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Proposed Rule

Airworthiness Directives; Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R 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), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Pratt & Whitney (PW) JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines. This proposed AD would require overhauling fan blade leading edges at the first shop visit after 4,000 cycles-in-service (CIS) since the last total fan blade overhaul was performed. This proposed AD results from reports of failed fan blades. We are proposing this AD to prevent high-cycle fatigue cracking at the blade root, which could result in uncontained failures of first stage fan blades and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by July 19, 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: (202) 493-2251.

Contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700; fax (860) 565-1605, for a copy of the service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

James Gray, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: james.gray@faa.gov; telephone (781) 238-7742; 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-2010-0514; Directorate Identifier 2010-NE-02-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 (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

We have received reports of 16 first stage fan blade root fractures, two of which resulted in penetration of the cowl and minor damage to the fuselage. Engineering investigation has determined that increased vibratory stress in the root and airfoil from eroded and blunt leading edges caused the fan blade failures. The primary cause of leading edge erosion is the operating environment, particularly rain and sand. The aerodynamic performance of the blade is diminished and vibratory stress in the airfoil and root is increased. This condition, if not corrected, could result in uncontained failures of first stage fan blades and damage to the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of PW JT8D Maintenance Advisory Notice MAN-JT8D-2-06, dated November 20, 2006, that describes procedures for overhauling the first stage fan blades at every shop visit where pairs of major mating flanges are separated.

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 overhauling the total set of stage 1 fan blades at:

  • The first shop visit after 4,000 CIS since the last total stage 1 fan blade overhaul or
  • The next shop visit after the effective date of this proposed AD if the CIS since the last total stage 1 fan blade overhaul is unknown and
  • Thereafter, at the next shop visit after 4,000 CIS since the last total stage fan blade overhaul.

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 1,527 engines installed on airplanes of U.S. registry. We also estimate that it would take about 63 work-hours per engine to perform the proposed actions, and that the average labor rate is $85 per work-hour. There would be no required parts. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $8,177,085.

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 Start Printed Page 27973detail 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.

Start List of Subjects

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-2010-0514; Directorate Identifier 2010-NE-02-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by July 19, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Pratt & Whitney (PW) JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines. These engines are installed on, but not limited to, Boeing 727 series, Boeing 737-200 series and McDonnell Douglas DC-9 airplanes.

Unsafe Condition

(d) This AD results from reports of failed fan blades. We are issuing this AD to prevent high-cycle fatigue cracking at the blade root, which could result in uncontained failures of first stage fan blades 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.

Initial Overhaul

(f) For engines where the cycles-in-service (CIS) since last overhaul are known, overhaul the total set of stage 1 fan blades at the first shop visit after 4,000 CIS since the last total stage 1 fan blade overhaul, or the next shop visit after the effective date of this AD, whichever occurs later. Guidance on performing a fan blade overhaul can be found in Pratt & Whitney JT8D Maintenance Advisory Notice, MAN-JT8D-2-06 and the Engine Manual Chapter/Section 72-33-21, Inspection 00.

(g) For engines where the CIS since last overhaul are unknown, overhaul the total set of stage 1 fan blades at the next shop visit after the effective date of this AD. Guidance on performing a fan blade overhaul can be found in Pratt & Whitney JT8D Maintenance Advisory Notice, MAN-JT8D-2-06 and the Engine Manual Chapter/Section 72-33-21, Inspection 00.

Repetitive Overhaul

(h) Thereafter, overhaul the total set of stage 1 fan blades at the first shop visit after 4,000 CIS since the last total stage 1 fan blade overhaul. Guidance on performing a fan blade overhaul can be found in Pratt & Whitney JT8D Maintenance Advisory Notice, MAN-JT8D-2-06 and the Engine Manual Chapter/Section 72-33-21, Inspection 00.

Definitions

(i) For the purpose of this AD, a shop visit is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges, except that the separation of engine flanges solely for the purposes of transporting the engine without subsequent engine maintenance does not constitute an engine shop visit.

Alternative Methods of Compliance

(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 James Gray, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: james.gray@faa.gov; telephone (781) 238-7742; fax (781) 238-7199, for more information about this AD.

(l) Pratt & Whitney JT8D Maintenance Advisory Notice MAN-JT8D-2-06, dated November 20, 2006, pertains to the subject of this AD. Contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700; fax (860) 565-1605, for a copy of this service information.

Start Signature

Issued in Burlington, Massachusetts, on May 13, 2010.

Peter A. White,

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

End Signature End Part End Supplemental Information

[FR Doc. 2010-11999 Filed 5-18-10; 8:45 am]

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