COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Aerospatiale (Socata) TB9 and TB10 (Tobago) Series Aeroplanes AD/TB10/8 Engine Mounts 1/87 DM Applicability: All aircraft with engine mounts TB 10.51.000.000. Requirement: Action in accordance with Aerospatiale Socata SB 16/1. Compliance: Within 50 hours time in service after 17 December 1986 and thereafter at intervals not exceeding 50 hours time in service until modified. Background: The manufacturer reports cracking of the engine mount weld clusters.