AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/RAD/77 and issues the following 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/77 Amdt 1 Goodrich Avionics Systems TAWS8000 8/2004 Applicability: Goodrich Avionics Systems, Inc. TAWS8000 Terrain Awareness Warning System (TAWS), part number (P/N) 805-18000-001, that incorporates hardware "Mod None", "Mod A" or "Mod B". Note 1: These systems are known to be installed on, but not limited to the following aeroplanes: Manufacturer Manufacturer Cessna Aircraft Company Dassault Aviation Gulfstream Aerospace LP/Israel Aircraft Industries Raytheon Aircraft Company Saberliner Corporation The New Piper Aircraft Inc 421, 500, 501, 525, 525A, 550, 551, 650 and S550 Mystère-Falcon 20 series 1125 Westwind Astra 100, 200, 300, 400A and F90 NA-265 PA-42-1000 Requirement: 1. Inspect the TAWS8000 TAWS installation in accordance with Goodrich Avionics Systems, Inc. Service Memo SM #134, dated 2 May 2003 or SM #134 revised 9 July 2003 and the applicable installation manual, to determine if both the TAWS8000 TAWS and any other device are connected to the same baro set potentiometer. 2. If, as a result of the Requirement 1 inspection, both the TAWS8000 TAWS and any other device are found to be connected to the same baro set potentiometer, remove the TAWS8000 TAWS, cap and stow the connecting wires in accordance with SM #134 and the applicable installation manual. Note 2: This Requirement applies to TAWS8000 TAWS with "Mod None", "Mod A" or "Mod B" hardware installed, not to systems with "Mod C" hardware. TAWS8000 units with "Mod C" hardware may be fitted in lieu of "Mod None", "Mod A" or "Mod B" units in accordance with Goodrich Avionics Systems Alert Service Bulletin #A117 dated 9 July 2003. Radio Communication and Navigation Equipment AD/RAD/77 Amdt 1 (continued) 3. TAWS8000 TAWS, P/N 805-18000-001, that incorporates hardware ''Mod None'', ''Mod A'' or ''Mod B'' may not be installed, either as a replacement part or new installation, on any aeroplane. Note 3: FAA AD 2004-08-15 Amdt 39-13584 Correction refers. Compliance: For Requirement 1 - Remains unchanged as 'Within the next five hours time in service after the effective date of original issue of this Directive'. For Requirement 2 - Remains unchanged as 'Before further flight immediately following the Requirement 1 inspection'. For Requirement 3 - Remains unchanged as 'As of the effective date of the original issue of this Directive. This Amendment becomes effective on 5 August 2004. Background: The United States Federal Aviation Administration (FAA) has advised that tests have shown that the TAWS8000 TAWS may cause altitude errors in other instruments. This Directive is intended to prevent the loading of the baro set potentiometer, which could result in an unacceptable altitude error. Such a condition could cause the pilot to make flight decisions that may put the aeroplane in an unsafe flight condition. The original issue of this Directive required the inspection of the TAWS installation and, if necessary, the removal of the TAWS if both the TAWS and any other device are connected to the same baro set potentiometer. The Directive also prohibited future installation of any TAWS8000 TAWS that incorporates hardware "Mod None", "Mod A" or "Mod B". This amendment introduces a revised Service Memo as an alternate method of compliance together with a note clarifying the status of TAWS8000 units with "Mod C" hardware incorporated. The original issue of this Airworthiness Directive became effective on 30 July 2003. James Coyne Delegate of the Civil Aviation Safety Authority 23 June 2004 The above AD is notified in the Commonwealth of Australia Gazette on 14 July 2004.