COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes AD/TB20/14 Amdt 1 Fuselage Frame NR 0 - Firewall 13/90 Applicability: TB20 and TB21 aircraft with S/Nos 1 to 1051 inclusive, except S/Nos 1040 and 1042. Requirement: Action in accordance with Aerospatiale Socata TB SB 42/1. Note 1: DGAC AD 89-175 (A) R1 refers. Note 2: Modification in accordance with kit number 9152 constitutes terminating action for this Directive. Compliance: Unless previously accomplished, - prior to exceeding 1500 hours total time in service or within 100 hours time in service after 27 December 1990, whichever occurs later, and thereafter at intervals not exceeding 500 hours time in service. Background: Country of origin AD. There is a possibility of cracks occurring at engine mount and landing gear attachment areas. Amendment 1 references latest requirement documents and adds to aircraft affected.