COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Piper PA-23 (Apache and Aztec) Series Aeroplanes AD/PA-23/10 Wing Front Spar Attachment Fitting - Reinforcement NK Applicability: Model PA-23 with S/Nos. prior to 23-322 as detailed in SB. Document: 1. Piper SB No. 142; or 2. FAA AD 55-21-2. Compliance: Forthwith.