COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Auxiliary Power Units AD/APU/7 High Pressure Turbine Disc 4/92 Applicability: Garrett Auxiliary Power Division model TSCP700-4B auxiliary power units, prior to S/N 90697 and model TSCP700-5 auxiliary power units prior to S/N 80443. Requirement: Action in accordance with the technical requirements of FAA AD 91-25-04. Note: Garrett Service Bulletin TSCP700-49-5892 Revision 2 dated 10 October 1990, refers. Compliance: Within 24 months after the issue date of this Directive. Background: This Directive has been raised due to reports of HPT disc ruptures. This condition, if not corrected, could lead to an uncontained HPT disc failure.