AD/HS 125/153 - Thrust Reverser Secondary Locks, Microswitches and Wiring

Overview

The Civil Aviation Regulations 1998, as amended by the legislative instrument F2006B10434, introduces specific airworthiness directives to address identified safety issues in certain aircraft models. One such directive, AD/HS 125/153, pertains to British Aerospace BAe 125 Series Aeroplanes, specifically the Series 1000A, 1000B, and Hawker 1000 aircraft. This directive was enacted to rectify potential safety hazards associated with thrust reverser mechanisms, which could inadvertently deploy during flight. The directive was issued by the Civil Aviation Safety Authority to ensure compliance with international safety standards, requiring the incorporation of thrust reverser secondary locks, microswitches, and wiring as specified in Hawker Raytheon Corporate Jets Service Bulletin SB. 78-14-3691A, B & E dated 21 June 1995. The policy objective of this directive is to mitigate the risk of in-flight thrust reverser deployment by mandating the installation of a secondary locking feature to meet certification requirements, with compliance expected prior to 1 March 1996.

Scope and Application

The Civil Aviation Regulations 1998, as amended, apply to all persons and entities involved in the operation, maintenance, and certification of aircraft within Australian airspace, as well as those engaged in international flights that involve Australian-registered aircraft. Specifically, this regulation targets BAe 125 Series 1000A, 1000B, and Hawker 1000 aircraft, both those pre-modification 253352 and those post-modification 253352. The regulation is aimed at ensuring that these aircraft meet specific safety standards concerning the thrust reverser systems. The requirement stipulates that the installation of thrust reverser secondary locks, microswitches, and wiring must be in accordance with Hawker Raytheon Corporate Jets Service Bulletin SB. 78-14-3691A, B & E dated 21 June 1995. This directive mandates compliance by 1 March 1996, addressing potential failures of the drive link or its attachments that could lead to an inadvertent in-flight thrust reverser deployment. The regulation ensures that these aircraft meet certification requirements by mandating the installation of a secondary locking feature to the thrust reversers. The application of this regulation is overseen by the Civil Aviation Safety Authority, which may extend or restrict its scope through subordinate instruments.

Key Provisions

The key provision of the Civil Aviation Regulations 1998, Part 39 - 105, specifically in the context of Airworthiness Directives for British Aerospace BAe 125 Series Aeroplanes, is found in AD/HS 125/153 (section 12/95). This directive applies to BAe 125 Series 1000A, 1000B, and Hawker 1000 aircraft, both pre and post modification 253352. The directive mandates that these aircraft must incorporate thrust reverser secondary locks, microswitches, and wiring as specified in Hawker Raytheon Corporate Jets Service Bulletin SB. 78-14-3691A, B & E dated 21 June 1995. This requirement is to address the potential failure of a drive link or its attachments, which could lead to an inadvertent in-flight thrust reverser deployment. Compliance with this directive is required prior to 1 March 1996. This Act imposes specific obligations on the parties governed by it. Operators and owners of the BAe 125 Series 1000A, 1000B, and Hawker 1000 aircraft must ensure that the thrust reverser secondary locks, microswitches, and wiring are installed in accordance with the specifications outlined in the Hawker Raytheon Corporate Jets Service Bulletin SB. 78-14-3691A, B & E. This involves making the necessary modifications to the aircraft to include the secondary locking features and ensuring that these modifications meet the certification requirements set forth by the manufacturer and regulatory authorities. Failure to comply with these directives could result in the aircraft not meeting the required airworthiness standards, which could in turn affect the safety and certification of the aircraft. Breaching the requirements set out in this directive could result in significant consequences. Although the Civil Aviation Regulations 1998 do not explicitly state penalties for non-compliance with Airworthiness Directives in this context, non-compliance generally leads to the aircraft being deemed unairworthy. This means that the aircraft would not be permitted to operate until the required modifications are made and compliance is verified by the relevant authorities. In more severe cases, continuous non-compliance could lead to enforcement actions by the Civil Aviation Safety Authority (CASA), including grounding of the aircraft and potential fines or legal action against the operator or owner. Additionally, there could be serious safety implications if the aircraft is operated without the mandated thrust reverser secondary locks, potentially leading to an in-flight incident or accident.