COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Auxiliary Power Units AD/APU/11 TSCP700 HPT Disc 1/97 Applicability: AlliedSignals TSCP700 Series Auxiliary Power Units, incorporating a High Pressure Turbine (HPT) disc identified with a serial number listed in AlliedSignals Service Bulletin TSCP700-49-A7168. Requirement: Remove from service affected HPT discs as identified in AlliedSignals Service Bulletin TSCP700-49-A7168. Note: FAA AD 96-18-17 also refers. Compliance: Effective 2 January 1997; prior to accumulating 7500 cycles since new or no later than 2 January 2000, whichever occurs first. Background: The manufacturer has advised that some HPT discs have been manufactured from nonconforming material which has required a reduction in service life.