AD 98-08-15 Airworthiness Directives; Boeing Model 747-100, -200, and -300 Series Airplanes

Models named: 747-100, -200, -300 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-100, -200, and -300 series airplanes having line positions 1 through 886 inclusive, certificated in any category; excluding airplanes on which the strut/wing modification has been accomplished in accordance with AD 95-13-07, amendment 39- 9287; or AD 95-10-16, amendment 39-9233; and excluding airplanes designated as Group 5 in Boeing Service Bulletin 747-54A2179, Revision 2, dated December 4, 1997. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (e) 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 detect and correct fatigue cracking or stress corrosion of certain areas of the wing strut (the midspar fitting vertical leg, aft bulkhead vertical chords, the midspar webs, and the canted closure webs), which could cause failure of the strut-to-wing interface, and consequent separation of the engine and strut from the airplane; accomplish the following: (a) Perform detailed visual and/or borescope inspections to detect fatigue cracking, stress corrosion, or fracture of the midspar fitting vertical legs, the aft torque bulkhead vertical chords, the midspar webs and the midspar canted closure webs at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable; in accordance with Part III of Section III of the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 54A2179, Revision 2, dated December 4, 1997. Thereafter, repeat the inspections in accordance with and at the times specified in the alert service bulletin. (1) For airplanes identified as Group 1 in the alert service bulletin: Perform the inspections on the inboard struts and the outboard struts, prior to the accumulation of 5,000 total landings, or within 90 days after the effective date of this AD, whichever occurs later. (2) For airplanes identified as Group 6 in the alert service bulletin: Perform the inspections on the inboard struts, prior to the accumulation of 5,000 total landings or within 90 days after the effective date of this AD, whichever occurs later. (3) For airplanes identified as Groups 2, 3, and 4 in the alert service bulletin: Perform the inspections on the inboard struts, prior to the accumulation of 12,000 total landings, or within 90 days after the effective date of this AD, whichever occurs later. (b) If any fatigue cracking, stress corrosion, or fracturing is detected during any inspection required by paragraph (a) of this AD that is within the limits specified in Boeing Alert Service Bulletin 747-54A2179, Revision 2, dated December 4, 1997, prior to further flight, repair in accordance with the alert service bulletin. (c) If any fatigue cracking, stress corrosion, or fracturing is detected during any inspection required by paragraph (a) of this AD that is beyond the limits specified in Boeing Alert Service Bulletin 747-54A2179, Revision 2, dated December 4, 1997, prior to further flight, accomplish corrective actions in accordance with a method approved by the Manager, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office (ACO), Seattle, Washington. (d) Accomplishment of the strut/wing modification specified in paragraph (d)(1) or (d)(2) of this AD, as applicable, constitutes terminating action for the requirements of this AD. (1) For airplanes equipped with General Electric Model CF6-45 or -50 series engines, or Pratt & Whitney Model JT9D-70 series engines: Accomplish the strut/wing modification in accordance with Boeing Alert Service Bulletin 747-54A2158, Revision 2, dated August 15, 1996. (2) For airplanes equipped with Pratt & Whitney Model JT9D series engines (excluding Model JT9D-70 engines): Accomplish the strut/wing modification in accordance with Boeing Alert Service Bulletin 747-54A2159, Revision 2, dated March 14, 1996. (e) 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, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (f) 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. (g) Except as provided by the requirements of paragraph (c) of this AD, the actions and the terminating modifications shall be done in accordance with Boeing Alert Service Bulletin 747-54A2179, Revision 2, dated December 4, 1997; Boeing Service Bulletin 747- 54A2158, Revision 2, dated August 15, 1996; and Boeing Service Bulletin 747-54A2159, Revision 2, dated March 14, 1996. (1) The detailed visual and borescope inspections shall be done in accordance with Boeing Alert Service Bulletin 747-54A2179, Revision 2, dated December 4, 1997. The incorporation by reference of that service bulletin was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (2) The strut/wing modification, if accomplished, shall be done in accordance with the Boeing Alert Service Bulletins listed in the following table. The incorporation by reference of those documents was approved previously by the Director of the Federal Register on January 22, 1997 (61 FR 66201, December 17, 1996): ------------------------------------------------------------------------ Revision Referenced service bulletin level Date ------------------------------------------------------------------------ 747-54A2158....................... 2 Aug. 15, 1996. 747-54A2159....................... 2 March 14, 1996. ------------------------------------------------------------------------ (3) Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. 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. (h) This amendment becomes effective on April 28, 1998. Issued in Renton, Washington, on April 6, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-9589 Filed 4-10-98; 8:45 am] BILLING CODE 4910-13-P