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 are described a system and method for operating a thrust reverser of an aircraft engine, the thrust reverser having a deployed state and a stowed state. The method comprises placing the thrust reverser in the stowed state when the thrust reverser is in the deployed state, a thrust lever associated with the engine is in a forward position, and the engine is rotating at a speed below an idle speed, wherein hydraulic pressure for stowing the thrust reverser is provided by a pump driven by the engine rotating at the speed below the idle speed.

Methods, apparatus, systems, and articles of manufacture are disclosed for a variable bleed valve assembly. An example variable bleed valve assembly a variable bleed valve (VBV) door corresponding to a bleed port and a first unison ring, the VBV door coupled to the first unison ring, the first unison ring to move in a circumferential direction between a first position and a second position causing the VBV door to move between the first position and the second position.

A braking system including a brake actuator, a control valve, a control assembly, and at least one pressure sensor. The control valve is disposed to direct hydraulic fluid to the brake actuator at a rate corresponding to a magnitude of a control signal. The control assembly includes a mixed-mode control system. The at least one pressure sensor is configured to measure a pressure of the hydraulic fluid to the brake actuator. The control assembly is configured to determine a position of the brake actuator. The mixed-mode control system is configured to determine a position command and a pressure command. The mixed-mode control system is configured to adjust the magnitude of the control signal based on at least one of the position command and the pressure command so as to reposition the brake actuator from a first position to a second position.

A system for use in servicing a machine. The system includes a tubular body including a longitudinal axis, a tip end, a dispensing nozzle defined at the tip end, and an interior channel in flow communication with the dispensing nozzle. The tubular body is configured to be flexible. An actuator is configured to selectively modify an orientation of the tubular body, and a reservoir is in flow communication with the interior channel. The reservoir is configured to supply a maintenance fluid to the tubular body for discharge from the dispensing nozzle.

A hydraulic motor-driven fuel boost pump includes redundant safeguards against overspeeding the impellers. A flow limiter limits the amount of hydraulic fluid that can be supplied to the hydraulic motor, thereby limiting the torque that can be applied to the impellers. A control valve also transitions between a non-restrictive operating state and a restrictive operating state. In the restrictive operating state the control valve regulates the displacement of the swash plate when in the non-restrictive operating state. The control valve does not counter the bias of the swash plate control spring when in the restrictive operating state.

A system for modulating airflow into a bore defined by a rotor of a gas turbine engine defining an axial direction, a circumferential direction, and a radial direction is provided. The system includes a movable member positioned forward of a first stage of rotor blades of the rotor. The movable member is movable between at least a first position and a second position to modulate airflow into the bore via a plurality of opening in fluid communication with the bore.

The subject matter of this specification can be embodied in, among other things, an engine assembly includes a nacelle configured to at least partially surround an engine, and a thrust reverser coupled to the nacelle, the thrust reverser having a thrust-reversing element movable relative to the nacelle between a stowed position and a deployed position, a hydraulic actuator operably coupled to move the thrust-reversing element between the stowed position and the deployed position, and a fluid control system configured to operate the hydraulic actuator, the fluid control system having an electrohydraulic servo valve operable to selectively route fluid between a pressurized fluid source, the hydraulic actuator, and a fluid return reservoir, and a bypass fluid line providing fluid communication between the hydraulic actuator and the fluid return reservoir independent of the electrohydraulic servo valve.

Locking actuators for thrust reverser actuation systems, engines and aircraft including the same, and associated methods. A locking actuator includes an actuator housing, an extension element, and a lock assembly. The extension element is configured to translate along an actuator axis to transition between a retracted state and an extended state. The lock assembly transitions between a locked state and an unlocked state independent of transitioning the extension element between the retracted and extended states. In examples, a thrust reverser actuation system includes an actuator assembly with the locking actuator and a hydraulic control assembly. In examples, an engine includes a thrust generator, a nacelle, a transcowl, and the thrust reverser actuation system. In examples, a method of operating a thrust reverser actuation system includes transitioning a lock assembly from a locked state to an unlocked state and transitioning an extension element from a retracted state to an extended state.

A system for use in servicing a machine. The system includes a tubular body including a longitudinal axis, a tip end, a dispensing nozzle defined at the tip end, and an interior channel in flow communication with the dispensing nozzle. The tubular body is configured to be flexible. An actuator is configured to selectively modify an orientation of the tubular body, and a reservoir is in flow communication with the interior channel. The reservoir is configured to supply a maintenance fluid to the tubular body for discharge from the dispensing nozzle.