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 104/28 Engine Mounting Attachment Fittings - Inspection 12/71 Applicability: All models. Document: Hawker Siddeley TNS CT(104) No. 226. Compliance: Before 1 April 1972.