AD 2008-13-27

This AD becomes effective August 6, 2008. The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of August 6, 2008.

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 Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: james.lawrence@faa.gov; telephone (781) 238-7176; fax (781) 238-7199.

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 was published in the Federal Register on August 28, 2007 (72 FR 49236). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states that:

This AD is issued following a case of non-commanded in-flight engine shut-down which occurred on an Arrius 2F turboshaft engine, following the seizing of the gas generator. The result may be an emergency autorotation landing, or, at worst, an accident.

Investigations of this event have revealed that the seizing of the gas generator was caused by the fracture of the separator cage of the gas generator front bearing, due to high-cycle fatigue cracks initiated in the lubrication slots of the separator cage.

Modification Tf 12 introduces a new gas generator front bearing without lubrication slots on the separator cage.

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public.

We have changed the compliance time from “at the next shop visit after the effective date of the AD, but no later than April 30, 2008” to “at the next shop visit after the effective date of this AD, but no later than 30 days after the effective date of this AD” to allow the operators more time to complete the requirements of this AD.

We reviewed the available data and determined that air safety and the public interest require adopting the AD with the changes described previously. We determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

The Mandatory Continuing Airworthiness Information (MCAI) and service information require the operators to comply with the requirements at the next shop visit after the effective date of the AD, but no later than April 30, 2008. We require compliance at the next shop visit after the effective date of this AD, but no later than 30 days after the effective date of this AD.

We estimate that this AD will affect 61 engines of U.S. registry. We also estimate that it will take about 10 work-hours per engine to comply with this AD. The average labor rate is $80 per work-hour. Required parts will cost about $111,440. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $6,846,640. Our cost estimate is exclusive of possible warranty coverage.

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 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 this 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. 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 regulatory evaluation of the estimated costs to comply with this AD and placed it in 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 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.

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 AD: