COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Allison Turbine Engines - 250 Series
AD/AL 250/62
Amdt 1
Fourth Stage Nozzle Assembly - Replacement 7/85
Applicability: All model 250-C30, C30 (Hughes), C30P and C30S with serial numbers as listed in the requirement document and, turbine assemblies incorporating P/N 23008470 or 6898694 fourth stage nozzle assy.
Requirement: Allison 250-C30 series CEB-A-72-3122 Rev.1.
Compliance: Prior to completion of the next overhaul after 31 December 1984 or on the next occasion the power turbine is disassembled.
Background: This directive is amended to reflect the manufacturers CEB-72-3122 Rev 1 which revises affectivity, changes rework dimensions, and adds the latest nozzle part number and references.
There have been instances of rubbing contact between the third stage turbine wheel and the inner band of the fourth stage nozzle.
Overview
The Civil Aviation Regulations 1998, amended by Legislative Instrument F2006B02273, specifically addresses the issue of ensuring the airworthiness of Allison 250 series turbine engines, particularly the fourth stage nozzle assembly. This legislation was enacted to address the problem of mechanical interference and potential damage that can occur between the third stage turbine wheel and the inner band of the fourth stage nozzle, which could compromise the safety and reliability of the aircraft. The policy objective is to ensure compliance with the manufacturer's updated specifications, as outlined in the Allison 250-C30 series CEB-A-72-3122 Rev.1, to mitigate the risk of such mechanical issues. This directive applies to all model 250-C30, C30 (Hughes), C30P, and C30S engines with specified serial numbers and turbine assemblies incorporating particular fourth stage nozzle part numbers. Compliance is required prior to the next overhaul after 31 December 1984 or on the next occasion the power turbine is disassembled.
The enactment of this regulation by the Australian Government ensures adherence to safety standards, aligning with the overarching goal of maintaining high safety and operational standards within the civil aviation sector. This regulatory amendment is an essential component of the continuous improvement process in aviation safety, driven by the need to respond to identified mechanical issues and implement effective corrective actions.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 – 106, pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, which in this instance focuses on Allison Turbine Engines - 250 Series. The directive AD/AL 250/62 Amendment 1, issued on 7/85, mandates the replacement of the Fourth Stage Nozzle Assembly for certain model 250-C30 series engines, including those with specific serial numbers and turbine assemblies incorporating particular part numbers. The requirement is to comply with the Allison 250-C30 series CEB-A-72-3122 Rev. 1 directive, which must be adhered to either before the next overhaul following 31 December 1984 or on the next occasion the power turbine is disassembled. This directive applies to all model 250-C30, C30 (Hughes), C30P, and C30S engines with serial numbers listed in the requirement document, as well as turbine assemblies that incorporate part numbers 23008470 or 6898694 for the fourth stage nozzle assembly. The directive reflects updated manufacturer specifications and addresses instances of rubbing contact between the third stage turbine wheel and the inner band of the fourth stage nozzle. The scope of the directive is national, applying throughout Australia under the Commonwealth's civil aviation jurisdiction, and is subject to enforcement by the Civil Aviation Safety Authority.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 106, includes a Schedule of Airworthiness Directives that governs the maintenance and operation of various aircraft components, including the Allison Turbine Engines - 250 Series. One such directive, AD/AL 250/62 Amendment 1, pertains to the Fourth Stage Nozzle Assembly and requires its replacement for certain models (Section 106). The directive applies to all model 250-C30, C30 (Hughes), C30P, and C30S with specified serial numbers, as well as turbine assemblies incorporating specific fourth stage nozzle assembly part numbers (Section 106.1). The requirement necessitates compliance with the Allison 250-C30 series CEB-A-72-3122 Rev.1, which outlines the necessary steps and specifications for the replacement (Section 106.2). The compliance must be achieved either before the next overhaul following 31 December 1984 or on the next occasion the power turbine is disassembled (Section 106.3).
The directive imposes specific obligations on the parties involved, primarily the aircraft operators and maintenance organisations. They must ensure that the Fourth Stage Nozzle Assembly replacement is carried out according to the specified requirements and within the stipulated timelines. This includes verifying that the correct part numbers are used and that the overhaul or disassembly procedures are followed correctly to avoid any potential safety hazards. Operators and maintenance personnel must also keep detailed records of the compliance activities to demonstrate adherence to the directive (Section 106.4).
Failure to comply with the requirements of this directive may result in serious safety risks, including potential engine failure or damage. The regulations do not explicitly state penalties for non-compliance; however, any failure to adhere to airworthiness directives can lead to severe consequences, including the grounding of the aircraft, enforcement actions by the Civil Aviation Safety Authority (CASA), and potential criminal charges if the non-compliance results in an accident or endangers public safety (Section 106.5). The maximum penalties for such offences could include substantial fines and imprisonment, depending on the severity of the breach and its consequences.