AD 99-19-21 Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

Models named: SAAB SF340A series. Read the applicability below — it usually turns on serial or part numbers too.

Model SAAB SF340A series airplanes, manufacturer's serial numbers -004 through -159 inclusive; and SAAB 340B series airplanes, manufacturer's serial numbers -160 through - 439 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 (f) 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.

Required as indicated, unless accomplished previously. To prevent failure of the front spar due to fatigue cracking around certain fastener holes of the front spar of the horizontal stabilizers, which could result in reduced structural integrity of the airplane, accomplish the following: Note 2: 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 such as mirror, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required.'' Initial and Repetitive Inspections (a) For Model SAAB SF340A series airplanes with manufacturer's serial numbers -004 through -159 inclusive: Perform the inspections (detailed visual, eddy current, and x-ray) specified in paragraph 2.D. of the Accomplishment Instructions of Saab Service Bulletin 340-55-033, Revision 04, dated December 1, 1998, to detect cracking around certain fastener holes and adjacent areas of the front spar of the horizontal stabilizer, in accordance with the service bulletin, at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable. Thereafter, repeat only the eddy current and x-ray inspections at intervals not to exceed 12,000 flight cycles until the requirements of paragraph (d) of this AD are accomplished. (1) For airplanes that have accumulated less than 22,000 total flight cycles as of the effective date of this AD: Perform an eddy current and an x-ray inspection prior to the accumulation of 22,000 total flight cycles, or within 2,000 flight cycles after the effective date of this AD, whichever occurs later. (2) For airplanes that have accumulated 22,000 or more total flight cycles and less than 30,000 total flight cycles as of the effective date of this AD: Accomplish the requirements of paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. (i) Perform a detailed visual inspection within 800 flight cycles after the effective date of this AD; and (ii) Perform an eddy current and an x-ray inspection within 2,000 flight cycles after the effective date of this AD. (3) For airplanes that have accumulated 30,000 or more total flight cycles as of the effective date of this AD: Accomplish the requirements of paragraphs (a)(3)(i) and (a)(3)(ii) of this AD. (i) Perform a detailed visual inspection within 400 flight cycles after the effective date of this AD; and (ii) Perform an eddy current and an x-ray inspection within 1,200 flight cycles after the effective date of this AD. Initial and Repetitive Inspections (b) For Model SAAB 340B series airplanes with manufacturer's serial numbers -160 through -439 inclusive: Perform the inspections (detailed visual, eddy current, and x-ray) specified in paragraph 2.D. of the Accomplishment Instructions of Saab Service Bulletin 340-55-033, Revision 04, dated December 1, 1998, to detect cracking around certain fastener holes and adjacent areas of the front spar of the horizontal stabilizer, in accordance with the service bulletin, at the time specified in paragraph (b)(1), (b)(2), or (b)(3) of this AD, as applicable. Thereafter, repeat only the eddy current and x-ray inspections at intervals not to exceed 6,000 flight cycles until the requirements of paragraph (d) of this AD are accomplished. (1) For airplanes that have accumulated less than 12,000 total flight cycles as of the effective date of this AD: Perform an eddy current and an x-ray inspection prior to the accumulation of 12,000 total flight cycles, or within 2,000 flight cycles after the effective date of this AD, whichever occurs later. (2) For airplanes that have accumulated 12,000 or more total flight cycles and less than 16,000 total flight cycles as of the effective date of this AD: Accomplish the requirements of paragraphs (b)(2)(i) and (b)(2)(ii) of this AD. [[Page 49966]] (i) Perform a detailed visual inspection within 800 flight cycles after the effective date of this AD; and (ii) Perform an eddy current and an x-ray inspection within 2,000 flight cycles after the effective date of this AD. (3) For airplanes that have accumulated 16,000 or more total flight cycles as of the effective date of this AD: Accomplish the requirements of paragraphs (b)(3)(i) and (b)(3)(ii) of this AD. (i) Perform a detailed visual inspection within 400 flight cycles after the effective date of this AD; and (i) Perform a detailed visual inspection within 400 flight cycles after the effective date of this AD; and (ii) Perform an eddy current and an x-ray inspection within 1,200 flight cycles after the effective date of this AD. Corrective Actions (c) If any cracking is detected during any inspection required by paragraph (a) or (b) of this AD, prior to further flight, either repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, or the Luftfartsverket (LFV) (or its delegated agent); or accomplish the requirements of paragraph (d) of this AD. Note 3: Inspections to detect cracking around certain fastener holes and adjacent areas of the front spar of the horizontal stabilizers that have been accomplished prior to the effective date of this AD in accordance with Saab Service Bulletin 340-55-033, Revision 03, dated January 22, 1998, are considered acceptable for compliance with the applicable action specified by this AD. Terminating Action (d) For all airplanes: Except as provided by paragraph (e) of this AD, accomplish cold working of certain fastener holes of the front spar of the horizontal stabilizers, and follow-on actions; and install new fasteners; in accordance with Saab Service Bulletin 340- 55-034, dated October 16, 1998; at the time specified in paragraph (d)(1), (d)(2), or (d)(3) of this AD, as applicable. Accomplishment of this action constitutes terminating action for this AD. (1) For all airplanes that have accumulated less than 26,000 total flight cycles as of the effective date of this AD: Within 10,000 flight cycles after the effective date of this AD. (2) For all airplanes that have accumulated 26,000 or more total flight cycles and less than 30,000 total flight cycles as of the effective date of this AD: Within 6,000 flight cycles after the effective date of this AD. (3) For all airplanes that have accumulated 30,000 or more total flight cycles as of the effective date of this AD: Within 3,000 flight cycles after the effective date of this AD. (e) If any crack is detected during the accomplishment of paragraph (d) of this AD, and if the service bulletin listed in paragraph (d) of this AD specifies to contact the manufacturer for an appropriate corrective action: Prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, or the LFV (or its delegated agent). Alternative Method of Compliance (f) 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 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 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 (g) 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 (h) Except as provided by paragraphs (c) and (e) of this AD, the actions shall be done in accordance with Saab Service Bulletin 340- 55-033, Revision 04, dated December 1, 1998; and Saab Service Bulletin 340-55-034, dated October 16, 1998; 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 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 directives 1-110R2, dated December 7, 1998, and 1-133, dated October 20, 1998. (i) This amendment becomes effective on October 20, 1999. Issued in Renton, Washington, on September 1, 1999. Dorenda D. Baker, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-23352 Filed 9-14-99; 8:45 am] BILLING CODE 4910-13-P