COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F50 (F27 Mk 50) Series Aeroplanes AD/F50/73 Hub Mounting Face Dowel Hole Inspection Following Propeller Overtorque 4/97 Applicability: All Fokker F27 Mk 50 series aircraft fitted with Dowty R352/6-123-F/1 or R352/6- 123-F/2 propellers. Requirement: Whenever a propeller is subject to an overtorque condition, as defined in Dowty Aerospace Mandatory SB F50-61-50 Revision 7 dated Dec 12, 1996, inspect the propeller in accordance with the reference SB. Note: RLD AD 89-079/3 dated December 31, 1996, which supersedes RLD AD 89-079/2 dated November 24, 1994 and UK CAA AD 023-05-89 refer. Compliance: Whenever a propeller overtorque occurs. This Airworthiness Directive becomes effective on 27 March 1997. Background: The manufacturer has reported several incidents of propellers being overtorque while in operational use. To enable operators to assess if propeller removal is required the propeller manufacturer has provided inspection procedures. This Directive has been relocated from CAO 107 AD/PR/30 with an effective date of 27 March 1997.