The method can include: monitoring a current value of a rate of reduction of torque of the shaft; providing a threshold value for the rate of reduction of torque of the shaft; and generating a signal indicative of the shaft shear event when the current value exceeds the threshold value.

Electric aircraft power plants and associated methods are provided. One power plant includes an emergency power unit (EPU) for providing electric power in the event of a malfunction of a battery pack of an electric aircraft to permit the electric aircraft to make an emergency maneuver. The EPU includes a rocket engine for generating a stream of exhaust fluid using a rocket propellant, a turbine operatively connected to extract energy from the stream of exhaust fluid generated by the rocket engine, and an electric generator operatively connected to be driven by the turbine and to supply electric power to an electric motor propelling the electric aircraft.

A method may include monitoring, by a controller, operation of a pump of at least one hydraulic fracturing rig during ramp-up of the pump. Each of the at least one hydraulic fracturing rig may further include an engine and a transmission. The method may further include detecting, by the controller, an issue in the operation of the pump based on the monitoring of the operation and performing an action based on the detecting of the issue.

A fuel flow system for a gas turbine engine includes a fuel inlet to admit a flow of fuel into the fuel flow system and a fuel outlet to direct the flow of fuel to the gas turbine engine from the fuel flow system. One or more pumps are positioned along a fuel flow path connecting the fuel inlet to the fuel outlet. A metering valve is in flow communication with the one or more pumps to meter the flow of fuel. A minimum pressure shut-off valve is fluidly connected to the one or more pumps, and a shutoff apparatus configured to permit selective energizing to stop the flow of fuel from the fuel outlet without operation of the metering valve.

A fuel flow system for a gas turbine engine includes a fuel inlet to admit a flow of fuel into the fuel flow system and a fuel outlet to direct the flow of fuel to the gas turbine engine from the fuel flow system. One or more pumps are positioned along a fuel flow path connecting the fuel inlet to the fuel outlet. A metering valve is in flow communication with the one or more pumps to meter the flow of fuel. A minimum pressure shut-off valve is fluidly connected to the one or more pumps, and a shutoff apparatus configured to permit selective energizing to stop the flow of fuel from the fuel outlet without operation of the metering valve.

A failure detection method and system for a propeller control unit coupled to a propeller are provided. An actual value of a blade angle and/or a rotational speed of the propeller are obtained. A comparison between the actual value and a threshold is performed. In response to determining, based on the comparison, that the actual value exceeds the threshold, the propeller control unit is caused to adjust the blade angle to bring the blade angle and/or the rotational speed towards the threshold. A subsequent actual value of the blade angle and/or the rotational speed is obtained. From the subsequent value, it is determined whether the blade angle and/or the rotational speed has been brought towards the threshold. In response to determining that the blade angle and/or the rotational speed has failed to be brought towards the threshold, failure of the propeller control unit is detected and an alert is output.

A system and method for controlling an aircraft turbine engine. The control system includes: a nominal-mode processing chain including a global corrector designed to control a speed of rotation of the turbine engine by delivering a position setpoint for a fuel metering device, and a local corrector designed to control a position of the fuel metering device by delivering a nominal-mode control current, a degraded-mode processing chain including a direct corrector designed to control the speed of rotation of the turbine engine by delivering a degraded-mode control current, and a mode management module designed to deliver, to the fuel metering device, the nominal-mode control current in the absence of failure of a position sensor measuring a position of the fuel metering device, and the degraded-mode control current in the case of failure of the position sensor.

A face seal assembly includes a seal carrier, a seal element supported by the seal carrier, a rotating seal plate interactive with the seal element to define a face seal, and a seal arrester configured to engage the seal carrier at a predetermined amount of wear of the seal element to stop wear of the seal element.

A method for operating a power plant, having at least one gas turbine engine and at least one fuel gas compressor, includes supplying fuel gas through a utility supply line, compressing the fuel gas to a plant supply pressure in the operating fuel gas compressor, and supplying the compressed fuel gas to a plant supply line. The gas turbine engine is operated at a set power output according to a power demand signal. If a failure of an operating fuel gas compressor is detected, the power output of the gas turbine engine is reduced to an emergency power output (which is lower than the set power output), and the power output of the gas turbine engine is restricted to the emergency power output. The reduction of the power output is performed in one single step and is controlled by at least one feedforward control signal.

A computer implemented method for detecting a damage to a gas turbine engine. The gas turbine engine includes a fan and a plurality of turbine stages including a low pressure turbine stage. The fan is drivably coupled to the low pressure turbine stage. The method includes receiving a first signal indicative of a speed of rotation of the fan. The method further includes receiving a second signal indicative of a speed of rotation of the low pressure turbine stage. The method further includes determining a difference metric representative of a difference between the speed of rotation of the fan and the speed of rotation of the low pressure turbine stage. The method further includes determining whether a damage event has occurred based on whether the difference metric passes a threshold.