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Proposed Rule

Airworthiness Directives; Pratt & Whitney PW2000 Series 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.

Start Preamble

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 Pratt & Whitney PW2000 series turbofan engines. This proposed AD would require a onetime focused visual and fluorescent penetrant inspection (FPI) of 21 suspect PW2000 8th stage high pressure compressor (HPC) drum rotor disk assemblies. This proposed AD results from a PW2037 8th stage HPC drum rotor disk assembly failure event caused by tooling damage that occurred during disk assembly manufacture. We are proposing this AD to prevent 8th stage HPC drum rotor disk assembly failure that could result in an uncontained engine failure and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by October 2, 2006.

ADDRESSES:

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

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
  • Fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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 comments on this proposed AD in the AD docket on the Internet at http://dms.dot.gov.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Mark Riley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7758; fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

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-2006-24452; Directorate Identifier 2006-NE-11-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://dms.dot.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 DOT Web site, anyone can find and read the comments in any of our dockets, including 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) or you may visit http://dms.dot.gov.

Examining the AD Docket

You may examine the docket that contains the proposal, any comments received and, any final disposition in person at the DOT Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the Docket Management Facility receives them.

Discussion

On March 10, 2005, a PW2037 uncontained 8th stage HPC drum rotor disk assembly failure event occurred. The event occurred during takeoff and resulted in an inflight engine shutdown. A subsequent investigation confirmed the primary cause of the failure to be tooling damage (an improperly blended toolmark) that occurred during disk assembly manufacture. Tooling damage resulted in excessive stresses in the disk web section, which led to the disk assembly failure and uncontained engine event. Further investigation confirmed that there are 21 suspect PW2000 8th stage HPC drum rotor disk assemblies currently in service worldwide that have the potential for similar machining damage occurring during disk assembly manufacture. This machining damage could result in failure of the 8th stage HPC drum rotor disk assembly and result in an uncontained engine failure and damage to the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of Pratt & Whitney Start Printed Page 43998Alert Service Bulletin PW2000 A72-706, dated February 17, 2006, that describes procedures for a onetime focused visual and FPI of suspect PW2000 8th stage HPC drum rotor disk assemblies that may have been damaged during original manufacture.

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 a onetime focused visual and FPI of 21 suspect PW2000 8th stage HPC drum rotor disk assemblies. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 15 engines installed on airplanes of U.S. registry. We also estimate that it would take about 70 workhours per engine to perform the proposed actions, and that the average labor rate is $80 per workhour. We do not expect that parts will be required. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $84,000 for the inspection.

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 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 regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

Pratt & Whitney: Docket No. FAA-2006-24452; Directorate Identifier 2006-NE-11-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by October 2, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Pratt & Whitney PW2037, PW2040, PW2037M turbofan engines. These engines are installed on, but not limited to Boeing 757 airplanes.

Unsafe Condition

(d) This AD results from a Pratt & Whitney PW2037 8th stage high-pressure compressor (HPC) drum rotor disk assembly failure event caused by tooling damage that occurred during disk assembly manufacture. We are issuing this AD to prevent 8th stage HPC drum rotor disk assembly failure that could result in an uncontained engine failure and damage to the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed at the next shop visit, not to exceed an additional 6000 engine cycles, after the effective date of this AD, when the 8th stage HPC drum rotor disk assembly is exposed and removed from the HPC module, unless the actions have already been done.

Inspect the 8th Stage Drum Rotor Disk

(f) Using the Accomplishment Instructions of Pratt & Whitney Alert Service Bulletin PW2000 A72-706, dated February 17, 2006, do a onetime focused visual and fluorescent penetrant inspection (FPI) of suspect 8th stage HPC drum rotor disk assemblies that may have been damaged during manufacture. Any 8th stage disk damage that exceeds the serviceable limits specified in Pratt & Whitney PW2000 Engine Manual, Part Number 1A6231, Chapter/Section 72-35-03, Inspection/Check-01/-04, can not be returned to service. Table 1 of the Accomplishment Instructions lists the part numbers and serial numbers of the HPC drum rotor disk assemblies requiring inspection.

(g) After the effective date of this AD, do not install any uninspected 8th stage drum rotor disk assemblies listed in Table 1 of the Accomplishment Instructions of Pratt & Whitney Alert Service Bulletin PW2000 A72-706, dated February 17, 2006, in any engine.

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.

Start Signature

Issued in Burlington, Massachusetts, on July 27, 2006.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. E6-12539 Filed 8-2-06; 8:45 am]

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