COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Lycoming Piston Engines AD/LYC/99 Diaphragm Fuel Pumps 13/96 DM Applicability: 1. All Lycoming new, remanufactured and overhauled fuel injected L/IO-320, -360, - 540; AEIO-320, -360, -540; HIO-360, TO-360 and O-540-L engines released by Textron Lycoming between 18 July 1995 and 14 August 1996 and fitted with a diaphragm fuel pump part number (P/N) LW-15473 with an identification/date code of 154739506, 154739507 or 154739510, and 2. All Textron Lycoming fuel injected L/IO-320, -360, -540; AEIO-320, -360, -540; HIO-360, TO-360 and O-540-L engines which have had a new diaphragm fuel pump P/N LW-15473 with an identification/date code of 154739506, 154739507 or 154739510 installed since 18 July 1995, and 3. All spare diaphragm fuel pumps P/N LW-15473 with an identification code of 154739506, 154739507 or 154739510. Requirement: Inspect applicable fuel pumps in accordance with Textron Lycoming Mandatory Service Bulletin No. 525. Note: An FAA Airworthiness Directive on this subject is pending. Compliance: Installed engines: Within 10 hours time in service effective 30 October 1996. Spare engines and spare fuel pumps: Prior to installation in an a aircraft effective 30 October 1996. Background: This directive has been issued to require the inspection of certain fuel pumps. The requirement addresses reports of sudden engine failure events which resulted from the fuel pump diaphragm retaining washer becoming separated from the pull rod assembly and lodging in the pump outlet valve. An investigation of the reports indicates the defect relates to a manufacturing fault.