AD 2010-21-17

This AD becomes effective November 12, 2010.

You can get the service information identified in this AD from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700; fax (860) 565-1605.

The Docket Operations office is located at Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.

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

The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to PW JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines. We published the proposed AD in the Federal Register on May 19, 2010 (75 FR 27972). That action proposed to require overhauling fan blade leading edges at the first shop visit after 4,000 CIS since the last total fan blade overhaul was performed.

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 AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Two commenters, Delta Airlines, Inc. and the National Transportation Safety Board, request that we extend the proposed AD comment period. The extension would allow time to determine the root cause of a fan blade failure on a Delta DC-9 airplane, occurring on June 14, 2010.

We do not agree. Extending the comment period would delay the rulemaking process. The root cause investigation can continue after the AD is issued. We did not change the AD.

Delta Airlines, Inc. requests clarification of the shop visit definition in paragraph (i) of the proposed AD. Specifically, clarify whether a gearbox removal or gearbox change would fit into the shop visit definition. Also, that we clarify that a nose cowl removal or a thrust reverser removal not be included in the shop visit definition. These actions involve components that mate to engine flanges.

We partially agree. We revised the definition of shop visit in the AD to include a clarification of “lettered flanges” after “pairs of major mating engine flanges.” The procedures referenced by the commenter are shop visits according to the definition in paragraph (i) of the AD. Since the nose cowl and thrust reverser are not engine components, they would involve the separation of an engine flange with a non-engine flange. A gearbox removal would not involve a lettered flange. You can find further information on what is a lettered flange in the engine manual.

Since we issued the proposed AD, we discovered that paragraphs (f) and (g) require clarification. We clarified those paragraphs in the AD, to state that the cycles-in-service apply to the fan blades.

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously.

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

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.

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

(3) Will 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 AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 as follows:

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

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