPI) for cracks and an optical comparator inspection (OCI) of the blade retention slots to confirm the hubs are within dimensional tolerances before returning them to service. This proposed AD results from an uncontained release of HPT 2nd stage blades and blade retention lugs. We are proposing this AD to detect cracks and remove nonconforming HPT 2nd stage hubs, which could result in an uncontained release of turbine blades and blade retention lugs, and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by January 13, 2009.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

  • Federal Rulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.
  • Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
  • Fax: (202) 493-2251.

Contact Pratt & Whitney, 400 Main Street, East Hartford, CT 06108 for the service information identified in this AD.

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FOR FURTHER INFORMATION CONTACT:

Mark Riley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: mark.riley@faa.gov; telephone (781) 238-7758, fax (781) 238-7199.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2008-1131; Directorate Identifier 2008-NE-37-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of the Web site, anyone can find and read the comments in any of our dockets, including, if provided, the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78).

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The Start Printed Page 67428street address for the Docket Operations office (telephone (800) 647-5527) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

On August 6, 2008, a PW2037 turbofan engine experienced an uncontained failure of multiple HPT 2nd stage blades. Although the root cause is still under investigation, we have determined that cracks in the blade retention lugs of the HPT 2nd stage hub resulted in fracture of multiple lugs, and release of 2nd stage blades. Optical comparator inspections (OCIs) performed on the blade retention slots of the HPT 2nd stage hub confirmed the slots were out of dimensional tolerances. HPT 2nd stage hubs with blade retention slots that are out of tolerance can cause cracks and fracture of multiple blade retention lugs and release of 2nd stage blades from the hub. This condition, if not corrected, could result in an uncontained release of turbine blades and blade retention lugs, and damage to the airplane.

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 products of this same type design. We are proposing this AD, which would require performing an FPI of the hub for cracks and an OCI of the blade retention slots on the forward and aft sides of the HPT 2nd stage hub for conformance to dimensional tolerances at the next HPT overhaul after the effective date of this AD.

Interim Action

These actions are interim actions and we are requiring reporting inspection data, including negative findings, to determine if we need to take further rulemaking actions in the future.

Costs of Compliance

We estimate that this proposed AD would affect 762 engines installed on airplanes of U.S. registry. We also estimate that it would take about 6 work-hours per engine to perform the proposed actions, and that the average labor rate is $80 per work-hour. No parts are required. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $365,760.

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 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 AD:

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 regulatory evaluation of the estimated costs to comply with this proposed AD. You may get a copy of this summary at the address listed under ADDRESSES.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

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 adding the following new airworthiness directive:

Pratt & Whitney: Docket No. FAA-2008-1131; Directorate Identifier 2008-NE-37-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by January 13, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Pratt & Whitney models PW2037, PW2037(M), and PW2040 turbofan engines. These engines are installed on, but not limited to, Boeing 757-200 and 757-300 airplanes.

Unsafe Condition

(d) This AD results from an uncontained release of high-pressure turbine (HPT) 2nd stage blades and blade retention lugs. We are issuing this AD to detect cracks and remove nonconforming HPT 2nd stage hubs, which could result in an uncontained release of turbine blades and blade retention lugs, and damage to the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed at the next HPT overhaul, unless the actions have already been done.

Performing Inspections on HPT 2nd Stage Hubs

(f) Perform a fluorescent penetrant inspection (FPI) of the hub for cracks. Pratt & Whitney Engine Manual part number 1A6231 (Chapter 72-52-00, Inspection/Check-02, (Subtask 72-52-16-230-007)) contains information on performing the FPI.

(g) Remove from service any cracked hubs.

(h) Any HPT 2nd stage hubs inspected as specified in paragraphs (f) of this AD, must pass an optical comparator inspection before the hubs are eligible for return to service. Pratt & Whitney Alert Service Bulletin, PW2000 A72-734, contains information about the inspection.

Reporting Requirements

(i) For 6 months from the effective date of the AD, and within 72 hours of completing the inspections required by this AD, report the following to the Engine Certification Office, ATTN: Mark Riley, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803:

(1) Inspection Date.

(2) Disk part number and serial number.

(3) Hours since new.

(4) Cycles since new.

(5) Hours since overhaul.

(6) Cycles since overhaul.

(7) Fluorescent penetrant inspection findings.

(8) Optical comparator inspection findings.

(j) Under the provisions of the Paperwork Reduction Act, the Office of Management and Start Printed Page 67429Budget (OMB) have approved the information collection requirements and has assigned OMB Control Number 2120-0056.

Definitions

(k) This AD defines an HPT overhaul as when the HPT is at its piece-part level.

Alternative Methods of Compliance

(l) 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.

Related Information

(m) Contact Mark Riley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: mark.riley@faa.gov; telephone (781) 238-7758, fax (781) 238-7199, for more information about this AD.

(n) Pratt & Whitney Alert Service Bulletin, PW2000 A72-734, contains information about the optical comparator inspection.

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Issued in Burlington, Massachusetts, on November 6, 2008.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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[FR Doc. E8-26909 Filed 11-13-08; 8:45 am]

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