Overview

The Airworthiness Directive (AD) AD/CT7/11 issued under the Civil Aviation Act 1988 by the Civil Aviation Safety Authority (CASA) on 14 September 2004 addresses an identified safety issue with General Electric (GE) CT7-2D1 turboshaft engines. This directive was enacted to mitigate the risk of uncontained failures in the 2nd stage turbine aft cooling plates of these engines, which could lead to catastrophic outcomes. The AD specifies the requirement to replace or prohibit the installation of certain cooling plates with serial numbers starting with specific sequences, to be implemented during the next disassembly of the gas generator turbine rotor assembly but no later than 5,000 cycles-since-new, and immediately after the directive's effective date. This measure aims to ensure the continued airworthiness and safety of the affected aircraft, particularly those equipped with GE CT7-2D1 turboshaft engines such as the Sikorsky S-70 helicopters. The directive became effective on 28 October 2004, following its notification in the Commonwealth of Australia Gazette on 6 October 2004.

Scope and Application

The Airworthiness Directive issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 specifically targets General Electric (GE) CT7-2D1 turboshaft engines equipped with 2nd stage turbine aft cooling plates, part number 6064T07P02, and certain serial numbers as outlined in the directive. This AD applies to engines installed in aircraft such as the Sikorsky S-70 helicopter. The directive mandates that the specified cooling plates must be replaced with ones not bearing the serial numbers listed or must not be installed into any engine, aiming to prevent potential uncontained failures. The directive applies nationwide within the Commonwealth of Australia and becomes effective from 28 October 2004. The AD requires compliance within specified timeframes; for the replacement of cooling plates, compliance is necessary at the next disassembly of the gas generator turbine rotor assembly but not later than 5,000 cycles-since-new, while the prohibition on installing the specified cooling plates must be adhered to immediately after the directive's effective date. This directive is notified in the Commonwealth of Australia Gazette on 6 October 2004, and no specific exclusions or exemptions are mentioned in the text.

Key Provisions

The Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) under section 39.1(1) of the Civil Aviation Safety Regulations 1998, applies specifically to General Electric Company (GE) CT7-2D1 turboshaft engines equipped with 2nd stage turbine aft cooling plates, part number (P/N) 6064T07P02, and specific serial numbers (SN) identified in the applicability section (section 1). The directive mandates that these cooling plates must be replaced with ones that do not have serial numbers specified in this directive (section 1). Additionally, it prohibits the installation of the specified cooling plates into any engine (section 1). The directive becomes effective on 28 October 2004 (section 1). This AD imposes several obligations on the parties it governs. Owners and operators of the affected aircraft must ensure that the specified 2nd stage turbine aft cooling plates are replaced during the next disassembly of the gas generator turbine rotor assembly but not later than 5,000 cycles-since-new (section 1). They must also ensure that the specified cooling plates are not installed into any engine following the effective date of this directive (section 1). Compliance with these requirements is mandatory to maintain airworthiness standards and prevent potential unsafe conditions. Failure to comply with this AD can result in civil or criminal consequences. Specifically, non-compliance with airworthiness directives is considered a breach of civil aviation regulations and can lead to enforcement actions by CASA. The potential penalties for non-compliance may include fines and, in severe cases, the grounding of the aircraft until the directive is complied with. Additionally, the individuals responsible for the non-compliance may face personal liability for any resulting accidents or incidents.