The ability of air motors to start and stop virtually instantaneously under load makes them very good lead screw drives. The high level of torque that can be generated, especially with geared units, is also useful when driving heavy loads with any precision. Air motor manufacturer, Dynatork has an application involving one of its Powergear units deployed on a hazardous area duty. This drives a heavy radial arm from a datum point to fixed positions, with position information fed back to the controller. Using analogue flow control valves, the speed of raise/descent can also be ramped.