Technology for operating an engine smoothly is provided. In an aircraft propulsion system, a controller causes at least a first engine among the plurality of engines to be stopped and causes a second engine, which has not been stopped, to be operated when an aircraft is flying in a prescribed flight mode and causes the first engine to be operated and causes the second engine to be stopped when a detector detects that the temperature related to the first engine is less than or equal to a first prescribed temperature.

Various implementations described herein are directed to an aircraft having a multi-engine configuration with multiple engines. The aircraft may have a flight control system coupled to the multiple engines with a multi-engine interface. The flight control system may be configured to shutdown at least one engine of the multiple engines during reduced-engine operation by continuously calculating altitude for the reduced-engine operation based on one or more of an aircraft descent rate of the aircraft and an engine restart time of the at least one engine.

A system for automated management of in-flight restarting of engines of an aircraft includes controllers, each engine of the aircraft being managed by one of the controllers. A controller that detects an engine that has stopped: cuts off the energy supply of the engine and performs a windmill engine start. If at least one other engine has stopped, prioritization of engine restarting includes: collecting information concerning a state of health of each engine; determining from the information collected information representing a probability of restarting each stopped engine; determining a sequential order of restarting the stopped engines as a function of information representing the probability of restarting each stopped engine. Each stopped engine continues to be windmill started until selection of the engine in question in the sequential order of restarting the stopped engines. Thus, the operational status of the aircraft is improved as quickly as possible.

Examples described herein provide a computer-implemented method that includes monitoring a hybrid electric turbine engine of an aircraft, the hybrid electric turbine engine including a first electric machine associated with a high speed spool and a second electric machine associated with a low speed spool. The method further includes receiving an indication of a failed electric machine, the failed electric machine being an electric machine on another hybrid electric turbine engine of the aircraft. The method further includes, responsive to detecting the failed electric machine, distributing power from one or more of the first electric machine or the second electric machine to a spool associated with the failed electric machine.

The aircraft can have a first engine secured to a first wing on a first side of a fuselage, and a second engine secured to a second wing on a second side of the fuselage, the second wing having a proximal end secured to the fuselage, and a distal end extending away from the fuselage. While operating the first engine, compressed gas can be conveyed from the first engine to a thrust generating device located at the distal end of the second wing.

The invention relates to a device for the rapid reactivation of a helicopter turbine engine (6), characterised in that it comprises a pneumatic turbine (7) mechanically connected to said turbine engine (6) so as to be able to rotate it and ensure reactivation thereof; a pneumatic storage (9) connected to said pneumatic turbine (7) by means of a pneumatic circuit (10) for supplying pressurised gas to said pneumatic turbine (7); a controlled fast-opening pneumatic valve (11) arranged on the pneumatic circuit (10) between said storage (9) and said pneumatic turbine (7) and suitable for being on demand placed at least in an open position in which the gas can supply said pneumatic turbine (7), or in a closed position in which said pneumatic turbine (7) is no longer supplied with pressurised gas.

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.

Multi-engine aircraft power and propulsion systems and methods of restarting an engine of a multi-engine aircraft during fight are provided. One such method comprises: determining a condition to the effect that a flame in the combustion equipment of the second gas turbine engine has been extinguished; responsive to the determination, supplying electrical power from the electrical energy storage system to one or more of the electric machines of the second gas turbine engine and operating said one or more electric machines as motors to limit a reduction in a speed of the one or more spools of the second gas turbine engine following extinguishment of the flame in its combustion equipment; and restarting the second gas turbine engine by relighting the combustion equipment of the second gas turbine engine.

There is described a method of operating a multi-engine system of an helicopter. The multi-engine system has a first turboshaft engine having a first shaft, a second turboshaft engine having a second shaft, a gearbox having a clutch system, and a range of rotation speeds defined as a placarded zone. The method generally has: rotating the first and second shafts at a flight rotation speed above the placarded zone when clutched to a load; decreasing a rotation speed of the first shaft from the flight rotation speed to a first idle rotation speed above the placarded zone; unclutching the first shaft from the load during the decreasing; and subsequently to the decreasing and the unclutching, simultaneously decreasing the rotation speeds of the first shaft and of the second shaft to a second idle rotation speed below the placarded zone, the simultaneously decreasing including clutching the first shaft to the load.

There is described a method of operating a multi-engine system of an helicopter. The multi-engine system has a first turboshaft engine having a first shaft, a second turboshaft engine having a second shaft, a gearbox having a clutch system, and a range of rotation speeds defined as a placarded zone. The method generally has rotating the first shaft at a flight rotation speed when clutched and rotating the second shaft at a first idle rotation speed when unclutched, the first idle rotation speed above the placarded zone; decreasing a rotation speed of the first shaft from the flight rotation speed to a given rotation speed within the placarded zone; decreasing a rotation speed of the second shaft to the given rotation speed; clutching the second shaft; and decreasing the rotation speeds of the first and second shafts to a second idle rotation speed below the placarded zone.