Why does no one talk about how often torque wrenches drift out of spec?

I was working a line maintenance shift at a small regional airport near Des Moines about 2 years ago. An old-timer mechanic named Don was helping me torque down some fan case bolts on a CRJ. I used my usual snap-on torque wrench and he just stopped me. He said 'when's the last time you calibrated that thing?' I told him it was over a year ago. He grabbed his own wrench and showed me the difference nearly 15 ft-lbs off. I had been under-torquing stuff on dozens of planes without knowing it. Has anyone else had a cal check catch a big surprise like that?

2 comments

2 Comments

jessica_hall4926d ago

Oh man that's rough. I had something similar happen with my click-type torque wrench a few years back while I was helping a buddy swap out his truck's water pump. We checked it against his beam style wrench and mine was reading about 10 pounds heavy. Good thing I caught it before I torqued the intake manifold or something worse. What do you use to keep track of your calibration schedule?

wilson.sam25d ago

Slap a calendar reminder on your phone and pretend it doesn't exist til you hear the dreaded click go wrong, just like I do. The real trick is losing the wrench for a few months so it resets the clock.