AD/B767/92 - Main Battery Shunt and Ground Stud (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

Boeing 767 Series Aeroplanes

AD/B767/92 Main Battery Shunt and Ground Stud 12/96

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Applicability: This Directive is applicable to Model 767 series aeroplanes listed in Boeing Alert Service Bulletin (ASB) 767-24A0112 Revision 1 dated 8 August 1996.

Requirement: 1. Perform an inspection of the main battery shunt in accordance with ASB 767- 24A0112 Revision 1.

2. Perform an inspection of the of the main battery ground stud in accordance with ASB 767-24A0112 Revision 1.

3. Rectify any discrepancies detected during the Requirement 1 and 2 inspections in accordance with the procedures in the ASB.

Note: FAA AD 96-19-10 Amdt 39-9757 refers.

Compliance: For Requirements 1 and 2 - Unless previously accomplished, prior to 16 November 1996.

For Requirement 3 - Before further flight.

This Airworthiness Directive becomes effective on 9 October 1996.

Background: The FAA has received reports indicating that interruptions of electrical power have occurred during flight, which resulted in the loss of battery power to the hot battery bus (HBB) on a Boeing 767 aeroplane. The HBB is the source of standby power for the aircraft and its loss could affect several aircraft systems during standby operations.

Investigations have revealed that power interruptions may have been caused by improper assembly of fasteners on the studs, cracked shunts, corroded or contaminated fasteners or improper torque of the fasteners. Loose fasteners on the shunt studs can create an open circuit or high resistance in the main battery ground stud connection which can cause an interruption to the battery charger and loss of the HBB.