Methods and systems for governing an aircraft propeller of an engine are described. The method comprises obtaining a fluid flow command for speed control of the propeller, determining pulse parameters of a pulse width modulated valve control signal for actuating a two-position solenoid valve in accordance with the fluid flow command based on an average fluid flow through the solenoid valve and an opening and closing time of the solenoid valve, generating the valve control signal with the pulse parameters as determined, and transmitting the valve control signal to the solenoid valve for actuating the solenoid valve, thereby controlling the speed of the propeller.

There is described herein the automation of propeller feather testing functions, whereby the test is automatically performed and a pass/fail signal is issued upon completion.

Methods and systems for validating a propeller control unit associated with a propeller having blades are provided. Actuation of a control valve of the propeller control unit is commanded to alter a pitch angle of the blades. One of an actual pitch angle of the blades and an actual rotational speed of the propeller is determined after a predetermined time delay has elapsed. The one of the actual pitch angle of the blades and the actual rotational speed of the propeller is compared to a corresponding one of a pitch angle threshold and a rotational speed threshold, the pitch angle threshold and the rotational speed threshold based on a commanded pitch angle. A warning signal is issued in response to determining one of the actual pitch angle failing to meet the pitch angle threshold and the actual rotational speed failing to meet the rotational speed threshold.

There is provided an hydraulic actuation system for an aircraft, the hydraulic actuation system includes an actuator (A), a primary actuation arrangement to provide hydraulic fluid to control the actuator (A), wherein the hydraulic actuation system is configured to detect a fault in the actuator (A). The hydraulic actuation system also includes a secondary actuation arrangement to provide hydraulic fluid to control the actuator (A) in response to a detection of a fault in the actuator (A).

There is provided an hydraulic actuation system for an aircraft, the hydraulic actuation system includes an actuator (A), a primary actuation arrangement to provide hydraulic fluid to control the actuator (A), wherein the hydraulic actuation system is configured to detect a fault in the actuator (A). The hydraulic actuation system also includes a secondary actuation arrangement to provide hydraulic fluid to control the actuator (A) in response to a detection of a fault in the actuator (A).

A propeller control unit (PCU) has: a pitch angle actuator; a valve operable to selectively fluidly connect the pitch angle actuator with a source of oil for controlling pitch angles of blades of a propeller and with a drain line for draining oil out of the pitch angle actuator for feathering the blades; and a bypass line having an inlet hydraulically between the valve and an inlet of the drain line, the bypass line having an outlet hydraulically between the inlet of the drain line and an outlet of the drain line.

A propeller control unit (PCU) has: a pitch angle actuator; a valve operable to selectively fluidly connect the pitch angle actuator with a source of oil for controlling pitch angles of blades of a propeller and with a drain line for draining oil out of the pitch angle actuator for feathering the blades; and a bypass line having an inlet hydraulically between the valve and an inlet of the drain line, the bypass line having an outlet hydraulically between the inlet of the drain line and an outlet of the drain line.

A variable pitch propeller assembly operatively coupled with an engine and methods for controlling the pitch of a plurality of propeller blades thereof is provided. In one example aspect, the variable pitch propeller assembly includes features for combining overspeed, feathering, and reverse functionality in a single secondary control valve. The secondary control valve is operable to selectively allow a controlled amount of hydraulic fluid to flow to or from a pitch actuation assembly such that the pitch of the propeller blades can be adjusted to operate the variable pitch propeller assembly in one of a constant speed mode, a feather mode, and a reverse mode.

A variable pitch propeller assembly operatively coupled with an engine and methods for controlling the pitch of a plurality of propeller blades thereof is provided. In one example aspect, the variable pitch propeller assembly includes features for combining overspeed, feathering, and reverse functionality in a single secondary control valve. The secondary control valve is operable to selectively allow a controlled amount of hydraulic fluid to flow to or from a pitch actuation assembly such that the pitch of the propeller blades can be adjusted to operate the variable pitch propeller assembly in one of a constant speed mode, a feather mode, and a reverse mode.

There is provided a method and a system for detecting and mitigating a propeller failure condition. An actual value of a rotational speed of the propeller and/or of a pitch angle of blades of the propeller is obtained. In response to determining that the speed is below a reference rotational speed for the propeller and/or determining that the pitch angle is above a pitch angle threshold, an actuator operatively connected to the blades is commanded to decrease the pitch angle to increase the speed towards the reference speed. After commanding of the actuator to decrease the pitch angle, a subsequent value of the speed and/or a subsequent value of the pitch angle is obtained. The actuator is commanded to hold the pitch angle in response to determining that the speed has failed to increase towards the reference speed and/or determining that the pitch angle has failed to decrease.