COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 47 (All Variants) Series Helicopters AD/BELL 47/1 Amdt 1 Synchronized Elevator Spar 11/76 Applicability: Model 47J S/Nos. 1420 to 1802. All model 47K. Document: 1. Bell SB No. 135; or 2. FAA AD 76-21-05. Compliance: Within 50 hours time in service after 25 November 1976 and thereafter at intervals not exceeding 50 hours time in service.