AD 99-09-11 Airworthiness Directives; Boeing Model 747 Series Airplanes Equipped With General Electric Model CF6-45 or -50 Series Engines; or Pratt & Whitney Model JT9D-3, -7, or -70 Series Engines; and 747-E4B (Military) Airplanes

Models named: 747 series, CF6-45 or -50 series, JT9D-3, -7, or -70 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747 series airplanes equipped with General Electric Model CF6-45 or -50 series engines, or Pratt & Whitney Model JT9D-3, -7, or -70 series engines, and all 747-E4B (military) airplanes, having steel attachment fittings of the diagonal brace to the nacelle struts; certificated in any category. Note 1: This AD excludes those airplanes that are included in the applicability of AD 97-20-01 R1, amendment 39-10982 (64 FR 985, January 7, 1999). Those airplanes have aluminum attachment fittings. Note 2: 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 (c) 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 fracture of the steel attachment fittings of the diagonal brace to the nacelle struts, which could result in failure of a nacelle strut diagonal brace load path and possible separation of the nacelle from the wing; accomplish the following: Initial Inspection (a) Gain access to the attachment fittings of the diagonal brace to the inboard and outboard nacelle struts through the aft fairing doors, and perform a detailed visual inspection to detect cracking or fracture of the steel attachment fittings of the diagonal brace to the inboard and outboard nacelle struts, at the applicable time specified in paragraph (a)(1) or (a)(2) of this AD. (1) For airplanes on which the strut and wing modification required by AD 95-10-16, amendment 39-9233, or AD 95-13-07, amendment 39-9287, has not been accomplished: Within 10 days after the effective date of this AD, accomplish the detailed visual inspection. (i) For airplanes equipped with General Electric Model CF6-45 or -50 series engines and/or Pratt & Whitney JT9D-3 or -7 series engines, repeat the inspection thereafter at intervals not to exceed 180 flight cycles. (ii) For airplanes equipped with Pratt & Whitney JT9D-70 series engines, repeat the inspection thereafter at intervals not to exceed 250 flight cycles. (2) For airplanes on which the strut and wing modification required by AD 95-10-16, amendment 39-9233, or AD 95-13-07, amendment 39-9287, has been accomplished: Within 30 days after the effective date of this AD or within 150 flight cycles after accomplishment of the modification, whichever occurs later, accomplish the detailed visual inspection. (i) For airplanes equipped with General Electric Model CF6-45 or -50 series engines or Pratt & Whitney JT9D-70 series engines, repeat the inspection thereafter at intervals not to exceed 600 flight cycles. (ii) For airplanes equipped with Pratt & Whitney JT9D-3 or -7 series engines, repeat the inspection thereafter at intervals not to exceed 350 flight cycles. Corrective Actions (b) If any cracking or fracture of any attachment fitting is detected during any inspection required by paragraph (a) of this AD, prior to further flight, replace the fitting with a new steel fitting in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate; or in accordance with data meeting the type certification of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. Alternative Methods of Compliance (c) 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. Special Flight Permits (d) 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. (e) This amendment becomes effective on May 10, 1999. [[Page 19885]] Issued in Renton, Washington, on April 16, 1999. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-10175 Filed 4-22-99; 8:45 am] BILLING CODE 4910-13-U