AD/AL 250/14 - Compressor Wheels, Glass Bead Peening

Overview

The Civil Aviation Regulations 1998, specifically under Part 39 - 106, incorporates the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives. One such directive, AD/AL 250/14, addresses issues with Allison Turbine Engines - 250 Series, focusing on compressor wheels and glass bead peening. This legislation was enacted to ensure the safety and airworthiness of aircraft engines by providing clear directives on the maintenance and overhaul of specific components, such as compressor assemblies, in certain engine series. The directive aims to rectify identified problems in earlier serial numbers of the compressor assemblies, ensuring they meet safety standards before being reinstalled in aircraft following their next overhaul. The regulations were introduced by the Commonwealth of Australia through the Civil Aviation Safety Authority, with a clear policy objective to enhance aviation safety by enforcing stringent maintenance and compliance standards. The directive mandates that all compressor assemblies with specific serial numbers must be addressed before any aircraft can be deemed airworthy following an overhaul after 1 December 1970. By doing so, the legislation seeks to mitigate potential risks associated with the use of older, potentially less reliable engine components, thereby protecting the integrity of civil aviation operations.

Scope and Application

The Civil Aviation Safety Authority (CASA) provides comprehensive regulation over the safety standards of aviation operations within Australia through the Civil Aviation Regulations 1998, which include specific directives on the airworthiness of aircraft components. One such directive, AD/AL 250/14, pertains to Allison Turbine Engines, specifically those in the 250 Series, which are critical components in the aviation industry. This directive applies to all Compressor Assemblies with specific serial numbers that were installed in 250-C18 series engines before CAC 21525B and in 250-C18A engines before CAC 21773B. Compliance with this directive is mandatory, requiring that the compressor wheels undergo glass bead peening before any installation in aircraft following the next overhaul completed after 1 December 1970. The directive is underpinned by Allison 250 CEB 106, which serves as the technical basis for ensuring the safety and airworthiness of these components. This regulation ensures that specified engines meet stringent safety standards, thereby contributing to the overall safety of civil aviation operations within Australia.

Key Provisions

The Civil Aviation Regulations 1998 (Cth), as amended, under Part 39 – 106, specifically address the airworthiness directives for Allison Turbine Engines - 250 Series, with a particular focus on the compressor wheels and their glass bead peening, as detailed in AD/AL 250/14 (11/70). This regulation mandates that all compressor assemblies with serial numbers prior to CAC 21525B, fitted to 250-C18 series engines, and all assemblies with serial numbers prior to CAC 21773B, fitted to 250-C18A engines, must adhere to the specified requirements. Compliance with this directive is crucial and must be achieved before the next overhaul following 1 December 1970. The obligations imposed by these regulations require that all relevant compressor assemblies be inspected and, if necessary, undergo glass bead peening to meet the specified safety standards. The Allison 250 CEB 106 document outlines the procedures and standards that must be met. Ensuring compliance involves a thorough examination and potentially the modification of the compressor wheels to ensure they are structurally sound and safe for use in the specified aircraft engines. Failure to comply with these directives can result in severe consequences, including the potential grounding of aircraft and the inability to obtain airworthiness certification. Failure to adhere to the provisions of AD/AL 250/14 (11/70) can result in significant legal and operational repercussions. Under the Civil Aviation Act 1988 (Cth), non-compliance with airworthiness directives is considered a serious offence. The Civil Aviation Safety Authority (CASA) has the authority to take enforcement actions against any person or entity that fails to comply with these regulations. Such actions may include the issuance of fines, the suspension or revocation of airworthiness certificates, and potential criminal charges against individuals responsible for the non-compliance. The maximum penalties for these offences can be substantial, reflecting the critical importance of adhering to these safety standards to ensure the safety of air travel. The regulatory framework established under the Civil Aviation Regulations 1998 aims to maintain the highest standards of safety in civil aviation. By imposing strict requirements on the maintenance and inspection of compressor wheels for Allison Turbine Engines - 250 Series, the legislation ensures that all aircraft utilising these engines meet rigorous safety criteria. The consequences of non-compliance are severe, highlighting the importance of adhering to these directives to prevent accidents and ensure the safety of all passengers and crew.