COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F27 Series Aeroplanes AD/F27/148 DC Generator Control Panel 12/99 Applicability: Model F27 Mk 100 through Mk 700 series aeroplanes, all serial numbers. Requirement: Inspect the DC generator control panels in accordance with STORK Fokker Service Bulletin F27/24-79 dated 28 April 1999. Note: RLD BLA 1999-093 (A) refers. Compliance: Within two calendar months from the effective date of this Directive and thereafter, at intervals not to exceed 4000 hours time in service. This Airworthiness Directive becomes effective on 2 December 1999. Background: The RLD has received numerous incident reports concerning DC generator overvoltage on F27 aeroplanes. These incidents invariably resulted in loss of both DC generator systems and loss of several other systems. Investigation revealed that the overvoltage was caused by incorrect installation of DC generator control panels, together with bad solder joints, bad wire insulation and incorrect functioning of the control panels. These conditions, if not detected and corrected, could result in further incidents of overvoltage of the aeroplane electrical system. This Directive requires the regular inspection of the control panels.