AD 2006-10-05

The FAA is adopting a new airworthiness directive (AD) for certain Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) and SAAB 340B airplanes. This AD requires a one-time inspection to see if a faulty uplock axle for the shock strut of the main landing gear (MLG) is installed, and replacing the uplock axle with a new uplock axle if necessary. This AD results from a report of a cracked uplock axle caused by hydrogen embrittlement during the manufacturing process. We are issuing this AD to prevent failure of the uplock mechanism, which, combined with a loss of hydraulic pressure, could result in an uncommanded extension of the MLG.

Final rule.

2006-10-05 SAAB AIRCRAFT AB: Amendment 39-14589. Docket No. FAA- 2006-24075; Directorate Identifier 2005-NM-235-AD.

Effective Date

(a) This AD becomes effective June 16, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to SAAB Model SAAB-Fairchild SF340A (SAAB/ SF340A) and SAAB 340B airplanes, certificated in any category; serial numbers SAAB SF340A-004 through -159 inclusive, and SAAB 340B-160 through -459 inclusive.

Unsafe Condition

(d) This AD results from a report of a cracked uplock axle of the main landing gear (MLG) shock strut caused by hydrogen embrittlement during the manufacturing process. We are issuing this AD to prevent failure of the uplock mechanism, which, combined with a loss of hydraulic pressure, could result in an uncommanded extension of the MLG.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Inspection To Determine Part Serial Number

(f) Within 6 months after the effective date of this AD, inspect the uplock axle of the MLG shock strut to determine whether an affected serial number (S/N) is installed. A review of airplane maintenance records is acceptable in lieu of this inspection if the S/N of the uplock axle can be conclusively determined from that review. Do the inspection in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-32-132, dated November 3, 2005.

Note 1: The Saab service bulletin refers to APPH Service Bulletins AIR83022-32-31, Revision 1; and AIR83064-32-11, Revision 1; both dated October 2005; as additional sources of service information for identifying uplock axles with affected S/Ns, and replacing the axles if necessary. The APPH service bulletins are attached to the Saab service bulletin.

Corrective Action

(g) Before further flight after accomplishing the inspection required by paragraph (f) ofthis AD: Replace with a new uplock axle any uplock axle with an affected S/N identified by the inspection in paragraph (f) of this AD. Do all actions in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-32-132, dated November 3, 2005.

Parts Installation

(h) As of the effective date of this AD, no person may install an uplock axle on any airplane if it has an affected S/N identified in accordance with paragraph (f) of this AD.

No Reporting Requirement

(i) Although the Accomplishment Instructions of Saab Service Bulletin 340-32-132, dated November 3, 2005, specify to send a report with the S/N of replaced uplock axles to APPH Ltd., this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with Sec. 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(k) Swedish airworthiness directive 1-199, effective November 9, 2005, also addresses the subject of this AD.

Material Incorporated by Reference

(l) You must use Saab Service Bulletin 340-32-132, dated November 3, 2005, including the attachments listed in Table 1 of this AD, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linkoping, Sweden, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or
at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .

Table 1.--APPH Service Bulletins Attached to Saab Service Bulletin

APPH service bulletin
Revision level
Date
AIR83022 32 31 ....
1
Oct. 2005.
AIR83064 32 11 ....
1
Oct. 2005.

Examining the Docket

You may examine the airworthiness directive (AD) docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) and SAAB 340B airplanes. That NPRM was published in the Federal Register on March 7, 2006 (71 FR 11349). That NPRM proposed to require a one-time inspection to see if a faulty uplock axle for the shock strut of the main landing gear (MLG) is installed, and replacing the uplock axle with a new uplock axle if necessary.

Comments

We provided the public the opportunity to participate in the development of this AD. We received no comments on the NPRM or on the determination of the cost to the public.

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed.

Costs of Compliance

This AD will affect about 248 airplanes of U.S. registry. The required inspection will take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $16,120, or $65 per airplane.

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 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. See the ADDRESSES section for a location to examine the regulatory evaluation.

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 Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):