Vent: Stop ziptieing bundles so tight on the wing runs

I had to redo a full harness on a 737 last week because some guy before me cranked down every ziptie like he was trying to strangle the wires. I get that you want it clean, but when you squeeze the bundle that tight you pinch the insulation and create stress points. Over time those wires can chafe or crack, especially in a vibration environment. I spent 4 hours cutting off 50 zipties and re-looming the whole thing because of microcracks I found near the wing root. It matters because that kind of damage won't show up on a continuity test but will fail you in a megohm test or cause intermittent faults later. Who else has had to deal with overzealous ziptie guys?

2 comments

2 Comments

bell.emma15d ago

That squeezing the wires like he was trying to strangle them" line hit home. A buddy of mine works avionics on Gulfstreams and he had to redo an entire engine harness once because some guy had ziptied the bundles so tight around a sharp edge it actually cut through the jacket on three wires. They only found it when a fault light came up during a taxi test. He said it took him two full days to strip it all out and re-loom it.

the_jana15d ago

That whole "squeezing the wires" thing is scary because it's such an easy mistake to make too lol. I remember reading about a similar issue with Boeing where overtightened clamps caused wire chafing that led to a hydraulic leak, and that's like a multi-million dollar jet. It sucks that one person's bad habit can cost somebody days of work like that.