AD 2000-13-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 2000 series airplanes, that requires repetitive detailed visual and dye penetrant inspections of the backup struts in the left and right nacelles to detect discrepancies; and corrective actions, if necessary. 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 backup struts in the left and right nacelles due to fatigue cracking, which could result in loss of fail-safe redundancy in the design of the nacelle in terms of load capability.

Final rule.

2000-13-09 SAAB AIRCRAFT AB: Amendment 39-11808. Docket 99-NM-368-AD.

Applicability: Model SAAB 2000 series airplanes, serial numbers -004 through -063 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 (d) 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 backup struts in the left and right nacelles due to fatigue cracking, which could result in loss of fail-safe redundancy in the design of the nacelle in terms of load capability, accomplish the following:

Repetitive Inspections
(a) For airplanes on which the dye penetrant inspection of the backup struts in the left and right nacelles specified in Saab Alert Service Bulletin 2000-A54-022, dated October 27, 1999, has not been accomplished prior to the effective date of this AD: Within 200 flight hours after the effective date of this AD, accomplish paragraphs (b)(1) and (b)(2) of this AD in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000.

NOTE 2: Accomplishment of the required actions in accordance with Saab Service Bulletin 2000-54-023, Revision 01, dated January 28, 2000, prior to the effective date of this AD, is acceptable for compliance with this AD.

(b) For airplanes on which the dye penetrant inspection of the backup struts in the left and right nacelle specified in Saab Alert Service Bulletin 2000-A54-022, dated October 27, 1999, has been accomplished prior to the effective date of this AD: Within 450 flight hours after the effective date of this AD, accomplish paragraphs (b)(1) and (b)(2) of this AD in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000.

(1) Perform a detailed visual inspection of the upper areas of the backup strut around the welding in the pipe and in the attachment fittings to detect any discrepancy (including fatigue cracking or a failed backup strut) by accomplishing all actions specified in paragraph B.(1) of the Accomplishment Instructions of the service bulletin, in accordance with the service bulletin. Repeat the detailed visual inspection thereafter at intervals not to exceed 450 flight hours.
NOTE 3: For the purposes of this AD, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids (e.g., mirror, magnifying lenses) may be used. Surface cleaning and elaborate access procedures may be required."

(2) Perform a dye penetrant inspection, using Penetrant Type 1 (fluorescent dye) sensitivity level 2, of the lower areas of the backup strut around the welding in the pipe and in the attachment fittings to detect any discrepancy (including fatigue cracking or a failed backup strut) by accomplishing all actions specified in paragraphs B.(2) and B.(3) of the service bulletin, as applicable, in accordance with the service bulletin.

(i) For airplanes on which all backup struts have accumulated less than 4,500 totalflight hours as of the effective date of this AD, repeat the dye penetrant inspection thereafter at intervals not to exceed 1,650 flight hours, until any backup strut on the airplane has accumulated 4,500 total flight hours; then perform the repetitive inspection thereafter at the interval specified by paragraph (b)(2)(ii) of this AD.

(ii) For airplanes on which any backup strut has accumulated 4,500 or more total flight hours as of the effective date of this AD, repeat the dye penetrant inspection thereafter at intervals not to exceed 900 flight hours.

Corrective Actions
(c) If any discrepancy (including fatigue cracking, a failed backup strut, or damage to the surrounding structure of the engine mount) is detected during any inspection required by this AD: Prior to further flight, accomplish the applicable corrective actions (including performing additional inspections of the engine mount surrounding structure, and replacing any discrepant backup strut in the hydraulicor electrical bay areas with a new backup strut) specified by paragraph C. of the Accomplishment Instructions of Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000, in accordance with the service bulletin. For any repair condition for which the service bulletin specifies to contact the manufacturer for appropriate action: Prior to further flight, repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Luftsfartsverket (LFV) (or its delegated agent). For a repair method to be approved by the Manager, International Branch, ANM-116, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

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

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits
(e) 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
(f) Except as provided by paragraph (c) of this AD, the actions shall be done in accordance with Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000. 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, Link ping, 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 5: The subject of this AD is addressed in Swedish airworthiness directive No. 1-150R1, dated January 31, 2000.
(g) This amendment becomes effective on August 11, 2000.

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 2000 series airplanes was published in the Federal Register on May 10, 2000 (65 FR 30023). That action proposed to require repetitive detailed visual and dye penetrant inspections of the backup struts in the left and right nacelles to detect discrepancies; and corrective actions, if necessary.

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.

Explanation of Change Made to the Final Rule
Paragraphs (a), (b), and (c) of the final rule have been revised to reference Saab Service Bulletin 2000-54-023, Revision 02, dated February 23, 2000, as the appropriate source of service information. Revision 01 of the servicebulletin was referenced in the proposed rule as the appropriate source of service information. A new NOTE 2 has also been added to give credit for accomplishment of the required actions in accordance with Revision 01 of the service bulletin prior to the effective date of this AD.

Interim Action
This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Conclusion
After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the rule with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 3 airplanes of U.S. registry will be affected by this AD, that it will take approximately 8 work hours per airplane to accomplish the required inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $1,440, or $480 per airplane, per inspection cycle.

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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact
The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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: