COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES General Electric Turbine Engines - CF6 Series AD/CF6/19 High Pressure Compressor Rotor Inertia Weld 9/91 Applicability: CF6 -80A and 80C2. Requirement: Action in accordance with the Technical Requirements of FAA AD 91-11-05, Amendment 39-7001. Note: GE Service Bulletins 72-531 Revision 2 and 72-314 Revision 2 refer. Compliance: As specified in the Requirement Document with a revised effective date of 5 September 1991 for Australian registered aircraft. Background: The FAA AD has been prompted by two high pressure compressor rotor stages 11-14 spool-shaft failures at the inertia weld. Failure of the weld in service will result in major power loss and it could be uncontained.