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/13 Horizontal Stabiliser Spar - Fatigue Inspection 3/80 Applicability: The following models and S/Nos. which have achieved 2000 hours or more total time in service and which incorporate horizontal stabiliser P/N 40221-61. Model S-2D: All S/Nos.; Model S-2R: S/Nos. 1416R thru 2560R; 5000R thru 5100R; Model S2R-T11: S/Nos. T11-001 and T11-002; Model S2R-T15: S/Nos. T15-001 thru T15-005; Model S2R-T34: S/Nos. 6000 thru 6049, T34-001 thru T34-019; Model S2R-R3S: S/Nos. R3S-001 thru R3S-008. Requirement: (a) Remove fuselage side skins to provide access to the inspection hole in the bottom of the horizontal stabiliser. (b) Disconnect the flying wires, left and right sides, from both upper and lower surfaces of the horizontal stabiliser to permit the exercising of the stabiliser. (c) Inspect the horizontal stabiliser front spar tube (P/N 40221 -19) in the area of both the left and right fuselage attach bushings as shown in Fig. 1 using a flashlight and an inspection mirror. IMPORTANT - the stabiliser must be exercised with both an up and down force at the tip during the inspection to ensure detection of crack. Note 1: The horizontal stabiliser assembly should be re-installed and the flying wires adjusted in accordance with the Rigging Procedures in Section VII of the Maintenance Manual, with the exception that the tension in each flying wire should be adjusted until the midpoint has a deflection of 0.30 + 0.05 inch with an applied side load of 20 pounds, rather than 35 pounds as stated in the Maintenance Manual. Note 2: FAA AD 80-04-06 Amdt. 39-3688 refers to this inspection. Note 3: Aircraft fitted with Horizontal stabiliser P/N 40221-70 are exempted from the requirements of this AD. Compliance: Within 25 hours' time in service after 18 March 1980 and thereafter at intervals not exceeding 500 hours' time in service. Background: This AD is based purely on United States Federal Aviation Administration requirements. No other background information is available at this stage. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES FIG 1.