COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Short SD3-60 Series Aeroplanes AD/SD3-60/30 Stub Wing and Outer Wing Strut Attachment Fittings Applicability: All models serial number SH301 to SH3642 inclusive. 11/90 Requirement: Inspect the left and right outer wing to strut attachment fittings and left and right stub wing to strut attachment fittings, as applicable by serial number, in accordance with Shorts SD3-60 Service Bulletin SD360-57-12. Note 1: UK CAA has classified this action as mandatory. Note 2: Embodiment of Service Bulletin SD360-57-03 will constitute terminating action for the purposes of this AD. Compliance: Prior to the accumulation of 9600 flight hours or prior to 29 November 1990 whichever is the later, and thereafter at intervals not to exceed 600 hours component time in service. Background: Damage tolerance evaluation of the SD3-30 type fittings installed on the affected aircraft has indicated that the maximum safe inspection interval is 600 hours. Undetected fatigue cracks in these fittings could result in loss of structural integrity of the wing. The manufacturer is currently developing a modification that will preclude the need for repetitive inspections.