Discussion
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 19, 2010 (75 FR 51187). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:
As a result of a change in the low-cycle fatigue lifing methodology for the IMI 834 material, the recommended service life of certain PW305A and PW305B Impellers has been reduced, as published in the Airworthiness Limitations (AWL) section of Engine Maintenance Manual (EMM).
The in-service life of impellers P/N 30B2185, 30B2486 and 30B2858-01 has been reduced from 12,000 to 7,000 cycles; and of P/N 30B4565-01 from 8,500 to 7,000 cycles.
This Airworthiness Directive (AD) is issued to mandate the incorporation of the revised in-service life limits for the affected impellers, in the AWL section of EMM, as introduced by Temporary Revision (TR) AL-8.
Within 30 days from the effective date of this AD, update AWL section of your PW305 EMM P/N 30B1402, to incorporate TR AL-8 for compliance with the revised in-service limits for the affected Impellers, installed on PW305A and PW305B engine.
Comments
We gave the public the opportunity to participate in developing this AD. We considered the comment received.
Request To Establish an Ending Engine Serial Number Applicability
One commenter, Bombardier--Learjet, asked us to establish an ending engine serial number (S/N) applicability for the proposed AD. The commenter said that any engine from S/N CA0651 forward will be linked to the updated engine maintenance manual (EMM) with the 7,000 cycle exducer life limit. Therefore, engines that have entered or will enter service with the appropriate Airworthiness Limitations already included in their EMM, will not be subject to this unsafe condition. To leave the AD applicability open-ended, will cause hours of unnecessary review and logbook entries for original equipment manufacturers (OEMs) and operators of engines that do not have an unsafe condition.
We don't agree. Because there are no mandatory links between the engine S/N and the EMM, there is no guarantee the EMM will stay with a particular engine S/N. Also, because the proposed AD is a onetime requirement to reduce the life limit for the exducer in the Airworthiness Limitations Section, the proposed AD won't cause hours of unnecessary review and logbook entries for OEMs and operators of engines. We didn't change the proposed AD.
Conclusion
We reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD as proposed.
Costs of Compliance
Based on the service information, we estimate that this AD will affect about 114 products of U.S. registry. We also estimate that it will take 0 work-hours per product to comply with this AD. Theaverage labor rate is $85 per work-hour. Required parts will cost about $54,288 per product. Based on these figures, we estimate the cost of the AD on U.S. operators to be $6,188,832. Our cost estimate is exclusive of possible warranty coverage.
Authority for This Rulemaking
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.
Regulatory Findings
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.Examining 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 (phone (800) 647-5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new AD: