AD 2004-14-11

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Saab Model SAAB 2000 series airplanes, that currently requires repetitive inspections for discrepancies of the upper and lower areas of the backup struts in the left and right nacelles; and corrective actions, if necessary. This amendment requires repetitive inspections for cracks in the lower areas of the backup struts, and corrective actions if necessary. This action also requires the eventual replacement of the backup struts with new, improved struts, which terminates the repetitive inspections. 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, and consequent separation of the engine from the airplane and subsequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2004-14-11 Saab Aircraft AB: Amendment 39-13720. Docket 2001-NM-316- AD. Supersedes AD 2000-13-09, Amendment 39-11808.

Applicability: Model SAAB 2000 series airplanes, certificated in any category, serial numbers -004 through -063 inclusive.

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, and consequent separation of the engine from the airplane and subsequent reduced controllability of the airplane, accomplish the following:

Inspection

(a) At the applicable time specified in Table 1 of this AD: Perform a fluorescent dye penetrant inspection for cracks of the lower ends of the backup struts in the left and right nacelles, in accordance with SAAB Service Bulletin 2000-54-025, dated September 7, 2001. Although the service bulletin specifies to submit certain information to the manufacturer, this AD does not require a report.

Table 1.--Fluorescent Dye Penetrant Inspection Compliance Times

If, as of the effective date of this new AD, the inspection required by AD 2000-13-09, amendment 39-11808--
And if the airplane has, as of the effective of this new AD--
Then do the inspection within- -

Has been done...................
Fewer than 4,500 flight cycles.
1,650 flight hours after accomplishment of the most recent inspection done
per AD 2000-13-09.
Has been done...................

4,500 or more flight cycles.
900 flight hours after the most recent inspection done per AD 2000-13-09.
Has not been done...............
Any number of flight cycles.
200 flight hours after the effective date of
this new AD.

Follow-On/Corrective Actions

(b) If no crack is found during the inspection required by paragraph (a) of this AD: Repeat the inspection at intervals not to exceed 1,650 flighthours, until the actions required by paragraph (d) of this AD have been done.

(c) If any crack is found during any inspection required by paragraph (a) of this AD: Replace the cracked strut with a new, improved strut before further flight in accordance with SAAB Service Bulletin 2000-54-024, dated September 7, 2001. Although the service bulletin provides the option of contacting the manufacturer for repair instructions, this AD requires that any alternative repair be done in accordance with a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the Luftfartsverket (LFV) (or its delegated agent). Replacement of a backup strut terminates the repetitive inspections required by this AD for that strut only.

Strut Replacement

(d) Except as required by paragraph (c) of this AD: Within 36 months after the effective date of this AD, replace all four backup struts in the electrical and hydraulic bays of the nacelles with new,improved struts, in accordance with the Accomplishment Instructions of SAAB Service Bulletin 2000-54-024, dated September 7, 2001. Replacement of all four backup struts terminates the requirements of this AD.

Alternative Methods of Compliance

(e) In accordance with 14 CFR 39.19, the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, is authorized to approve alternative methods of compliance for this AD.

Incorporation by Reference

(f) Unless otherwise specified in this AD, the actions shall be done in accordance with SAAB Service Bulletin 2000-54-024, dated September 7, 2001; and SAAB Service Bulletin 2000-54-025, dated September 7, 2001; as applicable. 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 National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .

Note 1: The subject of this AD is addressed in Swedish airworthiness directive 1-165, dated September 10, 2001.

Effective Date

(g) This amendment becomes effective on August 13, 2004.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 2000-13-09, amendment 39-11808 (65 FR 41871, July 7, 2000), which is applicable to certain Saab Model SAAB 2000 series airplanes, was published in the Federal Register on March 26, 2004 (69 FR 15740). The action proposed to require repetitive inspections for cracks in the lower areas of the backup struts, and corrective actions if necessary. That action also proposed to require the eventual replacement of the backup struts with new, improved struts, which would terminate the repetitive inspections.

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

This AD will affect about 3 airplanes of U.S. registry.

The inspection of the lower ends of the backup struts will take about 4 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this action on U.S. operators is estimated to be $780, or $260 per airplane, per inspection cycle.

Replacing all four backup struts will take about 80 work hours per airplane, at an average labor rate of $65 per work hour. Required parts will cost about $165,416 per airplane. Based on these figures, the cost impact of this action on U.S. operators is estimated to be $511,848, or $170,616 per airplane.

The cost impact figures discussed above are 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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-11808 (65 FR 41871, July 7, 2000), and by adding a new airworthiness directive (AD), amendment 39-13720, to read as follows: