Discussion
We received reports of fatigue cracks found in thrust attenuator paddles on Cessna Model 525A airplanes.
Four incidents of thrust attenuator paddles departing from airplanes have been reported. In two cases, the thrust attenuator paddles hit the rudder and caused structural damage to the rudder.
The thrust attenuator paddles are attached to the aft fuselage. The attachment fasteners fatigue and break.
It is also possible that a failed thrust attenuator paddle could depart the airplane and hit and damage the elevator.
This condition, if not corrected, could result in in-flight departure of the thrust attenuator paddles. This failure could lead to rudder and elevator damage and result in loss of control.
Relevant Service Information
We reviewed Cessna Citation Alert Service Letter ASL525A-78-01, Revision 1, dated October 27, 2009. The service information describes procedures for inspecting and modifying the thrust attenuator paddle assemblies.
FAA's Determination and Requirements of This AD
We are issuing this AD because we evaluated all the information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design. This AD requires repetitively inspecting the thrust attenuator paddle assemblies for loose and damaged fasteners and for cracks. This AD also requires replacing loose or damaged fasteners and replacing cracked thrust attenuator paddles.
This is considered interim action. Cessna is working on a design improvement to change the attachment fasteners from the currently used counter sunk rivets to universal head rivets. The FAA will consider taking additional rulemaking action to supersede this AD and terminate the above repetitive inspections when Cessna completes the design change, and the FAA approves it as addressing the unsafe condition.
FAA's Determination of the Effective Date
An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because the thrust attenuator paddles attached to the aft fuselage and the attachment fasteners are subject to fatigue. Fatigue in these parts could result in in-flight departure of the thrust attenuator paddles. This failure could lead to rudder and elevator damage and result in loss of control.
Therefore, we determined that notice and opportunity for public comment before issuing this AD are impracticable and that good cause exists for making this amendment effective in fewer than 30 days.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and an opportunity for public comment. We invite you to send any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number ``FAA-2009-1096; Directorate Identifier 2009-CE-056-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments.
We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive concerning this AD.
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 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 regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket.
Examining the AD Docket
You may examine the AD docket that contains the AD, the regulatory evaluation, any comments received, and other information on the Internet at http://www.regulations.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) 647-5527) is located at the street address stated 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.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA 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 (AD):