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-23/36 Amdt 1 Engine Mount - Inspection 5/72 Applicability: PA-23-250 series with S/Nos. 2505 and subsequent with engine mount P/No. 31215. Requirement: 1. For aircraft with engine mounts date-stamped prior to 26 May 1965, visually inspect the mounts for cracks in the following areas: (a) The lower forward lateral tube. (b) The three-tube horizontal diagonal truss in and around the three welded junctures with the lower forward lateral fore and aft tube; and (c) The lower left horizontal fore and aft tube. 2. For aircraft with engine mount date-stamped 26 May 1965 or later and having 1000 hours or more total time in service, visually inspect the engine mount tubes forward of the firewall for cracks. 3. If cracks are found accomplish either of the following: (a) Replace the engine mount prior to further flight with a new mount P/N 31215. After installation of a new mount continue repetitive inspection of this mount after 1000 hours total time in service as detailed in para. 2; or (b) Repair the engine mount prior to further flight in accordance with a scheme acceptable to the Secretary, and inspect the entire engine mount for cracks prior to installation using a magnetic particle method. Thereafter continue visual inspections of the mount at intervals not to exceed 100 hours time in service. Note 1: On engine mounts date-stamped prior to 26 May 1965, a pictorial description of the affected areas can be found in Piper SL No. 462. Note 2: FAA AD 68-7-4 Amdt. 39-576 as amended by amendments 39-1324 and 39-1426 also refers. Note 3: The engine mount is date-stamped on either of the two diamond-shaped gusset plates located near the upper firewall attachment points. Compliance: Within 50 hours time in service after 31 May 1972 unless already inspected within the last 50 hours time in service, and thereafter at intervals not exceeding 100 hours time in service.