COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 400 Series Aeroplanes AD/CESSNA 400/76 King Automatic Pilot Roll Axis Slip Clutch Setting 12/80 Applicability: Model 421C with S/Nos. 421C0401 and up which have King Radio Model KFC-200 Flight Control System installed under Supplemental Type Certificate SA1246CE. Document: 1. FAA AD 80-20-06, Amdt. 39-3937. Or 2. King Radio Installation Bulletin No. 167. Compliance: Within 25 hours time in service after 27 October 1980. Background: Cessna Aircraft made an aileron tab actuator change in 421C aeroplanes effective with S/No. 421C0401. This change has made it necessary to decrease the roll axis clutch torque in the KFC-200 Flight Control System to prevent the aircraft from exceeding 60 degrees bank angle in the event of a hardover roll axis malfunction.