COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series AD/TFE731/18 Digital Electronic Engine Control 2/90 Applicability: TFE 731-2, -5, -5AR, -5R series engines as listed in Garrett SB TFE 731-76-3049. Requirement: Replace suspect digital electronic engine controls (DEEC) as listed by serial number in Garrett SB TFE 731-76-3049. Note: FAA AD 89-22-16 refers. Compliance: Prior to 31 March 1990. Background: This Directive reflects advice from the manufacturer of a possibility that uncommanded thrust increase or decrease may occur due to a defect in certain electronic engine controls.