Example variable geometry systems with split actuation are disclosed herein. In one example, a compressor is provided that includes a compressor stage and an actuation system. The compressor stage includes a plurality of variable stator vanes arranged along a circumference of the compressor stage. The actuation system is to actuate a first variable stator vane of the compressor stage according to a first schedule and to actuate a second variable stator vane of the compressor stage according to a second schedule.

A hybrid engine includes a gas turbine engine having at least one compressor section and at least one turbine section operably coupled to a shaft. The hybrid engine includes an electric motor configured to augment rotational power of the shaft of the gas turbine engine. A controller is operable to monitor for a transient operation request of the hybrid engine, provide the transient operation request to one or more management systems of the hybrid engine to determine whether one or more faults are detected by the one or more management systems, modify one or more stall margin adjustment parameters of the gas turbine engine based on detecting the one or more faults by the one or more management system, and adjust operation of the hybrid engine based on the one or more stall margin adjustment parameters.

A fan assembly includes a fan duct, an inlet fan, and an outlet guide vane assembly. The inlet fan includes blades adapted to force fan exit air toward an aft end of the fan duct. The outlet guide vane assembly is located in the fan duct downstream of the inlet fan and is configured to adjust a direction of the fan exit air received from the blades. The outlet guide vane assembly includes a first plurality of vanes configured to rotate to redirect the fan exit air in a first direction, and a second plurality of vanes located downstream of the first plurality of vanes. The second plurality of vanes are configured to rotate to redirect the fan exit air flowing in the first direction in a second direction to minimize losses created by distortions in fan inlet air and created by the first vanes.

A fan assembly includes a fan duct, an inlet fan, and an outlet guide vane assembly. The inlet fan forces fan exit air toward an aft end of the fan duct. The outlet guide vane assembly is located in the fan duct downstream of the inlet fan and adjusts a direction of the fan exit air, and includes a plurality of outlet guide vanes and a plurality of actuation assemblies that control rotation of the outlet guide vanes about a pitch axis. The outlet guide vanes include a leading edge portion and a trailing edge portion rotatably coupled to an axially aft edge of the leading edge portion. The actuation assembly rotates the leading edge portion and the trailing edge portion to minimize losses created by distortions in fan inlet air and created by the leading edge portion redirecting the fan exit air in the first direction.

A fan assembly includes a fan duct, an inlet fan, and an outlet guide vane assembly. The inlet fan forces fan exit air toward an aft end of the fan duct. The outlet guide vane assembly is located in the fan duct downstream of the inlet fan and adjusts a direction of the fan exit air, and includes a plurality of outlet guide vanes and a plurality of actuation assemblies that control rotation of the outlet guide vanes about a pitch axis. The outlet guide vanes include a leading edge portion and a trailing edge portion rotatably coupled to an axially aft edge of the leading edge portion. The actuation assembly rotates the leading edge portion and the trailing edge portion to minimize losses created by distortions in fan inlet air and created by the leading edge portion redirecting the fan exit air in the first direction.

Systems and methods for adjusting airflow distortion in a gas turbine engine using a secondary airflow passage assembly are disclosed. A gas turbine engine can include a compressor section, a combustion section, and a turbine section in series flow and defining at least in part an engine airflow path. A casing can enclose the gas turbine engine and be at least partially exposed to a bypass airflow. The gas turbine engine can further include a secondary airflow passage assembly comprising a door and a duct, the duct defining an inlet located on the casing, the duct defining an outlet in airflow communication with the engine airflow path, the duct comprising an airflow passage extending between the inlet and outlet. The door can be moveable between an open and closed position to allow a portion of the bypass airflow to flow through the airflow passage to adjust airflow distortion.

A method for controlling a gas turbine engine on an aircraft in response to airflow distortion in an airflow path of the gas turbine engine is provided. In one embodiment, a method can include determining, by one or more control devices located on an aircraft, a distortion condition associated with the gas turbine engine. The method can further include determining, by the one or more control devices, a stall margin for the gas turbine engine based at least in part on the distortion condition. The method can further include determining, by the one or more control devices, an engine control parameter based at least in part on the stall margin. The method can further include controlling, by the one or more control devices, a component of the gas turbine engine based at least in part on the engine control parameter.

A gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a control unit to command the gas turbine engine to perform one of a rolling takeoff procedure and an unrestricted takeoff procedure. The control unit is configured command the gas turbine engine to perform the rolling takeoff procedure when information required to determine whether the unrestricted takeoff procedure can be performed is unavailable to the control unit.

A system and method for detecting inlet temperature distortion of an engine are described. The method comprises obtaining an outside air temperature from at least one first sensor, obtaining an inlet temperature of the engine from at least one second sensor, determining an inlet temperature distortion based on a difference between the outside air temperature and the inlet temperature, comparing the inlet temperature distortion to a threshold, and issuing an alert when the inlet temperature distortion exceeds the threshold.

A fan assembly includes a fan duct, an inlet fan, and an outlet guide vane assembly. The inlet fan includes blades adapted to force fan exit air toward an aft end of the fan duct. The outlet guide vane assembly is located in the fan duct downstream of the inlet fan and is configured to adjust a direction of the fan exit air received from the blades. The outlet guide vane assembly includes a first plurality of vanes configured to rotate to redirect the fan exit air in a first direction, and a second plurality of vanes located downstream of the first plurality of vanes. The second plurality of vanes are configured to rotate to redirect the fan exit air flowing in the first direction in a second direction to minimize losses created by distortions in fan inlet air and created by the first vanes.