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 250/51 Amdt 1 High Pressure Fuel Control Filter Assembly - Modification 6/83 Applicability: All models 250-C20, C20B and C20J engines fitted with CECO P/N 6895173 or P/N 6896727 high pressure fuel control filter assemblies. Document: Allison 250-C20, C20B and C20J Alert CEB-A-1144, Rev. 4. Note: FAA AD No. 82-13-03 refers. Compliance: For model 250-C20 and C20B : Forthwith. For model 250-C20J : Not later than 1st August 1983. Background: This Directive is issued to prevent possible metal contamination of the CECO Model MC-40 fuel control system power turbine governor which can result in power turbine rotor overspeed. It is raised in issue to Amdt 1 to include the model C20J as specified in Revision 4 of the Allison Document.