A system and method for determining performance of a turbine engine, and operation thereof. The system and method includes a plurality of sensors and one or more computing devices executing operations including acquiring a plurality of parameter sets each corresponding to a plurality of engine conditions in which each parameter set corresponding to each engine condition indicates a health condition at a plurality of locations at the engine; comparing the plurality of parameter sets to determine a health condition corresponding to a location at the engine; and generating a health condition prediction at the engine based on the compared parameters.

A valving system has an actuator member connected to move with an actuator piston and change the position of a valve member. There is a smaller face fluid chamber acting on a small area piston face, and a larger face fluid chamber acting on a larger face of the actuator piston. The torque motor has an armature and a flapper caused to move by current received at the armature. The flapper moves between two fluid ports to control the pressure in the larger face chamber. The flapper further has a positioning extension engaging a first feedback spring operable between it and a forward face of the actuator piston and providing a spring force in combination with a spring force from the positioning extension. A control is operable to provide current to the armature to control the fluid received in the larger face chamber. The controller is programmed to associate the current supplied to the armature to an actual position of the valve member. A method is also disclosed.