AD/ALF/12 - Introduction of Improved Third Stage Turbine Rotor Assembly

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, address numerous aspects of civil aviation safety, including the issuance of airworthiness directives to ensure the safe operation of aircraft. Specifically, Part 39 - 106 Civil Aviation Safety Authority Schedule of Airworthiness Directives includes a directive (AD/ALF/12) concerning AlliedSignal (Lycoming) turbine engines of the ALF502 and LF507 series, issued to rectify issues related to cracking in the third stage turbine disc blade retention slots. This directive was introduced to mitigate safety risks associated with these engine components and was effective from 1 January 1994. The requirement is to install improved or reworked third stage turbine rotor assemblies, ensuring compliance with specified service bulletins and related Federal Aviation Administration directives. The objective is to enhance the safety and reliability of these engines by addressing structural weaknesses identified in the turbine discs.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106, applies to all ALF502 L and R series engines with third stage rotor assemblies that fall within the scope of the Requirement Documents. This legislation is instrumental in ensuring the airworthiness of these particular engine models by mandating the installation of improved or reworked third stage turbine rotor assemblies. The requirement is intended to address the issue of cracking in the third stage turbine disc blade retention slots, thereby enhancing the safety and reliability of the engines. Compliance with this directive is necessary for maintaining the operational standards set by the Civil Aviation Safety Authority, with the directive becoming effective from 1 January 1994. The directive references Textron-Lycoming Service Bulletins ALF502L 72-270 or ALF502R 72-270 as applicable and is also associated with FAA AD 93-14-13, indicating a coordinated approach to engine safety across jurisdictions.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 106, include specific Airworthiness Directives (AD) issued by the Civil Aviation Safety Authority (CASA). One such AD is AD/ALF/12, which pertains to the introduction of improved third stage turbine rotor assemblies for AlliedSignal (Lycoming) Turbine Engines - ALF502 and LF507 Series. This directive became effective on 1 January 1994 and applies to all ALF502 L and R series engines with third stage rotor assemblies listed in the Requirement Documents. The primary requirement of this directive is the installation of improved or reworked third stage turbine rotor assemblies in compliance with Textron-Lycoming Service Bulletins ALF502L 72-270 or ALF502R 72-270, as applicable. The directive also references FAA AD 93-14-13 for additional context. The obligations imposed by AD/ALF/12 are clear and specific. Operators and owners of ALF502 L and R series engines must ensure that the identified third stage rotor assemblies are either replaced with improved versions or reworked to the specifications outlined in the referenced service bulletins. This involves detailed compliance with CASA’s requirements and the guidelines provided by Textron-Lycoming. Operators must maintain records and documentation demonstrating compliance with these standards and ensure that all personnel involved in the installation or rework process are adequately trained and qualified. Non-compliance with AD/ALF/12 can lead to significant civil and criminal consequences. CASA has the authority to enforce these regulations and may impose penalties on operators who fail to adhere to the directives. The specific penalties for breaches can include fines, suspension or revocation of airworthiness certificates, and in severe cases, criminal charges. The exact penalties are determined by the severity of the breach and the discretion of the court or regulatory body involved. It is crucial for operators to fully comply with these directives to avoid such adverse outcomes.