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. Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes AD/CESSNA 170/73 KAP 140 Autopilot System 2/2004 Applicability: Cessna 172R and 172S model aeroplanes listed below that are equipped with a Honeywell KAP 140 autopilot computer system, part number (P/N) 065-00176-2602, 065-00176-5402 or 065-00176-7702. Model Serial Numbers 172R 172S 17280001 through 17281073, 17281075 through 17281127 and 17281130 172S8001 through 172S9195, 172S9197, 172S9198 and 172S9200 through 172S9203 Requirement: 1. Unless previously accomplished, install and update the KC 140 autopilot computer system operating software in accordance with Honeywell Service Bulletin KC 140-M1 dated August 2002, as specified in Cessna Service Bulletin SB02-22-01 dated 25 November 2002. 2. Following Requirement 1 software installation, re-identify the KC-140 unit as follows: 1. Change the unit part number by attaching flavour sticker, P/N 057-02203- 0003, on the unit's serial tag; b. Attach an M decal, P/N 057-02984-0501, in front of the unit's serial number (this indicates that the unit's P/N has been changed); and c. Attach a software mod tag, P/N 057-05287-0301, in place of the old tag to indicate the software change to SW MOD 03/01. 3. KC 140 autopilot computer systems P/Ns 065-00176-2602, 065-00176-5402 and 065-00176-7702 may not be installed on any Cessna Model 172R or 172S aeroplanes as a replacement part unless the computer has been modified as specified in Requirements 1 and 2 of this Directive. Note: FAA AD 2003-24-13 Amdt 39-13382 refers. Compliance: For Requirement 1 - Within 100 hours time in service after the effective date of this Directive. Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes AD/CESSNA 170/73 (continued) For Requirement 2 - Before further flight after installing the update to the KC 140 autopilot computer system operating software. For Requirement 3 - As of the effective date of this Directive. This Airworthiness Directive becomes effective on 19 February 2004. Background: The United States Federal Aviation Administration (FAA) has received reports of inadvertent and undetected engagement of the autopilot system in Cessna Models 172R, 172S, 182S, 182T, T182T, 206H, and T206H aeroplanes. These aeroplanes are equipped with a Honeywell KAP 140 autopilot computer system installed in the centre instrument control panel near the throttle. This Directive requires the installation of an update to the operating software of the KAP 140 autopilot computer system, a change to the unit's part number and change of the software modification identification tag. These actions prevent unintentional engagement of the KAP 140 autopilot computer system, which could cause the pilot to take inappropriate actions. David Villiers Delegate of the Civil Aviation Safety Authority 7 January 2004 The above AD is notified in the Commonwealth of Australia Gazette on 28 January 2004.