G-BOAC - Wiring repair following fire
We spoke to the engineer who completed the repair to G-BOAC following the fire incident outlined
in the CAA report.
The following information was given.
"The reason for the splices was that the complete looms needed replacing which route from the aft under cabin floor down through what are called pressure bungs,( sealed tubes that carry the wiring looms from pressurised zones to non pressurised zones)
The looms are also divided to run through different bungs so we are talking a major job to unseal several bungs and remove looms not just the ones associated with the fuel quantity defect but others that are routed out to other systems.
The nature of routing cables through these bungs always mean that individual cables get crossed/tangled within the tubes and damage is easily caused by trying to pull them out even if the sealant can be removed completely.
This explains how the normally unacceptable number of inline splices came about.
Myself and a fellow engineer investigated the defect which was causing random serious fuel quantity indications and through a process of working outwards from the fuel tank and finally into the underbody fairings found the fire damaged looms.
The CAA gave an exceptional approval for the number of flights remaining.
Note: The splicing in of new cabling a major task alone,took several weeks.
A complete replacement of the looms would not have been carried out due to the amount of work involved and the aircraft would have been removed from service even earlier than the final end date."