| CPC F02D 29/02 (2013.01) [B64C 11/385 (2013.01); B64C 11/40 (2013.01); B63H 3/10 (2013.01); F02B 61/045 (2013.01)] | 16 Claims |

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1. A propeller controller comprising:
at least one electrohydraulic servovalve operable to selectively allow a flow of hydraulic fluid to or from a propeller dome;
a pitch lock valve selectively fluidly coupling the propeller dome to an inlet port of the at least one electrohydraulic servovalve, the pitch lock valve having an inlet fluidly coupled to the propeller dome and a set of outlets including a first outlet, a second outlet, and a third outlet, the pitch lock valve including a valve body moveable between a first position, wherein the first outlet and the second outlet are fluidly coupled with the inlet and a second position, wherein the third outlet is fluidly coupled to the inlet, and wherein, during an oil starvation condition, the pitch lock valve is configured to fluidly uncouple the propeller dome from the inlet port of the at least one electrohydraulic servovalve; and
a solenoid valve fluidly coupled between the third outlet and a drain line and operable to selectively open and close a flow of hydraulic fluid through the drain line.
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