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.