Abstract: An aircraft engine comprises an engine case, the engine case flange(s). A harness of wires extends in proximity to the engine case. The harness of wires includes two or more metal shield sleeves externally covering a bundle of wires in a longitudinal direction, the metal shield sleeves being at least partially electrically insulated from one another. A conductive contact between the at least one flange and at least one of the metal shield sleeve.

Abstract: Methods and systems for starting an aircraft propulsion engine are described herein. Operation of the engine is controlled by an engine controller having a first channel and a second channel. An engine start request is received on the second channel while the first channel is inactive. It is determined which one of the first channel and the second channel was used to conduct a last successful engine start. Responsive to determining that the last successful engine start was conducted on the second channel, a predetermined time period is waited to elapse and for the first channel to reinitialize before commanding, via the first channel, an engine start based on the engine start request.

Abstract: Methods and systems for feathering a propeller are described herein. A solenoid is configured to cause a propeller to feather when the solenoid is energized. An electronic controller is connected to the solenoid through a first electrical connection for energizing the solenoid to feather the propeller. A secondary mechanism is connected to the solenoid through a second electrical connection for energizing the solenoid to feather the propeller. The second electrical connection is independent from the first electrical connection.

Abstract: Methods and systems for starting an aircraft propulsion engine are described herein. Operation of the engine is controlled by an engine controller having a first channel and a second channel. An engine start request is received on the second channel while the first channel is inactive. It is determined which one of the first channel and the second channel was used to conduct a last successful engine start. Responsive to determining that the last successful engine start was conducted on the second channel, a predetermined time period is waited to elapse and for the first channel to reinitialize before commanding, via the first channel, an engine start based on the engine start request.

Abstract: An aircraft engine comprises an engine case, the engine case flange(s). A harness of wires extends in proximity to the engine case. The harness of wires includes two or more metal shield sleeves externally covering a bundle of wires in a longitudinal direction, the metal shield sleeves being at least partially electrically insulated from one another. A conductive contact between the at least one flange and at least one of the metal shield sleeve.

Abstract: There is described herein methods and systems for detecting electrically-conductive particles (chips) in fluid of an aircraft engine. The method comprises applying a plurality of excitation currents Ii across a magnetic chip detector mounted to a fluid system of the aircraft engine and measuring a corresponding plurality of resistance values Ri, where i is an integer that varies from 1 to N, and where N corresponds to a number of different excitation currents applied across the magnetic chip detector. The method further comprises determining a chip size indication Y from the plurality of resistance values Ri, and detecting a chip in the fluid when the chip size indication Y exceeds a threshold Ythres.

Abstract: There is described herein methods and systems for detecting electrically-conductive particles (chips) in fluid of an aircraft engine. The method comprises applying a plurality of excitation currents Ii across a magnetic chip detector mounted to a fluid system of the aircraft engine and measuring a corresponding plurality of resistance values Ri, where i is an integer that varies from 1 to N, and where N corresponds to a number of different excitation currents applied across the magnetic chip detector. The method further comprises determining a chip size indication Y from the plurality of resistance values Ri, and detecting a chip in the fluid when the chip size indication Y exceeds a threshold Ythres.

Abstract: The present disclosure relates combustor configurations for a gas turbine engine. In one embodiment, a combustor includes a combustor shell enclosing a first area of free space, and an igniter for the combustor shell, the igniter including a distal end. The combustor also includes one or more elements configured to retain the igniter and to interface with the combustor shell, wherein the igniter is retained that the distal end of the igniter is recessed from the first area of free space. According to another embodiment, a combustor configuration may include one or more elements configured to retain an igniter and interface with the combustor shell, wherein the one or more elements define a boundary between the combustor shell and one or more elements, and wherein the igniter is retained within the one or more elements such that the distal end of the igniter is recessed from the boundary.

Abstract: The present disclosure relates combustor configurations for a gas turbine engine. In one embodiment, a combustor includes a combustor shell enclosing a first area of free space, and an igniter for the combustor shell, the igniter including a distal end. The combustor also includes one or more elements configured to retain the igniter and to interface with the combustor shell, wherein the igniter is retained that the distal end of the igniter is recessed from the first area of free space. According to another embodiment, a combustor configuration may include one or more elements configured to retain an igniter and interface with the combustor shell, wherein the one or more elements define a boundary between the combustor shell and one or more elements, and wherein the igniter is retained within the one or more elements such that the distal end of the igniter is recessed from the boundary.

Abstract: Methods and associated devices useful for the health monitoring of igniters of gas turbine engines are disclosed. Exemplary embodiments disclosed include the use of an accumulated spark count to an igniter to obtain an indication of wear on the igniter and/or the remaining life of the igniter. An exemplary method disclosed includes: receiving one or more signals indicative of a commanded spark count to the igniter for one or more ignition events; processing the one or more signals indicative of the commanded spark count to the igniter, determining a total accumulated commanded spark count to the igniter; and generating one or more signals indicative of at least one of an estimated wear on the igniter or an estimated remaining life of the igniter based on the total accumulated commanded spark count to the igniter.

Abstract: Methods and associated devices useful for the health monitoring of igniters of gas turbine engines are disclosed. Exemplary embodiments disclosed include the use of an accumulated spark count to an igniter to obtain an indication of wear on the igniter and/or the remaining life of the igniter. An exemplary method disclosed includes: receiving one or more signals indicative of a commanded spark count to the igniter for one or more ignition events; processing the one or more signals indicative of the commanded spark count to the igniter, determining a total accumulated commanded spark count to the igniter; and generating one or more signals indicative of at least one of an estimated wear on the igniter or an estimated remaining life of the igniter based on the total accumulated commanded spark count to the igniter.

Abstract: Embodiments of the present invention enable a feedback-based VCO linearization technique. Embodiments include a frequency locked loop formed by feeding back a VCO's output into the VCO's input in negative phase by means of a frequency-to-voltage (F/V) converter. Embodiments enable constant VCO gain over a wide input tuning range and across PVT variations. Further, embodiments can be nested within a PLL, for example, with negligible area and power consumption overhead.

Abstract: A light fixture comprising a light emitting device, a first electrical path suitable for connecting the light emitting device to a first power circuit, a second electrical path suitable for connecting the light emitting device to a second power circuit and a connector element for acquiring a selected one of a first configuration and a second configuration. Wherein in the first configuration, the light emitting device is in electrical communication with the first electrical path for being powered by the first power circuit and in the second configuration, the light emitting device is in electrical communication with the second electrical path for being powered by the second power circuit.

Abstract: Embodiments of the present invention enable a feedback-based VCO linearization technique. Embodiments include a frequency locked loop formed by feeding back a VCO's output into the VCO's input in negative phase by means of a frequency-to-voltage (F/V) converter. Embodiments enable constant VCO gain over a wide input tuning range and across PVT variations. Further, embodiments can be nested within a PLL, for example, with negligible area and power consumption overhead.

Abstract: Embodiments of the present invention enable a feedback-based VCO linearization technique. Embodiments include a frequency locked loop formed by feeding back a VCO's output into the VCO's input in negative phase by means of a frequency-to-voltage (F/V) converter. Embodiments enable constant VCO gain over a wide input tuning range and across PVT variations. Further, embodiments can be nested within a PLL, for example, with negligible area and power consumption overhead.

Abstract: Embodiments of the present invention enable a feedback-based VCO linearization technique. Embodiments include a frequency locked loop formed by feeding back a VCO's output into the VCO's input in negative phase by means of a frequency-to-voltage (F/V) converter. Embodiments enable constant VCO gain over a wide input tuning range and across PVT variations. Further, embodiments can be nested within a PLL, for example, with negligible area and power consumption overhead.