COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DH114 (Heron) Series Aeroplanes AD/DH114/15 Top Centre Section Spar NK Attachment - Inspection and Modification Applicability: All models. Requirement: 1. Inspect Channels P/N 14FS2839-42 and Reinforcing Channels P/N 14FS383 and 386 in accordance with Hawker Siddeley Technical News Sheet Heron (114) F.7, Issue 2. 2. If found cracked, modify the channels in accordance with Heron Modification No. 792. Compliance: 1. At intervals not exceeding 300 hours time in service after 30 April 1964. 2. When Mod. 792 has been incorporated the inspection interval may be extended to 5,000 hours time in service or five years whichever occurs first.