81-19-05 McDONNELL DOUGLAS: Amendment 39-4216. Applies to McDonnell Douglas Model DC-9-80 series airplanes, certificated in all categories with thrust reverser barrel assemblies P/N 5938033-1 installed. Compliance required as indicated unless already accomplished. To prevent the separation of the thrust reverser from the airplane as a result of a failure of the brazed joint at the thrust reverser attach flange, accomplish the following:\n\n\tA.\tWithin three days from the effective date of this AD, and at intervals of 24 hours calendar time thereafter, conduct a visual inspection, with a 3 to 5 power magnifying glass, of the exhaust nozzle barrel assembly exterior skin P/N 5938033-5 at attach flange P/N 5938033-37 joint for buckling, obvious separation, or circumferential cracks especially in the zone 30 degrees above and below the thrust reverser stang fairings on each side. If buckling separation or cracks are found remove and replace barrel assembly prior to further flight. Chapter 78-30-01 of the maintenance manual contains additional information on this subject.\n\n\tB.\tWithin three days from the effective date of this AD inspect all thrust reversers to identify each thrust reverser barrel serial number. Remove from service reverser assemblies identified by the following barrel serial numbers.\n\n\tAccomplishment instructions for this inspection are contained in McDonnell Douglas Alert Service Bulletin A78-50 Revision 1, dated July 20, 1981, or later revisions approved by the Chief, Los Angeles Area Aircraft Certification Office, Northwest Region.\n\n\tSerial Numbers D3-0005, D3-0008, D3-0010 thru D3-0012, D3-0024, D3-0025, D3-0043, D3-0047, D3-0048, D3-0057, D3-0058, D3-0060, D3-0063, D3-0064, D3-0069, D3-0084, D3-0091, D3-0093, D3-0095, D3-0100 thru D3-0105, D3-0108, D3-0112, D3-0113, D3-0115, D3-0119, D3-0129A, D3-0132, D3-0137, D3-0156, D3-0162, D3-0165, and D3-0172. \n\n\tNOTE:\n\n\tTypical example of the number found on the reverser barrel assembly is "5938033-1-01-D3-0105." This number is located approximately six inches aft of the upper hydraulic thrust reverser latch and is etched on the exterior surface of the thrust reverser exhaust duct barrel assembly near top centerline. 5938033-1 is the part number and will be the same on each unit. The last six digits (D3-0105) constitute the listed serial number.\n\n\tC.\tWithin 120 days from the effective date of the AD modify all P/N 5938033-1 reverser barrel assemblies by welding the engine attach flange - outer barrel skin joint in accordance with the accomplishment instructions of McDonnell Douglas Service Bulletin 78-51 dated August 25, 1981, or later revisions approved by the Chief, Los Angeles Area Aircraft Certification Office, Northwest Region. Upon completion of this modification reidentify the reverser barrel assembly as P/N 5938033-501 and the thrust reverser assembly as P/N 5938050-501 in accordance with paragraph 2.B. (6) and (9) of the accomplishment instructions of the bulletin. This modification constitutes terminating action for all requirements of this AD. All reverser barrel assemblies removed from service per paragraph B above may be modified in accordance with this paragraph and returned to service.\n\n\tD.\tSpecial flight permits may be issued in accordance with FAR's 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.\n\n\tE.\tAlternative means of compliance or other actions which provide an equivalent level of safety may be used when approved by the Chief, Los Angeles Area Aircraft Certification Office, FAA Northwest Region. \tThe manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1).\n\n\tAll persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to the 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 Region, 9010 East Marginal Way South, Seattle, Washington 98108, or 4344 Donald Douglas Drive, Long Beach, California 90808.\n\n\tThis amendment becomes effective September 28, 1981.