Abstract: Methods and systems of starting a gas turbine engine are provided. During startup, a fuel pressure associated with a primary fuel supply of the gas turbine engine is monitored. A low-pressure event for the primary fuel supply is detected when the fuel pressure falls below a predetermined threshold. Responsive to detecting the low pressure event, an electric backup boost pump is activated by an engine controller to provide fuel to the gas turbine engine.

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 fuel control system for an aircraft engine, comprises a fuel feed conduit including an inlet end and an outlet end. A fuel metering mechanism is disposed in the fuel feed conduit between the inlet end and the outlet end operable to regulate flow through the fuel feed conduit. A position feedback sensor is operatively connected to the fuel metering mechanism and operable to generate a signal indicative of a position of the fuel metering mechanism.

Abstract: An assembly is provided for an engine. This engine assembly includes a fuel system, a sensor and a processing system. The fuel system includes a fuel source, an engine component and a fuel circuit configured to direct fuel from the fuel source to the engine component. The sensor is configured to provide sensor data indicative of a measured parameter of the fuel directed through the fuel circuit from the fuel source to the engine component. The processing system is configured to identify a fuel leak in the fuel system based on the sensor data. The fuel leak is identified when a measured value corresponding to the measured parameter of the fuel is less than an expected value corresponding to an expected parameter for the fuel directed through the fuel circuit from the fuel source to the engine component.

Abstract: A method of transitioning an electric snowmobile from a drive state to a reverse state comprising receiving at a controller a reverse request from a user interface of the electric snowmobile. Upon receipt of the reverse request, the controller transitions the electric snowmobile from a drive state to a reverse state when a speed signal associated with the electric snowmobile is below a predetermined speed threshold and transitions the electric snowmobile from a drive state to a reverse requested state when a speed signal associated with the electric snowmobile is above a predetermined speed threshold. In the reverse state, the controller drives the electric snowmobile in a reverse direction based on a throttle signal and in the reverse requested state, the controller does not drive operation of the electric snowmobile based on the throttle signal.

Abstract: A fuel system can include a first fuel circuit, a second fuel circuit, and an inert gas purge system operatively connected to both the first fuel circuit and the second fuel circuit to purge at least a portion of either or both of the first and/or second fuel circuit. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The first fuel circuit can include a first fuel manifold configured to fluidly communicate a first fuel supply with at least one dual fuel nozzles downstream of the first fuel manifold.

Abstract: A blade angle feedback assembly for an aircraft-bladed rotor is provided. The rotor is rotatable about a longitudinal axis and having an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor with adjustment of the blade pitch angle, the feedback device comprising a non-magnetically permeable body defining a root surface and a plurality of magnetically permeable position markers circumferentially disposed on the root surface, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the plurality of position markers as the feedback device rotates about the longitudinal axis.

Abstract: The method can include simultaneously conveying a controlled flow rate of jet fuel from a first reservoir area of the aircraft to a fuel nozzle across at least one auxiliary system, including the at least one auxiliary system using the controlled flow rate of jet fuel for operation and conveying a controlled flow rate of an alternative fuel from a second reservoir area of the aircraft to the fuel nozzle.

Abstract: The fuel system can have a jet fuel subsystem having a jet fuel conduit extending from a first reservoir area to a fuel nozzle across an auxiliary system operable using a flow of the jet fuel, at least one fuel delivery system operable to circulate a controlled flow rate of the jet fuel within said conduit and across the auxiliary system, a recirculation conduit branching off from the jet fuel conduit downstream of the auxiliary system, an actuator valve operable to selectively direct a flow of jet fuel to the at least one fuel nozzle or to the recirculation conduit; and an alternative fuel subsystem having an alternative fuel conduit extending from a second reservoir area to a fuel nozzle.

Abstract: A blade angle feedback assembly for an aircraft-bladed rotor is provided. The rotor is rotatable about a longitudinal axis and has an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor with adjustment of the blade pitch angle, the feedback device having a root surface, a plurality of position makers circumferentially disposed on the root surface, the plurality of position markers circumferentially spaced from one another and non-aligned with the longitudinal axis, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the plurality of position markers as the feedback device rotates about the longitudinal axis.

Abstract: Methods and systems of starting a gas turbine engine are provided. During startup, a fuel pressure associated with a primary fuel supply of the gas turbine engine is monitored. A low-pressure event for the primary fuel supply is detected when the fuel pressure falls below a predetermined threshold. Responsive to detecting the low pressure event, an electric backup boost pump is activated by an engine controller to provide fuel to the gas turbine engine.

Abstract: A blade angle feedback assembly for an aircraft-bladed rotor is provided. The rotor is rotatable about a longitudinal axis and having an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor with adjustment of the blade pitch angle, the feedback device comprising a non-magnetically permeable body defining a root surface and a plurality of magnetically permeable position markers circumferentially disposed on the root surface, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the plurality of position markers as the feedback device rotates about the longitudinal axis.

Abstract: A blade angle feedback assembly for an aircraft-bladed rotor is provided. The rotor is rotatable about a longitudinal axis and has an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor with adjustment of the blade pitch angle, the feedback device having a root surface, a plurality of position makers circumferentially disposed on the root surface, the plurality of position markers circumferentially spaced from one another and non-aligned with the longitudinal axis, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the plurality of position markers as the feedback device rotates about the longitudinal axis.