COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 204 Series Helicopters AD/BELL 204/21 Main Rotor Blades - Inspection NK Applicability: All models 204B with main rotor blades P/Nos. 204-012-001 (all dash numbers) and 204-011-250 (all dash numbers) which have achieved 600 hours' time in service. Requirement: To detect cracks in the main rotor blades, perform the following: 1. Visually inspect the upper surface of each blade in the area of the spare particularly between stations 110 and 165. 2. Cone each blade by inserting a wooden wedge between the mast and the static stop and raise the tip of the blade sufficiently to eliminate blade droop and obtain approx. 6 ins. (15 cms) blade cone at the tip; and 3. Visually inspect the undersurface of each blade particularly in the area of the spare between stations 110 and 165. Note: Refer to the Maintenance Manual Section 1, Page 1-23 and 1-24 Section II, Page 2-6, Para 2-7B for inspection requirements. Compliance: At each daily or overnight inspection after 11 November 1975.