COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DH114 (Heron) Series Aeroplanes AD/DH114/34 Amdt 1 Applicability: All models. Fuselage Keel Frame at Wing NK Rear Spar - Inspection Document: Hawker Siddeley TNS Heron (114) No. F.17, Issue 1. Compliance: Within 25 hours time in service or thirty days, after 1 May 1972 whichever occurs first and thereafter at intervals not exceeding 600 hours time in service. Note: Inspections performed in accordance with the preceding issue of this Directive may be regarded as the initial inspection required by para. 3 of the requirement document.