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. Dornier 328 Series Aeroplanes AD/DO 328/61 Hydraulics Leakage and Functional Checks 6/2006 Applicability: Dornier 328-100 aeroplanes. Requirement: Perform the major internal leakage test, the bypass valve of the return filter element test and the shut-off valve with bypass test according to section E, F(3) and F(4) of AMM TR 29-087 and TR 29-088 as applicable. Note: LBA AD 1997-189/2 dated 18 June 1998 refers. Compliance: For aircraft that have previously completed a C-Check inspection but have not complied with the above mentioned AMM TRs this AD must be performed not later than at the next A-Check after the effective date of this AD. For aircraft that have complied with the above mentioned AMM TRs or aircraft that have not yet performed a first C-Check no action is required until the next scheduled C-Check. This Airworthiness Directive becomes effective on 8 June 2006. Background: This AD is in response to possible high internal leakage rates within the components of the ground spoiler hydraulic supply system and build-up of pressure in the bypass valve return line. James Coyne Delegate of the Civil Aviation Safety Authority 28 April 2006