AD/TFE 731/11 - H.P. Turbine Blades P/N 3072455-10 Replacement

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, establish comprehensive standards for the safety and operation of civil aviation within the country. This legislation, particularly Part 39 - 106, which includes the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, addresses specific safety concerns related to aircraft components. One such directive is AD/TFE731/11, issued to mitigate risks associated with certain turbine engine blades. The directive targets the replacement of specific blades (P/N 3072455-10) in AlliedSignal (Garrett/AiResearch) TFE731 Series turbine engines, which were identified as having fatigue-related issues. The objective is to enhance aviation safety by ensuring that blades not subjected to frequency inspections, mixed with other blade parts, or manufactured from certain materials are replaced or removed from service, thus reducing the risk of in-flight failures. The directive is applicable to TFE 731-2-1C and -2-2B engines equipped with certain high-pressure turbine rotor assemblies. The requirement is to replace blades P/N 3072455-10 that have not undergone frequency inspections or were manufactured before March 1980. This intervention follows investigations into blade separations due to fatigue and aims to ensure the continued airworthiness of these engines by implementing the manufacturer's recommended corrective actions.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106, applies to the AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series, focusing on the H.P. Turbine Blades P/N 3072455-10. This regulation is mandated for TFE 731-2-1C and -2-2B engines fitted with H.P. Turbine Rotor assemblies P/N 3072570-6, -7, -9, -10, where the blades in question have not undergone frequency inspection or have been mixed with blades of other part numbers. The regulation is effective for the Commonwealth of Australia, overseen by the Civil Aviation Safety Authority (CASA). It applies to all relevant aircraft and engines operating within Australia and mandates compliance with specified inspection and replacement requirements. This directive does not include blades that have already been frequency inspected or those manufactured from GMR 235 material, which must be removed from service under separate directives. The regulation extends its application through subordinate instruments that may provide further detail or amendments as necessary.

Key Provisions

The key sections of the Civil Aviation Regulations 1998, specifically Part 39, pertaining to the Airworthiness Directive AD/TFE731/11, focus on the requirement for the replacement of certain high-pressure turbine blades (section 39-106). This directive applies to AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series, specifically to TFE 731-2-1C; -2-2B engines fitted with H.P. Turbine Rotor assemblies P/N 3072570-6, -7, -9, -10, that contain blades P/N 3072455-10, which have not been frequency inspected or mixed with any other P/N H.P. Turbine blades (section 39-106(1)). The requirement is to replace these blades with Garrett S.B. TFE 731-72-3291 Rev 1 of 24 May 1985 or comply with AD/AIR-T/52 Amdt 1 (section 39-106(2)). The Act imposes specific obligations on the entities governed by these regulations. These obligations include ensuring that the specified turbine blades are replaced or removed from service as per the directive. The directive mandates that the replacement or removal of blades must occur at the next removal of the H.P. Turbine Rotor assembly or at the next scheduled major periodic inspection after 31 March 1985, whichever is sooner (section 39-106(3)). Additionally, if applicable, the Service Bulletin TFE 731-72-3220 should be reviewed and accomplished to remove blades P/N 3072455-10 manufactured from GMR 235 material from service (section 39-106(4)). Non-compliance with the provisions of this directive may lead to various civil and criminal consequences. The Civil Aviation Safety Authority (CASA) may impose penalties for breaches of the regulations, which can include fines and other civil sanctions. The severity of these penalties can depend on the nature and extent of the non-compliance, but specific maximum penalties are not detailed within the text of the directive itself. It is essential for the governed entities to adhere to the outlined requirements to avoid potential enforcement actions by CASA.