COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 727 Series Aeroplanes AD/B727/98 Main Cargo Door Skin - Inspection and Modification 1/84 Applicability: All model 727-100 series aircraft with main cargo door of Boeing manufacture. Document: Boeing SB 727-52-79, Revision 5. Compliance: As detailed in requirement document. Background: Cargo door skin cracks have been found on aircraft in service, and have been assessed as a Safety of Flight item.