AD/B747/117 - Inspection of Cockpit Wire Bundles (Cth)

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

Boeing 747 Series Aeroplanes

AD/B747/117 Inspection of Cockpit Wire Bundles 4/93 Applicability: All model 747 series airplanes with the exception of the 747-400 series. Requirement: Visually inspect the wire bundles located above the P6 panel around station 400, water line 385, right butt line 15. If necessary, repair the wires and reposition the bundles in accordance with Boeing Alert Service Bulletin 747-24A2186 dated 14 January 1993.

Note: FAA AD 92-27-12 Amendment 39-8447 refers.

Compliance: Unless previously accomplished, inspect and if necessary repair the wire bundles prior to 15 April 1993. Thereafter, if the wire bundles do not meet the clearances specified in the Requirement Document, inspect the bundles at 120 day intervals until the bundles are repositioned.

Background: Recently, an electrical wiring short circuit was detected in the cockpit of a Boeing 747-300 series aircraft. The cockpit filled with smoke, numerous circuit breakers popped and sounds of electrical arcing were heard, resulting in a rejected take-off. A partial inspection of the world wide fleet revealed a further 11 cases of wire bundle damage in the same location as on the aircraft that experienced the incident.

The affected wire bundles contain wires that carry power and data for all the captain's and first officer's instruments (with the exception of standby airspeed, compass and altitude) that are necessary for continued safe flight. Compliance with this Directive will decrease the potential for a similar incident occurring.