SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number, “FAA-2006-25261; Directorate Identifier 2006-CE-38-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive concerning this proposed AD.

Discussion

We have received reports of the crew seat back cylinder lock bending at the aft end and failing. We have also received reports of cracks found in the cylinder lock assembly.

This condition, if not corrected, could result in failure of the crew seat back cylinder lock assembly. This failure could cause uncontrolled movement of the seat back, resulting in possible backward collapse during flight. Backward collapse of either crew seat back could result in an abrupt pitch-up ( printed page 45455) if the affected crew member continues to hold on to the control yoke during this failure and could cause difficulty in exiting the airplane from an aft passenger seat after landing.

Relevant Service Information

We have reviewed Cessna Single Engine Service Bulletin SB04-25-01, Revision 3, dated July 24, 2006.

This service bulletin describes procedures for installing Modification Kit MK172-25-10B on both crew seat back cylinder lock assemblies to replace the cylinder lock with a new model cylinder lock. This service bulletin also described procedures for doing an installation inspection on airplanes that have Modification Kit MK172-25-10A installed following Cessna Single Engine Service Bulletin SB04-25-01, Revision 2, dated June 5, 2006.

We have also reviewed Cessna Single Engine Service Bulletin SB04-25-02 Revision 1, dated October 17, 2005, and Revision 2, dated June 5, 2006.

These service bulletins describe procedures for installing a steel lock rod/bar on the crew seat to replace the crew seat back cylinder lock assembly.

FAA's Determination and Requirements of the Proposed AD

We are proposing this AD because we evaluated all information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design. This proposed AD would require you to install a modification kit on both crew seat back cylinder lock assemblies, which replaces the cylinder lock with a new model cylinder lock, or install a steel lock rod/bar on both crew seat back cylinder lock assemblies.

Costs of Compliance

We estimate that this proposed AD would affect 4,039 airplanes in the U.S. registry. We provide below total fleet costs for both the proposed modification and the proposed steel lock rod/bar installation; however, only one of these proposed actions would be required.

We estimate the following costs to do the proposed installation of the modification kit:

We estimate the following costs to do the proposed fabrication and installation of a steel lock rod/bar:

We estimate the following costs to do the proposed installation inspection on airplanes that have Modification Kit MK172-25-10A installed:

We have no method of determining the number of airplanes that may have the previously installed Modification Kit MK172-25-10A.

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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation:

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 regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. ( printed page 45456)

Examining the AD Docket

You may examine the AD docket that contains the proposed AD, the regulatory evaluation, any comments received, and other information on the Internet at http://dms.dot.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows: