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/F50/37 Auto Flight Idle Stop Mechanism 10/90 Applicability: Model F50 series with serial numbers 20103 through 20192 with Service Bulletin F50-76-008 Revision 1 incorporated. Requirement: Action in accordance with Fokker Service Bulletin F50-76-009. Note: RLD AD 90-044 refers. Compliance: Within 250 hours time in service after incorporation of SB F50-76-008 Revision 1, and thereafter at intervals not exceeding 250 hours time in service. Background: This Directive requires repetitive inspection of the auto flight idle stop mechanism to ensure correct solenoid stroke, which is affected by the gradual wear of the parts.