80-22-01 MCDONNELL DOUGLAS: Amendment 39-3946. Applies to Model DC-8 series airplanes with 20,000 or more hours time in service, certificated in all categories. \n\n\tCompliance required as indicated unless already accomplished. To prevent crack growth which could result in structural failure of the wing lower skin and rear spar lower cap, accomplish the following: \n\n\t(a)\tVisually inspect the lower inboard aft wing skin panels and aft tang of the rear spar cap in the vicinity of the dihedral break at wing station Xcw=69.500 per the Phase 1 accomplishment instructions (Part 2) of McDonnell Douglas Service Bulletin 57-88 dated January 23, 1980, (hereinafter referred to as SB 57-88) within the times specified below: \n\n\nFor airplanes with total hours time\n in service on or after the effective\ndate of this AD.\nInspect within additional \nhours time in service from \nthe effective date of this AD. \n\n20,000 to 24,999\t\n900\n25,000 to 29,999\t\n700\n30,000 to 34,999\t\n500 \n35,000 and over\t\n300\n\t\n\t(b)\tModify Clip P/N 5649893-47 (Left Side) and -48 (Right Side) per SB57-88, Part 2, Accomplishment Instructions, Paragraph G within the compliance schedule specified in Paragraph (a) of this AD. \n\n\t(c)\tPrecoin ream the six holes in lower wing skin identified in SB57-88, Part 2.H per instructions of SB57-88, Part 2.H, Condition II, Paragraph 1, within the compliance schedule specified in Paragraph (a) of this AD. \n\n\t(d)\tReam five attachment holes identified in SB57-88 Part 2.H per instructions of SB57-88 Part 2.H Condition II, Paragraph 2, within the compliance schedule specified in Paragraph (a) of this AD. \n\n\t(e)\tInspect the eleven attachment holes identified in Paragraphs (c) and (d) of this AD for cracks in wing skin and rear spar lower cap aft tang using eddy current methods per SB 57-88, Part 2.H, Condition II, Paragraph 3, within the compliance schedule specified in Paragraph (a) of this AD. \n\n\t(f)\tIf cracks are found, as a result of the inspections of Paragraphs (a) or (e) of this AD, repair prior to further flight as indicated: \n\n\t\t1.\tIf cracks are less than 2.5 inches in length, rework in accordance with appropriate Condition of Service Sketch (SS) 3154, or Paragraph (f)(2) of this AD. Rework per SS 3154 requires repetitive inspections per Paragraphs (a) and (e) of this AD at intervals not to exceed: 1200 hours additional time in service since the last inspection for Conditions I and VI of SS 3154 or 1800 hours additional time in service for Conditions II through V of SS 3154, and repair within 3600 additional hours time in service subsequent to rework per Paragraph (f)(2) of this AD. \n\n\t\t2.\tRepair cracks which are 2.5 inches in length or greater, but less than 7.0 inches in length per SB57-88, Part 2.H, Condition I, Paragraph 3. \n\n\t\t3.\tRepair cracks which are 7.0 inches in length or greater after obtaining approval of the proposed repair from the Chief, Aircraft Engineering Division, FAA Western Region. Submit exactlocation and dimension of crack with the proposed repair. \n\n\t(g)\tIf no cracks are found as a result of inspections of Paragraphs (a) and (e) of this AD, coin six holes outboard of wing station Xcw=69.500 per SB57-88 Part 2.H, Condition II, Paragraph 4, and revert to repetitive inspection requirements of Paragraph (i) of this AD. \n\n\t(h)\tReturn the aircraft to serviceable condition per the appropriate instructions of SB57-88 prior to flight. \n\n\t(i)\tConduct repetitive visual inspections per Paragraph (a) and eddy-current inspection of the 11 attachment holes per Paragraph (e) at intervals not to exceed 3,600 hours time in service since the last such inspection. (Note: Do Not re-ream the eleven attachment holes inboard of station Xcw=69.500 after the initial inspection of Paragraph (e) of this AD.) \n\n\t(j)\tInstallation of the preventive modification per S/B 57-88, Part 2.H, Condition I, Paragraph 3, eliminates the requirement for repetitive inspections required by Paragraph (i) ofthis AD. \n\n\t(k)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections required by this AD. \n\n\t(l)\tAlternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tThis amendment becomes effective October 23, 1980.