2010-6583. Airworthiness Directives; Pratt & Whitney (PW) Model PW2037, PW2037(M), and PW2040 Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for PW Model PW2037, PW2037(M), and PW2040 turbofan engines. This proposed AD would require removing erosion damage on fan blades with cutback leading edges and restoring the leading edge contour. This proposed AD results from reports from PW that fan blade leading edge erosion can result in a fan thrust deterioration mode (FTDM) condition, which reduces the engine's capability of producing full rated take-off thrust. We are proposing this AD to prevent loss of engine thrust from an FTDM condition, which could result in an inability to maintain safe flight.

DATES:

We must receive any comments on this proposed AD by May 24, 2010.

ADDRESSES:

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

• Federal eRulemaking 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: [phone].

You can get the service information identified in this proposed AD from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone [phone]; fax [phone].

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: [e-mail]; telephone [phone]; fax [phone].

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-2008-1095; Directorate Identifier 2008-NE-34-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 street address for the Docket Operations office (telephone [phone]) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

We have received reports from PW of leading edge erosion on PW2000 fan blades (LPC STG 1 Blade) with a cutback leading edge, part numbers (P/Ns) 1B6531, 1B6231-001, and 1A9031-001 (LPC STG1 Blade Set P/Ns 1B6521, 1B6221-001, and 1A9721-001). Leading edge erosion can result in an FTDM condition. Pratt & Whitney has found evidence of FTDM from engine test cell data, and on installed engines from PW2000 engine health monitoring data. The FTDM condition can result in an inability of the engine to meet full rated take off thrust and maintain safe flight.

Relevant Service Information

We have reviewed and approved the technical contents of PW Alert Service Bulletin (ASB) PW2000 A72-729, Revision 1, dated December 8, 2009, that describes procedures for removing erosion from the leading edge of the fan blades, and restoring the leading edge contour.

Differences Between the Proposed AD and the Manufacturer's Service Information

The PW ASB PW2000 A72-729, Revision 1, dated December 8, 2009, requires initial compliance by December 1, 2008, for PW2040 engines and by March 1, 2009, for PW2037 and PW2037(M) engines. This proposed AD would require initial compliance within 500 cycles-in-service after the effective date of this proposed AD for PW2037, PW2037(M) and PW2040 engines.

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 initial and repetitive maintenance to restore the leading edge contour of PW2000 fan blade P/Ns 1B6531, 1B6231-001, and 1A9031-001 (LPC STG1 blade set P/Ns 1B6521, 1B6221-001, and 1A9721-001.

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 480 engines installed on airplanes of U.S. registry. We also estimate that it would take about 12 work-hours per engine to perform the proposed actions, and that the average labor rate is $85 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 $489,600 per year.

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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

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:

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.

§ 39.13

[Amended]

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

Pratt & Whitney: Docket No. FAA-2008-1095; Directorate Identifier 2008-NE-34-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by May 24, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Pratt & Whitney (PW) PW2037, PW2037(M), and PW2040 turbofan engines with six or more fan blade (LPC STG1 blade), part numbers (P/Ns) 1B6531, 1B6231-001, or 1A9031-001 (LPC STG1 blade set P/Ns 1B6521, 1B6221-001, and 1A9721-001), with a cutback leading edge, installed. These engines are installed on, but not limited to, Boeing 757 airplanes.

Unsafe Condition

(d) This AD results from reports from PW that fan blade leading edge erosion can result in a fan thrust deterioration mode (FTDM) condition, which reduces the engine's capability of producing full rated take-off thrust. We are issuing this AD to prevent loss of engine thrust from an FTDM condition, which could result in an inability to maintain safe flight.

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.

Restoring the Fan Blade Leading Edge Contour

(f) Within 500 cycles-in-service after the effective date of this AD, restore the fan blade leading edge contour using one of the following:

(1) For engines installed on the airplane, use the Accomplishment Instructions, For Engines Installed on Aircraft, paragraphs 1. through 1.T. of PW Alert Service Bulletin (ASB) PW2000 A72-729, Revision 1, dated December 8, 2009.

(2) For engines that are not installed on the airplane, use the Accomplishment Instructions, For Engines Not Installed on Aircraft, paragraphs 1. through 1.S. of PW ASB PW2000 A72-729, Revision 1, dated December 8, 2009.

(g) Thereafter, repeat paragraphs (f)(1) or (f)(2) of this AD, within intervals of 1,000 cycles-since-last repair.

Alternative Methods of Compliance

(h) Pratt & Whitney PW2037, PW2040, PW2240, PW2337 Turbofan Engine Manual, Part No. 1A6231, Chapter/Section 72-31-12, Repair 14, is an approved alternative method of compliance to paragraphs (f)(1) and (f)(2) of this AD.

(i) Boeing 757 Airplane Flight Manual Document D631N002, Appendix 24, (Performance For Operation Of PW2000 Series Engines With Cutback Fan Blades Installed), is an approved alternative method of compliance to paragraphs (f)(1) and (f)(2) and (g) of this AD.

(j) 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

(k) Contact Mark Riley, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone], fax [phone], for more information about this AD.

(l) Pratt & Whitney ASB PW2000 A72-729, Revision 1, dated December 8, 2009, pertains to the subject of this AD. Contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone [phone]; fax [phone], for a copy of this service information.

Issued in Burlington, Massachusetts, on March 18, 2010.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.