COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 146 Series Aeroplanes AD/BAe 146/46 Amdt 1 Generator Control Unit 6/93 Applicability: BAe 146 Series 100/100A, 200/200A and 300/300A aircraft identified in British Aerospace Regional Aircraft Limited Service Bulletin SB.24-91-70488B&C dated 28 January 1993. Requirement: Action in accordance with British Aerospace Regional Aircraft Limited Mandatory Service Bulletin SB.24-91-70488B&C dated 28 January 1993. Note: CAA(UK) AD 023-01-93 refers. Compliance: Prior to 1 March 1996. Background: The aircraft manufacturer has established that a single phase fault current between 175 amps and 270 amps can activate the GCU undervoltage protection circuit rather than the overcurrent protection circuit resulting in the sequential loss of each main generator since the auto transfer circuit is not inhibited on undervoltage. Compliance with this Directive will decrease the probability of sequential generator loss. This amendment aligns the requirements with those of the country of origin's Airworthiness Directive.