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. Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes AD/DHC-8/112 Forward Engine Mount Assembly 3/2006 Applicability: Model DHC-8-400, DHC-8-401, and DHC-8-402 aircraft, serial numbers 4005, 4006, 4008 through 4016, 4018 through 4051, and 4053. Requirement: Action in accordance with Transport Canada AD CF-2002-07. Note: Bombardier Alert Service Bulletin A84-71-06 Revision A refers. Compliance: As specified in the Requirement document, with a revised effective date of 16 March 2006. This Airworthiness Directive becomes effective on 16 March 2006. Background: The manufacturer of the forward engine mount assembly has identified that a certain part number pre-production engine mount assembly had been installed as a production engine mount assembly. The pre-production engine mount assembly has a reduced fatigue life. Installation of a pre-production engine mount assembly may result in premature failure of the forward engine mount that would degrade the integrity of the engine/nacelle installation. David Villiers Delegate of the Civil Aviation Safety Authority 3 February 2006