The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to RRD Dart 528, 529, 532, 535, 542, and 555 series turboprop engines. We published the proposed AD in the Federal Register on July 11, 2006 (71 FR 39023). That action proposed to require a dimensional inspection of the IPT disk or an ultrasonic inspection of the seal arm contact between the HPT and the IPT disk seal arm and rework or replacement of the IPT disk if wear outside acceptable limits is found.
Examining the AD Docket
You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comment received.
Request To Incorporate by Reference and Publish the SBs
One commenter, the Modification and Replacement Parts Association (MARPA), requests that we incorporate by reference (IBR) the SBs referenced in the proposed AD. We agree. This final rule AD IBRs the documents necessary for accomplishing the requirements mandated by this AD. We did not change the AD.
MARPA also requests that we publish those SBs that we IBR, in Docket File FAA-2006-24825 of the Docket Management System (DMS). We are reviewing issues surrounding posting of service bulletins on the DMS as part of an AD docket. Once we have thoroughly examined all aspects of this issue and have made a final determination, we will consider whether our current practice needs to be revised. No change to the final rule is necessary in response tothis comment.
Change in Compliance Date
We found it necessary to change the compliance date in paragraph (f)(2)(i), which requires performing a dimensional inspection and repairing or replacing the IPT disk, if necessary. We changed the date from December 30, 2006, to June 30, 2007.
Conclusion
We have carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously.
Costs of Compliance
We estimate that this AD will affect 30 RRD Dart 528, 529, 532, 535, 542, and 555 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 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 adding the following new airworthiness directive: