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. British Aerospace BAe 146 Series Aeroplanes AD/BAe 146/128 Aft Fuselage Skin under APU Heat Shield 6/2007 Applicability: All Model BAe 146 and AVRO 146-RJ aircraft, all serial numbers. Requirement: Perform a detailed visual inspection in accordance with paragraph 2C of BAE Systems Inspection Service Bulletin (ISB) 53-191 initial issue, or later EASA approved revision. If corrosion is found during any inspection, before further flight, repair the affected area in accordance with paragraph 2D of ISB 53-191 initial issue, or later EASA approved revision. Note: EASA AD 2007-0075 refers. Compliance: Within one year after 7 June 2007, and thereafter at intervals not to exceed 2 years. The inspection interval may be extended to 4 years if the aircraft has been modified in accordance with BAE Systems Service Bulletin 53-193-60732A (Modification HCM60732A). This Airworthiness Directive becomes effective on 7 June 2007. Background: Corrosion has been found beneath the heat shield which is located around the APU exhaust outlet. Such corrosion could result in the fuselage being unable to sustain horizontal and vertical stabiliser loads, with potentially hazardous/catastrophic consequences. David Villiers Delegate of the Civil Aviation Safety Authority 24 April 2007