A method for quickly stopping the propulsion rotor of a helicopter after landing, comprising, following a request for quickly stopping the engine by a helicopter pilot, the following steps managed by the control unit of the turbomachine: Detecting the absence of the thermal stabilization phase of the gas generator of at least one turbomachine, controlling an extinction of the combustion chamber of the gas generator of at least one turbomachine, maintaining the rotation of the gas generator of which the combustion chamber is extinguished by means of said at least one electrical machine to ventilate the gas generator and stopping the main rotor of the helicopter by means of a mechanical brake.

Systems and methods for shutting down a gas turbine engine in response to a severe mechanical failure include determining a rate of change of one or more process conditions. If the rate of change of the one or more process conditions exceeds a respective predetermined failure threshold, a potential severe mechanical failure of the gas turbine engine may be determined. Steps may be taken to confirm the potential severe mechanical failure of the gas turbine engine. In response, an engine restart is prevented.

A monitoring system for a gas turbine includes a processor configured to receive an operating signal indicating an operating parameter of the gas turbine. The processor is configured to predict an occurrence of a lean blowout (LBO) event based on the operating parameter and an entropy ratio of combustion dynamics associated with a combustor of the gas turbine, wherein the LBO event corresponds to when the combustor stops firing. The processor is configured to send an alarm signal indicating the predicted LBO event to an electronic device prior to the occurrence of the LBO event.

A monitoring system for a gas turbine includes a processor configured to receive an operating signal indicating an operating parameter of the gas turbine. The processor is configured to predict an occurrence of a lean blowout (LBO) event based on the operating parameter and an entropy ratio of combustion dynamics associated with a combustor of the gas turbine, wherein the LBO event corresponds to when the combustor stops firing. The processor is configured to send an alarm signal indicating the predicted LBO event to an electronic device prior to the occurrence of the LBO event.

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.

Aircraft power and propulsion systems, aircraft comprising such power and propulsion systems, and methods of restarting a gas turbine engine of such power and propulsion systems during flight are provided. One such aircraft power and propulsion system comprises: a propulsive gas turbine engine comprising a plurality of spools, combustion equipment, one or more electric machines mechanically coupled with one or more of the spools and an electrically-powered fuel pump for delivering fuel to the combustion equipment; an electrical system connected with the one or more electric machines and the electrically-powered fuel pump, the electrical system comprising an energy storage system; and a control system configured to: responsive to a determination to the effect that a flame in the combustion equipment has been extinguished, control the electrical system to supply electrical power from the energy storage system to the fuel pump during an engine restart attempt.

A fuel control system for a gas turbine engine includes a fuel metering valve, a pressure raising and shut-off valve (PRSOV), and a shutoff effector including a first stage unit that is electrically powered and a second stage unit that is controlled by the first stage unit. The second stage unit actuates a valve member of the PRSOV between an open position that allows supply of a fuel to burners of the gas turbine engine and a closed position that prevents supply of the fuel to the burners. Upon loss of electrical power to the first stage unit during operation of the gas turbine engine, the first stage unit is configured to: control the second stage unit to actuate the valve member of the PRSOV to the closed position after a predetermined time duration; or retain the valve member of the PRSOV in the open position.

A fuel control system for a gas turbine engine includes a fuel metering valve, a pressure raising and shut-off valve (PRSOV), and a shutoff effector including a first stage unit that is electrically powered and a second stage unit that is controlled by the first stage unit. The second stage unit actuates a valve member of the PRSOV between an open position that allows supply of a fuel to burners of the gas turbine engine and a closed position that prevents supply of the fuel to the burners. Upon loss of electrical power to the first stage unit during operation of the gas turbine engine, the first stage unit is configured to: control the second stage unit to actuate the valve member of the PRSOV to the closed position after a predetermined time duration; or retain the valve member of the PRSOV in the open position.

A propulsion assembly having a propulsion system including an exhaust nozzle fastened to the nozzle wall on the outside thereof so as to define between them a chamber, and a heat exchanger system ensuring an exchange of heat energy between the hot combustion gases circulating in the exhaust nozzle and the colder fuel circulating in the supply pipe at least in part by thermal radiation through the nozzle wall. The heat exchanger system has a pipe portion arranged in the chamber and the exchange of heat energy takes place at this pipe portion. With such an arrangement, the heat energy of the combustion gases is transferred to the fuel for better combustion.

A propulsion assembly having a propulsion system including an exhaust nozzle fastened to the nozzle wall on the outside thereof so as to define between them a chamber, and a heat exchanger system ensuring an exchange of heat energy between the hot combustion gases circulating in the exhaust nozzle and the colder fuel circulating in the supply pipe at least in part by thermal radiation through the nozzle wall. The heat exchanger system has a pipe portion arranged in the chamber and the exchange of heat energy takes place at this pipe portion. With such an arrangement, the heat energy of the combustion gases is transferred to the fuel for better combustion.