COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Turbomeca Turbine Engines - Arriel Series AD/ARRIEL/11 Gas Generator Rear Bearing Chip Detector 5/99 Applicability: All Arriel 1 series engines. Requirement: Install Turbomeca Modification TU 208 in accordance with Turbomeca Service Bulletin No. 292 72 0163 Updating 1. Note: DGAC Airworthiness Directive 98-394(A) refers. Compliance: At next engine shop visit, regardless of the purpose of the visit, or prior to 31 December 1999, whichever occurs first. This Airworthiness Directive becomes effective on 20 May 1999. Background: This directive has been issued to add a gas generator rear bearing chip detector to the main chip detector warning system. The requirement follows reports of 6 gas generator rear bearing rupture events. The additional chip detector will provide the pilot with an in-flight warning of rear bearing chip detector contamination.