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/12 Power Turbine Nozzle Inspection 5/99 Applicability: Arriel 1A, 1A1, 1A2 and 1B models not incorporating Turbomeca Modification TU 38. Requirement: To detect cracking of the power turbine nozzle vanes which may result in an in flight shutdown of the engine, carry out an ultrasonic inspection of the internal face of the gas generator module rear bearing support in accordance with the procedure detailed in Turbomeca Service Bulletin No. 292 72 0213. Note: DGAC Airworthiness Directive 98-493 (A) refers. Compliance: At next engine shop visit, regardless of the purpose of the visit, or prior to 30 June 1999, whichever occurs first. This Airworthiness Directive becomes effective on 20 May 1999. Background: This directive has been issued to require a once only inspection of the gas generator rear bearing support. The requirement follows advice from the manufacturer of cracks developing in the bearing support.