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/AB139/1 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. Agusta AB139 and AW139 Series Helicopters AD/AB139/1 Amdt 1 Cockpit Door and Windows 3/2008 Applicability: Requirement 1 applicable helicopters: Model AW139 helicopters, serial number 41001, and serial number 31055 through 31080, except 31068, 31073, and 31074. Model AB139 helicopters, serial numbers 31005 through 31054, except 31007. Requirement 2 applicable helicopters: Model AW139 helicopters, serial numbers 31055 through 31089, 31092, 31093, 31095, 31097 through 31101, 31103 through 31107, and 41001 through 41003. Model AB139 helicopters, serial numbers 31005 through 31054, except 31007. Requirement: Requirement 1. Verify the correct geometry of the door frame and windows seal installation in accordance with Part I of Agusta Technical Bulletin (BT) 139-087 Revision A, or later EASA approved revision. Note 1: Instructions for the installation of an improved seal to increase the tolerance of the current design are provided in Part I of BT 139-087 Revision A. Requirement 2. Accomplish the required actions for the installation of an additional reinforcement on sliding windows in accordance with Part II of BT 139-087, Revision A. Note 2: EASA AD 2008-0011 refers. Compliance: Within 150 flight hours or 6 months after 13 March 2008, whichever occurs first. This Amendment becomes effective on 13 March 2008. Background: Operators have reported a number of occurrences of in-flight loss of cockpit door windows, both left and right side. Loss of a window could result in damage to critical components. This Directive requires verification of the correct geometry of the door frame and the window seal installation, and installation of an improved seal. Amendment 1 is issued in response to a new EASA AD, which requires the additional action of reinforcement of the sliding windows in the area where cracks have developed. David Villiers Delegate of the Civil Aviation Safety Authority 30 January 2008