COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DH 104 (Dove) Series Aeroplanes AD/DH 104/6 Amdt 1 Engine Mount Attachment Brackets - Inspection 3/75 Applicability: All models not modified in accordance with TNS CT (104) Nos. 50 and 65. Document: Hawker Siddeley TNS CT(104) Nos. 50 Issue 3 and 65 Issue 4. Compliance: At intervals not exceeding 50 hours time in service after 30 April 1973.