COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 204 Series Helicopters AD/BELL 204/7 Tail Rotor Yoke - Inspection NK Applicability: All 204B models fitted with tail rotor yoke P/N 204-010-781-9 or 204-010-781-5. Requirement: Inspect yoke assembly P/N 204-010-781-5 or 204-010-781-9 by magnetic particle method with particular emphasis on the threaded portion of the yoke spindle. Maximum amperage 1400 amps. DC or 1100 amps. AC. Do not exceed 4200 ampere turns. Compliance: At intervals not exceeding 100 hours time in service, after 6 October 1968.