AD 2011-25-09

This AD is effective January 10, 2012.

For service information identified in this AD, contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; phone: (860) 565-1605. You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803. For information on the availability of this material at the FAA, call (781) 238-7125.

James Gray, Aerospace Engineer, Engine Certification Office, FAA, 12 New England Executive Park; phone: (781) 238-7742; fax: (781) 238-7199; email: james.e.gray@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM published in the Federal Register on July 14, 2011 (76 FR 41430). That NPRM proposed to require removing certain P/N HPT stage 1 and HPT stage 2 airseals and HPT stage 1 airseal rings before their published life limit, and establishes a new lower life limit for these parts.

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA's response to each comment.

One commenter, Lufthansa Technik AG (Lufthansa), requested that we note in the AD that Chapter 5 will be revised and indicate when it will occur. Lufthansa believes this knowledge will help optimize planning for removal of parts that will be close to their reduced life limits when Chapter 5 is revised.

We do not agree. Although Chapter 5 may be revised in the future, we do not know when. If Chapter 5 is revised in the future, we will publish an NPRM that will allow the public an opportunity to comment. We did not change the AD as a result of this comment.

One commenter, SR Technics, requested that the AD define how to perform the pro-rata calculation of the parts' life limit after the effective date of the AD for parts that have been installed on engines with different thrust loads.

We do not agree. Information on how to track part life for parts that have been installed on engines with different thrust loads can be found in the relevant engine manual. We did not change the AD as a result of this comment.

One commenter, FedEx Express (FedEx), indicated that the proposed AD would affect 174 engines in its fleet and cost FedEx $8,149,290. FedEx requested that Pratt & Whitney, therefore, provide an industry support program to help alleviate this financial burden.

We do not agree. We do not have the authority to require a design approval holder to offer such a program. We did not change the AD as a result of this comment.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial changes to the Unsafe Condition paragraph made for clarification.

We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM (76 FR 41430, July 14, 2011) for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM (76 FR 41430, July 14, 2011).

We estimate that this AD will affect 869 engines installed on airplanes of U.S. registry. We also estimate that, because the removals will be performed at piece-part level, no additional work-hours will be required. Prorated life for the HPT is about $46,835 per engine. Based on these figures, we estimate the total cost of this AD to U.S. operators is $40,699,615.

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.

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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA 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 (AD):