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/82 Prevent GPS Navigation unit from Providing Erroneous Cross-Deviation 9/2004 Applicability: Garmin AT, formerly UPS Aviation Technologies, Apollo GX50/55/60/65 TSO- C129a global positioning system (GPS) navigation units as listed below with software versions 3.0 through 3.4 inclusive: Model Part Number Description Modification Level GX50 430-6050-400 Approach Certified GPS With any of the following mods: (H), (N), (P), (T) or (U); prior to (V) 430-6050-401 Approach Certified GPS Prior to (V) 430-5060-402 Approach Certified GPS Prior to (V) GX55 430-6050-200 Enroute/Terminal Certified GPS With any of the following mods: (E), (J), (K), (M) or (N); prior to (R): 430-6050-201 Enroute/Terminal Certified GPS With any of the following mods: (E), (J), (K), (M) or (N); prior to (R) 430-6050-202 Enroute/Terminal Certified GPS Prior to (R) 430-6050-203 Enroute/Terminal Certified GPS Prior to (R) GX60 430-6050-600 Approach Certified With any of the following GPS/COM mods: (H), (N), (S), (AB) or (AC);prior to (AE) 430-6050-601 Approach Certified GPS/COM With any of the following mods: (H), (N), (S), (AB) or (AC); prior to (AE) 430-6050-602 Approach Certified GPS/COM Prior to (AE) 430-6050-603 Approach Certified GPS/COM Prior to (AE) 430-6050-604 Approach Certified GPS/COM Prior to (AE) GX65 430-6050-800 Enroute/Terminal Certified GPS/COM With any of the following mods: (F), (L), (P), (Y) or (AA); prior to (AC) 430-6050-801 Enroute/Terminal Certified GPS/COM With any of the following mods: (F), (L), (P), (Y) or (AA); prior to (AC): 430-6050-802 Enroute/Terminal Certified GPS/COM Prior to (AC) 430-6050-803 Enroute/Terminal Certified GPS/COM Prior to (AC) 430-6050-804 Enroute/Terminal Certified GPS/COM Prior to (AC) Note 1: The above table was sourced from UPS Aviation Technologies Service Bulletin 561-4002-001, dated 19 April 2002, which was referenced in FAA AD 2004- 13-20 and the certification in the table refers to the FAA TSO C-129a class of the unit. Requirement: 1. Modify and test the software for the Apollo GX50/55/60/65 TSO-C129a GPS navigation unit by accomplishing all of the actions specified in paragraphs 3.B. and 3.C. of Service Bulletin (SB) 561-4002-001, dated 19 April 2002. 2. Reidentify the modified Apollo GX50/55/60/65 TSO-C129a GPS navigation unit, according to paragraph 3.D. of SB 561-4002-001. Note 2: FAA AD 2004-13-20 Amdt 39-13702 refers. Compliance: For Requirement 1 - Within six months after the effective date of this Directive. For Requirement 2 - Immediately following completion of Requirement 1. This Airworthiness Directive becomes effective on 2 September 2004. Background: The United States Federal Aviation Administration (FAA) has advised that, under certain conditions, Garmin AT, Apollo GX series GPS navigation units with software versions 3.0 to 3.4 may provide erroneous cross-deviation information, which could result in the aircraft deviating from its intended course for a brief period of time. This erroneous information may place an excessive workload on the flightcrew while they monitor other available navigation data to avoid deviating off course. To prevent the GPS unit from providing erroneous information, this Directive requires modification and testing of the software for the GPS navigation units. Bernard Malcolm Hole Delegate of the Civil Aviation Safety Authority 20 July 2004 The above AD is notified in the Commonwealth of Australia Gazette on 11 August 2004.