79-10-13 MCDONNELL DOUGLAS: Amendment 39-3472 as amended by Amendment 39-3554. Applies to DC-9 Series and Military C-9 Series airplanes, certificated in all categories. \n\n\tCompliance is required as indicated. \n\n\tTo detect fatigue cracks in the forward passenger entry door lock mechanism crank assembly parts, P/N 4918613-3 (crank) and P/N 4918613-5 (clevis) accomplish the following: \n\n\t(a)\tWithin the next 3,500 landings after the effective date of this AD, or before accumulating 22,500 total landings whichever occurs later, comply with the applicable program of inspections and/or corrective actions in accordance with paragraphs (b) and (c) below: \n\n\t(b)\tPrior to disassembly, visually inspect the crank assembly P/N 4918613-1 for proper engagement of serrations. If the serrations of the -3 and/or -5 parts are observed to be riding on the unserrated surface of the mating -3 and/or -5 parts, replace both parts per the requirement of paragraph (c)(1)(i) and/or (c)(1)(ii) and/or (c)(1)(iii) of this AD. \n\n\t(c)\tIf visual inspection of the P/N 4918613-1 crank assembly shows proper engagement of serrations, perform the dye penetrant inspections on the crank assembly parts, P/N 4918613-3 (crank) and P/N 4918613-5 (clevis), in accordance with the instructions contained in Paragraph 2 of McDonnell Douglas Service Bulletin 52-111, Revision 1, dated May 31, 1979. \n\n\t\t(1)\tIf a crack(s) is found in the -3 crank and/or the -5 clevis or there is evidence, (abrasion, etc.), that a serrated part was riding on an unserrated surface of the mating face, before further flight: \n\n\t\t\t(i)\treplace the part(s) with an unmodified -3 crank and/or -5 clevis; or, \n\n\t\t\t(ii)\treplace the part(s) with a -3 crank and/or a -5 clevis modified in accordance with the instructions contained in Paragraph 2 of McDonnell Douglas Service Bulletin 52-111, Revision 1, dated May 31, 1979; or, \n\n\t\t\t(iii)\treplace the cracked part(s) with a new crank, P/N 4918613-11, and/or a new clevis, P/N 4918613-13, in accordance with the instructions contained in Paragraph 2 of McDonnell Douglas Service Bulletin 52-111, Revision 1, dated May 31, 1979. \n\n\tNote: Any combination of parts listed in subparagraphs (i), (ii) and (iii) is acceptable. \n\n\t\t(2)\tIf no cracks are found and there is no evidence of a serrated part riding on the unserrated surface of the mating face; \n\n\t\t\t(i)\treinstall the part; or, \n\n\t\t\t(ii)\treplace the part(s) per (c)(1)(i) and/or (c)(1)(ii) and/or (c)(1)(iii) above. \n\n\t(d)\tReinstallation and/or replacement of parts in accordance with paragraphs (b), (c)(1) and (c)(2) constitutes terminating action for this AD. \n\n\t(e)\tOperators who have accomplished the objective of this AD prior to the effective date of this AD in a manner approved by the Chief, Aircraft Engineering Division, FAA Western Region are exempt from the provisions of this AD. \n\n\t(f)\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\t(g)\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 and modifications required by this AD. \n\n\t(h)\tFor the purpose of complying with this AD, subject to the acceptance by the assigned FAA Maintenance Inspector, the number of landings may be determined by dividing each airplane's hour's time in service by the operator's fleet average time from takeoff to landings for the airplane type. \n\n\t(i)\tUpon request of operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region may adjust the inspection interval 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 that operator. \n\n\tAmendment 39-3472 became effective June 20, 1979.This Amendment 39-3554 becomes effective September 13, 1979.