Abstract: In accordance with at least one aspect of this disclosure, a fluid system of an aircraft includes a primary fluid conduit that conveys a primary fluid, and a leak detection system disposed around at least a portion of the primary fluid conduit and forming one or more detection volumes. The leak detection system determines whether there is a primary fluid leak into the one or more detection volumes by sensing a pressure change in the one or more detection volumes.

Abstract: A multi-rotor electric machine having a stator, a first rotor magnetically coupled to the stator and a second rotor magnetically coupled to the stator is disclosed. A method of operating the electric machine comprises driving a gear via a first face of the gear using the first rotor and driving the gear via a second face of the gear using the second rotor.

Abstract: Methods and systems for measuring an axial position of a rotating component of an engine are described herein. The method comprises obtaining a signal from a sensor coupled to the rotating component, the rotating component having a plurality of position markers distributed about a surface thereof, the position markers having an axially varying characteristic configured to cause a change in a varying parameter of the signal as a function of the axial position of the rotating component. Based on the signal, the method comprises determining a rotational speed of the rotating component from the signal, determining the varying parameter of the signal, and finding the axial position of the rotating component based on a known relationship between the axial position, the rotational speed, and the varying parameter of the signal.

Abstract: An electric apparatus is provided that includes a fiber optic system and an electric conductor. The fiber optic system includes an inner cladding, an outer cladding and a fiber optic core between the inner cladding and the outer cladding. The electric conductor extends longitudinally along a centerline within the fiber optic system. The centerline may be a centerline of any one or more or all of the fiber optic system, the inner cladding, the outer cladding, the fiber optic core and/or the electric conductor.

Abstract: In accordance with at least one aspect of this disclosure, there is provided a fuel system for a gas turbine engine of an aircraft, including a main inlet feed conduit fluidly connected to a primary manifold feed conduit and a secondary manifold feed conduit. A primary manifold fluidly connects the primary manifold feed conduit to a plurality of primary fuel injectors, and a secondary manifold fluidly connects the secondary manifold feed conduit to a plurality of secondary fuel injectors.

Abstract: A multi-rotor electric machine having a stator, a first rotor magnetically coupled to the stator and a second rotor magnetically coupled to the stator is disclosed. A method of operating the electric machine comprises driving a gear via a first face of the gear using the first rotor and driving the gear via a second face of the gear using the second rotor.

Abstract: A system and method for measuring a speed of an engine are provided. The engine has a positive displacement pump drivingly connected to a rotor shaft thereof, the pump having an inlet for receiving a fluid supply and an outlet for outputting pressurized fluid. A sensor signal is received from a pressure sensing device provided at an inlet of the pump, the sensor signal comprising a series of periodic oscillations. A frequency of the oscillations is determined, the frequency proportional to a rotational speed of the rotor shaft. The speed of the engine is then determined from the frequency of the oscillations and the speed of the engine as determined is output for controlling operation of the engine.

Abstract: A flowmeter for gaseous fluid includes a conduit composed of non-electrically conductive material for passage of an ionized flow of the gaseous fluid therethrough. The flowmeter further includes an electromagnetic sensor arranged to measure a magnetic field generated about the conduit by the passage of the ionized flow and generate a signal proportional to the magnetic field.

Abstract: A multi-rotor electric machine having a stator, a first rotor magnetically coupled to the stator and a second rotor magnetically coupled to the stator is disclosed. A method of operating the electric machine comprises driving a gear via a first face of the gear using the first rotor and driving the gear via a second face of the gear using the second rotor.

Abstract: The magnetic chip detector system can have a first conductor member and a second conductor member both exposed to a liquid flow path and separated from one another by gap, each one of the conductor members having a magnetic field oriented into the liquid flow path, at least a first one of the magnetic fields being actively modifiable; an electrical energy source configured to induce a current circulation across the gap; and a meter configured to measure a response of the gap to the induced current circulation.

Abstract: There is provided a fluid level sensing device for monitoring a fluid level in an engine container. The fluid level sensing device comprises a floating device moveable in response to changes in the fluid level, the floating device including a magnetic element, and a sensing circuit comprising at least one solid state magnetic sensor and at least one transistor electrically connected to the at least one solid state magnetic sensor. The magnetic element is configured to activate the at least one solid state magnetic sensor when the floating device is proximate thereto, the at least one solid state magnetic sensor configured to, when activated, drive the at least one transistor to generate a sensing signal indicative of the fluid level.

Abstract: In accordance with at least one aspect of this disclosure, a fluid system of an aircraft includes a primary fluid conduit that conveys a primary fluid, and a leak detection system disposed around at least a portion of the primary fluid conduit and forming one or more detection volumes. The leak detection system determines whether there is a primary fluid leak into the one or more detection volumes by sensing a pressure change in the one or more detection volumes.

Abstract: In accordance with at least one aspect of this disclosure, a fluid system of an aircraft includes a primary fluid conduit that conveys a primary fluid, and a leak detection system disposed around at least a portion of the primary fluid conduit and forming one or more detection volumes. The leak detection system determines whether there is a primary fluid leak into the one or more detection volumes by sensing a pressure change in the one or more detection volumes.

Abstract: A gas turbine engine can have a magnetic chip detector system with a first conductor member and a second conductor member both exposed to a lubricant flow path of the gas turbine engine, at least a first one of the conductor members including an electromagnet including a coil wrapped around a ferromagnetic core. As part of an engine shutdown procedure, an intrinsic magnetic field strength within the ferromagnetic core can be increased by circulating electrical current in the coil, and the electrical current circulation can then be interrupted for the magnetic field to remain active during engine shutdown.

Abstract: Systems and methods for monitoring a pressure transducer are described. The method comprises sampling an output signal of a pressure transducer to obtain a plurality of pressure measurements as recorded by the pressure transducer, comparing the pressure measurements to a first pressure exposure limit associated with the pressure transducer, and recording data related to exposure of the pressure transducer to the first pressure exposure limit.

Abstract: Methods and systems of operating a gas turbine engine in a low-power condition are provided. In one embodiment, the method includes supplying fuel to a combustor by supplying fuel to a first fuel manifolds and a second fuel manifold of the gas turbine engine. The method also includes, while supplying fuel to the combustor by supplying fuel to the first fuel manifold: stopping supplying fuel to the second fuel manifold; and using a pump to drive gas into the second fuel manifold to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated fuel nozzles.

Abstract: Methods and systems for measuring an axial position of a rotating component of an engine are described herein. The method comprises obtaining a signal from a sensor coupled to the rotating component, the rotating component having a plurality of position markers distributed about a surface thereof, the position markers having an axially varying characteristic configured to cause a change in a varying parameter of the signal as a function of the axial position of the rotating component. Based on the signal, the method comprises determining a rotational speed of the rotating component from the signal, determining the varying parameter of the signal, and finding the axial position of the rotating component based on a known relationship between the axial position, the rotational speed, and the varying parameter of the signal.

Abstract: Methods and systems for measuring an axial position of a rotating component of an engine are described herein. The method comprises obtaining a signal from a sensor coupled to the rotating component, the rotating component having a plurality of position markers distributed about a surface thereof, the position markers having an axially varying characteristic configured to cause a change in a varying parameter of the signal as a function of the axial position of the rotating component. Based on the signal, the method comprises determining a rotational speed of the rotating component from the signal, determining the varying parameter of the signal, and finding the axial position of the rotating component based on a known relationship between the axial position, the rotational speed, and the varying parameter of the signal.

Abstract: A method for operating a glow plug includes controlling a temperature of the glow plug by switching between applying a voltage VH and applying a voltage VN<VH to the glow plug. Applying the voltage VH and applying the voltage VN causes a glow plug current to oscillate about a glow plug current threshold. The glow plug current threshold is associated with one of the voltage VH and the voltage VN. The method includes monitoring the glow plug current at the one of the voltage VH and the voltage VN.

Abstract: Methods and Systems for health-monitoring of a multi-channel pressure transducer of a gas turbine engine are described. The method comprises monitoring a deviation between a first channel and a second channel of a multi-channel pressure transducer over time, determining a rate of change of the deviation, extrapolating a trend over time based on the rate of change of the deviation to predict when the deviation will reach a threshold, and triggering a maintenance action for the pressure transducer based on the trend.