Some of AWSs are 10 meters high and wind sensors are mounted on the top of the tower.
Every years it is necessary to replace sensors for overhaul and calibration; sometimes operators have to climb the trellis to reach the sensor.
For accessing the top and preventing a fall, the operator employs the work positioning systems which enable to work supported in a harness under tension. In the backpack, sensors to replace and tools for repair and maintenance. Someone else is steady ate the ground for assistance if needed. In this situation it must prevent objects from falling.