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 125/76 APU Bonding 4/86 Applicability: All DH/HS/BH/B.Ae.125 series aircraft up to and including aircraft 258034 fitted with an Auxiliary Power Unit to Mod. 251605 or 258748. Requirement: Action in accordance with British Aerospace SB 49-32-(9210A). Note: The British CAA have classified this Service Bulletin as mandatory. Compliance: Before 31 December 1986. Background: To protect the A.P.U. system against a possible starter/generator live casing condition, and potential fire hazard.