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. Kelowna Flightcraft (General Dynamics/Convair) Series Aeroplanes AD/CONVAIR/17 Pilot and Co-Pilot Direct Vision 5/2006 Window Frame Casting Applicability: Model 340 and 440 aircraft, and all such model aircraft converted to turbopropeller power. Requirement: 1. Inspect all visible areas of the main body of each Pilot and Co-pilot Direct Vision Window Frame Casting (Casting) part numbers (P/N) 340-3110314-9, -10, -13, and -14, for cracks by means of either a visual inspection using an 8x magnifying glass, a dye penetrant method, or an eddy current method (with special attention given to the lower left and right hand corner of the Casting). If cracking is detected in a Casting accomplish the following as appropriate: 2. If the cracked Casting is completely severed at any point, replace the affected Casting with a new part, P/N 340-3110314-9 or -13 (left hand side) or P/N 340-3110314-10 or -14 (right hand side). The aircraft may be flown at a cabin pressure differential of zero p.s.i. to a base where the replacement can be accomplished. 3. If the cracked Casting is not completely severed at any point, replace the affected casting with a new part, P/N 340-3110314-9 or -13 (left hand side) or P/N 340-3110314-10 or -14 (right hand side); with the following operating restrictions applying until replacement: 1. The affected aircraft must be operated at a cabin pressure differential of zero p.s.i.; and, 2. Before the initial takeoff after detection of the initial crack, an operating limitation in the form of a placard must be installed in the affected aircraft in clear view of the pilots stating: "Operation Limitation. Pressurised Flight Prohibited." Note 1: For the purposes of complying with this Directive, the main body of the Casting includes only that part of the Casting which outlines the Direct View Window and does not include the attach flanges. Note 2: FAA AD 68-07-01 Amdt 39-568 refers. Compliance: For Requirement 1: For Castings with 4,500 or more hours time in service; within 250 hours time in service after 11 May 2006, and thereafter at intervals not to exceed 250 hours time in service. For Castings with less than 4,500 hours time in service; before the accumulation of 4,750 hours time in service, and thereafter at intervals not to exceed 250 hours time in service. 2. Before further flight; except that the aircraft may be flown at a cabin pressure differential of zero p.s.i. to a base where the replacement can be accomplished. 3. Within 250 hours time in service after detection of the initial cracking; with operating restrictions Requirements 3.a. and 3.b. in place until replacement. Note: Operators who do not have records of hours time in service of individual Castings, shall substitute aircraft hours time in service in lieu. This Airworthiness Directive becomes effective on 11 May 2006. Background: The FAA received numerous reports of cracks in the Pilot and Co-pilot Direct Vision Window Frame Castings. Such cracking affects the structural integrity of the Casting, and in some cases has caused loss of cabin pressurisation. David Villiers Delegate of the Civil Aviation Safety Authority 31 March 2006