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 105/3 Tail Rotor Gearbox Attachment 7/86 DM Applicability: All model BO 105 up to and including S/No 780. Requirement: Action in accordance with MBB Alert Bulletin No. 28. Compliance: Within 100 hours time in service after 20 June 1986 but no later than 31 July 1986. Background: Inspection of bolts supplied to the manufacturer has revealed flaws necessitating the replacement of the existing bolts.