COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Grob G115 Series Aeroplanes AD/GROB 115/4 Firewall Bonding Lead 11/91 Applicability: All G115A series aircraft S/No 8091 through 8109 inclusive, except S/Nos 8097, 8100 and 8102. Requirement: Action in accordance with the technical requirements of GROB G115 Service Bulletin TM 1078-18. Compliance: Within 25 hours Time in Service after 14 November 1991. Background: Grob have advised that during engine start, there is a possibility that a high resistance may occur at the bonding lead assembly mounted at the firewall. This may cause a reverse current to occur which may damage wiring and other aircraft components. To prevent this, the existing bonding bolt plate must be replaced with a modified bonding bolt plate (P/No 115-9006).