Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to adding an AD that would apply to PILATUS AIRCRAFT LTD. Model PC-12/47 and PC-12/47E airplanes. The NPRM was published in the Federal Register on May 1, 2015 (80 FR 24854). The NPRM proposed to correct an unsafe condition for the specified products and was based on mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country. The MCAI states:
During a continued airworthiness review, a potential unsafe condition was identified that could result from a disconnected aileron trim tab occurring above an altitude of 10.000 feet.
This condition, if not corrected, could lead, in case of a disconnection of an aileron trim tab, to undamped aeroplane vibrations, potentially resulting in structural failure.
To address this potential unsafe condition, Pilatus Aircraft Ltd. issued SB No. 27-021 to provide instructionsfor replacement of the aileron tab counter balance weight.
For the reason described above, this AD requires replacement of the aileron tab counter balance weight with a new, slightly heavier, aileron tab counter balance weight.
The MCAI can be found in the AD docket on the Internet at: http://www.regulations.gov/#!documentDetail;D=FAA-2015-1177-0002.
Comments
We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA's response to each comment.
Request Revision of Paragraph (e) Reason of the AD
Johan Kruger stated the sentence of paragraph (e) Reason in the proposed AD was incomplete and misleading:
We are issuing this AD to prevent a disconnected aileron trim tab, which could lead to undamped airplane vibrations, potentially resulting in structural failure.
Johan Kruger proposed replacing the above sentence with this sentence similar to the MCAI:We are issuing this AD to prevent undamped airplane vibrations, potentially resulting in structural failure in case of a disconnected aileron trim tab.
We agree with the commenter that the proposed sentence is clarification of the unsafe condition. We have adopted the proposed sentence in paragraph (e) of the AD.
Request Correction of Part Number (P/N)
Johan Kruger stated the cited part number (P/N) 27.15.12.037 of the aileron trim tab assembly quoted is wrong in paragraphs (f)(2) and (f)(3) of the proposed AD; the correct P/N is 527.15.12.037. We infer that the commenter requested correction of the incorrect P/N.
We agree with the commenter that the P/N in the proposed AD is incorrect. We have changed the incorrect P/N to 527.15.12.037 in paragraphs (f)(2) and (f)(3) of the AD.
Request Correction of Misleading Wording in Paragraph (f)(4) of the AD
Johan Kruger commented the wording in paragraph 2(f)(4) is misleading, ``. . . provided that an aileron trim tab assembly, P/N 527.15.12.037 or 527.15.12.038 is not installed on the airplane.''
Johan Kruger further wrote that Pilatus proposed the wording be changed to read, ``. . . provided that an
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aileron trim tab assembly, P/N 527.15.12.037 or 527.15.12.038 is not installed on that aileron assembly.''
We infer the commenter means paragraph (f)(4) of the AD.
We agree with the commenter. Aileron trim tab assemblies will only be associated with aileron assemblies and not by airplane. The aileron assemblies themselves are associated with the airplane number. We have adopted the proposed wording in paragraph (f)(4) of the AD.
Conclusion
We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM(80 FR 24854, May 1, 2015) for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM (80 FR 24854, May 1, 2015).
We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.
Relative Service Information Under 1 CFR Part 51
We reviewed PILATUS AIRCRAFT LTD. PILATUS PC-12 Service Bulletin No: 27-021, dated January 20, 2015. The service information describes procedures for replacement of the aileron tab counter balance weight. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section of this final rule.
Costs of Compliance
We estimate that this AD will affect 303 products of U.S. registry. We also estimate that it would take about 5.5 work hours per product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Required parts would cost about $1,000 per product.
Based on these figures, we estimate the cost of the AD on U.S. operators to be $444,652.50, or $1,467.50 per product.
According to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate.
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 theFAA 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),
(3) Will not affect intrastate aviation in Alaska, 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.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015- 1177; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone (800) 647-5527) is 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.