AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AS 355/50 Amdt 3 and issues the following AD under subregulation 39.1 (1) of CAR 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 AS 355 (Twin Ecureuil) Series Helicopters AD/AS 355/50 Amdt 4 Tail Rotor Hub Pitch Change Bearings 13/2002 Applicability: AS 355 helicopters versions E, F, F1, F2, and N fitted with tail rotor hub pitch change plate, P/N's 350A33-2004-00/-01/-02/-03/-05 and not incorporating Mod 076551 as detailed in Eurocopter AS 355 Service Bulletin No. 65.00.15R1. Requirement: 1. Check the rotational torque of the tail rotor pitch change plate bearing in accordance with paragraph 2.B (1) of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3. 2. Carry out the axial play, friction point and brinelling check in accordance with paragraph 2.B (2) of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3. 3. Before installation of a spare pitch change plate assembly carry out the requirements of paragraphs 2.B 1 and 2.B 2 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3. 4. Disposition of components subject to the inspections as required by Items 1 - 3 of this Directive shall be in accordance with paragraph 2.B 3 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3. Note 1: DGAC AD 1999-085-076(A) R3 refers. Note 2: Incorporation of Eurocopter Service Bulletin AS 350 65.00.38.P5 constitutes terminating action for this Directive. Compliance: 1. Unless previously accomplished; within 10 flying hours after 31 October 2002. 2. At intervals not to exceed 50 flying hours from the previous check (without exceeding 6 months between two checks). 3. Prior to installation of a tail rotor pitch change plate assembly or a tail rotor gearbox assembly. 4. During compliance with Requirements 1, 2, or 3, as applicable. The compliance times of Amendment 3 of this Directive remain unchanged by this issue. Eurocopter AS 355 (Twin Ecureuil) Series Helicopters AS/AS 355/50 Amdt 4 (continued) This Amendment becomes effective on 26 December 2002. Background: In service reports have revealed deterioration of the tail rotor hub pitch change plate bearing may result in the seizure of the bearing and loss of control of the aircraft. This Directive introduces measures to check for correct rotational torque, and regular maintenance checks to ensure the integrity of the assembly. Amendment 1 was issued to correct Compliance Statement 2 to reflect the DGAC repetitive inspection requirements and to include the more stringent compliance requirements of DGAC 1999-084-057(A) R1 dated 14 May 1999. Amendment 2 provides terminating action for this Directive and adds reference to disposition of components subject to the required inspections. Amendment 2 of this Airworthiness Directive became effective on 15 June 2000. Amendment 3 was issued to reflect replacement of Eurocopter Service Bulletin No. 05.00.30 R2 with Eurocopter Alert Service Bulletin No. 05.00.30 Revision 3. The Service Bulletin was upgraded to Alert status with no change to the technical content of the Service Bulletin. Amendment 4 of this Airworthiness Directive has been issued to correct a typographical error in Amendment 3. Amendment 3 of this Airworthiness Directive became effective on 31 October 2002. The original issue of this Airworthiness Directive became effective on 20 May 1999. James Coyne Delegate of the Civil Aviation Safety Authority 18 November 2002 The above AD is notified in the Commonwealth of Australia Gazette on 4 December 2002.