COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Embraer EMB-110 (Bandeirante) Series Aeroplanes AD/EMB-110/51 Generator Control Unit Overvoltage Protection Circuit Applicability: This Directive is applicable to all EMB-110 Bandeirante aircraft. 3/96 DM Requirement: 1. Perform a functional test of both generator control unit (GCU) overvoltage protection circuits in accordance with Embraer Service Bulletin SB 110-24-0037 dated 6 November 1995. 2. Replace the GCU with a serviceable unit. Note: CTA (Brazil) AD 95-11-02R1 Amdt 39-754 refers. Compliance: For Requirement 1 - Within 200 hours time in service or two calendar months, whichever occurs first, after 17 January 1996 and thereafter at intervals not exceeding 600 hours time in service. For Requirement 2 - Before further flight, if the GCU fails the Requirement 1 functional test. Background: Embraer has advised of instances concerning malfunction of voltage control and GCU overvoltage protection circuits. The reported malfunctions may cause damage to the electrical and electronic systems of the aircraft, including complete loss of generated power. Actions specified by this Directive are designed to provide early detection of malfunctioning circuitry.