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-2/28 Amdt 1 Tail Rotor Blade Spar - Inspection 2/68 Applicability: All model B2, B2A and B2B. Document: Brantly SB No. B2B-68-1. Compliance: At intervals not exceeding 100 hours time in service after 22 February 1968.