AD 2001-16-02 Airworthiness Directives; Boeing Model 747-100, -200B, -200F, -200C, -100B, -300, -100B SUD, -400, -400D, -400F, and 747SR Series Airplanes

Models named: 747-100, -200B, -200F, -200C, -100B, -300, -100B SUD, -400, -400D, -400F. Read the applicability below — it usually turns on serial or part numbers too.

All Model 747-100, -200B, -200F, -200C, -100B, -300, -100B SUD, -400, -400D, -400F, and 747SR series airplanes, 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 (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 find and fix cracking of the frame web, strap, inner chords, and inner chord angle of the forward edge frame of the number 5 main entry door cutout, which could result in severing of the frame, inability of the edge frame to react door stop loads, and consequent rapid depressurization of the airplane, accomplish the following: Repetitive Inspections (No Terminating Action) (a) Inspect the airplane for cracks per Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001; at the later of the times specified in either paragraph (b) or (c) of this AD, per Table 1 as follows: Table 1.—Inspection Requirements Type of inspection Area to inspect (1) Detailed Visual Strap inner chords forward and aft of the web, and exposed web adjacent to the inner chords on station 2231 frame from stringer 23 through 31 per Figure 5 or Figure 6 of the service bulletin, as applicable. (2) Surface High Frequency Eddy Current (HFEC) Station 2231 inner chord angles at lower main sill interface per Figure 5 or Figure 6 of the service bulletin, as applicable. (3) Open Hole HFEC Station 2231 frame fastener locations per Figures 4 and 7, and either Figure 5 or 6 of the service bulletin, as applicable. (4) Surface HFEC Around fastener locations on station 2231 inner chords from stringer 23 through 31 per Figure 5 or Figure 6 of the service bulletin, as applicable. (5) Low Frequency Eddy Current Station 2231 frame strap in areas covered by the reveal per Figure 5 or Figure 6 of the service bulletin, as applicable. (b) Do the inspections per Table 1 at the applicable time specified in the logic diagram in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001. Where the compliance time in the logic diagram specifies a compliance time beginning, “from receipt of this service bulletin,” this AD requires that the compliance time begin “after the effective date of this AD.” Repeat the inspections after that at intervals not to exceed 3,000 flight cycles. (c) Within 3,000 flight cycles after accomplishment of the inspections specified in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, dated May 4, 2000; or Revision 1, dated July 6, 2000; repeat the inspections after that at intervals not to exceed 3,000 flight cycles. Note 2: There is no terminating action currently available for the inspections required by paragraph (a) of this AD. Note 3: Where there are differences between the AD and the alert service bulletin, the AD prevails. Repair (d) If any cracking is found during any inspection required by paragraph (a) of this AD, before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis 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 approval letter must specifically reference this AD. Alternative Methods of Compliance (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 4: 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 (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. Incorporation by Reference (g) The inspections shall be done in accordance with Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001. 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. Effective Date (h) This amendment becomes effective on September 12, 2001. Issued in Renton, Washington, on July 26, 2001. Vi L. Lipski, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 01-19245 Filed 8-7-01; 8:45 am] BILLING CODE 4910-13-P