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 35/18 Horizontal Stabiliser Hinge Pin Bushing Installation - Inspection 12/81 Applicability: All models 35 & 36 with S/Nos. referenced in Gates Learjet Service Bulletin No. 35/36-27-13 or with S/Nos. referenced in subsequent issues of that Service Bulletin. Document: Gates Learjet SB 35/36-27-13. Compliance: Within 100 hours time in service after 31 December, 1981. Background: The horizontal stabiliser hinge pin bushings may move out of their mating fittings during normal service.