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/CL-600/35 Amdt 1 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. Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes AD/CL-600/35 Amdt 2 Main Landing Gear Main Fitting 9/2007 Applicability: Model CL-600-2B19 aircraft, equipped with main landing gear fittings part number 601R85001-3 and 601R85001-4 (MDI part number 17064-101, -102, -103, and -104). Requirement: In accordance with Part VI of Transport Canada AD CF-1999-32R3 and Part IV of AD CF-2004-18R1: Replace the affected main landing gear main fittings with new main fittings, part number 601R85001-83 and 601R85001-84 (MDI part number 17064-107 and 17064-108; in accordance with Bombardier Service Bulletin (SB) 601R-32-093 original issue, SB 601R85001 Revision A, or SB 601R85001 Revision B, or later Transport Canada approved revision. Note: Incorporation of the new main fittings terminates the need to comply with Parts I, II, III, IV, and V of AD CF-1999-32R3; and with Parts I, II, and III of associated AD CF-2004-18R1. Compliance: Unless already accomplished, before 30 September 2007. This Amendment becomes effective on 30 August 2007. Background: There have been three reported cases of premature failure of the main landing gear main fitting. The reports indicated that a circumferential crack was found on the fitting at the radius between the fitting cylinder area and the upper attachment lug for the shock strut. Amendment 1 added servicing of the main landing gear shock struts, and repetitive inspection of the shock strut for nitrogen pressure and visible chrome dimensions. Further investigation revealed that, under certain conditions, a mis-serviced shock strut could lead to premature failure of the fitting. This amendment also allowed the eddy current inspection interval to be increased under certain conditions. Amendment 2 is issued in response to a revision of the related Transport Canada AD, which requires replacement of affected main landing gear main fittings. The original issue of this Airworthiness Directive became effective on 24 February 2000. David Villiers Delegate of the Civil Aviation Safety Authority 11 July 2007