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/CF6/20 High Pressure Compressor Rotor Stages 11 to 14 Vane to Spool Rubs Applicability: CF6-80A and CF6-80C2. Requirement: Action in accordance with the Technical Requirements of FAA AD 91-15-25 Amendment 39-7090. Note: GE Service Bulletins 72-459 Revision 2 and 72-130 Revision 2 refer. 11/91 Compliance: As specified in the Requirement Document with an effective date of 28 November 1991. Background: The FAA AD is prompted by reports of HPCR stages 11-14 spool-shafts found in service with spool rub. This condition, if not corrected could result in uncontained engine failure.