COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Parachute Equipment AD/PARA/1 GQ Security Aeroconical (SAC) Parachutes 6/88 Applicability: All model 79A1684 parachute canopies. Requirement: Remove or obliterate TSO-C23b marking from the parachute canopy and remove canopy from service. FAA AD 88-05-08 refers. Compliance: Forthwith. Background: Defective canopies have been found both in Australia and overseas where the fabric adjacent to mesh panels has deteriorated in strength. Australian Parachute Federation (APF) Rigging Advisory Circular (RAC) No 314 refers.