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 39.1 (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. Radio Communication and Navigation Equipment AD/RAD/83 Honeywell MST 67A Transponder 10/2004 Applicability: Honeywell International (formerly AlliedSignal; Bendix King) MST 67A Mode S transponders with the following part number/serial number ranges: Part Number 066-01143-1101, -1202 and -1301 066-01143-1602 Serial Number Range All serial numbers up to and including 1141 All serial numbers up to and including 1503 Requirement: 1. If not previously accomplished, modify the transponder in accordance with Honeywell Software Bulletin (SWB) MST 67A-SW2 (P/N 605-07740-0024) Revision 4 dated March 2003. Modifications accomplished in accordance with earlier versions of SWB MST 67A-SW2, prior to the effective date of this Directive, are considered acceptable for compliance with this Requirement. 2. MST 67A transponders may not be installed on any aeroplane as a replacement part, unless modified in accordance with Requirement 1. Note: RLD AD 2003-036 (AB), CAA(UK) AD 001-01-2003 and DGAC AD 2003- 036(AB) refer. Compliance: For Requirement 1 - Before 30 November 2004. For Requirement 2 - As of effective date of this Directive. This Airworthiness Directive becomes effective on 30 September 2004. Radio Communication and Navigation Equipment AD/RAD/83 (continued) Background: The European Transponder Monitoring and Testing Facility identified the Honeywell MST 67A transponder as not responding correctly to Mode S 'all call' (UF 11) interrogations. This could result in aircraft not being detected by air traffic control in a Modes S radar environment. Gary J Carr Delegate of the Civil Aviation Safety Authority 16 August 2004 The above AD is notified in the Commonwealth of Australia Gazette on 8 September 2004.