COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 47 (All Variants) Series Helicopters AD/BELL 47/75 Amdt 2 Applicability: All models. Control Tubes 10/86 Requirement: 1. Visually inspect the control tubes referenced in Bell SB 47-11-73-1 and Kawasaki- Bell S.B. KSB-Bell 334 for evidence of corrosion pits, particularly in the lower four (4) inches of each tube assembly; or 2. Inspect the control tubes referenced in Bell SB 47-11-73-1 and Kawasaki-Bell S.B. KSB-Bell 334 for evidence of corrosion using a suitable radiographic technique; or 3. Remove the lower end fittings from the control tubes and visually inspect the internal surface of the tube for evidence of corrosion. Compliance: 1. Within 25 hours time in service after 31 December 1973 and thereafter at intervals not exceeding 50 hours time in service. 2 & 3. Within 25 hours time in service after 31 December 1973 and thereafter at intervals not exceeding 3 years. Background: The manufacturer has received reports of failure of fore and aft control tubes caused by corrosion. This Directive has been amended to include Kawasaki-Bell Helicopters.