COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Gates Learjet 24 & 25 Series Aeroplanes AD/LEARJET/6 Wing Flap System - Inspection 8/74 Applicability: All models: 24 with S/Nos. 24-100 to 24-296. 25 with S/Nos. 25-003 to 25-175. Document: Gates Learjet SB No. 23/24/25-257. Compliance: Within 25 hours time in service after 27 August 1974.