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Found a stat about wiring errors in the 737 that caught me off guard
I was reading the Boeing fault isolation manual for the 737NG and saw that over 40% of intermittent avionics problems traced back to loose pins in the D-sub connectors, has anyone else run into that number before?
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terry_thomas20d ago
I've seen that 40% number thrown around in some training materials, but my experience tells a different story. In the field, I've found maybe 10-15% of intermittent issues are actually loose pins in D-subs. The other 85% end up being bad ground straps, chafed wires behind the panel, or even just cold solder joints on the back of the connector itself. I once spent three days chasing a ghost in a 737-800 that kept losing the autopilot, turned out to be a cracked resistor on the inline filter, not a pin at all. Take those numbers with a grain of salt, they come from controlled lab conditions where they're purposely testing for connector faults. Real world aviation is messy, and wiring problems hide in all sorts of places the manual doesn't highlight.
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stella_baker20d ago
That 40% number always bugged me too. Real wiring gremlins just don't play by lab rules.
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