COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 190 and 195 Series Aeroplanes AD/CESSNA 190/4 Upper Landing Gear Bulkhead 9/73 Applicability: All models 190 and 195. Requirement: Action in accordance with Cessna SL SE73-15. Compliance: Within 25 hours time in service after 28 September 1973 and thereafter at intervals not exceeding 100 hours time in service.