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/TB20/10 Nose Landing Gear Hydraulic Line 11/87 Applicability: To all model TB20 and TB21 aircraft with S/Nos up to and including 760. Aircraft S/Nos. 643, 644, 752 and 753 are excluded from the requirements of this AD. Requirement: Relocate L/H nose gear undercarriage hydraulic pipe in accordance with Aerospatiale Socata SB No.34. Note: Bureau veritas AD 87-117(A) refers. Compliance: Next scheduled inspection for maintenance release issue after 30 October 1987. Background: The manufacturer has reported chafing of the L.H. nose gear hydraulic line by the rudder control rod. If the chafed line developed a leak a situation could occur where aircraft had to land with its undercarriage not locked down.