COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Robinson R44 Series Helicopters AD/R44/5 Amdt 1 Low RPM Warning Unit 5/97 DM Applicability: This Directive is applicable to R44 helicopters serial numbers 0001 through 0312 inclusive, 0314 and 0315. Requirement: Adjust the A569-6 low RPM warning unit so that the warning horn operates between 96% and 97% rotor RPM in accordance with the procedures contained in the Maintenance Manual. Note: FAA AD 97-02-15 Amdt 39-9900 refers. Compliance: Unless previously accomplished, then prior to 12 April 97. This Airworthiness Directive becomes effective on 12 March 97. Background: The actions specified by this Directive are intended to minimise the possibility of pilot mismanagement of the main rotor RPM, which could result in an unrecoverable main rotor stall and subsequent loss of the helicopter. The amendment to the AD increases the applicability to include all serial numbers that have not had this action completed by the manufacturer in response to FAA AD 97-02-15. The amendment also aligns the rotor RPM threshold to that detailed in FAA AD 97-02-15.