COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Brantly B-2 Series Helicopters AD/B-2/3 Tail Rotor Drive - Inspection 12/60 Applicability: All model B-2. Document: Brantly SB No. 3. Compliance: At intervals not exceeding 100 hours time in service.