COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Propellers - Variable Pitch - Dowty Rotol AD/PR/9 Hub Driving Centre - Inspection NK Applicability: All model (c) R184/4-30-4/50 propellers not incorporating Mod. No. (c) VP 2486. Document: Dowty Rotol SB No. 61-633. Compliance: Before exceeding 2500 hours total time in service and thereafter at intervals not exceeding 750 hours time in service.