COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 320 Series Aeroplanes AD/CESSNA 320/12 Amdt 1 Turbocharger 9/87 Applicability: All models 320D, 320E, and 320F fitted with Continental model TSIO-520-B engines. Requirement: Remove the turbosupercharger turbine insulation blanket or stainless steel heat shields and visually inspect the complete surface of the TCM turbosupercharger assembly P/N 632729 (AID P/N 406610) for cracks, bulges, or burnt areas. Note: Turbine housings exhibiting any cracks, bulges, or burnt areas shall be replaced before further flight. Compliance: Prior to accumulating 425 hours total time in service and thereafter at each issue of a new Maintenance Release. Background: This Airworthiness Directive was originally raised to reflect the requirement of FAA AD 70-3-4, effective 31 January 1970. This Amendment is raised to clarify the Requirement, and include reference to stainless steel heat shields, that were fitted beginning with 1972 models.