Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, form the backbone of aviation safety regulation in the country. Among these regulations, Part 39 - 105 specifically addresses airworthiness directives to ensure the safe operation of aircraft. One such directive, AD/PA-23/86, pertains to Piper PA-23 (Apache and Aztec) series aeroplanes, targeting an issue identified by the Bureau of Air Safety Investigation (BASI). The directive was introduced following an investigation into a Piper PA-23 fire that occurred due to the cable connecting the ammeter to the battery melting as it passed through a metal clamp, subsequently causing extensive damage. The policy objective of this directive is to mitigate the risk of such incidents by requiring regular inspection and, where necessary, the replacement of the cable clamp and ensuring proper cable routing to prevent friction damage. Compliance with this directive must be achieved within 25 hours of the aircraft being in service after the directive's implementation date of 4 March 1993.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates that the Airworthiness Directive AD/PA-23/86 applies to all Piper PA-23 series aeroplanes, regardless of their serial numbers. This legislation is concerned with the inspection and potential replacement of the ammeter cable clamp to prevent electrical failures that could lead to catastrophic outcomes such as fires. The directive is issued under the authority of the Civil Aviation Safety Authority and is applicable across the Commonwealth of Australia. It demands that within 25 hours of time in service after the directive's effective date of 4 March 1993, aircraft operators must inspect the ammeter cable clamp, ensuring it is not metal without cushion insulation, check for cable damage, and repair or replace as necessary. Furthermore, the directive stipulates that cables must be secured using insulated clamps as per MS-21919, ensuring they are firmly attached and correctly aligned, and that they are protected from rubbing against the co-pilot’s control column. This directive extends its application through subordinate instruments as required by the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, under PART 39 - 105, specifically mandate the inspection and replacement of the ammeter cable clamp in Piper PA-23 (Apache and Aztec) series aeroplanes. This is outlined in AD/PA-23/86 (section 1). The directive requires the inspection of the clamp securing the cable connecting the battery to the ammeter (section 1.1). If the clamp is metal and lacks a cushion insulation lining, it must be removed and the cable inspected for any damage (section 1.2). Any damaged cable must be repaired or replaced as necessary (section 1.3). Additionally, the cable must be secured using a cushioned (insulated) type clamp that meets the specifications of MS-21919 as detailed in FAA-AC 43.13-1A (section 1.4). The clamps must be correctly sized to secure the cable firmly, ensuring it passes centrally through the clamp axis (section 1.4). Furthermore, it is essential to ensure that cables are free from rubbing by the co-pilot’s control column (section 1.5). If the existing clamps have insulation liners, these must be checked for any damage (section 1.6). Compliance with these provisions is mandatory, and the required inspections and repairs must be completed within 25 hours of the aircraft being in service after 4 March 1993 (section 2). This compliance requirement ensures that all Piper PA-23 aircraft meet the necessary safety standards to prevent similar incidents from occurring. The investigation conducted by the Bureau of Air Safety Investigation (BASI) revealed that a fire in a Piper PA-23 aircraft was caused by the melting of the cable connecting the ammeter to the battery where it passed through a metal supporting clamp, resulting in severe damage to the cabin and fuselage (section 3). Poor routing of the ammeter cable also led to rubbing by the co-pilot’s control column, exacerbating the issue. Breach of these safety directives can result in serious consequences. Non-compliance with the specified inspection and repair requirements can lead to potential safety hazards, including electrical fires, which could result in catastrophic outcomes. The Civil Aviation Safety Authority (CASA) may impose penalties on aircraft operators or owners who fail to adhere to these regulations. The specific penalties can include fines or other enforcement actions, depending on the severity and impact of the non-compliance. These measures are in place to ensure that all aircraft maintain the highest standards of safety and reliability.