Discussion
On February 7, 2006, we issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that would apply to all Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes equipped with certain crew seat bucket assemblies with and without a backrest recline system. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on February 14, 2006 (71 FR 7698). The NPRM proposed to require you to replace the backrest tubes on certain crew seat bucket assemblies at a specified time and add a life limit for the backrest tubes.
Comments
We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA's response to each comment:
Comment Issue No. 1: Remove Reference to PC12 Maintenance Manual Temporary Revision No. 04-13, Dated June 15, 2005The manufacturer states that PC-12 Interactive Electronic Technical Publication (IETP) Revision 9 (which will include Aircraft Maintenance Manual (AMM) Revision 17) will supersede PC12 Maintenance Manual Temporary Revision No. 04-13, dated June 15, 2005, by March 31, 2006, by incorporating the information into the IETP.
The commenter requests to remove the reference to PC12 Maintenance Manual Temporary Revision No. 04-13, dated June 15, 2005, from the final rule AD action.
We agree with the commenter and will change the final rule AD action.
Comment Issue No. 2: Change the Compliance Time for Replacing Certain Crew Seat Bucket Assemblies
The manufacturer states the life limit and the compliance time for replacing crew seat bucket assemblies without a recline system, part numbers (P/Ns) 959.30.01.131, 959.30.01.132, 959.30.01.133, and 959.30.01.134 (or FAA-approved equivalent P/Ns), is too conservative. The manufacturer states there have not been any of these seats found with cracks and they have confidence the life limit could be increased from 10,000 hours time-in-service (TIS) to 12,163 hours TIS.
The manufacturer requests the compliance time for initial replacement be increased from "upon the accumulation of 10,000 TIS or within the next 100 hours TIS after the effective date of the AD, whichever occurs later," to "upon the accumulation of 10,000 TIS or within the next 500 hours TIS after the effective date of the AD, whichever occurs later."
We partially agree with the commenter. Since there have not been any reported cracks on the above referenced crew seat bucket assemblies and there is confidence from the manufacturer that there is a 2,163- hour TIS "cushion," we agree that increasing the threshold compliance time from 100 hours TIS to 500 hours TIS can be done without compromising the safety of crew seat bucket assemblies with 10,000 hours or less TIS. For crew seat bucket assemblies with more than 10,000 hours TIS, we have established a compliance time for initial replacement of 100 hours TIS or upon the accumulation of 10,500 hours TIS, whichever occurs later.
We will change the final rule AD action to reflect this change.
Conclusion
We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for incorporating the concerns addressed by the commenter and minor editorial corrections. We have determined that we should incorporate the concerns addressed by the commenter, and 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.
Cost of Compliance
We estimate that this AD affects 260 airplanes in the U.S. registry.
We estimate the following costs to do the replacement:
Labor cost
Parts cost
Total cost per airplane
Total cost on U.S. operators
3 workhours $65 per hour =
$195 per seat bucket
assembly.
$600 per seat bucket
assembly. 2 seats on each airplane.
$195 + $600 = $795 per seat
bucket assembly.
$795 per seat bucket assembly 2 per airplane = $1,590. $1,590 260 = $413,400.
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 regulationis within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this AD.
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 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 summary of the costs to comply with this AD(and other information as included in the Regulatory Evaluation) and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "Docket No. FAA-2004-19220; Directorate Identifier 2004-CE-27-AD" in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. FAA amends Sec. 39.13 by adding the following new AD: