AD/ALF/5 - Fourth Stage Turbine Rotors Assembly P/N 2-141-170-23 and -27 - Replacement

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, include specific provisions aimed at ensuring the safety and airworthiness of aircraft. One such provision is found in Part 39 - 106, which deals with the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives. This regulatory framework is crucial in maintaining high safety standards in the aviation sector, and it addresses the need to ensure that all aircraft components meet specific safety and performance criteria. The particular Airworthiness Directive AD/ALF/5 issued for AlliedSignal (Lycoming) Turbine Engines - ALF502 and LF507 Series, mandates the replacement of the fourth stage turbine rotors assembly to mitigate risks associated with casting defects. This directive seeks to ensure that all applicable engines comply with stringent inspection procedures and manufacturer requirements within a specified timeframe, thereby enhancing overall aviation safety.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 106, mandates the Airworthiness Directives (AD) for ensuring the safe operation of civil aircraft, including the maintenance and replacement of components such as the fourth stage turbine rotors of AlliedSignal (Lycoming) Turbine Engines, particularly the ALF502 and LF507 series. This regulation applies to all Avco Lycoming ALF 502 Series Turbofan engines listed in the requirement document, which must comply with either Avco Lycoming Service Bulletin ALF 502-72-0038, Revision 1, or AD/LYC-T/22. This directive ensures that the engines meet the stringent safety requirements set by the manufacturer, which include replacing the fourth stage turbine rotors to eliminate casting defects identified through enhanced inspection procedures. Compliance with this directive is required within the next 10 engine operating hours, thereby ensuring that the engines meet the specified airworthiness standards. The Federal Aviation Administration (FAA) AD T83-03-51 also refers to this directive, highlighting its importance in maintaining engine safety.

Key Provisions

The key operative sections of this legislation are Section 1, which specifies the applicability of the directive, and Section 2, which outlines the compliance requirements. Section 1 (1) details that this directive applies to all Avco Lycoming ALF 502 Series Turbofan engines as listed in the requirement document. Section 2 (1) mandates that compliance must be achieved within the next 10 engine operating hours. This is achieved by adhering to the manufacturer's requirement document, which details an improved fourth turbine rotor incorporating blades inspected for casting defects through more stringent procedures. The obligations imposed by this Act on the relevant parties include ensuring that the specified engines are equipped with the improved fourth stage turbine rotors as outlined in the manufacturer's requirement document. The requirement document can be either Avco Lycoming SB ALF 502-72-0038, Rev. 1, or AD/LYC-T/22, and this compliance must be achieved within the specified timeframe. Additionally, the directive supersedes the requirements of the Avco Lycoming SB ALF502-72-0027 listed in AD/LYC-T/21. It is also noted that FAA AD T83-03-51 refers to this directive, further emphasising the importance of compliance. Failure to comply with the provisions of this directive can result in significant consequences. Although specific penalties are not detailed within the text, non-compliance with civil aviation safety directives can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions may include fines, suspension or revocation of airworthiness certificates, and other regulatory penalties. The severity of these consequences underscores the importance of adhering to the outlined directives to ensure the safety and airworthiness of the aircraft involved.