90-24-11 BOEING: Amendment 39-6814. Docket No. 90-NM-81-AD. \n\n\tApplicability: All Model 727 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo detect cracks in the Body Station 1183 pressure bulkhead web and strap, accomplish the following: \n\n\tA.\tFor airplanes with 40,000 or more flight cycles on February 6, 1986 (the effective date of Amendment 39-5222), within the next 300 flight cycles, unless accomplished within the last 3,200 flight cycles, and thereafter at intervals not to exceed 3,500 flight cycles, inspect and repair, if necessary, in accordance with paragraph D. of this AD. \n\n\tB.\tFor airplanes with 33,000 or more flight cycles and less than 40,000 flight cycles on February 6, 1986, within the next 1,500 flight cycles, unless accomplished within the last 2,000 flight cycles, and thereafter at intervals not to exceed 3,500 flight cycles, inspect and repair, if necessary, in accordance withparagraph D. of this AD. \n\n\tC.\tFor airplanes with fewer than 33,000 flight cycles on February 6, 1986, prior to the accumulation of 30,000 flight cycles or within the next 3,500 flight cycles after February 6, 1986, whichever occurs later, and thereafter at intervals not to exceed 3,500 flight cycles, inspect and repair, if necessary, in accordance with paragraph D. of this AD. \n\n\tD.\tAccomplish a close visual inspection of the web in accordance with Figure 1 of Boeing Alert Service Bulletin 727-53A0171, Revision 1, dated January 17, 1986, or Revision 2, dated December 14, 1989. If cracks are detected, prior to further flight, repair in accordance with paragraph E. or F. of the Accomplishment Instructions of the service bulletin. \n\n\tE.\tFor airplanes repaired by the installation of the doubler in accordance with Boeing Service Bulletin 727-53A0171, Original Issue, within the next 15,000 flight cycles after that repair, incorporate the vertical reinforcing strap and spacers described in paragraph F. of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-53A0171, Revision 1, dated January 17, 1986, or Revision 2, dated December 14, 1989. \n\n\tF.\tThe following constitutes terminating action for the repetitive inspections required by paragraphs A., B., and C. of this AD: \n\n\t\t1.\tThe preventive modification described in paragraph D. of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-53A0171, Revision 1, dated January 17, 1986, or Revision 2, dated December 14, 1989. \n\n\t\t2.\tThe repairs described in paragraphs E. and F. of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-53A0171, Revision 1, dated January 17, 1986, or Revision 2, dated December 14, 1989. \n\n\tG.\tFor airplanes repaired or modified with blind fasteners: Within 3,500 flight cycles after the effective date of this AD, and thereafter at intervals not to exceed 3,500 flight cycles, accomplish a visual inspection for cracks and loose or missing fasteners, in accordance with Boeing Alert Service Bulletin 727- 53A0171, Revision 2, dated December 14, 1989. If cracks are detected, prior to further flight, repair in accordance with the service bulletin. If loose or missing fasteners are detected, prior to further flight, replace with protruding head solid fasteners. Replacement with protruding head solid fasteners constitutes terminating action for the repetitive inspections required by this paragraph. \n\n\tH.\tAn alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\tNOTE: The request should be submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO. \n\n\tI.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD. \n\n\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. \n\n\tAirworthiness Directive 90-24-11 supersedes AD 86-02-06 R1, Amendment 39-5331. \n\tThis amendment (39-6814, AD 90-24-11) becomes effective on December 26, 1990.