Captured an image of the gas turbines personnel installing the weights on the blades during the gas turbines balancing exercise. This is inside the gas turbines, the prime mover of similar operating principles with the commercial aircraft jet engines only somewhat bigger. This is a highly specilized job, of which the error tolerance is zero.
But no matter how specialized it is, the concept is very much simple. It more or less like a wheel balancing, where weights will counterbalance the force and to make it equalibrium.