Tried to use a stethoscope on a turbine, big mistake in Phoenix

I was chasing a high-frequency vibration on a CFM56-7B and thought I could pinpoint it with a mechanic's stethoscope through the cowling, but the fan blade noise just wrecked my ears for 3 hours. Turns out I needed an accelerometer and a vibration analyzer, which we finally got from the tool crib after my hearing went fuzzy. Anyone else burned half a shift using the wrong diagnostic tool before giving in and pulling the proper gear?

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mia_singh241mo ago

Did you ever read that thing about how turbine engines basically scream in frequencies that can cook your inner ear? I saw a writeup once about how the CFM56 fan blade pass frequency sits right in that nasty range where your ears get overloaded before your brain even registers the pain. You probably got lucky it was only 3 hours of fuzzy hearing, that could have been permanent damage. It's crazy how we all try to cheat with the quick tool before admitting we need the fancy gear. I remember a guy on another forum saying he used a laser tachometer on a spinning shaft and almost blinded himself with the reflection, so at least you kept your eyes.

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