My torque wrench lied to me and I almost paid for it at 12,000 feet

Took an older Snap-on torque wrench out of my box last week to do a hub install on a Cessna 172. The click felt fine on the bench, same as always, so I torqued every nut on that wheel to spec. Next day the owner calls saying he heard a ticking on takeoff roll. Pulled the wheel back off and found two nuts that had backed off about a quarter turn. Turns out the wrench was clicking at 18 ft-lbs instead of 20, the internal spring had drifted after 8 years of daily use. I sent it out for calibration that afternoon and bought a cheap digital adapter as a backup. How often do you guys actually check your torque tools, or is it just me who trusted one until it almost caused a wheel departure?

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1 Comment

danielmason23d ago

The whole "almost caused a wheel departure" thing feels kinda dramatic, honestly. I mean, two nuts backed off a quarter turn, that's not exactly a wheel flying off the plane mid-flight. You caught it on the ground before anything serious happened. Ive had a cheap Harbor Freight torque wrench for like 10 years now and never once checked it, and the last calibration sticker on it is from 2014. Still clicks when it clicks, if that makes sense. Maybe you just needed to give that old Snap-on a little more oomph or count clicks differently, some of them are finicky like that. Obviously calibration matters for critical stuff, but a quarter turn of slack on a hub is annoying, not life-threatening.