86-23-07: Vertical Fin/Fuselage Structure

86-23-07 BRITISH AEROSPACE: Amendment 39-5464. Applies to Model B.121 Series I, II, and III (all serial numbers) airplanes certificated in any category. Compliance: Required initially within 50 hours time-in-service (TIS) for airplanes having or upon accumulating 2,450 hours or more TIS, and thereafter at intervals of 50 hours TIS, unless already accomplished. To assure the integrity of the vertical fin/fuselage attachment structure, accomplish the following: (a) Visually inspect for cracks in the following areas: (1) Center Angle, Part Number (P/N) BE-10-10085 in accordance with paragraph 3. "ACTION" subparagraph (c) of British Aerospace (BAe) Service Bulletin (S/B) No. B121/86, dated March 29, 1984. (i) If cracks are found that equal or exceed the conditions shown in paragraph 3. "ACTION" subparagraph (c) of BAe S/B No. B121/86, prior to further flight, repair in accordance with repair instructions obtained from the manufacturer, British Aerospace, and approved by the Manager, Aircraft Certification Staff, AEU-100, Europe, Africa and Middle East Office, FAA, c/o American Embassy, 1000 Brussels, Belgium (hereinafter referred to as "Manager, AEU-100"). (ii) If no cracks are found or if cracks do not exceed the limits shown in paragraph 3. "ACTION" subparagraph (d) of BAe S/B No. B121/86, repeat the inspection at intervals not exceeding 50 hours TIS. (2) The underside of Diaphragm Decking upper, P/N BE-10-10155/1, in accordance with paragraph 3. "ACTION" subparagraph (d) of BAe S/B No. B121/86, dated March 29, 1984. (i) If cracks are found, prior to further flight, repair in accordance with repair instructions obtained from the manufacturer, British Aerospace, and approved by the Manager, AEU-100. (ii) If no cracks are found, repeat the inspection at intervals not exceeding 50 hours TIS. (3) The heel of the side skin attachment flange (left and right) adjacent to the tailplane front spar attachment bolts in accordance with paragraph 3. "ACTION" subparagraph (e) of BAe S/B No. B121/86, dated March 29, 1984. (i) If cracks are found, prior to further flight, repair in accordance with repair instructions obtained from the manufacturer, British Aerospace, and approved by the Manager, AEU-100. (ii) If no cracks are found, repeat the inspection at intervals not exceeding 50 hours TIS. (b) Extension or elimination of the repetitive inspections specified in this AD may be included as part of the FAA-approved repair obtained in accordance with paragraphs (a)(1)(i), (a)(2)(i), and (a)(3)(i) of this AD. (c) Aircraft may be flown in accordance with Federal Aviation Regulation 21.197 to a location where this AD can be accomplished. (d) An equivalent means of compliance with this AD may be used if approved by the Manager, Aircraft Certification Staff, AEU-100, Europe, Africa and Middle East Office, FAA, c/o American Embassy, 1000 Brussels, Belgium. All persons affected by this directive may obtain a copy of the document referred to herein upon request to British Aerospace, Engineering Department, Post Office Box 17414, Dulles International Airport, Washington, D.C. 20041; Telephone (703) 435-9100, or FAA, Office of the Regional Counsel, Room 1558, 601 East 12th Street, Kansas City, Missouri 64106. This amendment becomes effective on December 18, 1986.