COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Skyfox Aviation (Calair/Hedaro) CA21 and CA22A Series Aeroplanes AD/CA21/1 Air Filter Box Rear Mounting Bracket 1/96 Applicability: CA 22A aircraft. Requirement: 1. Visually inspect the rivets securing the air filter box rear mounting bracket. If the rivets are loose, broken or missing, replace with MS20470AD4-4 solid rivets. 2. Remove the air filter box from the aircraft and replace the pop rivets securing the rear mounting bracket with MS20470AD4-4 or MS20470AD5-4 solid rivets. Note: Skyfox Aviation Service Bulletin 9 Iss.2 refers. Compliance: For Requirement 1, before next flight after 4 January 1996. For Requirement 2, at the next inspection for issue of a Maintenance Release or within 100 hours time in service, whichever occurs first. Background: The pop rivets originally fitted could work loose and be ingested into the engine. This AD requires fitment of solid rivets.