Jet engine makers estimate they lose millions of dollars each year because nuts that seal fluid lines and hoses, called b-nuts, aren’t screwed on just right. If the b-nuts are deemed too loose or too tight during testing, the engine has to be fixed before it can power a plane with paying passengers.
Until recently, there were few good ways to tell if the nut had hit that sweet spot. Workers with torque wrenches had to rely on their skill and judgment to nail the delicate balance.