AD/TPE 331/40 - Scavenge Oil Pump Assembly

Overview

The Civil Aviation Regulations 1998, as amended, include a legislative instrument (F2006B07451) which addresses the safety of AlliedSignal (Garrett/AiResearch) Turbine Engines, specifically the TPE 331 Series. This directive was enacted to address the problem of severe erosion and fracture of the beryllium copper main shaft nut in the scavenge oil pump assembly, which had led to turbine failures. The Civil Aviation Safety Authority, as the relevant regulatory body, issued this Airworthiness Directive to ensure compliance with Garrett (AlliedSignal) Service Bulletin TPE 331-72-0533 Revision 2, mandating inspections and modifications of the affected engines. The policy objective is to mitigate the risk of turbine failure through proactive maintenance actions, ensuring the continued airworthiness and safety of these aircraft engines. The requirement is to inspect and modify applicable engines in accordance with the specified service bulletin, with a compliance deadline set at the next access to affected parts, within 1800 hours of time in service after 15 June 1989, or before further operation after 1 January 1991, whichever is sooner.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106, which pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, applies to the TPE 331 series of AlliedSignal (Garrett/AiResearch) turbine engines. This directive targets turboprop and turboshaft engines within the TPE 331 series, including specific models such as the TPE 331-25; -43; -47; -55; -61; -1; -2; -3; -5; -6; -8; -10 and -11, and the TSE 331-3U. The regulation mandates that these engines must be inspected and modified in line with the requirements specified in Garrett (Allied Signals) Service Bulletin TPE 331-72-0533 Revision 2. Compliance with this directive is critical and must be achieved at the next opportunity for accessing the affected parts, or within 1800 hours of time in service following 15 June 1989, or before further operation after 1 January 1991, whichever is sooner. This directive stems from the necessity to prevent turbine failures, particularly addressing severe erosion and fracture issues in the beryllium copper main shaft nut, which previous sampling methods had not adequately detected. The directive references FAA AD 89-07-07 Amdt 39-6140 and is designed to mitigate risks by implementing an improved oil scavenge pump outlet port that reduces the engine's susceptibility to nut erosion.

Key Provisions

The Civil Aviation Regulations 1998, specifically under Part 39, section 106, mandates the Airworthiness Directives for the AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series. This directive (AD/TPE 331/40) pertains to the Scavenge Oil Pump Assembly, issued on 6/89, and applies to the TPE 331-25; -43; -47; -55; -61; -1; -2; -3; -5; -6; -8; -10 and -11 series turbo prop and TSE 331-3U turbo shaft engines. According to section 106 of the Regulations, operators must inspect and modify these engines in line with Garrett (Allied Signal) Service Bulletin TPE 331-72-0533 Revision 2, and this aligns with FAA AD 89-07-07 Amendment 39-6140. Compliance with this directive must be achieved unless it has already been done, at the next access to affected parts, or within 1800 hours in service after 15 June 1989, or prior to further operation after 1 January 1991, whichever is sooner. The obligations under this directive are clear: operators must ensure that the inspections and modifications specified in the Garrett Service Bulletin are carried out on the affected engines. This involves the inspection of the scavenge oil pump assembly and any necessary modifications to prevent severe erosion and fracture of the beryllium copper main shaft nut, which has been identified as a potential safety issue. This requirement is to ensure the continued airworthiness and safety of the aircraft operating these engines. The directive specifies the particular engines that must be inspected and modified, ensuring that all relevant operators are aware of their responsibilities. Failure to comply with the Airworthiness Directive can result in significant legal and safety repercussions. Under the Civil Aviation Regulations 1998, non-compliance with airworthiness directives can be considered a breach of operational standards, leading to potential enforcement actions by the Civil Aviation Safety Authority (CASA). Such breaches can result in the grounding of aircraft until the required modifications are completed, leading to operational disruptions and financial losses for operators. In severe cases, CASA can impose fines or other penalties, which could further escalate depending on the severity and frequency of non-compliance. Additionally, operators may face legal action from passengers or third parties in the event of an accident or incident related to non-compliance with airworthiness directives.