AD 2011-25-10

This AD is effective January 17, 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.

Stephen K. Sheely, Aerospace Engineer, Engine Certification Office, FAA, 12 New England Executive Park, Burlington, MA 01803; phone: (781) 238-7750; fax: (781) 238-7199; email: stephen.k.sheely@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 13, 2011 (76 FR 41144). That NPRM proposed to require:

• For HPC shafts that have more than 4,500 cycles-since-new (CSN) on the effective date of this AD, removing the HPC shaft from service within 500 cycles-in-service (CIS) after the effective date of this AD or at the next shop visit after the effective date of this AD, whichever occurs first.

• For HPC shafts that have 4,500 or fewer CSN on the effective date of this AD, removing the HPC shaft from service before exceeding 5,000 CSN.

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

One commenter, FedEx Express, requested that the FAA clearly state the exemption of JT9D-7R4E1 and -7R4E1H engine models from this requirement.

We partially agree. We do not agree that it is necessary to specifically exempt the JT9D-7R4E1 and -7R4E1H engine models because the Applicability paragraph clearly states that this AD applies only to the PW JT9D-7R4H1 turbofan engine model. All other models (including the JT9D-7R4E1 and -7R4E1H models) are automatically excluded from the compliance requirements. However, we do agree that the installation prohibition statement could be misinterpreted to go beyond the scope of the AD applicability. Therefore, we revised this AD by adding “JT9D-7R4H1” to paragraph (i)(2).

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM (76 FR 41144, July 13, 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 41144, July 13, 2011).

We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

We estimate that this AD does not affect any engines installed on airplanes of U.S. registry.

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):