COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Airtractor AT-300, 400 and 500 Series Aeroplanes AD/AT/5 Engine Mount Ring on Vibro-Damp Mount Assembly - Inspection Applicability: All models AT-300 and AT-301. Document: Snow Engineering Co. Service Letter No. 50. Compliance: 1. Within 100 hours time in service after 31st July 1983 and thereafter as per requirement document. 2. Repeat bolt removal at each 1000 hours time in service. Background: The manufacturer reports cracking of attach brackets and excessive wear of attachment bolts. 7/83