AD 99-22-17

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and 340B series airplanes, that requires removal of certain main landing gear downlock and brake hydraulic swivel brackets and replacement with new, redesigned brackets. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the downlock or brake swivels. Brake swivel failure could cause the loss of inboard or outboard brakes. Downlock swivel failure could cause the loss of hydraulic fluid in the main hydraulic system, as well as the loss of nose wheel steering operation, extension and retraction capability of landing gear and flaps, and operation of the propeller brake (if installed).

Final rule

99-22-17 SAAB AIRCRAFT AB: Amendment 39-11395. Docket 99-NM-199-AD. Issued October 22, 1999.
Applicability: Model SAAB SF340A series airplanes, serial numbers SF340A-004 through -159 inclusive, and Model SAAB 340B series airplanes, serial numbers SF340B-160 through -339 inclusive; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the main landing gear (MLG) downlock or brake hydraulic swivels and consequent loss of certain hydraulic-powered operations, accomplish the following:

Bracket Replacement
(a) Within 12 months after the effective date of this AD, remove the MLG downlock and brake hydraulic swivel brackets and replace with new, improved parts, in accordance with Saab Service Bulletin 340-29-009, Revision 02, dated July 2, 1999.

NOTE 2: Accomplishment, prior to the effective date of this AD, of the bracket replacement in accordance with Saab Service Bulletin 340-29-009, dated August 20, 1992, or Revision 1, dated April 15, 1993, is considered acceptable for compliance with the requirements of paragraph (a) of this AD.

Alternative Methods of Compliance
(b) An alternative method of compliance or adjustment of the compliance timethat provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, International Branch, ANM-116.

Special Flight Permits
(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Incorporation by Reference
(d) The replacement shall be done in accordance with Saab Service Bulletin 340-29-009, Revision 02, dated July 2, 1999. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linkoping, Sweden. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 4: The subject of this AD is addressed in Swedish airworthiness directive SAD No. 1-145, dated July 2, 1999.

(e) This amendment becomes effective on December 7, 1999.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Saab Model SAAB SF340A and 340B series airplanes was published in the Federal Register on August 30, 1999 (64 FR 47146). That action proposed to require removal of certain main landing gear downlock and brake hydraulic swivel brackets and replacement with new, redesigned brackets.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 200 airplanes of U.S. registry will be affected by this AD, that it will take approximately 2 work hours per airplane to accomplish the required replacement, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,375 per airplane. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $299,000, or $1,495 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to 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.

39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: