COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Robinson R44 Series Helicopters AD/R44/7 Clutch Assembly 13/97 Applicability: All R44 helicopter S/N 0001 through to and including 0322 fitted with C018-1 clutch assembly. Requirement: Replace C018-1 clutch assembly with a C018-2 or C018-2A clutch assembly as detailed in Robinson R44 SB 23 dated 30 May 1997. Note: FAA AD 97-16-02 Amdt 39-10092 refers. Compliance: Unless previously carried out within 50 hours time in service after the effective date of this directive or by 31 December 1997, whichever occurs first. This airworthiness directive becomes effective on 4 December 1997. Background: The manufacturer has advised that a number of sprag clutches assemblies were found worn excessively. This could result in loss of power to the rotor system, or should engine failure occur, an inability of the helicopter to autorotate in an emergency.