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/F50/47 Nose Landing Gear Retraction Mechanism 10/91 Applicability: Serial number 20103 to 20108 inclusive, and 20110 to 20131 inclusive. Requirement: Action in accordance with the Technical Requirements of RLD AD 90-057, dated 23 May 1990. Note: Fokker Service Bulletin F50-32-004, dated 17 April 1990 refers. Compliance: Prior to exceeding 12 000 pressurisation cycles. Background: During full-scale fatigue testing, cracks were found near a lightening hole in the nose landing gear link assembly. To improve the fatigue life of this component, this AD calls for the replacement of the current retraction link assembly with a reinforced unit.