AD/VIPER/9 - Engine Centre Section

Overview

The Civil Aviation Regulations 1998, as amended by F2006B07591, address the safety concerns arising from the thermal stress and subsequent structural failure of the compressor casing/centre section joint in Rolls Royce Viper series engines. Enacted by the Commonwealth of Australia, this regulation aims to ensure the airworthiness of specific Viper engines by requiring inspections to prevent structural failures that could lead to catastrophic engine failure during operation. The regulation is designed to safeguard the integrity of engines in service before a specified date and those awaiting installation, underscoring the policy objective to maintain high safety standards in civil aviation. Compliance with the specified service bulletins is mandatory to mitigate risks associated with the identified mechanical issues.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106, applies to all Viper series Rolls Royce turbine engines, namely the Viper Mk 601-22 and the Viper Mk 520, 521, and 522. The legislation mandates inspections on the engine compressor casing/centre section joint flange for these engines, ensuring adherence to the guidelines stipulated in the relevant Rolls Royce service bulletins. The regulation is applicable to engines in service prior to 6 August 1990 and to uninstalled engines before they are installed in an aircraft. The geographic scope of the Act is national, as it pertains to the Civil Aviation Safety Authority, a federal body. The regulation does not explicitly state any exclusions or exemptions but mandates compliance with the specified service bulletins for the identified engines, thereby extending its reach through the subordinate Rolls Royce service bulletins.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 106 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, mandate the inspection of the engine compressor casing/centre section joint flange for Rolls Royce Viper Series engines (section 9/90). This requirement applies to Viper Mk 601-22 and Viper Mk 520, 521, and 522 engines, both those in service prior to 6 August 1990 and those installed prior to being mounted on an aircraft. The directive aims to address a specific issue identified in an investigation, where the compressor casing/centre section joint had separated at the top, leading to significant bending loads on the turbine mainshaft and subsequent spline failure. The separation is believed to have been caused by thermal stress that pulled fastener inserts from the centre section. To comply with the directive, operators and maintainers must follow the procedures outlined in the relevant Rolls Royce Service Bulletins. For Viper Mk 601-22 engines, Service Bulletin No 72-A173 provides the necessary inspection guidelines, while for Viper Mk 520, 521, and 522 engines, Service Bulletin No 72-A388 should be consulted. These bulletins detail the specific inspection methods and criteria to ensure the compressor casing/centre section joint flange is in a safe condition. Ensuring compliance with these bulletins is critical to prevent similar incidents and maintain the airworthiness of the engines. The obligations imposed by this directive include conducting thorough inspections of the specified engines as per the outlined service bulletins. Operators and maintenance personnel must verify that the compressor casing/centre section joint flange is free from defects or signs of stress that could lead to a similar failure. Documentation of all inspections and any corrective actions taken must be maintained as part of the engine’s service records, ensuring traceability and accountability. Failure to comply with these inspection requirements may result in the engine being deemed unairworthy, potentially leading to grounding of the aircraft until the issue is rectified. Non-compliance with the airworthiness directives can lead to significant legal and operational consequences. If an engine is found to be non-compliant, it may be grounded, leading to flight cancellations and financial losses for the operator. In terms of legal ramifications, failure to adhere to the specified inspection and maintenance requirements can result in enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions can include fines, enforcement notices, and in severe cases, prosecution. The maximum penalties for non-compliance with airworthiness directives are not explicitly stated in the provided text, but they can include substantial fines and potential imprisonment for individuals found guilty of breaches.