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/4 Application of Pre-Primer to Propeller Blades NK Applicability: As detailed in the requirement document. Document: Dowty Rotol SB No. 61-157 (Mod. No. (c) VP 1941). Compliance: Before installation in an aircraft following next overhaul completed after 28 February 1966.