86-20-08 MCDONNELL DOUGLAS: Amendment 39-5434. Applies to McDonnell Douglas Model DC-8 series -10 through -50, -61, -61F, -71, and -71F airplanes with left and/or right wing front spar lower cap Part Numbers 5597838-1, -2, not modified in accordance with McDonnell Douglas DC-8 Service Bulletin 57-90, dated October 3, 1983, certificated in any category. Compliance required as indicated. \n\n\tTo prevent the loss of structural integrity of the left and/or right wing due to metal fatigue failure of the front spar lower cap, prior to the accumulation of 30,000 flight-hours or within 200 flight-hours after the effective date of this AD, whichever occurs later, accomplish the following, unless already accomplished within the last 3,400 flight-hours: \n\n\tA.\tVisually or eddy current inspect left and right wing front spar lower cap, P/N's 5597838-1, -2, between Stations Xfs = 515.000 and Xfs = 526.760 for cracks in accordance with paragraph 2.B. of McDonnell Douglas DC-8 Service Bulletin57-90 dated October 3, 1983, or later FAA-approved revisions. \n\n\tB.\tIf no crack is found, accomplish repetitive inspections on the spar cap in accordance with paragraph A. of this AD, at intervals not to exceed 3,600 flight-hours or one calendar year, whichever occurs first. \n\n\tC.\tIf crack(s) are found, before further flight: \n\n\t\t1.\tFor cracks within repairable limits, as defined by paragraph 2.B. of DC-8 Service Bulletin 57-90, repair cracked spar cap in accordance with paragraph 2.B. of that service bulletin. \n\n\t\t2.\tFor cracks greater than those specified by the above service bulletin, repair in a manner approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tD.\tModification of the attach holes in the forward tang of the front spar lower cap in accordance with paragraph 2.B. of DC-8 Service Bulletin 57-90 constitutes terminating action for the repetitive inspection requirements in paragraph B. of this AD. \n\n\tE.\tAlternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tF. \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 McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Director, Publications and Training, C1-L65 (54-60). These documents also may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Los Angeles Aircraft Certification Office, 4344 Donald Douglas Drive, Long Beach, California. \n\n\tThis Amendment becomes effective October 20, 1986.