AIRWORTHINESS DIRECTIVE On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/DHC-1/44 and issues the following 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. De Havilland DHC-1 (Chipmunk) Series Aeroplanes AD/DHC-1/44 Amdt 1 Mandatory Modifications, Inspections 17/2011 and Replacements Applicability: All Canadian production DHC-1 aircraft as specified in the requirement document. Requirement: Carry out the modifications, inspections and replacements in accordance with Transport Canada Airworthiness Directive CF-49-05. Note: De Havilland Aircraft of Canada Limited Technical News Sheet Leaflet C-3, C-4, C-6, C-7, C-10 and Design Leaflets CM1003, Mod.278, Mod.322 refer. Compliance: Within 6 months after the effective date unless previously accomplished. This Amendment becomes effective on 26 August 2011. Background: Modifications, inspections and replacements relating to Rudder Bars, Wheel Hubbolts, Brake Disc Clips, Support Brackets, Rudder Mass Balance Weight, Fuselage Longerons, Helical Tension Spring, Safety Harness Attachments, and Rear Brake Lever assemblies are mandated by Transport Canada. Amendment 1 of this directive reduces the applicability of this directive to Canadian Chipmunks only. Mike Higgins Delegate of the Civil Aviation Safety Authority 23 August 2011