COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DHC-3 (Otter) Series Aeroplanes AD/DHC-3/33 Wing Strut to Fuselage Tie Bar 13/87 Applicability: All models. Requirement: Action in accordance with de Havilland Canada SB 3/37 Rev B. Note: Canadian AD CF-82-26 refers. Compliance: Prior to the initial issue of a Certificate of Airworthiness and thereafter at periods not exceeding 12 months. Background: Tie bar lugs have been found corroded as well as the internal channel section under the cabin floor.