Rant: chafed wire in the tail cone took me all day Tuesday

I was chasing a intermittent comm fault on a CRJ-900 that had the crew writing up static on VHF 2. Checked antennas, checked the cable with a VSWR meter, everything looked fine. Turned out to be a chafed coax where it passes through a grommet near the aft pressure bulkhead. The braid was grounding out only when the airframe flexed on the ground, so it passed every bench test I threw at it. Took me 7 hours and a borrowed borescope to finally spot the tiny wear mark. I've seen this same issue on three other tails now, so I'm wondering if there's a better routing path or a known AD for this spot. Anyone else run into this on the -900 specifically?

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troy_wilson820d ago

Man, seven hours on a ghost fault like that is brutal. Spent a whole shift once chasing a similar gremlin on a 145, turned out to be a wire tie rubbing against a hydraulic line, nearly lost my mind. The fact that it only shows up on the ground is the worst kind of tease, makes you feel like you're the one hearing static. Good catch with the borescope, though, that's the kind of find that keeps the next guy from pulling his hair out.