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 47/17 Amdt 1 Tail Rotor Pitch Change Bearings - Inspection and Life Limitations 11/67 Applicability: All model 47D and D1, 47G, G2 and H1 helicopters. Requirement: 1. Inspection: Inspect pitch change control shaft P/N 47-641-034 or P/N 47-641-045 as follows: (a) Remove shaft from tail rotor gear box in accordance with Bell Service Manual. (b) Mount shaft at acme screw thread end in collet. (c) Measure concentricity of bearing shaft diameter. This diameter must be concentric within 0.060 TIR. (d) If diameters are not concentric within 0.060 shaft must be straightened within this tolerance. 2. Life Limitation: Tail rotor pitch change bearings P/N R4AF4 also identified by Bell P/N 47-641-146-1 and alternate P/N SIRP and 7R4AXIC shall be retired from service after accumulation of 100 hours time in service; or 3. FAA AD 58-23-1. Compliance: Inspect at intervals not exceeding 600 hours time in service after 1 September 1971.