AD/TFE 731/18 - Digital Electronic Engine Control

Overview

The Civil Aviation Regulations 1998, as amended by the legislative instrument F2006B07401, is part of the legislative framework governing civil aviation in Australia and is enforced by the Civil Aviation Safety Authority (CASA). This particular amendment, which was enacted to address a specific safety concern related to AlliedSignal (Garrett/AiResearch) turbine engines of the TFE731 series, was introduced to ensure the airworthiness of these engines by mitigating the risk of uncommanded thrust changes that could potentially arise from defects in the digital electronic engine controls (DEEC). The policy objective behind this legislation is to maintain and enhance the safety standards in civil aviation by requiring the replacement of identified suspect DEECs, ensuring compliance by a specified deadline. The enactment of this regulation underscores the commitment of CASA to uphold stringent safety measures in the aviation industry, in alignment with international standards and recommendations from engine manufacturers.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39, applies to all aircraft operators and maintenance personnel who handle or service AlliedSignal (Garrett/AiResearch) TFE731 series turbine engines. These engines, including models TFE 731-2, -5, -5AR, and -5R, must comply with the Airworthiness Directive AD/TFE731/18 concerning the replacement of suspect digital electronic engine controls (DEEC). This requirement applies to any person or entity that operates or maintains these engines in Australia, ensuring adherence to safety standards mandated by the Civil Aviation Safety Authority. The directive is national in scope, ensuring that all operators within the Commonwealth are bound by the same safety regulations. There are no stated exclusions or exemptions, and compliance must be achieved by the specified deadline of 31 March 1990. The application of the directive may be extended or clarified through subordinate instruments, ensuring that the regulations remain current and relevant.

Key Provisions

The primary sections of this legislative instrument, particularly Section 106 of the Civil Aviation Regulations 1998, mandate the replacement of suspect digital electronic engine controls (DEEC) for specific TFE 731 series engines. The directive, AD/TFE731/18, applies to TFE 731-2, -5, -5AR, and -5R series engines as identified in Garrett SB TFE 731-76-3049. The main requirement is the replacement of DEECs listed by serial number in the referenced service bulletin to mitigate the risk of uncommanded thrust changes, which could be caused by a defect in the electronic engine controls. This directive is closely aligned with FAA AD 89-22-16, reflecting international standards and safety practices. The Act imposes several obligations on the parties or entities it governs, primarily focusing on compliance with the specified timeline and the replacement of the identified DEECs. Operators and maintainers of aircraft equipped with the affected TFE 731 series engines must ensure that the necessary replacements are carried out before the compliance deadline, which is set as 31 March 1990. This requirement is crucial to maintaining the airworthiness of the aircraft and ensuring safety in air operations. The directive necessitates that all affected DEECs are replaced, as identified in the Garrett service bulletin, to prevent any potential safety hazards arising from the mentioned defect. Failure to comply with the provisions of this directive could result in significant consequences. The Civil Aviation Safety Authority (CASA) may take enforcement actions against non-compliant operators, which could include fines, operational restrictions, or other regulatory penalties. While the specific penalties are not detailed in the text, such breaches could also lead to aircraft being grounded until the necessary compliance is achieved. The overarching goal is to ensure that all affected aircraft meet the required safety standards to protect passengers, crew, and the general public from potential hazards. The directive underscores the importance of timely and thorough compliance to uphold the high safety standards expected in civil aviation.