AIRWORTHINESS DIRECTIVE On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B727/93 Amdt 3 and issues the following 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. Boeing 727 Series Aeroplanes AD/B727/93 Amdt 4 Forward Entry Door Frame 6/2006 Applicability: Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series aircraft; as identified in Boeing Alert Service Bulletin 727-53A0153 Revision 7, dated 14 August 2003, or later FAA approved revision. Requirement: Action in accordance with the technical requirements of FAA AD 2006-07-10 Amdt 39-14537. Compliance: As specified in the Requirement document, with a revised effective date of 8 June 2006. This Amendment becomes effective on 8 June 2006. Background: Cracking of the forward entry door forward frame has been found in service. Undetected cracking of the frame at Body Station 303.9 could result in cracking of the fuselage skin and consequent rapid decompression of the aircraft. Amendment 2 reduced the inspection threshold from 25,000 to 15,000 landings; based on service experience. Amendment 3 required repetitive inspections of aircraft previously modified, in response to reports of cracking of frames previously modified. Amendment 4 is issued in response to a new FAA AD, which was prompted by new reports of cracking of the forward entry doorway frame of aircraft previously modified. This Directive requires adding new post-repair and post-modification inspections for previously repaired or modified aircraft, mandating the optional modification, and introducing additional aircraft to applicability. Richard Castles Delegate of the Civil Aviation Safety Authority 28 April 2006