There's a lot of misunderstandings in the comments here. When you're dealing with complex wiring harnesses and wiring runs, there are always problems. For exam

There's a lot of misunderstandings in the comments here. When you're dealing with complex wiring harnesses and wiring runs, there are always problems. For example, the A380 and one of Boeing's new airliners were delayed because stuffing the wiring harness in the nose didn't work. In the case of airplanes, things flex and bend, causing wire chafing. So there's no black and white answer to, "Is the wiring perfect?" The only good solutions are: 1) When new airplanes are made, improve the wire layout 2) When old airplanes get a heavy maintenance check (D-check), possibly inspect and redo the wiring then. 3) Consider using conduit for safety-critical runs. Makes it harder to inspect, though. :) Anyway, the Swissair 111 fire/crash was because of new gambling screens igniting flammable materials. Sure that was an electrical fire, but from adding entertainment equipment. Swissair 111: "flammable material used in the aircraft's structure" https://en.wikipedia.org/wiki/Swissair_Flight_111 https://en.wikipedia.org/wiki/Swissair_Flight_111 Source: commercially-rated pilot