AD 98-15-21 Airworthiness Directives; Boeing Model 747-100 Series Airplanes

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

Model 747-100 series airplanes; as listed in Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995; 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 (g) 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 fuel leakage onto an engine and a resultant fire, accomplish the following: Restatement of Requirements of AD 95-02-15, Amendment 39-9134 (a) For airplanes on which the terminating action (fastener replacement) specified in Boeing Service Bulletin 747-57A2266, dated June 6, 1991; Revision 1, dated May 21, 1992; or Revision 2, dated June 10, 1993; has not been accomplished: Prior to the accumulation of 13,000 total flight cycles, or within 9 months after March 23, 1995 (the effective date of AD 95-02-15, amendment 39-9134), or within 2,000 flight cycles after the immediately preceding inspection accomplished in accordance with AD 92-07-11, amendment 39-8207, whichever occurs latest, accomplish the inspections specified in paragraphs (a)(1), (a)(2), and (a)(3) of this AD in accordance with Boeing Service Bulletin 747-57A2266, Revision 3, dated March 31, 1994, or Revision 4, dated November 3, 1994. Repeat these inspections thereafter at intervals not to exceed 2,000 flight cycles until the inspections required by paragraph (c) or (d) of this AD, as applicable, are accomplished. (1) Perform a detailed visual inspection to detect cracking of the wing front spar chords, stiffeners, and rib posts between the fastener heads between FSS 570 and FSS 684; and (2) Perform an ultrasonic inspection of the web under the upper and lower chord footprints to detect cracking of the wing front spar web between FSS 570 and FSS 684; and (3) Perform an ultrasonic inspection of the fasteners in the web-to-chords, and of the fasteners in the top two and bottom two rows in the web-to-stiffeners and web-to-rib posts of the wing front spar to detect cracked or broken fasteners between FSS 570 and FSS 684. (b) For airplanes on which the terminating action (fastener replacement) specified in Boeing Service Bulletin 747-57A2266, dated June 6, 1991; Revision 1, dated May 21, 1992; or Revision 2, dated June 10, 1993; has been accomplished: Within 18 months after accomplishing the terminating action specified in the original issue, Revision 1, or Revision 2 of the service bulletin, or within 9 months after March 23, 1995, whichever occurs later, accomplish the inspections specified in paragraphs (b)(1), (b)(2), and (b)(3) of this AD, in accordance with Boeing Service Bulletin 747-57A2266, Revision 3, dated March 31, 1994, or Revision 4, dated November 3, 1994. Repeat these inspections thereafter at intervals not to exceed 2,000 flight cycles until the inspections required by paragraph (c) or (d) of this AD, as applicable, are accomplished. (1) Perform a detailed visual inspection of the wing front spar chords, stiffeners, and rib posts between the fastener heads between FSS 570 and FSS 684; and (2) Perform an ultrasonic inspection of the web under the upper and lower chord footprints to detect cracking of the wing front spar web between FSS 570 and FSS 636 and between FSS 675 and FSS 684; and (3) Perform an ultrasonic inspection of the fasteners in the web-to-chords, and of the fasteners in the top two rows and bottom two rows in the web-to-stiffeners and web-to-rib posts of the wing front spar to detect cracked or broken fasteners between FSS 570 and FSS 636 and between FSS 675 and 684. New Requirements of this AD (c) For airplanes identified as Configuration A in Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995: Prior to the accumulation of 13,000 total flight cycles, or within 6 months after the effective date of this AD, or within 2,000 flight cycles after the immediately preceding inspection accomplished in accordance with paragraph (a) or (b) of this AD, whichever occurs latest, accomplish the inspections specified in paragraphs (c)(1), (c)(2), (c)(3), and (c)(4) of this AD, in accordance with Figure 3 of Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995. Repeat these inspections thereafter at intervals not to exceed 2,000 flight cycles. Accomplishment of these inspections terminates the inspections required by paragraphs (a) and (b) of this AD. (1) Perform a detailed visual inspection to detect damage and fuel leaks in the general area of the web of the wing front spar between FSS 570 and FSS 684. (2) Perform an eddy current inspection to detect cracks along the web near the edges of the vertical flange of the upper and lower chords of the wing front spar between FSS 570 and FSS 684. (3) Perform an ultrasonic inspection to detect cracks in the web around the first two fastener holes in the stiffeners and rib posts between FSS 570 and FSS 684. (4) Perform an ultrasonic inspection to detect cracked or broken fasteners in the fasteners attaching only the web to the chords, in the top two and bottom two rows of the fasteners attaching the web to the stiffeners, and in the top two and bottom two rows of the fasteners attaching the web to the rib posts. This inspection area is located between FSS 570 and FSS 684. (d) For airplanes identified as Configuration B in Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995: Within 18 months following accomplishment of the terminating action (fastener replacement) specified in Boeing Service Bulletin 747- 57A2266, dated June 6, 1991, Revision 1, dated May 21, 1992, or Revision 2, dated June 10, 1993; or within 12 months after the effective date of this AD; or within 2,000 flight cycles after the immediately preceding inspection accomplished in accordance with paragraph (a) or (b) of this AD; whichever occurs latest; accomplish the inspections specified in paragraphs (d)(1), (d)(2), (d)(3), and (d)(4) of this AD in accordance with Figure 4 of Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995. Repeat these inspections thereafter at intervals not to exceed 2,000 flight cycles. Accomplishment of these inspections terminates the inspections required by paragraphs (a) and (b) of this AD. (1) Perform a detailed visual inspection to detect damage and fuel leaks in the general area of the web of the wing front spar between FSS 570 and FSS 636 and between FSS 675 and FSS 684. (2) Perform an eddy current inspection to detect cracks along the web near the edges of the vertical flange of the upper and lower chords of the wing front spar between FSS 570 and FSS 636 and between FSS 675 and FSS 684. (3) Perform an ultrasonic inspection to detect cracks in the web around the first two fastener holes in the stiffeners and rib posts between FSS 570 and FSS 636 and between FSS 675 and FSS 684. (4) Perform an ultrasonic inspection to detect cracked or broken fasteners in the fasteners attaching only the web to the chords, in the top two and bottom two rows of the fasteners attaching the web to the [[Page 39489]] stiffeners, and in the top two and bottom two rows of the fasteners attaching the web to the rib posts. This inspection area is located between FSS 570 and FSS 636 and between FSS 675 and FSS 684. (e) If any discrepancy (i.e., cracking, fuel leakage, broken fasteners) is detected during any inspection required by this AD, prior to further flight, repair in accordance with paragraphs E. and H. (as applicable) of the Accomplishment Instructions of Boeing Service Bulletin 747-57A2266, Revision 3, dated March 31, 1994; Boeing Service Bulletin 747-57A2266, Revision 4, dated November 3, 1994; or Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995. Thereafter, continue to inspect the remaining fasteners in accordance with paragraph (c) or (d) of this AD, as applicable, until the terminating action specified in paragraph (f) of this AD is accomplished. If any crack is found that cannot be removed by oversizing the fastener hole, prior to further flight, repair it in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (f) Replacement of the fasteners in the web-to-chords and of the fasteners in the web-to-stiffeners and web-to-rib posts, as specified in Boeing Service Bulletin 747-57A2266, Revision 3, dated March 31, 1994; Revision 4, dated November 3, 1994; or Revision 5, dated August 3, 1995; with oversized fasteners on each wing spar in accordance with the service bulletin constitutes terminating action for the repetitive inspections required by paragraphs (a), (b), (c), (d), and (e) of this AD. (g) 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. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (h) 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. (i) The actions shall be done in accordance with Boeing Service Bulletin 747-57A2266, Revision 3, dated March 31, 1994; Boeing Service Bulletin 747-57A2266, Revision 4, dated November 3, 1994; and Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995. (1) The incorporation by reference of Boeing Alert Service Bulletin 747-57A2266, Revision 5, dated August 3, 1995, is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (2) The incorporation by reference of Boeing Service Bulletin 747-57A2266, Revision 3, dated March 31, 1994; and Boeing Service Bulletin 747-57A2266, Revision 4, dated November 3, 1994, was approved previously by the Director of the Federal Register as of March 23, 1995 (60 FR 9613, February 21, 1995). (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. (j) This amendment becomes effective on August 27, 1998. Issued in Renton, Washington, on July 15, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-19455 Filed 7-22-98; 8:45 am] BILLING CODE 4910-13-P