AD/ELECT/4 - Magnetos BTH - Earthing Modification

Overview

The Civil Aviation Regulations 1998, specifically within Part 39 - 107 Civil Aviation Safety Authority Schedule of Airworthiness Directives, addresses safety concerns related to the electrical equipment of aircraft, particularly focusing on the modification of magnetos in certain aircraft models. The legislation was enacted to ensure the airworthiness and safety of aircraft by mandating specific modifications to the electrical components to prevent potential malfunctions and ensure reliable operation. The policy objective is to maintain a high standard of safety within the civil aviation sector by addressing and rectifying identified issues through directed modifications and compliance requirements. The regulations, established by the Commonwealth of Australia, are overseen by the Civil Aviation Safety Authority, which is tasked with enforcing these standards to protect the public and enhance the safety of air travel. The specific directive, AD/ELECT/4, pertains to the modification of magnetos in certain aircraft types to ensure the positive connection of the magneto switch lead to the magneto earthing spring and brush assembly, thereby mitigating risks associated with electrical faults and ensuring compliance before the aircraft is put into service.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107, applies to aircraft maintenance and operations within the Commonwealth of Australia, with the Civil Aviation Safety Authority (CASA) being the regulatory body. This particular Airworthiness Directive (AD) AD/ELECT/4 pertains to the modification of magnetos for specific aircraft types, including BTH AG4, SG4, and MC1, which must have screened contact breaker covers. The AD mandates a specific modification to ensure the positive connection of the magneto switch lead to the magneto earthing spring and brush assembly. The modification involves removing the earthing spring and brush assembly from the contact breaker cover, removing the switch lead set screw and tab washer, drilling out the thread for this screw in the insert, cutting a channel in the brass insert, and then replacing the contact breaker cover spring and brush assembly. Compliance with this directive is required before the magneto is installed in an aircraft. This regulation does not specify exclusions or exemptions but does require adherence to the outlined procedures to ensure safety and compliance with civil aviation standards.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 107, establish the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives (AD) which govern the mandatory modifications and checks for ensuring the safe operation of aircraft. AD/ELECT/4 pertains to magnetos, specifically the BTH AG4, SG4, and MC1 types, requiring modifications to the contact breaker cover to ensure the positive connection of the magneto switch lead to the magneto earthing spring and brush assembly. This modification is outlined in section 107.2.16.2.3 and is mandatory before the equipment is installed in an aircraft. Under these regulations, the entities responsible for the aircraft must ensure that the modifications are carried out as specified. This involves several detailed steps, such as removing the earthing spring and brush assembly from the contact breaker cover, removing the switch lead set screw and tab washer, drilling out the thread for the screw in the insert, cutting a channel in the brass insert, and replacing the contact breaker cover spring and brush assembly. The requirement is clear: these modifications must be made before the equipment is installed in any aircraft to maintain compliance with safety standards. Failure to comply with these airworthiness directives can result in serious consequences. The Civil Aviation Regulations 1998 impose obligations on the entities responsible for the aircraft to ensure that the specified modifications are made. If these modifications are not carried out as required, the aircraft may be deemed non-compliant, leading to potential grounding or refusal to certify the aircraft as airworthy. Such non-compliance not only poses safety risks but may also lead to regulatory action, including fines and sanctions against the responsible parties. The exact penalties for breaches of these regulations are not specified in the excerpt but can be severe, reflecting the critical nature of these safety requirements.