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/F50/36 Alternate Brake System Cables 9/90 Applicability: F27 Mark 50 aircraft with S/Nos 20103 through 20181. Requirement: Action in accordance with Fokker SB F50-32-006 Rev 1. Note 1: RLD BLA 89-063 Issue 2 refers. Note 2: Compliance with Part 2 of the Requirement document is considered terminating action for this Directive. Compliance: Unless already carried out in the 900 hours time in service prior to 6 September 1990 - Prior to exceeding 100 hours time in service after 6 September 1990 or at the next scheduled inspection for issue of Maintenance Release after 6 September 1990, whichever occurs later, and thereafter at intervals not exceeding 1000 hours time in service, until terminating action is carried out. Background: Country of origin AD. Excessive cable wear has been experienced which is attributed to a too small pulley radius, cable vibrations and perhaps more frequent use of alternate brakes. Terminating action replaces pulleys.