COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 737 Series Aeroplanes AD/B737/20 Amdt 2 Engine Fire/Overheat Detection Module 4/90 Applicability: All model 737-200, -300 and -400 series aircraft. Requirement: 1. Inspect the engine fire/overheat detection module to determine the module part number. 2. If part number 10-61096-41, -71, -81, -91, -92 or 1062061-1, 2, -3, -11 or -12 is installed, modify the control module in accordance with Walter Kidde Aerospace Service Bulletin 899315-26-326 (for -200 series aeroplanes), or 899315-26-324 (for -300 and -400 series aeroplanes) as applicable. Note: FAA AD 89-08-12 R1 refers. Compliance: Prior to 22 August 1990. Background: Boeing have advised that certain Walter Kidde engine fire/overheat warning systems may become inoperative after an electrical power transfer, with no indication of failure given to flight crew. This could jeopardize continued safe flight and landing. Amendment 2 to this Directive is issued to delete reference to the Australian CAA Flight Manual amendment which will be issued separately and to mandate incorporation of the referenced Walter Kidde Service Bulletins.