AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BAe 146/53 Amdt 2 and issues the following AD under subregulation 39.1 (1) of CAR 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. British Aerospace BAe 146 Series Aeroplanes AD/BAe 146/53 Amdt 3 APU Bay Forward Firewall 5/2002 Applicability: All Series BAe 146 aircraft and all Avro 146-RJ aircraft, which have embodied Modification HCM36019A. Requirement: Action in accordance with BAE Systems Mandatory Service Bulletin 26-035 Revision 2. Note: UK CAA AD 007-05-95 refers. Compliance: Before 19 July 1995 for the initial inspection, and thereafter at intervals not to exceed 200 cycles until the embodiment of Modification Service Bulletin 26-035-36179A, or; every 500 cycles after embodiment of 26-36-36179B. The compliance time for the initial inspection requirement remains unchanged by this issue. This Airworthiness Directive becomes effective on 16 May 2002. Background: Reports have been received of cracking on the forward face of the APU bay forward firewall bulkhead. Amendment 1 introduced Modification 26-36-36179B to the compliance requirements. Amendment 2 deleted reference to the Garrett APU installation in the applicability, as this Directive requires an inspection of the firewall regardless of APU type. Amendment 3 is issued in response to a revision of the Requirement document, which changes the compliance inspection interval of 400 cycles to 500 cycles. Amendment 2 of this Airworthiness Directive became effective on 23 May 1996 Amendment 1 of this Airworthiness Directive became effective on. 7 December 1995. British Aerospace BAe 146 Series Aeroplanes AD/BAe 146/53 Amdt 3 (Continued) The original issue of this Airworthiness Directive became effective on 19 July 1995. David Alan Villiers Delegate of the Civil Aviation Safety Authority 27 March 2002 The above AD is notified in the Commonwealth of Australia Gazette on 24 April 2002.