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/F50/49 Windshield Wiper Rotary Selector Switch Replacement Applicability: All F27 Mk 50 aircraft serial numbers 20103 to 20199 inclusive. Requirement: Action in accordance with Fokker Service Bulletin F50-30-012 Revision 1. Note: Netherlands AD 91-123 also refers. Compliance: Prior to 2 March 1992. Background: Fokker have advised that certain windshield wiper rotary selector switches 1/92 manufactured by Marquette are prone to burn out. This may cause damage to the electrical wiring, insulation material and pitot static lines, and may also result in smoke on the flight deck.