Overview

The Airworthiness Directive issued under the Civil Aviation Safety Authority (CASA) Act 1998, specifically pursuant to subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998, addresses a critical safety issue identified with the Honeywell MST 67A Mode S transponders. The directive was introduced to ensure that these transponders operate safely and effectively in a Mode S radar environment, thereby preventing potential detection failures by air traffic control. This directive is necessary to correct an unsafe condition that could compromise air safety. The directive was issued by Gary J Carr, a delegate of the Civil Aviation Safety Authority, and the directive became effective on 30 September 2004. The primary policy objective of this directive is to mandate specific modifications to the transponders to ensure they meet the required safety standards and to avoid any potential hazards to aircraft operating in a Mode S radar environment.

Scope and Application

The Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Safety Regulations 1998 applies specifically to the Honeywell International MST 67A Mode S transponders with certain part number and serial number ranges. These are the transponders with part numbers 066-01143-1101, -1202, -1301, and -1602, and serial numbers up to and including 1141 and 1503. The directive is issued in the interest of correcting an identified unsafe condition where the transponders may not respond correctly to Mode S 'all call' interrogations, potentially leading to aircraft not being detected by air traffic control in a Mode S radar environment. The directive mandates modifications to these transponders in accordance with Honeywell Software Bulletin MST 67A-SW2 Revision 4 dated March 2003, with modifications from earlier versions also deemed acceptable if completed before the effective date of this Directive. Additionally, it stipulates that MST 67A transponders must not be installed on any aeroplane as a replacement part unless they have been modified as per the directive. The compliance timeline is set such that the modifications must be completed before 30 November 2004, while the restriction on the installation of unmodified transponders takes effect as of the directive's effective date of 30 September 2004.

Key Provisions

The Airworthiness Directive (AD) AD/RAD/83 issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 (CASR) mandates specific actions concerning the Honeywell MST 67A Mode S transponders with certain part number and serial number ranges. The AD applies to transponders with part numbers 066-01143-1101, -1202, -1301 and 066-01143-1602, and serial numbers up to and including 1141 and 1503. The directive requires modifications to these transponders to ensure compliance with safety standards. Specifically, the transponders must be modified in accordance with Honeywell Software Bulletin (SWB) MST 67A-SW2 (P/N 605-07740-0024) Revision 4 dated March 2003, and modifications completed using earlier versions of the bulletin are acceptable, provided they were done before the effective date of the directive. Additionally, the AD prohibits the installation of unmodified MST 67A transponders on any aircraft as replacement parts. The AD imposes clear obligations on the entities governed by it. Firstly, it mandates that any Honeywell MST 67A transponders within the specified part and serial number ranges must be modified in accordance with the instructions provided in the Honeywell Software Bulletin MST 67A-SW2 Revision 4 dated March 2003. This modification must be completed by 30 November 2004. Secondly, it prohibits the installation of any unmodified MST 67A transponders on aircraft as replacement parts. This prohibition takes effect immediately upon the AD’s effective date of 30 September 2004. Non-compliance with these obligations could result in severe consequences for the safety and regulatory compliance of the affected aircraft. Failure to comply with the AD could result in civil and criminal penalties. The AD is a legally binding directive issued under the authority of the Civil Aviation Safety Authority (CASA), and non-compliance can be seen as a violation of the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998. Civil penalties may include fines, suspension or revocation of airworthiness certificates, and other administrative sanctions. Criminal penalties may also apply, particularly if the non-compliance is found to have contributed to an aviation incident or accident. The exact penalties would depend on the severity of the breach and the resulting consequences.