Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to Pilatus Aircraft Ltd. Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC- 6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2- H4, PC-6/C-H2, and PC-6/C1-H2 airplanes. The NPRM was published in the Federal Register on November 4, 2016 (81 FR 76883). 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:
The proper installation of the aileron counterweight requires a combination, peculiar to each aileron, of anchor nut types, bolt types, number of washers, and the definition of the bolt torque. Some combinations of counterweight and attaching parts, which could result in reduced thread engagement, have been reported on a PC-6aeroplane.
This condition, if not detected and corrected, may lead to a disconnection of the aileron counterweight from the aileron, possibly resulting in reduced control of the aeroplane.
To address this potential unsafe condition, Pilatus issued Service Bulletin (SB) No. 57-006 (hereafter referred to as `the SB' in this AD) to provide inspection instructions.
For the reason described above, this AD requires identification and inspection of the affected aileron mass-balance counterweight attachment parts and, depending on findings, accomplishment of applicable corrective action(s).
The MCAI can be found in the AD docket on the Internet at: https://www.regulations.gov/document?D=FAA-2016-9357-0002.
Comments
We gave the public the opportunity to participate in developing this AD. The following presents the comment received on the proposal and the FAA's response to the comment.
Request for Clarification on the Unsafe Condition
Lukas Owens stated that inthe event of loss of the ailerons, some degree of roll control is available by using the secondary effect of rudder. The requester stated that while not an efficient way to turn the aircraft, a pilot has at least some directional control and that short or rapid bursts of power may increase the effectiveness of the rudder to some degree, acting as a form of torque and slipstream effect. The requester asked why the AD change is needed or how it is justified.
We infer that the commenter, in addition to asking why the AD action is necessary and how it is justified, believes the AD action is not needed and is not justified. However, the commenter does not present solutions that address the unsafe condition of the mass balance weight potentially separating from the airplane. For this reason, we have not changed this AD based on this comment.
Conclusion
We reviewed the relevant data, considered the comment received, and
[[Page 12406]]
determined that air safety and thepublic interest require adopting the AD as proposed except for minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.
Related Service Information Under 1 CFR Part 51
Pilatus Aircraft Ltd. has issued Pilatus PC-6 Service Bulletin No. 57-006, dated May 13, 2016. The service information describes procedures for removal, installation, and inspection of the ailerons, aileron balance tabs, and the aileron counterweights and their attaching parts. 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 document.
Costs of Compliance
We estimate that this AD will affect 30 products of U.S. registry. We also estimate that it would take about 2 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 $100 per product.
Based on these figures, we estimate the cost of this AD on U.S. operators to be $8,100, or $270 per product.
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),
(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 FlexibilityAct.
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-2016- 9357; 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 this AD, 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.