AD/DART/25 - High Pressure Impeller Replacement

Overview

The Civil Aviation Regulations 1998, specifically PART 39 - 106, address the issue of ensuring the airworthiness of aircraft by issuing directives that mandate certain maintenance actions to mitigate safety risks. The Act was enacted by the Commonwealth of Australia and was designed to fill the gap in ensuring the safety of civil aviation operations, particularly concerning the maintenance and operation of aircraft engines. The Civil Aviation Safety Authority (CASA) is the enforcing body and the policy objective is to ensure that aircraft meet safety standards through timely and appropriate maintenance actions. The legislative instrument F2006B08711 focuses on Rolls Royce Dart Series engines, which are required to replace the high-pressure impeller to prevent vane tip failures caused by specific vibrations within the engine's operating range. This directive is a response to identified safety issues with pre-Mod.1475 standard high-pressure impellers and is aligned with similar directives from the UK Civil Aviation Authority (CAA). The compliance requirement mandates that the replacement must be carried out by 30 June 1995, ensuring that affected engines are serviced and meet the necessary safety standards to prevent potential failures.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106 concerning Airworthiness Directives, applies to all Rolls Royce Dart Series engines that incorporate a pre-Mod.1475 standard High Pressure Impeller. This legislative instrument is a regulatory mandate issued by the Civil Aviation Safety Authority (CASA), enforcing the replacement of the high pressure impeller in compliance with Rolls Royce Service Bulletin Da 72-307, Revision 5 dated September 1994 (RR Mod.1475). This directive is pertinent to all entities and individuals who operate or maintain such engines within the Commonwealth of Australia. The requirement to replace the high pressure impeller is mandatory and must be carried out at the first engine shop visit where the HP compressor area is exposed, but no later than 30 June 1995. The legislation references the UK Civil Aviation Authority's AD 004-09-94 for further guidance, underscoring its international relevance and cooperation in aviation safety standards. The exclusions or exemptions from this directive are not explicitly detailed in the provided text, but it is implied that all applicable engines must comply with the specified requirements.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39, Subpart 106, includes Airworthiness Directives (ADs) aimed at ensuring the safety of aviation operations. One such AD is AD/DART/25, which concerns the high pressure impeller replacement for Rolls Royce Dart Series engines (section 1). This directive applies to all Rolls Royce Dart Series engines that incorporate a pre-Mod.1475 standard High Pressure Impeller (section 2). The main requirement of this directive is that these engines must have their high pressure impeller replaced in accordance with Rolls Royce Service Bulletin Da 72-307, Revision 5 dated September 1994 (RR Mod.1475) (section 3). For reference, the UK Civil Aviation Authority (CAA) also issued an AD (004-09-94) on this matter (section 4). Compliance with AD/DART/25 is mandatory and must be achieved by the first engine shop visit at which the high pressure compressor area is exposed, but no later than 30 June 1995 (section 5). Entities governed by this directive, primarily aircraft operators and maintenance providers, must ensure that the high pressure impeller replacement is performed correctly and in a timely manner. This includes adhering to the specifications outlined in the Rolls Royce Service Bulletin Da 72-307, Revision 5, and ensuring that the replacement is carried out by appropriately qualified personnel. Operators must also maintain accurate records of compliance with this directive, which may be subject to audit and inspection by the Civil Aviation Safety Authority (CASA). Failure to comply with the requirements of AD/DART/25 could result in the engine being deemed unairworthy, potentially leading to grounding of the aircraft until the necessary modifications are completed. Failure to comply with the provisions of AD/DART/25 can result in serious consequences. Under the Civil Aviation Act 1988, non-compliance with an AD can be considered an offence. Specifically, section 609 of the Act provides that it is an offence for an operator to use an aircraft that does not comply with applicable ADs. In the case of AD/DART/25, failure to replace the high pressure impeller as required could lead to enforcement actions by CASA, including fines, enforcement notices, or even prosecution. The maximum penalties for such offences can include substantial fines and, in some cases, imprisonment. Additionally, failure to comply with ADs can also lead to civil liability for damages arising from incidents caused by non-compliance, further underscoring the importance of adhering to these safety directives.