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. Agusta A109 Series Helicopters AD/A109/55 Hydraulic Pipe Interference 4/2007 Applicability: Agusta A109E Helicopters up to Serial Number (S/N) 11158 inclusive and S/N 11501 to 11510 inclusive. Requirement: 1. Inspect and replace as necessary hydraulic pipes with Part Number (P/N) 109-0761-64-103 and P/N 109-0761-65-103 as detailed in Part I and Part II of Agusta "Bollettino Tecnico" (BT) 109EP-73 original issue or later approved revision. 2. Replace the hydraulic pipes P/N 109-0761-64-103 and P/N 109-0761-65-103 with new pipes P/N 109-0763-96-101 and P/N 109-0763-97-101 in accordance with Agusta Bollettino Tecnico (BT) 109EP-73 original issue or later approved revision. 3. Do not install hydraulic pipes P/N 109-0761-64-103 and P/N 109-0761-65-103 on any Agusta 109E helicopter. Note: EASA AD 2007-0038 dated 21 February 2007 refers. Compliance: 1. Within the next 50 flight hours after the effective date of this AD. Thereafter repeat at intervals not to exceed 100 flight hours. 2. No later than 30 November 2007. 3. From 30 November 2007. This Airworthiness Directive becomes effective on 12 April 2007. Background: There has been reported interference between the hydraulic pipe and the tail rotor control rod assembly on some A109E helicopters. This AD requires an inspection for interference between the pipes and introduces a replacement P/N pipe in conjunction with a fixing method for those pipes. This provides for an increase in the clearance between the pipes and tail rotor control assembly. If not corrected damage to the hydraulic pipes could lead to loss of the No. 1 hydraulic system in flight. David Punshon Delegate of the Civil Aviation Safety Authority 28 February 2007