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/F50/9 Door External Handles 3/89 Applicability: F27-050 S/Nos 20103 to 20108 and 20110. Requirement: Action in accordance with Fokker SB F50-52-007. Note: RLD AD 88-91 refers. Compliance: Prior to 30 June 1989. Background: Excessive wear in the door external handle mechanism allows moisture ingress and may subsequently freeze the door operating mechanism.