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. Piper PA-23 (Apache and Aztec) Series Aeroplanes AD/PA-23/92 Stabilator Outboard Nose Rib - Installation 2/2009 Applicability: All model PA-23-250 with serial numbers 27-7654001 to 27-7754041 equipped with stabilators Piper part number 15658-2, -3, -22, or -23. Requirement: 1. Reinforce the mounting of the stabilator tube and weight assemblies by installing additional nose ribs by means of Piper Kit 761 141 or equivalent kit in accordance with Piper SL No. 807A. Note 1: USA AD 78-02-03 (Amdt 39-3128) paragraph (d) refers. 2. Balance the stabilator in accordance with paragraph 4-65 of the Piper PA-23-250 "Aztec" Service Manual when the above modification is incorporated. Note 2: USA AD 78-02-03 (Amdt 39-3128) paragraph (e) refers. Compliance: Unless already accomplished, within 100 hours time in service following the date of effectivity of this Amendment. This Airworthiness Directive becomes effective on 12 February 2009. Background: USA AD 78-02-03 paragraphs (a) and (c) are mandated in Australia by AD/PA-23/70 and AD/PA-23/73 respectively. Paragraph (b) specifies once-only action and was previously mandated by AD/PA-23/70 Amendment 1. Paragraph (d) is mandated by this AD. David Punshon Delegate of the Civil Aviation Safety Authority 24 December 2008