COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Ayres Thrush (Snow) Commander Series Aeroplanes AD/AC-SNOW/18 Wing Front Spar Corrosion 6/93 Applicability: Models Serial Numbers S2D all serial numbers S2R 5000 through 5099, 1380R,, and 1416R through 2583R S2R-R1340 R1340-001 through R1340-030 (with or without DC suffix) S2R-R3S R3S-001 through R3S-011 (with or without DC suffix) S2R-R1820 R1820-001 through R1820-035 (with or without DC suffix) S2R-T11 T11-001 through T11-005 (with or without DC suffix) S2R-T15 T15-001 through T15-029 with or without DC suffix) and T15- 031 (with or without DC suffix); and T27-001 through T27-029 (with or without DC suffix) and T27-031 (with or without DC suffix) S2R-T34 6000 through 6049,, T34-001 through T34-178 (with or without DC suffix); T41-001 through T41-178 (with or without DC suffix) and T34-180 (with or without DC suffix); and T41-180 (with or without DC suffix) S2R-T45 T45-001 through T45-003 (with or without DC suffix) S2R-T65 and S2RHG-T65 T65-001 through T65-010 (with or without DC suffix) S2R-G6 G6-101 through G6-107 (with or without DC suffix) Requirement: 1. Inspect the wing front spar for corrosion in accordance with the "Accomplishment Instructions: I. Inspection of Front Spar" section of Ayres Service Bulletin SB-AG-29. 2. If corrosion is found; treat and repair the corrosion damage in accordance with the "Accomplishment Instructions: II. Repairs" section of Ayres Service Bulletin SB-AG-29. Note: FAA AD 93-01-03 Amdt 39-8456 refers. Compliance: 1. Prior to 27 August 1993, unless already accomplished, and thereafter at intervals not to exceed 12 calendar months. 2. Prior to further flight, if corrosion is found. Background: The investigation of an accident involving one of the affected aircraft revealed extensive corrosion on the upper and lower portions of the front spar. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES