84-07-04 R1 MCDONNELL DOUGLAS: Amendment 39-4838 as amended by amendment 39-5831. Applies to certain McDonnell Douglas Model DC-9-10 and -30 series airplanes, certificated in all categories which correspond to the factory serial numbers listed in McDonnell Douglas DC-9 Service Bulletin No. 53-174, dated August 4, 1983 (hereinafter referred to as S/B 53-174), or later revisions approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tCompliance required as indicated in the body of this AD, unless previously accomplished. \n\n\tTo detect fatigue cracks in the non-ventral aft pressure bulkhead and repair, if necessary, accomplish the following: \n\n\tA.\tPrior to the accumulation of 37,500 landings, or within the next 2,500 landings after the effective date of this AD, whichever occurs later, perform an initial eddy current inspection of the aft pressure bulkhead webs as shown on McDonnell Douglas Service Sketch 3483 of S/B 53-174, or later revisions approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tB.\tIf no cracks are found in aircraft Group I, as referenced in S/B 53-174, perform repetitive eddy current inspections at intervals not to exceed 14,000 landings until a preventive modification has been accomplished in accordance with the Accomplishment Instructions in S/B 53-174, or later revisions approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. After the accumulation of an additional 30,000 landings from the date of the crack preventive modification installation, reinstate eddy current inspections at intervals not to exceed 17,500 landings. \n\n\tC.\tFor aircraft Groups II and III, as referenced in S/B 53-174: If no cracks are found perform repetitive eddy current inspections at intervals not to exceed 17,500 landings until a crack preventive modification has been accomplished in accordance with the Accomplishment Instructions in S/B 53-174, or later revisions approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. After the accumulation of an additional 30,000 landings from the date of the crack preventive modification installation, reinstate the eddy current inspection at intervals not to exceed 17,500 landings. \n\n\tD.\tFor all aircraft Groups (i.e., I, II, and III, as referenced in S/B 53-174): If cracks are found, repair cracked area per the crack preventive modification in accordance with the Accomplishment Instructions in S/B 53-174, and, after the accumulation of an additional 30,000 landings from the date of repair, reinstate the repetitive eddy current inspection at intervals not to exceed 17,500 landings. \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.\tUpon request of operator, an FAA Maintenance Inspector, subject to prior approval of the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region, may adjust the initial 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 that operator. \n\n\tG.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplanes unpressurized to a base in order to comply with the requirements of this AD. \n\n\tH.\tFor the purposes of complying with this AD, subject to acceptance by the assigned FAA Maintenance Inspector, the number of landings may be determined by dividing each airplane's hours time in service by the operator's fleet average time from takeoff to landing for the DC-9 airplane. \n\n\tAll persons affected by this directive who have not already received the appropriate service document from the manufacturer may obtain copiesupon request to the McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Director, Publications and Training, C1-750 (54-60). This document may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or at 4344 Donald Douglas Drive, Long Beach, California. \n\n\tAD 84-07-04, amendment 39-4838 became effective May 6, 1984. \n\n\tThis Amendment 39-5831 becomes effective February 28, 1988.