AD 2004-25-20

To prevent fatigue cracking of the drag and shear angles of the wing, which could result in reduced structural integrity of the nacelle attachment to the wing, accomplish the following:

(a) Do the inspections required by paragraphs (a)(1) and (a)(2) of this AD, at the applicable time specified in paragraph (b) of this AD.

(1) Do a detailed inspection for cracking of the shear angles which attach the nacelle to the front spar of the wing, and an eddy current inspection for cracking around the fasteners and in the radii of the shear angles, by doing all the actions per the Accomplishment Instructions of Saab Service Bulletin 2000-54-026, Revision 01, dated June 20, 2002.

(2) Do an endoscope inspection of the upper and lower drag angles for cracking, and an eddy current inspection for cracking around the fasteners where applicable, by doing all the actions per the Accomplishment Instructions of Saab Service Bulletin 2000-54-028, Revision 01, dated June 20, 2002.

Note 1: For the purposes of this AD, a detailed 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 such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(b) Do the inspections required by paragraph (a) of this AD at the applicable compliance time specified in paragraph (b)(1), (b)(2), or (b)(3) of this AD. Repeat the inspections thereafter at intervals not to exceed 4,000 flight cycles until the modification required by paragraph (e) of this AD is done.

(1) For airplanes that have accumulated 14,000 or more total flight cycles as of the effective date of this AD: Inspect within 500 flight cycles after the effective date of this AD.

(2) For airplanes that have accumulated 10,000 or more total flight cycles, but fewer than 14,000 total flight cycles as of the effective date of this AD: Inspect within 1,000 flight cycles after the effective date of this AD, but not later then 14,500 total flight cycles.

(3) For airplanes that have accumulated fewer than 10,000 total flight cycles as of the effective date of this AD: Inspect within 2,000 flight cycles after the effective date of this AD, but not later then 11,500 total flight cycles.

(c) If any cracking is found during any inspection required by this AD: Except as provided by paragraph (f) of this AD, do the actions specified in and at the times specified in Table 1 of the Accomplishment Instructions of Saab Service Bulletin 2000-54-026, Revision 01, dated June 20, 2002; or Saab Service Bulletin 2000-54-028, Revision 01, dated June 20, 2002; as applicable. Where the service bulletins specify to contact the manufacturer, before further flight, repair the cracking in accordance with a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the Luftfartsverket (or its delegated agent). Instead of repairing the cracking, doing the modifications required by paragraph (e) of this AD before further flight, terminates the repetitive inspections required by paragraphs (a) and (b) of this AD.

(d) Inspections done before the effective date of this AD per Saab Service Bulletins 2000-54-026 and 2000-54-028, both dated April 26, 2002, are considered acceptable for compliance with the corresponding actions specified in this AD.

(e) Except as provided by paragraph (c) of this AD: Do the modifications of the drag and shear angles of the wing at the times specified in paragraphs (e)(1) and (e)(2) of this AD. Accomplishment of these modifications ends the repetitive inspections required by paragraphs (a) and (b) of this AD.

(1) Before the accumulation of 20,000 total flight cycles: Modify the shear angles that attach the nacelle to the front spar of the wing by doing all the actions per the Accomplishment Instructions of Saab Service Bulletin 2000-54-027, dated November 4, 2002.

(2) Before the accumulation of 24,000 total flight cycles: Modify the upper and lower drag angles by doing all the actions per the Accomplishment Instructions of Saab Service Bulletin 2000-54-029, dated November 4, 2002.

(f) Although the Saab service bulletins referenced in this AD recommend submitting certain information to the manufacturer, this AD does not include such a requirement.

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

(h) Unless otherwise specified in this AD, the actions shall be done in accordance with the service bulletins listed in Table 1 of this AD.

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, Linköping, 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 2: The subject of this AD is addressed in Swedish airworthiness directives 1-174 and 1-175, both effective April 30, 2002; and Swedish airworthiness directives 1-1180 and 1-181, both effective November 8, 2002.