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-23/44 Amdt 1 Pitch Trim Switch - Modification 9/77 Applicability: Models PA-23-250 and PA-E23-250 with S/Nos. 27-3837 27-4796, fitted with Rocker Type Trim Switch on Pilot's Control Wheel. Document: 1. Piper SB No. 527; or 2. FAA AD 77-09-10. Compliance: Within 100 hours time in service after 28 February 1977.