COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 125 Series Aeroplanes AD/HS 125/114 Generator Control Unit (GCU) Earth Wire 2/91 DM Applicability: All BAe 125 aircraft as listed in the Requirement document. Requirement: Action in accordance with BAe SB 24-A278. Note: Compliance with this SB has been classified Mandatory by the UK CAA. Compliance: Prior to 31 January 1991. Background: Loss of GCU earth connection can result in a DC generator overvoltage which can cause battery overheat and subsequent failure.