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 35/20 Engine Firewall Sealing 8/82 Applicability: Learjet 35-001 to 35-482; Learjet 36-001 to 36-050. Document: Gates Learjet Service Bulletin SB35/36-71-2 refers. Compliance: Within 150 hours after 31 August 1982. Background: Manufacturers requirement to improve fireproofing at the engine pylon firewall.