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/TB10/6 Amdt 1 Horizontal Stabilizer Balance Weight Support 11/85 Applicability: All model TB9 and TB10 with S/Nos 001 to 474 inclusive. Requirement: Action in accordance with SOCATA S.B. No. 25 ATA 55-10. Note: Bureau Veritas AD 85-90-(A) refers. Compliance: Prior to 30 June 1986. Background: The manufacturer has devised a modification to separate the natural frequencies of the balance weight support and the stabilizer thereby preventing the possibility of flutter. This amendment changes the compliance requirement to conform with the requirement document and French AD.