COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Gates Learjet 35 and 36 Series Aeroplanes AD/LEARJET 35/13 Upper Cabin Door Lock Mechanism Bolts - Modification Applicability: All model 35 with S/Nos. 35-001 to 35-274 and 278; All model 36 with S/Nos. 36-001 to 36-044. 4/80 Requirement: Modify the upper cabin door lock mechanism bolts by installing Gates Learjet Kit No. AMK 79-9. Compliance: Within 150 hours time in service after 30 April 1980. Background: Modification kit AMK 79-9 provides an additional safety feature to the upper cabin door lock mechanism by installing drilled bolts and lockwiring these bolts in-situ.