90-20-18 BOEING: Amendment 39-6747. Docket No. 90-NM-46-AD. \n\n\tApplicability: Model 727 series airplanes, listed in Boeing Service Bulletin 727-53-0082, Revision 5, dated November 9, 1989, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo detect delamination of the upper body skin bonded tear straps from Fuselage Station 277 to Station 1130, accomplish the following: \n\n\tA.\tWithin 14 months from August 20, 1981 (the effective date of Amendment 39-4194), inspect the upper body skin bonded tear straps for delamination from the upper body skin in accordance with the ultrasonic inspection procedures described in Boeing Service Bulletin 727-53-0082, Revision 3, dated June 19, 1981; Revision 4, dated April 16, 1982; or Revision 5, dated November 9, 1989. \n\n\tB.\tIf the ultrasonic inspection required by paragraph A. of this AD reveals areas of delamination, prior to further flight, inspect the areas for corrosion in accordance with Boeing Service Bulletin 727-53-0082, Revision 5. \n\n\tC.\tPerform either of the following repetitive inspections: \n\n\t\t1.\tWithin 24 months from the initial inspection, reinspect as required by paragraph A. of this AD, and in accordance with the following schedule: \n\n\t\t\ta.\tRepeat inspections for Group I airplanes starting with Zone I, alternating between Zones I, II, and III at intervals not to exceed 24 months, in accordance with Boeing Service Bulletin 727-53- 0082, Revision 3, 4, or 5. \n\n\t\t\tb.\tRepeat inspections for Group II airplanes alternating between Zones I and II at intervals not to exceed 24 months, in accordance with Boeing Service Bulletin 727-53-0082, Revision 3, 4, or 5. \n\n\t\t\tc.\tAny strap found delaminated, while inspecting a zone, must be inspected along its entire length (e.g., stringer 14R to stringer 14L) prior to further flight. \n\n\t\t2.\tWithin 30 months from the initial inspection, reinspect Zones I, II, and, if applicable, Zone III, as required by paragraph A. of this AD. Repeat the inspection at intervals not to exceed 30 months. \n\n\tD.\tIf tear strap corrosion is detected or bond delaminations exceed the limits specified in Boeing Service Bulletin 727-53-0082, Revision 5, prior to further flight, repair in accordance with the service bulletin. \n\n\tE.\tIf tear strap corrosion is not detected and bond delaminations are within the limits specified in Boeing Service Bulletin 727-53-0082, Revision 5, perform either of the following: \n\n\t\t1.\tRepair in accordance with the service bulletin prior to further flight. \n\n\t\t2.\tReinspect for delamination growth and corrosion at intervals not to exceed 24 months in accordance with the service bulletin. \n\n\tF.\tRepairs or modifications made in accordance with Boeing 727 Structural Repair Manual Subject 53-30-4, Paragraph 2.C., Method II or V; or Paragraph 2.D., Method III; terminate the inspection requirements of paragraph C. of this AD for the repaired area. \n\n\tG.\tBlind fasteners installedin accordance with Boeing 727 Structural Repair Manual Subject 53-30-4, Paragraph 2.D., Method IV, are approved as an interim repair only. \nInspect blind fastener repair for loose or missing fasteners within the next 3,000 landings after the effective date of this AD, and thereafter at intervals not to exceed 2,500 landings. \n\n\t\t1.\tReplace the tear strap blind splice fasteners with solid fasteners prior to accumulating 10,000 landings or within the next 10,000 landings after the effective date of this AD, whichever occurs later. NOTE: Splice fasteners are the 9 rivets at the terminating end of a tear strap. Each body station that has tear straps has 4 locations where the tear straps terminate with 9 splice rivets; just above stringer (S) 4L, S-4R, S-10L, and S-10R. \n\n\t\t2.\tReplace the remaining tear strap blind fasteners with solid fasteners prior to accumulating 20,000 landings or within the next 10,000 landings after the effective date of this AD, whichever occurs later.In skin gauges .063 inches or greater, use solid fastener BACR15CE6D. \n\n\tIn skin gauges less than .063 inches, use solid fastener MS20470D6. Replacement with solid fasteners terminates the inspection requirements of this AD for the repaired area. \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, Northwest Mountain Region. \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 in order to comply with the requirements of 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 90-20-18 supersedes AD 81-17-07, Amendment 39-4191. \n\tThis amendment (39-6747, AD 90-20-18) becomes effective on October 29, 1990.