A gas turbine engine may include a fuel manifold extending circumferentially around a diffuser case of the gas turbine engine. The fuel manifold may include a fuel supply inlet interface for receiving fuel into the fuel manifold and a plurality of fuel delivery outlet interfaces for delivering fuel to a combustor of the gas turbine engine. The gas turbine engine may also include a valve coupled to the fuel manifold. The valve may be configured to control fuel distribution in the fuel manifold. The valve may be disposed between two fuel delivery outlet interfaces of the plurality of fuel delivery outlet interfaces. The valve may be configured to at least decrease fuel flow to one of the plurality of fuel delivery outlet interfaces. The valve may be configured to at least decrease fuel flow to half of the plurality of fuel delivery outlet interfaces.

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.

The invention relates to an auxiliary system for mechanically driving a relay shaft (8) of a helicopter propulsion system, comprising: a hydraulic motor (7), mechanically connected to said relay shaft (8); a hydraulic circuit (10) for supplying a pressurised liquid to said hydraulic motor(7) a controlled, fast-opening hydraulic valve (11) arranged on the hydraulic circuit (10); a pyro-hydraulic storage unit (9) driven by a control unit (12) and connected to said hydraulic valve (11), said pyro-hydraulic storage unit (9)comprising: an enclosure (20) including a piston (16) that defines a main compartment (17) having at least one solid propellant cartridge (19) and a compartment (18) for a liquid supply; an ignition charge (25) connected to said main compartment (17) and suitable for initiating the combustion of at least one solid propellant cartridge (19) upon receiving a command from said control unit (12).

A combustion staging system includes a splitting unit receiving a metered fuel flow and controllably splitting the received flow into pilot and mains flows. Pilot and mains fuel manifolds distribute fuel. A cooling flow recirculation line provides a cooling flow to the mains manifold during pilot-only operation, and a return section to collect mains manifold cooling flow. The cooling flow enters a delivery section and exits the return section. A fuel recirculating control valve on the delivery section has an open position so that the cooling flow enters the delivery section during pilot-only operation; a shut off position prevents the cooling flow entering the delivery section through the cooling flow orifice during pilot and mains operation. A supplementary valve bleeds or feeds cooling flow. The mains manifold cooling flow pressure is determined by the cooling flow and pressure raising orifices flow numbers, and a control setting of the supplementary valve.

A fuel assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a fuel valve that meters flow of fluid between a combustor and a fuel supply, and a controller in communication with the fuel assembly. The controller is programmed to receive data corresponding to a present rotational speed of a gas turbine engine component and data corresponding to at least one present flight condition, and is programmed to cause a flow rate from the fuel valve to change in response to determining that a rate of change in an acceleration rate relating to the present rotational speed meets at least one predetermined threshold. At least one predetermined threshold relates to an engine light-off event of the combustor and is based upon the at least one present flight condition.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.

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 system for controlling an operation of a combustor in a gas turbine that includes: an acoustic sensor configured to periodically measure a pressure of the combustor and generate a raw data stream having the pressure data points resulting from the periodic measurements; and a blowout detection unit configured to receive the raw data stream from the acoustic sensor. The blowout detection unit may include a processor and a machine-readable storage medium on which is stored instructions that cause the processor to execute a procedure related to a detection of a blowout precursor. The procedure may include an ensemble approach in which the detection of the blowout precursor depends upon a outcomes generated respectively by separate detection analytics.

A system for light-off detection in a gas turbine engine according to an example of the present disclosure includes, among other things, a computing device that has memory and a processor. The computing device is configured to execute a data module and a comparison module. The data module is programmed to access data that corresponds to a present rotational speed of a gas turbine engine component. The comparison module is programmed to cause an indicator to be generated in response to determining that an acceleration rate relating to the present rotational speed meets at least one predetermined acceleration threshold, the indicator relating to an engine light-off condition.

Systems and methods for conditionally performing engine operational tests for a turbine engine are provided. A system comprising at least one processor can be configured to obtain sensor data associated with at least one sensor for a turbine engine. The sensor data identifies a current fuel flow associated with the turbine engine. The system can determine a predicted fuel flow of the turbine engine based at least in part on the current fuel flow and a fuel flow reduction associated with an engine operational test. The system can compare the predicted fuel flow to at least one threshold. The system can selectively initiate the engine operational test based on comparing the predicted fuel flow to the at least one threshold.