Abstract: Aircraft power plants and associated methods are provided. A method for driving a load on an aircraft includes: transferring motive power from an internal combustion (IC) engine to the load; discharging a flow of first exhaust gas from the IC engine when transferring motive power from the IC engine to the load; receiving the flow of first exhaust gas from the IC engine into a combustor; mixing fuel with the first exhaust gas in the combustor and igniting the fuel to generate a flow of second exhaust gas; receiving the flow of second exhaust gas at a turbine and driving the turbine with the flow of second exhaust gas from the combustor; and transferring motive power from the turbine to the load.

Abstract: Methods and systems for starting an aircraft gas turbine engine are described. The method comprises, in a first phase of a startup upon receipt of a start request, modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor of the gas turbine engine.

Abstract: A method of determining an inlet total air pressure includes determining a first parameter indicative of a first inlet total air pressure. The method includes executing a sequence that includes: determining a mass air flow passing through the air inlet based on the first parameter, determining a Mach number of air passing through the air inlet based on the mass air flow, determining a static air pressure at the air inlet, determining an air pressure ratio based on the Mach number, generating a subsequent parameter indicative of the revised inlet total air pressure based on the air pressure ratio and the static air pressure, and substituting the subsequent parameter for the first parameter. The method includes executing at least one additional instance of the sequence with the subsequent parameter, and outputting the subsequent parameter as the inlet total air pressure.

Abstract: A method of operating an engine of an aircraft, the engine having a bleed air system. The method includes in flight, directing pressurized air from a source of pressurized air external to the engine to the bleed air system of the engine. An aircraft, comprising a first engine having a bleed air system, a second engine having a bleed air system, and a source of pressurized air that is external to the first and/or the second engine, the source of pressurized air being selectively fluidly connectable to the bleed air system of the first and/or the second engine, is also disclosed.

Abstract: A diffuser pipe has a tubular body defining a pipe center axis extending therethrough. The tubular body includes a first portion extending in a generally radial direction from an inlet of the tubular body, a second portion extending in a generally axial direction and terminating at a pipe outlet, and a bend portion fluidly linking the first portion and the second portion. The tubular body has a length defined between the inlet and the pipe outlet. The tubular body has cross-sectional profiles defined in a plane normal to the pipe center axis. An area of the cross-sectional profile at the pipe outlet is at least 20% greater than an area of the cross-sectional profile at a point upstream from the pipe outlet a distance corresponding to 10% of the length of the tubular body.

Abstract: An electric machine system described herein comprises a first electric machine rotor, a first gear and a second gear. The first gear is connected to the first electric machine rotor and to a first input/output shaft. The second gear is connected to the first electric machine rotor and to a second input/output shaft. The first electric machine rotor is disposed between the first gear and the second gear.

Abstract: A coupling nut for sealingly engaging a ferrule of a fluid line to a component of a hydraulic system, has: a shank extending along a central axis and having threads to engage a nipple, the threads extending circumferentially around the central axis, the shank defining an inner passage extending along the central axis and sized to receive the fluid line; and a head extending from the shank circumferentially around the inner passage relative to the central axis, the head: defining faces circumferentially distributed about the central axis and edges at junctions between the faces, the faces including torque-transmitting faces each facing a direction having a circumferential component relative to the central axis, and having a cross-section in a plane normal to the central axis, the cross-section defining a plurality of symmetry planes containing the central axis, the torque-transmitting faces free of intersection with the plurality of symmetry planes.

Abstract: A probe shielding arrangement comprises a sleeve having a radially inner end mounted to a turbine housing and a radially outer end floatingly received in a probe boss on an exhaust case. The sleeve circumscribes an annular cavity around the probe. The annular cavity is sealed at opposed ends thereof to form a dead air cavity around the probe for insulation purposes.

Abstract: A structure is provided for a gas turbine engine. This gas turbine engine structure includes an engine case, an engine pylon and an engine line. The engine case includes a base, a mounting boss and a first support element. The base extends axially along and circumferentially about an axial centerline of the engine case. The mounting boss projects radially out from the base. The first support element projects radially out from the base and laterally out from the mounting boss. The first support element is configured as or otherwise includes a peripheral boss. The engine pylon is mounted to the mounting boss. The engine line is coupled to the peripheral boss.

Abstract: A multi-engine aircraft includes first and second gas turbine engines for providing motive power to the aircraft, each of the first and second engines comprising an air system, an air pressure line extending between and fluidly connecting the air systems of the first and second engines, and a pressure wave damper communicating with the air pressure line extending between the first and second engines.

Abstract: A method of operating a multi-engine system of an aircraft having first and second engines includes accumulating compressed air in a pressure vessel external to the engines, and operating the first and second engines asymmetrically, by controlling the first engine to operate in an active operating condition providing sufficient power and/or rotor speed for demands of the aircraft, and controlling the second engine to operate in a standby operating condition wherein the second engine produces less power output than the first engine. In response to a power demand request, the second engine is accelerated out of the standby operating condition by introducing therein compressed air from the pressure vessel at a location upstream of a combustor of the second engine.

Abstract: Lubricant pump systems and associated methods for aircraft engines are provided. The method includes receiving an input torque, dividing the input torque between a first load path receiving a first portion of the input torque, and a second load path receiving a second portion of the input torque. A first lubricant pump of the aircraft engine is driven via the first load path using the first portion of the input torque. A second lubricant pump of the aircraft engine is driven via the second load path using the second portion of the input torque. When a malfunction of the second lubricant pump occurs, the method includes ceasing to drive the first lubricant pump and the second lubricant pump using the input torque.

Abstract: An assembly is provided for a turbine engine. This turbine engine assembly includes a static structure, a conduit and a bracket. The static structure includes a port. The conduit extends longitudinally through the port. The bracket couples the conduit to the static structure. The bracket includes a first base mount, a second bade mount, a conduit mount, a first damper and a second damper. The first base mount is attached to the static structure. The second base mount is attached to the static structure. The conduit mount is mechanically coupled with the conduit. The first damper is between the first base mount and the conduit mount. The second damper is between the second base mount and the conduit mount.

Abstract: The gas turbine intake can have a swirl housing having an inlet portion fluidly connecting an exhaust conduit, an annular outlet defined around a central axis and fluidly connecting a turbine gas path, a swirl path extending circumferentially around the central axis from the inlet portion to a circumferential outlet, the circumferential outlet fluidly connected back into the inlet portion, and vanes located in the swirl housing, the vanes circumferentially interspaced from one another relative the central axis and located radially inwardly from the swirl path relative the central axis, the swirl path being free of the vanes.

Abstract: An orifice pack is provided for delivering pressurized air to a compressor bleed valve of a gas turbine engine. The orifice pack has a diffusion chamber in serial flow communication with a tapering passage and a first outlet passage for venting a first portion of the pressurized air from the diffusion chamber. A second outlet passage branches off from the diffusion chamber at an axial location between the inlet and the tapering passage. The second outlet passage is fluidly connected to the compressor bleed valve for directing a second portion of the pressurized air from the diffusion chamber to the compressor bleed valve.

Abstract: An electronic controller for an engine and a propeller, a control system and related methods are described herein. The control system comprises the controller having a first channel and a second channel independent from and redundant to the first channel. Each channel comprises a control processor configured to receive first engine and propeller parameters and to output, based on the first engine and propeller parameters, at least one engine control command and at least one propeller control command. Each channel also comprises a protection processor configured to receive second engine and propeller parameters and to output, based on the second engine and propeller parameters, at least one engine protection command and at least one propeller protection command. The control system comprises sensors for measuring the parameters of the engine and/or the propeller and effectors configured to control the engine and the propeller.

Abstract: An aircraft has an exhaust duct assembly disposed in a low-pressure turbine portion of a gas turbine engine to discharge exhaust gas to the outside and includes a duct having an inlet through which an exhaust gas is introduced, an exhaust portion through which the exhaust gas is exhausted, and a mounting bore formed therethrough; a duct housing in which the duct is disposed therein, and including a mounting hole into which the exhaust portion is inserted; a shaft housing disposed inside the mounting bore, inserted into the duct housing so that one end thereof faces the inlet of the duct, and having a driving axis of the low-pressure turbine portion disposed therein; and a sealing portion having a ring shape, being coupled to one end of the shaft housing, and maintaining airtightness between the driving axis and the shaft housing.

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 the combustor by supplying fuel to the first fuel manifold via a first flow divider valve and supplying fuel to the second fuel manifold via a second flow divider valve. While supplying fuel to the combustor by supplying fuel to the first fuel manifold, the method includes stopping supplying fuel to the second fuel manifold and supplying pressurized gas to the second fuel manifold via the second flow divider valve to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated nozzles.

Abstract: The present disclosure relates to a housing for an engine component. The housing comprises a wall made of a light alloy. An epoxy primer coating having at least one layer of a primer containing at least 80 wt. % epoxy covering the wall. An intumescent paint coating having at least one layer of intumescent paint directly covering the epoxy primer. And, an epoxy top coat directly covering the intumescent paint coating, the epoxy top coat having at least one layer of a top coat containing at least 80 wt. % epoxy.

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.