AD/APU/11 - TSCP700 HPT Disc

Overview

The Civil Aviation Regulations 1998, specifically in Part 39 - 107, addresses safety directives concerning auxiliary power units through Airworthiness Directives. Enacted by the Commonwealth of Australia, these regulations aim to ensure the safety and airworthiness of aircraft components. This legislative instrument, AD/APU/11, was introduced to address issues related to the High Pressure Turbine (HPT) discs in AlliedSignals TSCP700 Series Auxiliary Power Units. The problem it sought to resolve involved HPT discs manufactured from nonconforming material, necessitating a reduction in their service life to prevent potential safety hazards. The policy objective is to mandate the removal of these affected HPT discs from service to mitigate risks associated with the use of nonconforming materials. The Civil Aviation Safety Authority, under the authority of the Commonwealth of Australia, issued this directive to ensure compliance with safety standards. The requirement is for operators to remove the affected HPT discs from service as identified in AlliedSignals Service Bulletin TSCP700-49-A7168, either before they accumulate 7500 cycles since new or no later than 2 January 2000, whichever comes first. This directive aligns with similar actions taken by the Federal Aviation Administration in the United States, as referenced by FAA AD 96-18-17.

Scope and Application

The Civil Aviation Regulations 1998, as amended, applies to all entities and persons operating aircraft in Australia, including commercial airlines, private aircraft operators, and maintenance service providers, particularly those working with AlliedSignals TSCP700 Series Auxiliary Power Units (APUs). Specifically, the regulation targets the High Pressure Turbine (HPT) discs identified with serial numbers listed in AlliedSignals Service Bulletin TSCP700-49-A7168. The requirement under this regulation is to remove from service any affected HPT discs to ensure compliance with safety standards. The geographic reach of this regulation is national, applying across all states and territories within Australia. The regulation mandates that affected HPT discs must be removed from service either before they accumulate 7500 cycles since new or no later than 2 January 2000, whichever comes first. The regulation extends its applicability through reference to FAA AD 96-18-17, indicating an alignment with international standards to maintain consistent safety protocols.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 107, addresses the requirements for airworthiness directives, including the removal and replacement of certain components in auxiliary power units (APUs). Section AD/APU/11 focuses on the AlliedSignals TSCP700 Series APUs, requiring the removal of High Pressure Turbine (HPT) discs identified in AlliedSignals Service Bulletin TSCP700-49-A7168 (Section 1/97). This directive applies to those HPT discs manufactured from nonconforming materials, which have been found to have a reduced service life (Section 1/97). Operators and owners of AlliedSignals TSCP700 Series APUs must adhere to the directive by removing the specified HPT discs from service. This requirement is crucial to maintaining the safety and reliability of the APUs, ensuring they operate within their intended parameters and do not pose a risk during flight. The directive applies to all HPT discs with serial numbers listed in the referenced service bulletin, and compliance must be achieved by either removing the discs before they accumulate 7500 cycles since new or by no later than 2 January 2000, whichever comes first (Section 1/97). The regulations impose a clear obligation on operators and owners to identify the affected HPT discs, remove them from service in accordance with the specified timeline, and replace them with compliant parts. This involves meticulous record-keeping to track the operational cycles of the HPT discs and ensuring that the replacements are carried out by authorised personnel. The directive also references FAA AD 96-18-17, indicating a cross-reference with another regulatory authority's directive for consistency in safety measures. Failure to comply with the airworthiness directive can result in severe consequences. Non-compliance may lead to grounding of the affected APUs, which could in turn affect the airworthiness of the aircraft itself. Such violations can result in civil penalties, including fines and potential legal action against the operator or owner. Additionally, failure to adhere to these regulations can lead to criminal charges, depending on the severity and intent behind the non-compliance. The exact penalties are not specified in the regulations but could include substantial fines and imprisonment under broader aviation safety laws.