Discussion
We have received several reports of fatigue cracking on Cessna Models 402A and 402B airplanes in the area of the auxiliary wing spar where the main landing gear trunnion is mounted. Other models with similar design that share the same risk of auxiliary wing spar cracking include Cessna Models 401, 401A, 401B, and 402.
This condition, if not corrected, could result in failure of the wing auxiliary spar web and cause landing gear collapse during normal landing. This could lead to loss of control and passenger injury.
Cessna has shown the FAA that parts with cracks in this area that are 0.5 inch or more need immediate replacement as they pose an immediate safety of flight issue. Cessna's analysis also shows that residual strength in the wing, up to ultimate design loads, will remain with cracks less than 0.5 inch, and the growth of these cracks is slow.
Because analysis shows that a repetitive inspection program can provide an interim acceptable level of safety, the FAA will allow repetitive inspections when a crack less than 0.5 inch is found in the wing auxiliary spar during the initial inspection required by this action. Cracks need to be monitored (inspected every 50 hours time-in- service (TIS)) to show they do not reach 0.5 inch.
If any crack reaches 0.5 inch or more, then the cracked part must be replaced before further flight.
If no crack reaches 0.5 inch or more, then the cracked part must be replaced within 200 hours TIS or 12 months, whichever occurs first, regardless of crack growth.
Relevant Service Information
We reviewed Cessna Service Bulletin MEB08-8, dated December 23, 2008. The service information describes procedures for inspecting the wing auxiliary spar webs for cracks and replacing the left web/right web with a new left web/right web.
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:
An inspection of the auxiliary wing spar near the location where the main landing gear trunnion is mounted for cracks;
Immediate replacement if cracks are 0.5 inch or more;
Repetitive inspections (50 hours TIS) with replacement at 200 hours TIS or 12 months, whichever occurs first, if cracks are found that are less than 0.5 inch; and
A report to the FAA and Cessna if any cracks are found.
The FAA considers this interim action. We will work with Cessna and evaluate the crack reports and all other information. Based on this information, we may initiate additional rulemaking action.
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 cracks in the wing auxiliary spar web could lead to failure in this area and could cause landing gear collapse during normal landing. This could lead to loss of control and passenger injury. Some of the affected airplanes are operated 100 hours TIS or more monthly. Therefore, the repetitive inspections on these airplanes would occur in short intervals, and the replacement would be required within 2 months. 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-2009-0118; Directorate Identifier 2008-CE-073-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 FAAwith 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):