76-04-04 MCDONNELL DOUGLAS: Amendment 39-2522 as amended by Amendment 39-2600. Applies to all Model DC-8 Series airplanes except -62, -62F, -63, and -63F, certificated in all categories. \n\n\tCompliance required as indicated. \n\n\tTo prevent possible fatigue failure of the wing front spar lower cap, P/N 5597838-1 or -2, accomplish the following: \n\n\t(a)\tFor those airplanes which have had the original 17 interference fit fasteners replaced that attach the #1 and #4 pylon cant bulkhead shear clips to the wing lower spar cap forward flange, comply with Paragraph (c) within the next 1600 hours time in service after the effective date of this AD or before the accumulation of 30,000 hours total time in service, whichever occurs later, unless accomplished within the last 2600 hours time in service, and thereafter at intervals not to exceed 4200 hours time in service. \n\n\t(b)\tFor those airplanes which have not had the original 17 interference fit fasteners replaced that attach the #1 and#4 pylon cant bulkhead shear clips to the wing lower spar cap forward flange, comply with Paragraph (c) within the next 3200 hours time in service after the effective date of this AD or before the accumulation of 30,000 hours total time in service, whichever occurs later, unless accomplished within the last 1000 hours time in service, and thereafter at intervals not to exceed 4200 hours time in service. \n\n\t(c)\tInspect the wing front spar lower cap, P/N 5597838-1 or -2, for cracks in accordance with the instructions in McDonnell Douglas DC-8 Alert Service Bulletin A57-82, Revision 1 dated February 6, 1976, or later FAA-approved revisions, or in accordance with an inspection method approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\t(d)\tIf cracks are found which are limited to the lower forward horizontal tang and have not progressed aft into the lower aft tang or vertical leg of the cap, repair before further flight in accordance with DC-8 Service Bulletin57-82 dated March 17, 1976, or later FAA-approved revisions, or DC-8 Service Rework Drawing 5802723, or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. If cracks are found which exceed the above limits, repair before further flight in accordance with DC-8 Service Rework Drawing 5802712, Revision "B" or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\t(e)\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 substantiating data to justify the increase for the operator. \n\n\t(f)\tThe repetitive inspections required by Paragraphs (a) or (b) may be discontinued for those airplanes which have incorporated the preventative rework, involving stress coining of the fasteners holes and installation of interference fit fasteners in accordance with either Service Rework Drawing 5802712, Revision "B", or Service Rework Drawing 5802723, or McDonnell Douglas DC-8 Service Bulletin 57-82, dated March 17, 1976, or later FAA-approved revisions, or in accordance with an equivalent rework method approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tAmendment 39-2522 became effective February 25, 1976. \n\n\tThis amendment 39-2600 becomes effective May 13, 1976.