83-06-03 MCDONNELL DOUGLAS: Amendment 39-4590. Applies to McDonnell Douglas Model DC-9-30, -40, and -50 series airplanes, with the following MLG strut serial numbers installed: R4429N, R4430 through R4436, R4438 through R4449, R4462 through R4469, R5415 through R5420, R7475, R7476, R7478 through R7526, R8734, R8736, R8742, and R8743, certificated in all categories. Compliance required prior to December 14, 1983, unless previously accomplished. \n\n\tTo prevent failure of the main landing gear support structure, accomplish the following: \n\n\tA.\tPerform an eddy current inspection to determine the heat treat condition of the restrictor support tube in accordance with the Accomplishment Instructions of McDonnell Douglas DC-9 Service Bulletin 32-186, original issue, dated January 29, 1982, or later revisions approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tB.\tReplace restrictor tubes if any are found to be improperly heat treated in accordance with the above service bulletin. \n\n\tC.\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\tD.\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\tAll persons affected by this directive who have not already received these 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, C1-750 (54-60). These documents also may be examined at FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington 98168, or Los Angeles Aircraft Certification Office, 4344 Donald Douglas Drive, Long Beach, California 90808. \n\n\tThis amendment becomes effective April 28, 1983.