COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DH114 (Heron) Series Aeroplanes AD/DH114/30 Main Undercarriage - Inspection NK Applicability: All models fitted with down lock operating lever assemblies P/N 14-2U. 181A/1. Document: Hawker Siddeley TNS Heron (114) No. U.12 Issue 1. Compliance: As detailed in requirement document.