Rant: old mechanic told me I was chasing false pressure readings for 2 months

Had a 727 engine with a bleed pressure issue that was driving me nuts. Kept pulling the sensor and swapping it out, thinking it was bad. Then this retired guy from Pratt & Whitney walks by, watches me for a minute, and says the problem is probably the ground wire on the harness, not the sensor itself. I checked it with a multimeter and yeah, 15 ohms of resistance where there should be zero. Two months of chasing ghosts (and $400 in parts) because I didn't check the simple stuff first. How often do you guys see wiring cause false readings like that?

2 comments

2 Comments

alex_nguyen16d ago

Ground wire issues are definitely a thing but people act like it's some hidden secret from the gods. Every old timer has a story about a loose wire causing a month long headache. You swapped a sensor out for $400 because you didn't check the basics first, that's on you not on some mystical wiring gremlin. A multimeter check on the harness ground should be step one on any aircraft system that's acting up. Half the time it's just corrosion or a bad crimp anyway. Not saying it's not frustrating but let's not pretend this is some rare deep dive knowledge.

valh3216d ago

Is it really that big of a deal though? I mean, @alex_nguyen, you're right that basics matter, but a month-long headache from a loose wire sounds like bad luck more than a hidden secret. Either way, it's still annoying but not exactly some ancient wisdom.