AD/HS 125/131 - Hydraulic System Accumulator

Overview

The Civil Aviation Regulations 1998, specifically within Part 39 - 105, detail the Civil Aviation Safety Authority's (CASA) schedule of airworthiness directives, aiming to ensure that aircraft maintain safe operational standards. One such directive, AD/HS 125/131, targets the British Aerospace BAe 125 series aeroplanes, focusing on the hydraulic system accumulator to mitigate the risk of hydraulic fluid contamination leading to potential compression ignition. This directive was introduced to address safety concerns identified by the United Kingdom's Civil Aviation Authority (UK CAA), mandating compliance with the outlined instructions to ensure the integrity and safety of these aircraft. The directive requires all model 125 BAe 125 series aircraft up to and including the 800 series to have their hydraulic system accumulators charged with nitrogen, as per the Mandatory Service Bulletin No 29-89-3269A, unless this action has already been undertaken. The policy objective behind this requirement is to prevent possible hydraulic fluid contamination that could lead to hazardous conditions, thereby enhancing the overall safety and reliability of the aircraft. The directive must be adhered to prior to 31 August 1993, underscoring the urgency and importance of this safety measure as classified by the UK CAA.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105, mandate the application of airworthiness directives for the British Aerospace BAe 125 Series Aeroplanes, including all models up to and including the 800 series. This legislation requires operators of these aircraft to follow the instructions set out in Mandatory Service Bulletin No 29-89-3269A concerning the hydraulic system accumulator. The directive mandates that unless previously addressed, the accumulators must be charged with nitrogen to prevent potential hydraulic fluid contamination and the risk of compression ignition. The requirement was classified as mandatory by the UK Civil Aviation Authority and must be complied with prior to 31 August 1993. The regulation applies nationally within Australia and extends to any entity operating these aircraft, ensuring a standardised approach to safety across the industry. The scope of the Act is not limited to a specific jurisdiction but encompasses all Commonwealth airspace and aircraft registered under Australian law.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates certain safety directives for various aircraft types. One such directive, AD/HS 125/131, pertains to the hydraulic system accumulators of British Aerospace BAe 125 Series aeroplanes, up to and including the 800 series aircraft (Regulation 39 - 105.1). The directive requires that unless previously executed, action must be taken in accordance with the "2. Accomplishment Instructions" outlined in Mandatory Service Bulletin No 29-89-3269A. The requirement is to charge the accumulators with nitrogen due to the risk of hydraulic fluid contamination leading to possible compression ignition. This compliance has been classified as mandatory by the UK Civil Aviation Authority (CAA) and must be achieved prior to 31 August 1993. The obligations imposed by this directive are clear and precise. Operators of British Aerospace BAe 125 Series aeroplanes must ensure that the hydraulic system accumulators are charged with nitrogen. This action must be performed in line with the instructions provided in the specified Mandatory Service Bulletin, No 29-89-3269A. The directive underscores the necessity of adhering to these specific safety instructions to mitigate the risk of hydraulic fluid contamination and subsequent potential hazards. Failure to comply with the requirements set out in AD/HS 125/131 can result in significant consequences. Although the specific penalties or legal ramifications are not detailed within the text, non-compliance with civil aviation safety directives generally can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions may include fines, grounding of the aircraft, or other regulatory measures to ensure safety standards are met. It is imperative for operators to adhere strictly to these directives to avoid any legal or safety-related repercussions.