AD/HS 125/74 - Wire Loom Chafe

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, are pivotal in ensuring the safety and regulation of civil aviation within Australia. Specifically, Part 39 of these regulations deals with Airworthiness Directives, which are legally binding instructions issued by the Civil Aviation Safety Authority (CASA) to ensure that aircraft meet safety standards. One such directive, AD/HS 125/74, was introduced to address the specific issue of wire loom chafing in British Aerospace BAe 125 Series Aeroplanes, particularly models 400B to 700B. This directive was prompted by an incident where wire loom chafing led to arcing and electrical overheating, posing a significant safety risk. The policy objective behind AD/HS 125/74 is to mandate regular inspections to prevent such incidents, ensuring the continued airworthiness and safety of the affected aircraft models. The directive requires operators to inspect the area adjacent to the TKS de-icing pump for any signs of wire loom chafing damage, in accordance with the specified British Aerospace Service Bulletin 24-255. This action is intended to mitigate the risk of electrical overheating and arcing, thereby maintaining the safety standards prescribed by CASA. The directive also references CAA Airworthiness Directive 005-10-85, which further underscores the importance of this safety measure. Compliance with this directive is mandatory, with a specified deadline of 31 March 1986, highlighting the urgency and critical nature of the issue it addresses.

Scope and Application

The Civil Aviation Regulations 1998, specifically under Part 39 - 105 and the Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to all British Aerospace BAe 125 Series 400B to 700B aeroplanes that have been post-modified as per serial number 252049. This legislation mandates that operators of these aircraft conduct an inspection of the area adjacent to the TKS de-icing pump to ascertain whether there is any damage due to wire loom chafing, following the requirements outlined in British Aerospace 125 Service Bulletin 24-255. It is imperative that this inspection be completed before the deadline of 31 March 1986, as stipulated in the CAA Airworthiness Directive 005-10-85, which references an incident of wire loom chafing that resulted in arcing and an electrical overheat. The application of these regulations is governed at the Commonwealth level, ensuring a uniform standard across Australia for the safety and airworthiness of the specified aircraft.

Key Provisions

The Civil Aviation Regulations 1998, Part 39 - 105, specifically the Airworthiness Directive (AD) AD/HS 125/74, addresses the issue of wire loom chafing on British Aerospace BAe 125 Series Aeroplanes. Section (1) of the directive specifies that the requirement applies to all HS-125 series 400B to 700B aeroplanes that have undergone Post Modification 252049. The primary focus of this directive is to mandate an inspection of the area adjacent to the TKS de-icing pump to check for any damage caused by wire loom chafing. This inspection must be carried out in accordance with the detailed requirements outlined in British Aerospace 125 S.B. 24-255. Additionally, the directive references CAA Airworthiness Directive 005-10-85 for further context and guidance. The obligations imposed by this directive on the operators and maintainers of HS-125 series aeroplanes are clear and specific. Operators must ensure that the inspection is conducted by qualified personnel who are trained and competent to perform the required checks. The inspections must be thorough, and any identified issues must be documented and addressed in accordance with the guidance provided in the referenced British Aerospace service bulletin. Failure to conduct these inspections or to act on any identified issues could result in the aeroplane being deemed unairworthy, potentially leading to grounding and operational delays. Breaching the requirements of this Airworthiness Directive can result in significant consequences. The Civil Aviation Safety Authority (CASA) may impose penalties for non-compliance, which can include fines and other administrative actions. In more severe cases, the failure to adhere to the directive could lead to the grounding of the aeroplane, preventing it from operating until the necessary inspections and repairs are completed. Additionally, there could be implications for the operators' licence if CASA determines that the breach was due to negligence or a failure to follow required procedures. The maximum penalties for such breaches are detailed in the Civil Aviation Regulations, with specific provisions addressing non-compliance and the associated sanctions.