In accordance with at least one aspect of this disclosure, a pump selector system can include a primary pump fluidly connected to provide a primary flow to a fluid destination, a secondary pump fluidly connected to provide a secondary flow to the fluid destination, and a selector valve disposed downstream of the primary pump and the secondary pump. The selector valve can be configured to toggle between a first position configured to allow flow from the primary pump to flow to the fluid destination and to block flow from the secondary pump to the fluid destination, and a second position configured to allow flow from the secondary pump to flow to the fluid destination and to block flow from the primary pump to the fluid destination.

A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

A speed control system and a power load balance detector for a turbine is provided. The speed control system includes a speed wheel with a plurality of teeth. A timer stores a time stamp when each of the teeth passes by a speed probe. A first speed estimate is determined for overspeed protection, and a second speed estimate is determined for operational speed control. The power load balance detector trips or shuts down the turbine when an unbalance is above a first threshold and the speed of the turbine is above a second threshold.

When a combination of a vane type of a stator vane and a vane type of a stator vane for one straightening plate is the same as a combination of a vane type of a stator vane and a vane type of a stator vane for the other straightening plate, positions of the first straightening plate side connection portions and the second straightening plate side connection portions of the one straightening plate and the other straightening plate are the same as each other. When the combinations are different from each other, at least one of the positions of the first straightening plate side connection portions of the one straightening plate and the other straightening plate and the positions of the second straightening plate side connection portions of the one straightening plate and the other straightening plate are different from each other.

A fuel and oil system comprising a fuel pump; an oil pump. A first electric motor controller configured to supply a variable electrical drive. A second electric motor controller configured to supply a variable electrical drive. A fixed electrical drive. The fuel pump is selectively connected to and driven by the first electric motor controller or the second electric motor controller. The oil pump is selectively connected to and driven by the second electric motor controller or the fixed electrical drive.

A turbine apparatus is disclosed including a first article and a second article disposed between the first article and a hot gas path of a turbine. The first article includes at least one first article cooling channel in fluid communication with and downstream from a cooling fluid source, and the second article includes at least one second article cooling channel in fluid communication with and downstream from the at least one first article cooling channel. A method for redundant cooling of the turbine apparatus is disclosed including flowing a cooling fluid from the cooling fluid source through at least one first article cooling channel, exhausting the cooling fluid from the at least one first article cooling channel into at least one second article cooling channel, and flowing the cooling fluid through the at least one second article cooling channel.

A method includes obtaining a first test matrix for a first aircraft system and a second test matrix for a second aircraft system. The method also includes, during a first operational test of the first test matrix, obtaining sensor data that includes second sensor data that is not specified by the first test matrix. The method includes evaluating a second operational test of the second test matrix by processing the second sensor data using a second analytic model of the second aircraft system. The method also includes generating second predicted sensor data based on the evaluation of the second operational test. The method includes generating a second error measure by comparing a second subset of the sensor data to the second predicted sensor data. The method includes determining, based at least in part on a range of the second sensor data, a test coverage metric of the second test matrix.

A burner head for a fuel manifold. The burner head has: a mains fuel injector; a pilot fuel injector; a fuel source; a first isolation valve connected to the fuel source; and a staging valve. The staging valve is connected to the first isolation valve, and the staging valve has a mains fuel conduit connected to the mains fuel injector and a pilot fuel conduit connected to the pilot fuel injector. The first isolation valve and the staging valve are connected in series, such that fuel from the fuel source must pass through the first isolation valve before arriving at the staging valve.

A fuel leak detection system for hydrogen fuel system including a monitored component. The fuel leak detection system including a sensor and controller communicatively coupled to the sensor. The sensor is positioned to monitor at least a portion of the monitored component. The sensor is configured (i) to sense a parameter corresponding to a hydrogen fuel leak of the monitored component and (ii) to generate an output. The controller is configured (i) to receive the output of the sensor, (ii) to determine, based on the output of the sensor, if a leak has occurred in the monitored component, and (iii) to generate an output indicating a fuel system leak when the controller determines that the leak has occurred in the monitored component. The monitored component may be a component of one of a fuel tank, a power generator, and a fuel delivery assembly.

An actuation system is provided for varying the pitch of the blades of a variable pitch fan or propeller. The actuation system includes a first actuator and a second actuator. The actuation system further includes a first linkage which operably connects the first actuator to the blades such that operation of the first actuator varies the pitch of the blades via the first linkage. The actuation system further includes a second linkage which operably connects the second actuator to the first actuator such that operation of the second actuator varies the pitch of the blades by series connection of the second linkage to the first linkage.