COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 400 Series Aeroplanes AD/CESSNA 400/89 Engine Truss 7/86 Applicability: All models 441 with S/Nos. 441-001 to 441-0362 Requirement: Action in accordance with Cessna Service Bulletin CQB85-24 Compliance: As per Requirement Document. Background: In service cracking may occur at the welded joints in the engine truss as described in the Service Bulletin.