AD 2015-02-08

This AD is effective March 11, 2015.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of March 11, 2015.

For service information identified in this AD, contact Rolls-Royce Corporation, 450 South Meridian Street, Mail Code NB-01-06, Indianapolis, IN 46225; phone: 317-230-1667; email: CMSEindyOSD@rolls-royce.com; Internet: www.rolls-royce.com. You may view this service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125.

Kyri Zaroyiannis, Aerospace Engineer, Chicago Aircraft Certification Office, Small Airplane Directorate, FAA, 2300 E. Devon Ave., Des Plaines, IL 60018; phone: 847-294-7836; fax: 847-294-7834; email: kyri.zaroyiannis@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain RRC AE 2100 series turboprop engines and AE 3007A and 3007C series turbofan engines. The NPRM published in the Federal Register on October 2, 2014 (79 FR 59461). The NPRM was prompted by reports of pitting in the wheel bores and subsequent RRC analysis that concluded that lower life limits are needed for the affected turbine wheels. The NPRM proposed to require reducing the approved life limits of the affected turbine wheels and performing an ECI of certain RRC engines with affected turbine wheels. We are issuing this AD to prevent uncontained failure of the turbine wheels, damage to the engine, and damage to the airplane.

We gave the public the opportunity to participate in developing this AD. We have considered the comment received. An anonymous commenter supported the NPRM (79 FR 59461, October 2, 2014).

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting this AD as proposed except for minor editorial changes, e.g., verb tense changes and word changes appropriate to a final rule. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM (79 FR 59461, October 2, 2014) for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM (79 FR 59461, October 2, 2014).

We reviewed:

• Rolls-Royce (RR) Alert Service Bulletin (ASB) No. AE 2100D2-A-72-085, dated July 25, 2013.

• RR ASB No. AE 2100D3-A-72-277, dated July 25, 2013.

• RR ASB No. AE 2100P-A-72-019, dated July 25, 2013.

• RR ASB No. AE 3007A-A-72-407, Revision 1, dated August 29, 2014.

• RR ASB No. AE 3007A-A-72-408, Revision 1, dated August 29, 2014.

• RR ASB No. AE 3007C-A-72-316, dated December 6, 2013.

These service bulletins describe procedures for inspecting high-pressure turbine (HPT) stage 2 wheels and identify life-limit reduction for all affected HPT wheels. You can find this information at http://www.regulations.gov by searching for and locating Docket No. FAA-2014-0462.

We estimate that this AD will affect 664 engines installed on airplanes of U.S. registry. We also estimate that it will take about 1 hour to perform an ECI in the bore of the turbine wheel for affected engines. The average labor rate is $85 per hour. We estimate the pro-rated replacement cost would be $30,688 for a 1st stage gas generator turbine wheel; $63,693 for a HPT stage 1 wheel; $13,941 for an HPT stage 2 wheel; and $13,186 for a 4th stage turbine wheel. We also estimate that these parts would be replaced during an engine shop visit at no additional labor cost. Based on these figures, we estimate the total cost of this AD on U.S. operators to be $11,317,969.

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 to the extent that it justifies making a regulatory distinction, 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):