A hybrid-electric propulsion system for an aircraft includes a propulsor and a turbomachine. The turbomachine includes a high pressure turbine drivingly coupled to a high pressure compressor through a high pressure spool. The hybrid electric propulsion system further includes an electrical system including a first electric machine, a second electric machine, and an electric energy storage unit electrically connectable to the first and second electric machines. The first electric machine is coupled to the high pressure spool of the turbomachine and the second electric machine is coupled to the propulsor for driving the propulsor to provide a propulsive benefit for the aircraft. The hybrid electric propulsion system also includes a controller configured to provide electrical power from an electric power source to the first electric machine to drive the first electric machine to start, or assist with starting, the turbomachine.

An assistance device for a free-turbine engine of an aircraft having at least two free-turbine engines, the device including an electrical starter machine for providing prolonged assistance to the gas generator of a first engine using energy produced by an electric generator machine driven by the second engine, the device further including at least one electricity storage member electrically connected to the electrical starter machine for providing a burst of assistance to the gas generator, wherein the electrical starter machine is powered by a first power converter enabling it to exchange energy with the storage member for providing the burst of assistance, and that transmits thereto the energy supplied by a second power converter for the prolonged assistance.

An assistance device for a free-turbine engine of an aircraft having at least two free-turbine engines, the device including an electrical starter machine for providing prolonged assistance to the gas generator of a first engine using energy produced by an electric generator machine driven by the second engine, the device further including at least one electricity storage member electrically connected to the electrical starter machine for providing a burst of assistance to the gas generator, wherein the electrical starter machine is powered by a first power converter enabling it to exchange energy with the storage member for providing the burst of assistance, and that transmits thereto the energy supplied by a second power converter for the prolonged assistance.

There is described a method and system for in-flight start of an engine. The method comprises rotating a propeller; generating electrical power at an electric generator embedded inside a propeller hub from rotation of the propeller; transmitting the electrical power from the electric generator to an engine starter mounted on a core of the engine via an electric power link; and driving the engine with the engine starter to a sufficient speed while providing fuel to a combustor to light the engine to achieve self-sustaining operation of the engine.

There is described a method and system for in-flight start of an engine. The method comprises rotating a propeller; generating electrical power at an electric generator embedded inside a propeller hub from rotation of the propeller; transmitting the electrical power from the electric generator to an engine starter mounted on a core of the engine via an electric power link; and driving the engine with the engine starter to a sufficient speed while providing fuel to a combustor to light the engine to achieve self-sustaining operation of the engine.

There is provided a method of operating a gas turbine engine. The gas turbine engine comprises a staged combustor comprising an arrangement of fuel spray nozzles in which fuel flow is biased to a subset of the nozzles adjacent one or more ignitors during a re-light procedure. The method comprises providing fuel to the combustor having a calorific value of at least 43.5 MJ/kg. Also disclosed is a gas turbine engine.

There is provided a method of operating a gas turbine engine. The gas turbine engine comprises a staged combustor comprising an arrangement of fuel spray nozzles in which fuel flow is biased to a subset of the nozzles adjacent one or more ignitors during a re-light procedure. The method comprises providing fuel to the combustor having a calorific value of at least 43.5 MJ/kg. Also disclosed is a gas turbine engine.

An example system includes a common electric starter controller configured to control electric starters of a plurality of gas-turbine engines that are configured to propel an aircraft, wherein the common electric starter comprises: a driver configured to generate, using electrical energy sourced from a battery of the aircraft, power signals that control the electric starters; and a plurality of bus bars configured to directly connect the common electric starter controller to the battery and transport the electrical energy from the battery to the common electric starter controller.

An example system includes a common electric starter controller configured to control electric starters of a plurality of gas-turbine engines that are configured to propel an aircraft, wherein the common electric starter comprises: a driver configured to generate, using electrical energy sourced from a battery of the aircraft, power signals that control the electric starters; and a plurality of bus bars configured to directly connect the common electric starter controller to the battery and transport the electrical energy from the battery to the common electric starter controller.

The invention deals with the restriction on the mode change of an engine due to latching in the case of restarting the engine that has stopped in flight. A FADEC that controls an engine of an aircraft in accordance with a mode, includes a latch operating section that latches the mode, and an in-parking/in-flight determining section that determines whether the aircraft is on the ground or flying off the ground. The latch operating section operates when the in-parking/in-flight determining section determines the aircraft is on the ground, and does not operate when the in-parking/in-flight determining section determines that the aircraft is in fight.