AD/RAD/63 - KT 76A ATC Transponder

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, serve to regulate civil aviation and ensure safety within the industry. Among these regulations, PART 39 - 107 pertains to the Civil Aviation Safety Authority (CASA) and its role in issuing Airworthiness Directives. One such directive, AD/RAD/63, specifically addresses the issue of AlliedSignal KT 76A Air Traffic Control (ATC) Transponders transmitting misleading encoding altimeter information. This problem was identified by the Federal Aviation Administration (FAA), which led to the introduction of this directive to prevent such transmissions, thereby enhancing aviation safety. The directive was issued by CASA and became effective on 10 September 1998, with compliance required no later than 10 September 1999.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 – 107 Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to AlliedSignal KT 76A Air Traffic Control (ATC) Transponders with particular part numbers and serial number ranges, which are known to be installed on a variety of aircraft types including those from Cessna Aircraft Company, Twin Commander Aircraft Company, New Piper Aircraft Corporation, Raytheon Aircraft Corporation, and Mooney Aircraft Corporation. This directive is applicable on a national level and mandates that the two resistor network modules, RM401 and RM402, in the specified transponders must be replaced with new glass-coated parts to prevent the transmission of misleading encoding altimeter information. The replacement must be carried out in accordance with the ‘Modification Procedure’ outlined in AlliedSignal Service Bulletin SB KT 76A-7 dated July 1996, and compliance must be achieved prior to the transponders being installed in an aircraft but no later than 10 September 1999. The directive became effective on 10 September 1998, aligning with an advisory from the Federal Aviation Administration (FAA).

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 – 107, includes a Schedule of Airworthiness Directives concerning the KT 76A ATC Transponder, referenced as AD/RAD/63. This directive applies to AlliedSignal KT 76A Air Traffic Control (ATC) Transponders with particular part and serial numbers, installed on various aircraft models including those manufactured by Cessna, Piper, Raytheon, Mooney, and McDonnell Douglas Helicopter Company. The primary requirement of this directive is to replace the two resistor network modules, RM401 and RM402, with new glass-coated parts as per the 'Modification Procedure' outlined in AlliedSignal Service Bulletin SB KT 76A-7 dated July 1996. This modification is known as Mod 7. The directive mandates that this replacement must be completed before the transponder is installed in an aircraft and no later than 10 September 1999, although the directive itself became effective on 10 September 1998. The obligations imposed by this directive are stringent and clear. Operators and owners of aircraft equipped with the specified KT 76A ATC Transponders must ensure that the replacement of the resistor network modules is carried out in strict adherence to the prescribed modification procedure. The directive specifies a timeframe within which the modification must be completed, necessitating timely action to avoid non-compliance. The directive also mandates that compliance is verified before the transponder is reinstalled in the aircraft, ensuring that the safety modifications are implemented before the aircraft returns to service. Failure to comply with the requirements of this Airworthiness Directive can result in serious consequences. The Civil Aviation Regulations 1998 do not explicitly state penalties for non-compliance within the directive itself, but general provisions of the regulations may apply. Non-compliance could potentially lead to enforcement actions by the Civil Aviation Safety Authority (CASA), which might include fines, grounding of the aircraft, or other regulatory penalties. Additionally, continued operation of an aircraft with non-compliant equipment could pose safety risks, potentially leading to accidents or incidents, which could result in severe civil or criminal liability for the operator.