AD/APU/7 - High Pressure Turbine Disc

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority, were enacted to regulate aviation safety standards and ensure the safe operation of aircraft in Australia. The specific legislative instrument, F2006B02439, is a schedule of airworthiness directives aimed at addressing potential safety hazards associated with aircraft components. One such directive, AD/APU/7, pertains to high-pressure turbine discs in Garrett Auxiliary Power Division model TSCP700-4B and TSCP700-5 auxiliary power units. This directive was introduced to address the risk of high-pressure turbine disc ruptures, which could lead to uncontained failures and pose significant safety risks. The policy objective is to mandate actions in accordance with the technical requirements of FAA AD 91-25-04, with compliance expected within 24 months from the issue date of the directive.

Scope and Application

The Civil Aviation Safety Authority (CASA) has issued Airworthiness Directive AD/APU/7 concerning the high-pressure turbine disc of Garrett Auxiliary Power Division's model TSCP700-4B and model TSCP700-5 auxiliary power units. This directive applies to units with serial numbers prior to 90697 for model TSCP700-4B and prior to 80443 for model TSCP700-5. The directive mandates compliance with the technical requirements specified in FAA AD 91-25-04 and references Garrett Service Bulletin TSCP700-49-5892 Revision 2 dated 10 October 1990. Compliance is required within 24 months from the issue date of this directive, which was raised due to reports of high-pressure turbine disc ruptures that could potentially lead to uncontained failures. The directive applies nationally and affects entities operating these specific auxiliary power units within Australia, ensuring they adhere to the specified safety requirements to mitigate the risk of catastrophic failures.

Key Provisions

The Civil Aviation Regulations 1998 (Cth), particularly Part 39 - 107, mandate specific safety directives concerning the operation of auxiliary power units (APU) in certain aircraft. Section (4/92) specifies that Garrett Auxiliary Power Division model TSCP700-4B units, manufactured prior to serial number 90697, and model TSCP700-5 units, manufactured prior to serial number 80443, are subject to this directive. These units must adhere to the technical requirements outlined in FAA AD 91-25-04. The directive references Garrett Service Bulletin TSCP700-49-5892 Revision 2, dated 10 October 1990, which provides additional technical guidance. The Act imposes several obligations on the operators of these aircraft. Primarily, it mandates that any actions required to bring the units into compliance must be carried out within 24 months from the issue date of the directive. This timeframe is critical to ensure that the potential safety hazard is addressed promptly and effectively. Non-compliance with these directives can lead to severe safety risks, including the possibility of an uncontained failure of the high-pressure turbine disc. Failure to comply with the provisions of this directive can have significant legal consequences. The regulations do not specify explicit penalties within the text provided, but generally, non-compliance with Civil Aviation Regulations can result in enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions might include fines, operational restrictions, or even grounding of the aircraft until compliance is achieved. The potential severity of the consequences underscores the importance of adhering to these safety directives to maintain the integrity and safety of air travel. Given the potential for catastrophic outcomes from uncontained high-pressure turbine disc failures, the directive's emphasis on timely compliance is evident. The safety of passengers, crew, and the public relies on the adherence to these stringent regulations. Therefore, entities governed by these provisions must ensure that all necessary actions are taken within the specified timeframe to mitigate the risk of such failures. The overarching goal is to maintain the highest standards of aviation safety and prevent incidents that could arise from the non-compliance with these critical directives.