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 250/71 Turbine Splined Adapter Locknut Torque 12/86 TX
Applicability: Model 250-C28 and -C30 series and turbines with serial numbers CAT 70001 through 70802 and 70804: CAT 28001 through 28046: and CAT 90001 through 95436 and 95438, and those turbines which have not been assembled or had turbine splined adapter locknut torque checked in accordance with: CEB-A-72-2132/3146; THO- 2639W-RFR-85 dated 7 February 1985; C28 Overhaul Manual Temporary Revision 72-7 dated 22 January 1986; C30 Overhaul Manual Revision 1 dated 1 July 1985, or
CSL-2071/3073 dated 1 June 1985.
Requirement: Inspect the gas generator turbine splined adapter locknut torque in accordance with Allison CEB-A-72-2132/3146 dated 1 October 1985 or approved equivalent.
FAA Emergency Priority Letter AD 86-20-13 refers.
Compliance: Unless already accomplished, within 5 hours’ time in service after 27 October 1986 but not later than 31 October 1986.
Background: Allison CSL-A-2084/3087 dated 10 September 1986 advises a recent contained C30 turbine wheel failure. Excessive wear and/or fretting of the splined connection between turbine splined adapter and turbine to compressor shaft can result from insufficient torque on the splined adapter locknut. This can lead to disconnect, overspeed and failure of the gas generator turbine. This Directive is issued to prevent excessive wear and/or fretting occurring due to improper torque of the splined adapter locknut.
Overview
The Civil Aviation Regulations 1998 were enacted to regulate civil aviation safety in Australia, ensuring that aircraft and related operations meet safety standards. One of the legislative instruments under this act is the AD/AL 250/71 concerning the Allison Turbine Engines - 250 Series. This directive was introduced to address the problem of excessive wear and fretting of the splined connection between the turbine splined adapter and turbine to compressor shaft due to insufficient torque on the splined adapter locknut. Such issues can lead to significant risks such as turbine disconnect, overspeed, and failure of the gas generator turbine. The policy objective behind this directive is to enhance aviation safety by ensuring the proper torque of the splined adapter locknut is maintained. Compliance with this directive is mandatory, with inspections required within specific time frames to mitigate these risks.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 106, applies to all Model 250-C28 and -C30 series Allison Turbine Engines with specified serial numbers, including those with serial numbers CAT 70001 through 70802 and 70804; CAT 28001 through 28046; and CAT 90001 through 95436 and 95438, and those turbines that have not been assembled or had their turbine splined adapter locknut torque checked in accordance with specified technical documents. This regulation, issued by the Civil Aviation Safety Authority (CASA), is applicable across the Commonwealth of Australia and affects all entities involved in the operation and maintenance of the specified turbine engines. The requirement under this directive is to inspect the gas generator turbine splined adapter locknut torque in accordance with Allison CEB-A-72-2132/3146 dated 1 October 1985 or an approved equivalent. Compliance with this directive must be achieved within 5 hours of time in service after 27 October 1986, but no later than 31 October 1986, unless already accomplished. This directive aims to prevent potential failures arising from insufficient torque on the splined adapter locknut, which could lead to serious safety issues such as turbine disconnect, overspeed, and gas generator turbine failure.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 106, outlines the requirements for the maintenance and airworthiness of certain Allison Turbine Engines, notably the 250 Series (1). The primary focus of this legislation is the maintenance directive AD/AL 250/71, which mandates a detailed inspection and torque check of the gas generator turbine splined adapter locknut (2). This directive applies to specific models and serial numbers of the 250-C28 and -C30 series, as well as turbines with certain serial numbers (3). The directive requires that the torque of the turbine splined adapter locknut be inspected and checked in accordance with specified maintenance documents, such as Allison CEB-A-72-2132/3146 (4).
The legislation imposes clear obligations on the entities and parties involved. Operators and maintainers of the specified turbine engines are required to conduct the inspection and torque check within a specific timeframe, unless this has already been completed. The compliance period mandates that the inspection and necessary torque adjustments be completed within 5 hours of the turbine being in service after 27 October 1986, but no later than 31 October 1986 (5). This ensures that any issues related to improper torque are identified and rectified promptly, thereby enhancing the safety and reliability of the turbine engines.
Failure to comply with the provisions set out in the Civil Aviation Regulations and the specific airworthiness directive can lead to significant legal consequences. While the Regulations themselves do not specify exact penalties, non-compliance with airworthiness directives can result in serious safety risks, and potentially severe civil or criminal penalties under other aviation laws. Operators and maintainers can face actions from the Civil Aviation Safety Authority, which could include fines, suspension of operational licenses, or other regulatory sanctions (6). Given the critical nature of turbine engine safety, adherence to these regulations is essential to avoid these potential consequences.