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/TB20/11 Hydraulic Brake Line Clearance 11/87 Applicability: All model TB20 and TB21 up to S/No 755 inclusive, except S/Nos 630, 631, 634, 636, 643, 648, 649, 656, 657, 658, 659, 661, 662, 663, 664, 750, 751, 752 and 753. Requirement: Action in accordance with Aerospatiale Socata SB No 33. Note: Bureau Veritas AD 87-118(A) refers. Compliance: Within 100 hours time in service or at the next scheduled inspection for maintenance release issue after 30 October 1987 whichever is the earlier. Background: The manufacturer has reported instances of the cockpit hydraulic brake lines being damaged by the aileron and rudder control rods.