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. Reims Aviation F406 Series Aeroplanes AD/F406/18 Landing Gear Emergency Blowdown Bottle - 2 9/2009 Applicability: Model F 406 aircraft, all serial numbers, equipped with a part number 4063700-1 landing gear emergency blowdown bottle with serial number 23, 25, 27, 31, 32, 36, 37, 38 or 39. Requirement: Rework the landing gear emergency blowdown bottle in accordance with the Accomplishment Instructions of Reims Aviation Industries Service Bulletin F406-69 initial issue, or later EASA approved revision. After the effective date of this Directive, installation on any Model F 406 aircraft of a part number 4063700-1 landing gear emergency blowdown bottle with serial number 23, 25, 27, 31, 32, 36, 37, 38 or 39 is prohibited, unless they have been previously reworked in accordance with Reims Aviation Industries Service Bulletin F406-69 initial issue, or later EASA approved revision. Note: EASA AD 2009-0128 refers. Compliance: Within 4 months after 27 August 2009, unless already accomplished. This Airworthiness Directive becomes effective on 27 August 2009. Background: Since the issue of EASA AD 2007-0190 (AD/F406/17), several instances of leakage of the new part number 4063700-1 blowdown bottle have been reported. Investigation revealed the cause of leakage was due to a manufacturing process which has now been resolved; therefore AD/F406/17 remains valid. Unless corrected, loss of blowdown bottle pressure could result in the inability to extend the landing gear in an emergency situation. David Villiers Delegate of the Civil Aviation Safety Authority 15 July 2009