Can we talk about how much of a modern airframe is just wiring?

I was reading an old FAA report from 2018 about a regional jet upgrade. It said the total wire length added was over 12 miles. Twelve miles. In one plane. I had to read it twice. That's like running cable from the airport to the next town over. It really hit me when I was doing a harness check last week on a CRJ. You pull one bundle and it feels like it never ends. It's all just copper and shielding and connectors now. The actual metal of the plane feels secondary. Makes you wonder what happens when all that stuff starts to age at once. Has anyone else had a job where the wire weight felt like it was the main thing you were fixing?

3 comments

3 Comments

jennifer_jenkins3d agoOG Member

Yeah, that part about the metal feeling secondary really got me. It's not just the weight, it's the sheer amount of stuff that can go wrong. You get a single chafed wire in the middle of one of those bundles and the troubleshooting is a nightmare. The plane's bones are still there, but its nerves are this huge, fragile web. It makes aging fleets a real puzzle, because that stuff doesn't wear out in a nice, predictable way like metal fatigue.

the_thea3d ago

Twelve miles is just crazy to picture. You're basically flying a spool of wire with wings at that point. @jennifer_jenkins is right about the troubleshooting being a nightmare. I saw a job where they had to chase a fault in the in-flight entertainment system. They ended up pulling up floor panels for half the cabin just to follow one line. The actual fix was a tiny rub-through, but finding it took two days. All that hidden mass just waiting to cause problems.

ryantorres3d ago

Yeah, and like @jennifer_jenkins said, it's not a predictable wear item... it's all just hidden until it fails. You can do all the checks on the frame, but a wire bundle just sits there quietly rotting from vibration for years. Then one day a whole system just drops because one strand finally gave up. Makes you wonder how much of the plane's real "age" is just that hidden wiring getting more and more brittle.