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 250/78 Superior Turbine Bearings 13/96 Applicability: All Allison Model 250-B15G, -B17F, -B17F/1, - B17F/2, -C18, -C18A, -C18B, - C18C, -C20, -C20B, -C20F, -C20J, -C20S, -C20W, -C20R, -C20R/1, -C20R/2, - C20R/4, -C28B, -C28C, -C30, -C30P, -C30M, -C30S and C30G turbine engines fitted with Superior Air Parts Inc. Parts Manufacturing Approval (PMA) bearings part number (P/N) A6871505 and/or P/N A23007152. Note 1: This directive is only applicable to Allison 250 turboprop and turboshaft engines fitted with bearings manufactured by Superior Air Parts Inc. Requirement: 1: Engines fitted with a Superior Air Parts Inc. No. 5 bearing P/N A6871505: 1. Perform a visual inspection of the engine oil filters in accordance with (IAW) Superior Turbine Service Bulletin No. T95-SB001 Revision A. b. Replace Superior Air Parts Inc. bearing P/N A6871505 with an Allison Engine Company bearing P/N 6871505. 2: Engines fitted with a Superior Air Parts Inc. No. 8 bearing P/N A23007152: a. Perform a visual inspection of the engine oil filters IAW Superior Turbine Service Bulletin No. T95-SB002 Revision A. Replace Superior Air Parts Inc. No. 8 bearing P/N A23007152 with an Allison Engine Company bearing P/N 23031478. Note 2: FAA Airworthiness Directive 96-19-01 refers. Note 3: Replacement of the Superior Air Parts Inc. bearings with Allison Engine Company bearings constitutes a terminating action for this directive. Compliance: 1. a. Prior to 31 December 1996 and thereafter at intervals not to exceed 25 hours' time in service for engines with less than 300 hours' time in service since installation of the subject bearing and thereafter at intervals not to exceed 100 hours' time in service. 1. b. At next access to the affected bearing. 2. a. Prior to 31 December 1996 and thereafter at intervals not to exceed 25 hours' time in service for engines with less than 300 hours' time in service since installation of the subject bearing and thereafter at intervals not to exceed 100 hours' time in service. 2. b. At next access to the affected bearing. This Airworthiness Directive becomes effective on 5 December 1996. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Background: This directive has been issued to require the inspection and replacement of certain turbine bearings. The requirement follows reports of premature wear and failures of the applicable bearings. Bearing failure could result in turbine and subsequently, engine failure.