AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters AD/DAUPHIN/84 Main Rotor Hub-to-Main Rotor 6/2006 TX Mast Bolted Attachment Applicability: Model SA 365 N, and N1 helicopters, Model AS 365 N2 and N3 helicopters, and Model SA 365 C, C1, C2, and C3 helicopters; delivered before 27 March 2006, and equipped with a main rotor hub-to-main rotor mast (MRH/mast) bolted attachment assembled by Eurocopter. Requirement: 1. On MRH/mast assemblies affected by Applicability section of this Directive, and having logged less than 280 flight hours: Check the tightening torque of the MRH/mast assembly attachment bolts, in accordance with paragraph 2.B. of Eurocopter AS 365N Alert Service Bulletin (ASB) No. 62.00.22, or SA 365 C ASB No. 65.44, as applicable. 2. On MRH/mast assemblies affected by Applicability section of this Directive, and having logged more than 280 flight hours: Check the tightening torque of the MRH/mast assembly attachment bolts, in accordance with paragraph 2.B. of Eurocopter AS 365N ASB No. 62.00.22, or SA 365 C ASB No. 65.44, as applicable. Note: EASA Emergency AD 2006-0084-E refers. Compliance: 1. Within 300 flight hours after 13 April 2006. 2. Within 20 flight hours after 13 April 2006. This Airworthiness Directive becomes effective on 13 April 2006. Background: Several reports were received of tightening torque loss detected on the main rotor hub-to-main rotor mast bolted attachment on Eurocopter assembled attachments with less than 300 operating hours. A loss of tightening torque can lead to deterioration of the MRH/mast attachment and possible loss of the main rotor. David Villiers Delegate of the Civil Aviation Safety Authority 12 April 2006