94-25-01 BOEING : Amendment 39-9085. Docket 94-NM-207-AD.\n Applicability: Model 747 series airplanes having line numbers 202 through 396 inclusive, equipped with Pratt & Whitney Model JT9D-70 engines, certificated in any category.\n 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 use the authority provided in paragraph (c) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.\n Compliance: Required as indicated, unless accomplished previously. \n To prevent failure of a spring beam, which could lead to the loss of an outboard strut, accomplish the following:\n (a) Prior to the accumulation of 10,000 total flight cycles or within 30 days after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to detect cracking of the upper, lower, and side surfaces of the spring beam from the root of the clevis lugs to the forward journal, in accordance with Boeing Alert Service Bulletin 747-54A2171, dated October 31, 1994. (Remove the gap covers and fairing access panels to perform this inspection.)\n NOTE 2: The area of inspection is illustrated in Figure 3 of the service bulletin.\n (1) If no cracking is detected, repeat theinspection thereafter at intervals not to exceed 300 flight cycles.\n (2) If any cracking is detected, prior to further flight, accomplish the requirements of paragraphs (a)(2)(i), (a)(2)(ii), and (a)(2)(iii) of this AD, in accordance with the service bulletin.\n (i) Replace the cracked spring beam with a new spring beam.\n (ii) Perform the detailed visual inspection required by paragraph (a) of this AD to detect cracking of the other spring beam on the affected strut. Also perform a detailed visual inspection to detect damage of all spring beam support fittings of the affected strut. Prior to further flight, replace any cracked or damaged parts with new parts.\n (iii) Repeat the inspection of the surfaces of the spring beam required by paragraph (a) of this AD thereafter at intervals not to exceed 300 flight cycles. \n (b) Accomplishment of all of the following actions in accordance with Boeing Overhaul Manual, Section 54-00-01, constitutes terminating action for the requirements of this AD.\n (1) Remove the spring beam. \n (2) Accomplish a fluorescent dye penetrant inspection.\n (3) Zero-time overhaul the spring beam.\n (4) Reinstall that spring beam. \n (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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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.\n NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n (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.\n (e) The inspections and replacement shall be done in accordance with Boeing Alert Service Bulletin 747-54A2171, dated October 31, 1994. 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 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.\n (f) This amendment becomes effective on December 22, 1994.