A fuel supply system for a turbine engine that provides a modulated thrust control malfunction accommodation (TCMA) is disclosed. An example fuel supply system includes a fuel supply line to supply fuel to a combustion engine, a fuel metering valve coupled to the fuel supply line, the fuel metering valve to control a flow of fuel through the fuel supply line to the combustion engine, a throttle valve coupled to the fuel supply line downstream of the fuel metering valve, the throttle valve to bleed off fuel supplied to the combustion engine based on a pressure difference across the fuel metering valve, and a controllable servo coupled to the throttle valve, the controllable servo to control the throttle valve based on a sensor output indicative of the pressure difference.

A fuel supply system for a turbine engine that provides a modulated thrust control malfunction accommodation (TCMA) is disclosed. An example fuel supply system includes a fuel supply line to supply fuel to a combustion engine, a fuel metering valve coupled to the fuel supply line, the fuel metering valve to control a flow of fuel through the fuel supply line to the combustion engine, a throttle valve coupled to the fuel supply line downstream of the fuel metering valve, the throttle valve to bleed off fuel supplied to the combustion engine based on a pressure difference across the fuel metering valve, and a controllable servo coupled to the throttle valve, the controllable servo to control the throttle valve based on a sensor output indicative of the pressure difference.

A method and system for controlling fuel flow to an aircraft engine during start are provided. Following light-off, an actual value of at least one engine operating parameter is obtained. Based on a difference between the actual value and a target value, a first command is generated to cause fuel flow to be provided to the engine's combustor according to a computed fuel flow rate defined by a fuel schedule of the engine. When the computed fuel flow rate is within a fuel flow rate limit, the first command is output. Otherwise, a limiting factor is applied to the computed fuel flow rate to limit a reduction in fuel flow to the combustor and a limited fuel flow rate is obtained, and a second command is output to cause fuel flow to be provided to the combustor according to the limited fuel flow rate.

A method and system for controlling fuel flow to an aircraft engine during start are provided. Following light-off, an actual value of at least one engine operating parameter is obtained. Based on a difference between the actual value and a target value, a first command is generated to cause fuel flow to be provided to the engine's combustor according to a computed fuel flow rate defined by a fuel schedule of the engine. When the computed fuel flow rate is within a fuel flow rate limit, the first command is output. Otherwise, a limiting factor is applied to the computed fuel flow rate to limit a reduction in fuel flow to the combustor and a limited fuel flow rate is obtained, and a second command is output to cause fuel flow to be provided to the combustor according to the limited fuel flow rate.

A method of controlling a gas turbine engine includes the steps of: detecting a shaft break event in a shaft connecting a compressor of the gas turbine engine to a turbine of the gas turbine engine; and in response to this detection, activating a shaft break mitigation system which introduces a fluid into a gas flow of the gas turbine engine downstream of the turbine, or increases an amount of a fluid being provided into the gas flow of the gas turbine engine downstream of the turbine, whereby the fluid reduces an effective area of a nozzle for the gas flow so as to reduce the mass flow rate of the gas flow through the turbine.

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.

A method and system for controlling fuel flow to an aircraft engine during start are provided. Following light-off, an actual value of at least one engine operating parameter is obtained. Based on a difference between the actual value and a target value, a first command is generated to cause fuel flow to be provided to the engine's combustor according to a computed fuel flow rate defined by a fuel schedule of the engine. When the computed fuel flow rate is within a fuel flow rate limit, the first command is output. Otherwise, a limiting factor is applied to the computed fuel flow rate to limit a reduction in fuel flow to the combustor and a limited fuel flow rate is obtained, and a second command is output to cause fuel flow to be provided to the combustor according to the limited fuel flow rate.

A method and system for controlling fuel flow to an aircraft engine during start are provided. Following light-off, an actual value of at least one engine operating parameter is obtained. Based on a difference between the actual value and a target value, a first command is generated to cause fuel flow to be provided to the engine's combustor according to a computed fuel flow rate defined by a fuel schedule of the engine. When the computed fuel flow rate is within a fuel flow rate limit, the first command is output. Otherwise, a limiting factor is applied to the computed fuel flow rate to limit a reduction in fuel flow to the combustor and a limited fuel flow rate is obtained, and a second command is output to cause fuel flow to be provided to the combustor according to the limited fuel flow rate.

A gas turbine engine shut-down system includes a pump configured to draw a flow of fuel from a source, a fuel nozzle configured to receive the flow of fuel from the pump, a fuel shut-off valve in fluid communication with the pump, a recirculation circuit for circulating excess fuel to a location upstream of the pump; a solenoid valve in communication with the pump and the recirculation circuit; and a fuel-bypass valve. The fuel-bypass valve includes a first opening connected to the fuel pump, a second opening connected to the fuel shut-off valve, a third opening connected to the recirculation circuit, a fourth opening connected to the solenoid valve, and a piston disposed within the fuel-bypass valve and movable between a plurality of positions.

A gas turbine engine shut-down system includes a pump configured to draw a flow of fuel from a source, a fuel nozzle configured to receive the flow of fuel from the pump, a fuel shut-off valve in fluid communication with the pump, a recirculation circuit for circulating excess fuel to a location upstream of the pump; a solenoid valve in communication with the pump and the recirculation circuit; and a fuel-bypass valve. The fuel-bypass valve includes a first opening connected to the fuel pump, a second opening connected to the fuel shut-off valve, a third opening connected to the recirculation circuit, a fourth opening connected to the solenoid valve, and a piston disposed within the fuel-bypass valve and movable between a plurality of positions.