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/CF6/6 First Stage High Pressure Turbine Disc Embossment Radii Applicability: CF6-45, -50 Series engines. 8/86 Requirement: Remove from service, first stage high pressure turbine discs identified by serial number in General Electric S.B. A72-859, Rev 1, and return to manufacturer for inspection of both the forward and aft embossment radii. Reference Document - FAA AD 86-12-03, Amdt 39-5311. Compliance: Prior to 5,500 cycles disc life since new. Background: This Directive has been issued to require removal from service, certain first stage high pressure turbine discs. The manufacturer advises, the discs may contain stress risers which could adversely affect the service life of the disc.