The FAA proposed to amend 14 CFR part 39 by superseding AD 2007-02-07, Amendment 39-14894 (72 FR 2610, January 22, 2007), with a proposed AD. The proposed AD applies to RRD Dart 528, 529, 532, 535, 542, and 552 Series turboprop engines. We published the proposed AD in the Federal Register on November 9, 2007 (72 FR 63508). That action proposed to require deleting the Dart 555 series engines from the applicability paragraph of the proposed AD, and to list the Dart 552 series turboprop engines in the applicability paragraph of the proposed AD.
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 (telephone (800) 647-5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.
Request To Correct a Typographical Error in the Costs of Compliance Section
One commenter asks us to change "turbofan engines'' in the Costs of Compliance Section to "turboprop engines.'' The commenter states that the Dart engine is a turboprop engine, not a "turbofan engines.''
We agree. We changed "turbofan engines'' in the Costs to Comply section to "turboprop engines.''
Request To Add Airplane Models to the Applicability Paragraph
The same commenter states that paragraph (c) Applicability, appears to omit some models of airplanes that might use the engines. The commenter states that the Dart engine is installed by supplemental type certificate on certain General Dynamics Convair model airplanes, and that those airplanes can still be found in the FAA's registry database.
We partially agree. We must identify in paragraph (c) Applicability, all engine models that are affected by this AD. We list the aircraft models that might use those engines to help readers to determine if they might have an affected engine. However, for clarity, we have changed the applicability paragraph to include the General Dynamics Convair models that might use these engines under supplemental type certificates.
Change of Compliance End Dates
We changed the compliance end dates in paragraphs (f)(2)(i) from June 30, 2007, to June 30, 2008, and paragraph (f)(2)(ii) from April 30, 2008, to July 31, 2008. We changed the compliance dates to avoid unnecessary grounding of aircraft while still meeting our safety concerns.
Conclusion
We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Costs of Compliance
We estimate that this AD will affect 30 RRD Dart 528, 529, 532, 535, 542, and 552 series turboprop engines installed on airplanes of U.S. registry. We also estimate that it will take about 50 work-hours per engine to perform the proposed actions, and that the average labor rate is $80 per work-hour. Required parts will cost about $50,000 per IPT disk. We estimate that 25 percent, or eight engines, will require IPT disk replacement. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $500,000.
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 have 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 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); 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 summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.
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 Federal Aviation Administration 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 removing Amendment 39-14894 (72 FR 2610, January 22, 2007), and by adding a new airworthiness directive, Amendment 39-15623, to read as follows: