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/F50/22 Elevator Trim Cable Pulley Bracket and Mounting 8/89 Applicability: Serial numbers 20103 through 20108 and 20110 through 20123. Requirement: Reinforce elevator trim cable pulley brackets and mountings in accordance with Fokker Service Bulletin F50-27-008 dated 3 February 1989. Note: Netherlands AD 89-24 refers. Compliance: Prior to the accumulation of 8000 flight cycles. Background: Stress analysis has shown that the increased tension in the elevator trim cables will decrease the fatigue life of the pulley brackets and mountings.