AD/ELECT/6 - Magneto - BTH - Contact Breakers Assembly - Modification

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), were enacted to establish comprehensive safety standards within the aviation sector. Part 39, specifically focusing on airworthiness directives, addresses various technical and safety requirements for aircraft operations to ensure the safety of air travel. One such directive, AD/ELECT/6 concerning Magneto - BTH - Contact Breakers, targets the modification of specific types of magnetos to mitigate risks associated with their automatic earthing features. The directive applies to all BTH type AG4, SG4, and MC1 magnetos fitted with contact breaker assemblies that automatically earth the magneto primary winding when the contact breaker cover is removed. This regulation aims to enhance safety by requiring the removal or modification of these assemblies to prevent potential hazards. CASA's objective is to ensure that such modifications are made before the magnetos are reinstalled in aircraft, thereby maintaining the highest safety standards in civil aviation.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107, apply to all BTH type AG4, SG4 and MC1 magnetos fitted with contact breaker assemblies that include an automatic earthing device. This regulation is enforced by the Civil Aviation Safety Authority (CASA) and has a national reach across Australia. The regulation mandates that these specific types of magnetos must be modified to ensure safety standards are met. The requirement is to remove the automatically earthing type contact breaker assembly and either replace it with one that lacks an automatic earthing feature or modify the existing one by removing these features. The reassembly must then be completed using a retaining screw with a standard head that ensures direct contact for the carbon button in the contact breaker cover, and the coiled wire spring from the cover must be removed. This modification must be completed before the magneto is installed in an aircraft. The regulation does not specify any exclusions, exemptions, or thresholds, and compliance is strictly enforced by CASA to maintain the safety and reliability of civil aviation equipment.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 107, under the Civil Aviation Safety Authority (CASA) schedule of airworthiness directives, includes AD/ELECT/6, which pertains to modifications on BTH type magnetos. This directive applies to all BTH type AG4, SG4, and MC1 magnetos fitted with contact breaker assemblies that include an automatic earthing device (section 1). The requirement is to either replace the existing contact breaker assembly with one that does not have automatic earthing features or modify the existing assembly by removing those features (section 1(a) and (b)). Furthermore, the reassembly must be done using a retaining screw with a standard head that ensures direct contact for the carbon button in the contact breaker cover (section 2). Lastly, the coiled wire spring from the contact breaker cover must be removed (section 3). The obligations under this directive are clear and specific. Aircraft owners or operators must ensure that the modifications outlined are carried out before the magneto is reinstalled in the aircraft (section ANO 107.2.16.2.5). This includes the removal of the automatically earthing contact breaker assembly, the replacement or modification as specified, and the reassembly with the appropriate retaining screw. Additionally, the coiled wire spring must be entirely removed, ensuring no remnants are left in the assembly. Compliance with these requirements is mandatory and must be verified before the magneto is deemed airworthy for installation in an aircraft. Failure to comply with the provisions of AD/ELECT/6 can result in serious consequences. Any breach of these directives can be considered non-compliance with airworthiness requirements, potentially leading to enforcement actions by CASA. This may include fines or other penalties as stipulated in the Civil Aviation Act 1988. Additionally, operating an aircraft with non-compliant modifications could result in the aircraft being grounded until the required modifications are completed. The specific penalties for non-compliance are not detailed in the legislative instrument but can be severe, reflecting the critical nature of ensuring electrical equipment in aircraft meets safety standards.