Spider hub Oil transfer sleeve Propeller governor (CSU) Propeller Moves forward from PBA to REV Servo piston (dome) Blade actuating lever Feathering spring Figure 7-49.  Pitch change mechanism.  to reset the beta valve inward, and repeat the process. Move  the reset arm on the CSU rearward by the interconnecting  rod at the same time the blade angle moves toward reverse.  This causes the reset lever and reset post to move down in  the CSU, bringing the reset lever closer to the speeder spring  cup. As propeller speed increases due to the increase in engine  power, the governor counterweights begin to move outwards.  Since the reset lever is closer to the speeder spring cup, the  cup contacts the reset lever before the counterweights would  normally reach the on-speed position (95 percent propeller  speed instead of 100 percent). As the reset lever is pushed up  by the counterweights/speeder spring cup, the Py air bleeds  from the fuel control unit (FCU) which lowers the fuel flow,  engine power, and thus propeller speed. In reverse, propeller  speed remains 5 percent below the selected propeller speed  so that the control valve remains fully open, and only the beta  valve controls the oil flow to the propeller dome. In this mode, the propeller speed is no longer controlled by  changing the blade angle. It is now controlled by limiting  engine power. Bringing the propeller lever to the feather  position causes the speed selection lever on the CSU to  push the feathering valve plunger and allows propeller servo  oil to dump into the reduction gearbox sump. The pressure  loss in the propeller hub causes the feathering spring and  the propeller counterweights to feather the propeller. In the  event of a propeller overspeed not controlled by the propeller  overspeed governor (oil governor), the counterweights in the  propeller governor move outward until the speeder spring cup  contacts the reset lever.  [Figure 7-53]  The movement of the  reset lever around its pivot point opens the Py air passage. Py  bleeds into the reduction gearbox limiting the fuel supply to  the engine. This prevents the propeller/power turbines from  accelerating beyond 106 percent rpm. The oil overspeed governor houses a set of counterweights  connected to a control valve that is driven by a beveled  gear mounted on the propeller shaft.  [Figure 7-54]  The  counterweight’s centrifugal force is acting against two springs:  a speeder spring and a reset spring. When the propeller speed  reaches a specified limit (4 percent over maximum propeller  speed), the governor counterweights lift the control valve and  bleed off propeller servo oil into the reduction gearbox sump,  causing the blade angle to increase. An increase in blade pitch  7-34