AD/TPE 331/53 - Third Stage Replacement

Overview

The Civil Aviation Regulations 1998, specifically within Part 39 and the Schedule of Airworthiness Directives, include AD/TPE 331/53, which was enacted in 1998 by the Civil Aviation Safety Authority (CASA) to address potential safety risks associated with the AlliedSignal (Garrett/AiResearch) Turbine Engines, particularly the TPE 331 series. This directive was introduced to ensure the safety of air travel by mandating the replacement of certain third stage turbine stators that had not been inspected according to specific criteria. The objective of this directive is to prevent potential mechanical failures that could lead to severe consequences, as highlighted by the risk of fatigue cracking causing the stator to move aft and contact the turbine wheel, potentially resulting in an uncontained failure. This regulatory measure aims to maintain the integrity and safety of aircraft operations by enforcing timely inspections and necessary replacements as outlined in the AlliedSignal Service Bulletin.

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 AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series. This regulation is aimed at ensuring the airworthiness of specified TPE331 engines that incorporate a part number (P/N) 868379-3 third stage turbine stator, which has not been inspected in accordance with National Flight Services Alert Service Bulletin (ASB) Number NF- A72-10961. The directive mandates the replacement of the applicable third stage turbine stator P/N 868379-3 in line with AlliedSignal Service Bulletin TPE331-A72-0861 Revision 2. Notably, the directive is effective from 21 May 1998, and it emphasises that its requirements do not supersede the in-service inspection requirements of Airworthiness Directive AD/TPE331/41 Amdt. 2. The regulation applies across the Commonwealth of Australia and is enforced by the Civil Aviation Safety Authority to ensure compliance with safety standards.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39, Section 106, detail a directive concerning the replacement of third stage turbine stators for certain AlliedSignal (Garrett/AiResearch) TPE 331 Series turbine engines (106.01). This applies to engines with specific part numbers (106.02) that have not been inspected as per the National Flight Services Alert Service Bulletin (ASB) Number NF-A72-10961. The directive mandates the replacement of the affected third stage turbine stator, P/N 868379-3, in accordance with AlliedSignal Service Bulletin TPE331-A72-0861 Revision 2 (106.03). It is important to note that this directive does not override the in-service inspection requirements of Airworthiness Directive AD/TPE331/41 Amendment 2 (106.04). The entities governed by this directive are required to ensure that the specified engines are inspected and, if necessary, that the third stage turbine stator is replaced. Compliance with the directive must follow the detailed instructions provided in the requirement document (106.05). This directive became effective on 21 May 1998 (106.06). The underlying reason for this directive is to address potential fatigue cracking in the third stage turbine stator, which could lead to the stator moving aft and coming into contact with the third stage turbine wheel, resulting in an uncontained failure of the turbine wheel (106.07). Failure to comply with the provisions of this directive may lead to serious consequences. Specifically, the Civil Aviation Safety Authority can impose penalties or take legal action against those who do not adhere to the requirements set out in the directive. The maximum penalties for such breaches are detailed in the broader Civil Aviation Regulations, which can include fines and other civil or criminal sanctions depending on the severity and intent of the breach. Non-compliance with airworthiness directives is taken seriously to ensure the safety and reliability of civil aviation operations.