AD/RAD/82 - Prevent GPS Navigation unit from Providing Erroneous Cross-Deviation

Overview

The Civil Aviation Safety Authority Act 1998, enacted by the Australian Parliament, provides the legislative framework for regulating civil aviation safety in Australia. This Act empowers the Civil Aviation Safety Authority (CASA) to issue Airworthiness Directives (ADs) to address identified safety issues. The AD/RAD/82, issued on 2 September 2004, is one such directive aimed at addressing an unsafe condition identified in certain Garmin AT Apollo GX series GPS navigation units. These units, with specific software versions, were found to potentially provide erroneous cross-deviation information under certain conditions, which could lead to deviations from the intended flight course and increased workload on the flight crew. The directive mandates the modification and testing of the affected GPS units' software, along with reidentification of the modified units, to ensure airworthiness and mitigate the identified risk.

Scope and Application

The Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Safety Regulations 1998 addresses a specific safety concern regarding Garmin AT, formerly UPS Aviation Technologies, Apollo GX series GPS navigation units. This directive applies to certain models of GX50, GX55, GX60, and GX65 GPS navigation units, specifically those with software versions 3.0 through 3.4 inclusive, as listed in the applicability section. The directive mandates modifications and testing of the software to prevent the units from providing erroneous cross-deviation information, which could potentially lead to navigational errors. The directive applies to these GPS units across the Commonwealth of Australia and requires compliance within specified timeframes. The directive is effective from 2 September 2004, and it is published in the Commonwealth of Australia Gazette on 11 August 2004. There are no stated exclusions or exemptions within the directive, and it is enforceable as per the regulations set forth in the Civil Aviation Safety Regulations 1998.

Key Provisions

The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998 (CASR) applies to specific Garmin AT, formerly UPS Aviation Technologies, Apollo GX series GPS navigation units with certain software versions (3.0 through 3.4 inclusive). The directive mandates modifications to these units to prevent them from providing erroneous cross-deviation information (AD/RAD/82). The required modifications and testing must be completed as specified in paragraphs 3.B and 3.C of Service Bulletin (SB) 561-4002-001 dated 19 April 2002, and the units must be reidentified as per paragraph 3.D of the same bulletin. Compliance with these requirements must occur within six months of the directive's effective date, with reidentification of the units to be done immediately after the software modification and testing. The AD imposes obligations on the operators and owners of the affected aircraft to ensure that the specified GPS navigation units are modified and tested according to the instructions outlined in the directive. Operators must ensure that the units are reidentified following the completion of the required modifications. These obligations are critical to maintaining the airworthiness of the affected aircraft and ensuring safe navigation operations. Failure to comply with this AD may result in serious safety implications, as the GPS units may provide erroneous cross-deviation information, leading to potential deviations from the intended flight path. While the directive does not explicitly state specific penalties for non-compliance, non-compliance with airworthiness directives can lead to enforcement actions by the Civil Aviation Safety Authority (CASA), including fines, suspension of airworthiness certificates, or other regulatory actions. The seriousness of the potential safety risks underscores the importance of adhering to the AD's requirements.