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. Embraer EMB-135 and EMB-145 Series Aeroplanes AD/EMB-145/23 Main Landing Gear Trailing Arm Pins 24/2010 Applicability: Embraer model EMB-135BJ, EMB-135ER, EMB-135KE, EMB-135KL, EMB-135LR, EMB-145, EMB-145EP, EMB-145ER, EMB-145EU, EMB-145LR, EMB-145LU, EMB-145MK, EMB-145MP, EMB-145MR and EMB-145XR airplanes. Requirement: Action in accordance with ANAC Airworthiness Directive 2009-02-01. Note: Embraer Service Bulletin Nos. 145-32-0122, and 145-52-0047, or 145LEG-32-0033 and 145LEG-52-0014 refer. Compliance: As stated in the requirement document with a revised effective date of 13 December 2010 and a revised Compliance time of 2 months from the effective date, unless accomplished previously. This Airworthiness Directive becomes effective on 13 December 2010. Background: It has been found occurrences of main landing gear (MLG) trailing arm pins broken due to a fatigue mechanism induced by an excessive torque applied during the assemblage of auxiliary door support attachment and consequent deformation of the MLG trailing arm axle. A broken pin can lead to loss of the MLG trailing arm axle, disconnecting the trailing arm from the main strut, which affects the airplane controllability on ground. Mike Higgins Delegate of the Civil Aviation Safety Authority 25 November 2010