COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Teledyne Continental Motors Piston Engines AD/CON/67 Valve Retainer Key 8/93 DM Applicability: All engines manufactured/remanufactured/overhauled by Teledyne Continental Motors (TCM) in the period July 29 1992 and March 30 1993, as listed by serial number in TCM mandatory service bulletin (MSB) No. 93-12, dated MAY 12 1993, which have less than 25 hours TIS since installation, and all Cylinder assemblies supplied by TCM between JULY 29 1992 and MARCH 30 1993, which have less than 25 hours TIS since installation. Requirement: Verify proper valve retainer key installation in accordance with TCM Mandatory Service Bulletin No. MSB 93-12. Note: FAA Airworthiness Directive 93-10-02 refers. Compliance: Effective June 7 1993; unless previously accomplished, before further flight. Background: This Directive has been issued to require an inspection of certain TCM engines and cylinders for correct assembly of the valve retainer keys. The requirement follows advice of two overseas events in which missing valve retainer keys resulted in engine failure.