Abstract: A gas turbine engine and method of starting, the gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor. The method comprises an acceleration phase, a bowed-rotor cooling phase, during the acceleration, and a combustion phase. The bowed-rotor cooling phase comprises a time where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor. The combustion phase occurs after the bowed-rotor cooling phase and upon reaching the combustion speed, wherein fuel is supplied to the gas turbine engine is turned on.

Abstract: A gas turbine engine and method of starting, the gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor. The method comprises an acceleration phase, a bowed-rotor cooling phase, during the acceleration, and a combustion phase. The bowed-rotor cooling phase comprises a time where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor. The combustion phase occurs after the bowed-rotor cooling phase and upon reaching the combustion speed, wherein fuel is supplied to the gas turbine engine is turned on.

Abstract: A method of operating a turbine engine that includes actuating a starter motor of the turbine engine such that a motoring speed of the turbine engine increases, and actuating a plurality of variable stator vanes of the turbine engine such that the plurality of variable stator vanes are at least partially open to control the motoring speed of the turbine engine.

Abstract: A method of starting a gas turbine engine includes determining an abnormal shutdown condition during operation of the gas turbine engine and determining a first set of lightoff parameters for the gas turbine engine. The method also includes restarting the gas turbine engine using the first set of lightoff parameters. The method further includes iteratively determining subsequent first sets of lightoff parameters and restarting the gas turbine engine using a respective subsequent first set of the determined subsequent first sets of lightoff parameters until the gas turbine maintains a first set of operational parameters, where the first set of operational parameters is representative of a robust lightoff of the gas turbine engine.

Abstract: A method of starting a gas turbine engine having a rotor comprising at least a shaft-mounted compressor and turbine, with a casing surrounding the rotor includes an acceleration phase, a bowed-rotor cooling phase, during the acceleration, and a combustion phase. The bowed-rotor cooling phase comprises a time where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor. The combustion phase occurs after the bowed-rotor cooling phase and upon reaching the combustion speed, wherein fuel is supplied to the gas turbine engine.

Abstract: 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.

Abstract: A method for controlling a gas turbine engine is provided. The method includes determining if a potential icing condition exists, for example, by determining whether a corrected fan speed percentage is below a predetermined fan speed threshold. If a potential icing condition exists, a fuel regulator may operate according to a first control algorithm by restricting the flow of fuel to the engine if the corrected core speed percentage of the core engine exceeds a predetermined core speed threshold. If a potential icing condition does not exist such that the fan section and core engine of the gas turbine engine are operating normally, the fuel regulator may operating according to a second control algorithm that does not include such a hard compressor speed limit.

Abstract: Systems and methods for stabilizing an aircraft in response to a yaw movement are provided. In one embodiment, a method includes detecting a yaw movement of the aircraft. The yaw movement can cause a front portion of the aircraft to move towards a first side of the aircraft. The method can further include, in response to the yaw movement, initiating a trim process resulting in a thrust differential. The trim process can include increasing thrust in one or more engines on the first side of the aircraft and decreasing thrust in one or more engines on a second side of the aircraft. The method can include controlling the trim process based at least in part on a detected yaw movement of the aircraft.

Abstract: A method of starting a gas turbine engine includes determining an abnormal shutdown condition during operation of the gas turbine engine and determining a first set of lightoff parameters for the gas turbine engine. The method also includes restarting the gas turbine engine using the first set of lightoff parameters. The method further includes iteratively determining subsequent first sets of lightoff parameters and restarting the gas turbine engine using a respective subsequent first set of the determined subsequent first sets of lightoff parameters until the gas turbine maintains a first set of operational parameters, where the first set of operational parameters is representative of a robust lightoff of the gas turbine engine.

Abstract: Systems and methods for stabilizing an aircraft in response to a yaw movement are provided. In one embodiment, a method includes detecting a yaw movement of the aircraft. The yaw movement can cause a front portion of the aircraft to move towards a first side of the aircraft. The method can further include, in response to the yaw movement, initiating a trim process resulting in a thrust differential. The trim process can include increasing thrust in one or more engines on the first side of the aircraft and decreasing thrust in one or more engines on a second side of the aircraft. The method can include controlling the trim process based at least in part on a detected yaw movement of the aircraft.

Abstract: 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.

Abstract: A method of operating a turbine engine that includes actuating a starter motor of the turbine engine such that a motoring speed of the turbine engine increases, and actuating a plurality of variable stator vanes of the turbine engine such that the plurality of variable stator vanes are at least partially open to control the motoring speed of the turbine engine.

Abstract: A method of starting a gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor.

Abstract: A method and apparatus for providing large transient identification for advanced control with multiple constraints. A request to change a current operating condition of a controlled plant is detected. A value of a control constraint corresponding to the request to change the current operating condition of the controlled plant is determined. A magnitude of a transient error corresponding to the request relative to the value of the control constraint is determined and the current operating condition of the controlled plant is adjusted based on the determined magnitude of the transient error.

Abstract: A method and apparatus for providing large transient identification for advanced control with multiple constraints. A request to change a current operating condition of a controlled plant is detected. A value of a control constraint corresponding to the request to change the current operating condition of the controlled plant is determined. A magnitude of a transient error corresponding to the request relative to the value of the control constraint is determined and the current operating condition of the controlled plant is adjusted based on the determined magnitude of the transient error.