COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Eurocopter BO 105 Series Helicopters AD/BO 105/14 Dual Hydraulic System Switch Over 10/89 DM Applicability: All model BO 105 helicopters with tandem hydraulic units P/N 105-45028 having valve body manifolds D133-756E, D133-756, ZE1-126-1, ZE2-126-1 or ZE2-126 installed in either No. 1 or 2 hydraulic system. Requirement: Action in accordance with MBB Alert Service Bulletin No ASB-BO 105-40-102. Note: LBA AD 89-123 refers. Compliance: Within 50 hours time in service after 25 August 1989 or by 30 September 1989, whichever occurs first. Background: Due to possible excessive wear in the servo connecting components a functional test of the hydraulic system switch over is required.