A fuel supply system for a turbomachine, comprising a fuel circuit comprising pressurizer at the output of the circuit, a pump arranged to send into the circuit a fuel flow rate which is an increasing function of the rotational speed of a shaft of the pump, and a control circuit arranged to control the device to comply with a flow rate setpoint at the output of the fuel circuit. The system further comprises a feedforward corrector circuit configured to calculate an increment of the flow rate setpoint as a function of the engine speed of the turbomachine and of a variation in the engine speed of the turbomachine, and to add this increment to the flow rate setpoint. A method of regulating the pump is also described.

A gas turbine engine including a first rotor assembly comprising a first drive shaft extended along a longitudinal direction; a housing coupled to the first rotor assembly to provide rotation of the first rotor assembly around an axial centerline; a first accessory assembly, wherein the first accessory assembly sends and/or extracts energy to and from the first rotor assembly; and a first clutch assembly disposed between the first rotor assembly and the first accessory assembly. The first clutch assembly engages and disengages the first rotor assembly to and from the first accessory assembly.

A thrust reverser actuation system for a jet propulsion engine for a vehicle, the thrust reverser actuation system comprising: a plurality of hydraulically-driven thrust reverser actuators for actuating one or more thrust reverser components of the jet propulsion engine, each actuator comprising: a hydraulic circuit; and a bi-directional electrically-driven pump configured to pump hydraulic fluid through the hydraulic circuit, wherein the hydraulic circuit and the pump are configured such that the direction of the pump dictates the direction of the actuation of the actuator.

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 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 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 starter assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a fluid-actuated starter coupled to a spool, and a controller operable to cause a reduction in torque output of the starter in response to determining that a first threshold is met. The first threshold relates to an engine operational condition. A method for starting a gas turbine engine is also disclosed.

The subject matter of this specification can be embodied in, among other things, an actuator apparatus includes an output member configured to actuate between a first positional configuration and a second positional configuration, a source fluid reservoir, a fluid velocity resistor configured to provide a predetermined resistance to fluid flow, a fluid velocity fuse configured to flow fluid flows having a first predetermined range of fluid velocities and to block fluid flows having second predetermined range of fluid velocities, and a fluid actuator assembly configured to urge fluid flow from the source fluid reservoir through the fluid velocity resistor and the fluid velocity fuse based on actuation of the output member.

A nacelle may include a track lock for a thrust reverser. The track lock may comprise a track lock blade which prevents the thrust reverser from accidentally deploying. The track lock blade may comprise a pressurized blade chamber which receives hydraulic fluid through a bore in a piston. In the event of failure of the track lock blade, the hydraulic fluid may leak from the track lock blade and be apparent upon visual inspection.

A system for controlling the geometry of a variable geometry compressor. The system having: a mechanical linkage operable to vary the compressor geometry; a first fluid-powered actuator arranged to operate the linkage and configured to be powered by a pressurised supply of an incompressible fluid; and a second fluid-powered actuator arranged to operate the linkage and configured to be powered by a pressurised supply of a compressible fluid. Wherein the first and second actuators are further arranged to operate in combination on the mechanical linkage such that a first actuator force exerted by the first actuator on the mechanical linkage sums with a second actuator force exerted by the second actuator on the mechanical linkage.