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. Pratt and Whitney Turbine Engines - PW4000 Series AD/PW4000/16 Front Pylon Mount Bolts 18/2010 Applicability: Pratt & Whitney (PW) PW4164, PW4168, and PW4168A series turbofan engines, with front pylon mount bolts, part number (P/N) 54T670 or 51U615, installed. These engines are installed on, but not limited to, Airbus A330 series airplanes. Requirement: Unless previously accomplished, perform the initial torque checks and inspections in accordance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705. Repeat the torque checks and inspections in accordance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705. Replacement of the forward engine mount bearing housing, P/N 59T794 or P/N 54T659 with P/N 52U420, using SB PW4G-100-71-22, dated 15 January 2002, or later FAA approved revision, constitutes terminating action to the inspection requirements of paragraph (h) of the requirement document, FAA AD 2006-16-05 Amendment 39-14705. Later revisions to PW ASB PW4G-100-A71-9, Revision 1, dated 24 November 1997, PW ASB PW4G-100-A71-18, Revision 2, dated 15 January 2002, and PW ASB PW4G-100-A71-32, dated 15 April 2005, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2006-16-05 Amendment 39-14705, are considered acceptable for compliance with the equivalent Requirements of this AD. Compliance: As specified in the Requirement Document with a revised effective date of 13 September 2010. This Airworthiness Directive becomes effective on 13 September 2010. Background: This AD results from analysis by the manufacturer that MP159 material pylon bolts do not meet the full life cycle torque check interval requirement, in a bolt-out condition. This AD is issued to prevent front pylon mount bolt and primary mount thrust load path failure, which could result in an engine separating from the airplane. Charles Lenarcic Delegate of the Civil Aviation Safety Authority 9 September 2010