77-23-06 R2 MCDONNELL DOUGLAS: Amendment 39-3079 as amended by Amendment 39-3105 is further amended by Amendment 39-4012. Applies to Model DC-8 Series Airplanes, certificated in all categories. \n\n\tCompliance required as indicated. \n\n\tTo detect cracks and prevent failure of the flap link support fittings, comply with the following: \n\n\t(a)\tWithin the next 1500 landings after the effective date of this AD, unless already accomplished, determine whether the flap link support fittings at stations Xw97.906, Xf219.498 and Xf339.723 are 7075-T6 or 7075-T73 aluminum. If the fitting is 7075-T73 aluminum, no further action is necessary per this AD. If the fitting is 7075-T6 aluminum, accomplish Paragraph (b). Fitting material may be determined by reference to the part number. If fitting material cannot be positively identified by part number, the eddy current procedure of McDonnell Douglas DC-8 Service Bulletin 27-260, dated July 12, 1977, or later FAA approved revision, must be used. The following part number fittings are all 7075-T73 material. \n\n\n5614372-501\n5614376-506\n7760086-514 \n5614374-503\n5614376-507\n7760086-515 \n5614374-504\n5614376-508\n7760086-516 \n5614376-501\n7760086-509\n7760086-517 \n5614376-502\n7760086-510\n7760086-518 \n5614376-505\n7760086-513\n7760086-519 \n\n7760086-520 \n\n\t\n\t(b)\tWithin the next 1500 landings after the effective date of this AD, unless already accomplished, and thereafter at intervals not to exceed 1500 landings, perform the ultrasonic inspection procedure for cracks per McDonnell Douglas DC-8 Service Bulletin 27-260, dated July 12, 1977, or later FAA approved Revision. \n\n\t(c)\tFittings failed or cracked in the side brace attach area must be replaced with like serviceable parts before further flight. \n\n\t(d)\tSpare parts must be examined and identified in accordance with the procedures of DC-8 Service Bulletin 27-260, dated July 12, 1977, or later FAA approved revision, before installation on an airplane.(e)\tEquivalent inspections and repairs may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\t(f)\tSpecial flight permits may be issued in accordance with FAR's 21.197 and 21.199 to authorize operation of an airplane to a base for the accomplishment of the inspections required by this AD. \n\n\t(g)\tUpon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains adequate substantiating data to justify the increase for that operator. \n\n\tAmendment 39-3079 became effective December 23, 1977. \n\n\tAmendment 39-3105 became effective January 4, 1978. \n\n\tThis amendment 39-4012 becomes effective January 13, 1981.