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 204/16 Amdt 1 Transmission Support Case - Inspection NK Applicability: All model 204B. Requirement: Visually inspect the two lift link attachment lugs on the transmission main support case for cracking. Compliance: At intervals not exceeding 100 hours' time in service after 17 July 1974.