control valve assembly 74 shown in fig2 u2013 4 unlike the single stage valve assembly 74 shown in fig2 and 3 flow control valve assembly 374 includes a pilot valve assembly 373 which controls flow via controlling the positioning of a spool valve member 320 like the earlier embodiment flow control valve assembly 374 includes a valve body 321 that includes a top surface with an actuation fluid inlet 360 an actuation fluid drain 362 and an actuation fluid passage 380 spool valve member 320 includes a biasing hydraulic surface 322 always exposed to fluid pressure inlet 360 and a control hydraulic surface 324 exposed to fluid pressure in a pressure control chamber 331 hydraulic surfaces 322 and 324 are preferably about equal in effective area such that spool valve member 320 is substantially hydraulically balanced when the fluid pressure acting on the opposite ends is equal this is facilitated by spool valve member 320 including a pressure communication passage 327 spool valve member 320 also includes a low pressure annulus 326 that connects actuation fluid passage 380 to actuation fluid drain 362 when spool valve member 320 is biased to its drain position as shown by biasing spring 330 when pressure in control chamber 331 is low fluid pressure on surface 322 moves spool valve member 320 to its actuation position compressing spring 330 and moving annulus and radial passages 325 to communicate fluid from actuation fluid inlet 360 to actuation fluid passage 380 at the same time annulus 326 moves out of fluid communication with actuation fluid passage 380 pressure in control chamber 331 is controlled by pilot valve assembly 373 pilot.