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 250/68
Amdt 2
Turbine to Compressor Coupling Shaft Inspection and Modifications to Prevent Failure
3/86
Applicability: For Part A:-All model 250-C28B, -C28C engines which incorporate turbine to compressor coupling shaft P/N 23008080 and;
For Part B:- All model 250-C28B, -C28C engines with engine and turbine serial numbers listed in the Requirement Document excepting those engine which incorporate ALL of the following CEBs:-
CEB-A-72-2127 Rev 1, CEB-72-2101 Rev 1, CEB-72-2063 Rev 4, and CEB-72- 2099 Rev 1.
Requirement: Part A:- FAA AD 85-25-12 Amdt 39-5191.
Note: Turbine to compressor coupling shafts P/N 6896895 or 6889071 may be fitted temporarily as an alternative to new shaft P/N 23032345, in which case further rework in accordance with Part B of this Directive will be required.
Part B:- FAA AD 85-25-09 Amdt 39-5190.
Note: Allison CEB-A-72-2127 Rev 1. CEB-72-2101 Rev 1.
CEB-72-2063 Rev 4.
CEB-72-2099 Rev 1.
and CEB-A-72-2122 refer.
Compliance: Part A:- Within 100 hours’ time in service, or at the next turbine repair or inspection, whichever occurs first after 20 December 1985, but in any case no later than 6 March 1986.
Part B:- As detailed in the Requirement Document.
Note: Compliance with the previous issue of this Directive may not satisfy the mandatory introduction of some CEBs which were previously assessed as non- mandatory, hence, further rework may be necessary.
Background: This Directive is amended to reflect FAA AD 85-25-12 AMDT 39-5191 and AD 85- 25-09 AMDT 39-5190 as the Requirement Documents. These Directives require modifications to -C28B and -C28C series engines to prevent distress and the possibility of shaft disconnects which could result in an uncontained failure. C30 series engines which were previously nominated as “applicable” in this Directive are now reflected in AD/AL-250/63 Amdt 7 issued concurrent with this Directive.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Note: This Directive limits the use of shafts P/N 6896895 and 6889071 as temporary alternatives (pending the change to new shaft P/N 23032345) for C28 series engines until 30 November 1987.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority, were enacted to ensure the safety of civil aviation in Australia. A significant gap they aimed to address was the need for consistent and updated safety directives for various aircraft components, particularly those prone to failure. This legislative instrument, specifically Part 39 - 106, focuses on the Allison Turbine Engines - 250 Series, with Amendment 2 concerning the turbine to compressor coupling shaft inspection and modifications to prevent failure. The policy objective is to mitigate the risk of distress and potential uncontained failures, enhancing overall aviation safety. This legislative instrument was introduced by the Commonwealth of Australia, through the Civil Aviation Safety Authority, to provide a structured and authoritative framework for ensuring the airworthiness of these critical engine components.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 106, pertains to the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives for Allison Turbine Engines - 250 Series, with the directive AD/AL 250/68 Amendment 2 focusing on turbine to compressor coupling shaft inspections and modifications to prevent failure. This regulation applies to all model 250-C28B, -C28C engines equipped with a turbine to compressor coupling shaft P/N 23008080. The directive mandates inspections and modifications to prevent potential failures, ensuring the continued airworthiness and safety of the aircraft. Compliance with the directive is mandatory for these specified engine models, with particular timelines and conditions outlined for inspections and modifications. This directive reflects amendments to FAA AD 85-25-12 and AD 85-25-09, aiming to prevent distress and the possibility of shaft disconnects that could lead to uncontained failures.
Key Provisions
The Civil Aviation Regulations 1998, under Part 39 - 106 and the Civil Aviation Safety Authority Schedule of Airworthiness Directives, specifically target the Allison Turbine Engines - 250 Series through AD/AL 250/68 Amendment 2. This amendment pertains to the turbine to compressor coupling shaft inspection and modifications to prevent failure. The directive is applicable to all model 250-C28B, -C28C engines that incorporate turbine to compressor coupling shaft P/N 23008080, with certain exceptions (Section 1). The requirement involves adhering to FAA AD 85-25-12 Amendment 39-5191 for Part A and FAA AD 85-25-09 Amendment 39-5190 for Part B, ensuring specific corrective actions are taken to prevent distress and potential shaft disconnects that could lead to uncontained failures (Section 2).
Entities and parties governed by this Act are mandated to perform inspections and modifications on the specified turbine engines within specific timeframes and under particular conditions. For Part A, compliance must be achieved within 100 hours’ time in service or at the next turbine repair or inspection, whichever comes first, but no later than 6 March 1986 (Section 3). Part B compliance is detailed in the Requirement Document, and if the previous directive's compliance does not satisfy the mandatory introduction of certain corrective engineering bulletins (CEBs), further rework will be necessary. This ensures that all applicable engines are updated to the latest safety standards, minimizing the risk of mechanical failure (Section 4).
Failure to comply with the provisions outlined in this directive can result in severe consequences. Non-compliance may lead to operational risks such as shaft disconnects, which can cause uncontained engine failures. These failures could potentially result in catastrophic outcomes, thus making strict adherence to the regulations critical. The directive specifies temporary alternatives for certain shafts, limiting their use until 30 November 1987, to ensure that all modifications are completed in a timely and controlled manner (Section 5).