COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 212 Series Helicopters AD/BELL 212/18 Tail Rotor Pitch Horns - Inspection 10/77 Applicability: All models fitted with pitch change horns P/N 212-010-716-5 or -9. Document: 1. Bell SB No. 212-77-7; or 2. FAA AD 77-17-03. Compliance: Within 25 hours time in service after 15 September 1977 and thereafter at intervals not to exceed 100 hours.