Abstract: An aspect includes a method for motoring control for multiple engines of an aircraft is provided. A controller can determine a motoring time of a first engine starting system to cool a first engine. The controller can compare the motoring time of the first engine starting system with a motoring time of one or more other engine starting systems of one or more other engines of the aircraft. The motoring time of the first engine starting system can be controlled relative to a tolerance of the motoring time of the one or more other engine starting systems by adjusting the motoring time of the first engine starting system relative to the one or more other engine starting systems in a motoring sequence based on comparing the motoring time of the first engine starting system with the motoring time of the one or more other engine starting systems.

Abstract: An aspect includes a method for motoring control for multiple engines of an aircraft is provided. A controller can determine a motoring time of a first engine starting system to cool a first engine. The controller can compare the motoring time of the first engine starting system with a motoring time of one or more other engine starting systems of one or more other engines of the aircraft. The motoring time of the first engine starting system can be controlled relative to a tolerance of the motoring time of the one or more other engine starting systems by adjusting the motoring time of the first engine starting system relative to the one or more other engine starting systems in a motoring sequence based on comparing the motoring time of the first engine starting system with the motoring time of the one or more other engine starting systems.

Abstract: An aspect includes a system for pre-start motoring control for multiple engines of an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to control a motoring time of the first engine starting system relative to one or more other engine starting systems of one or more other engines of the aircraft by adjusting the motoring time of the first engine starting system within a tolerance of the motoring time of the one or more other engine starting systems in a pre-start motoring sequence.

Abstract: A method of controlling lubrication flow to a first engine component, a second engine component and a lubrication tank of a gas turbine engine according to an example of the present disclosure includes, among other things, determining more than one condition experienced by the gas turbine engine, comparing with a processor on a controller the more than one condition against an engine performance model stored in memory on the controller, wherein the engine performance model includes stored relationship values between the more than one condition and a position of a scheduling valve, the scheduling valve disposed between the lubricant tank and the first engine component and between the lubricant tank and the second engine component, pumping a lubricant from the lubricant tank through a conduit to the scheduling valve using a pump, and controlling the position of the scheduling valve to vary a flow of the lubricant to two or more of the first engine component, the second engine component and the lubrication tank

Abstract: A method of controlling lubrication flow to a first engine component, a second engine component and a lubrication tank of a gas turbine engine according to an example of the present disclosure includes, among other things, determining more than one condition experienced by the gas turbine engine, comparing with a processor on a controller the more than one condition against an engine performance model stored in memory on the controller, wherein the engine performance model includes stored relationship values between the more than one condition and a position of a scheduling valve, the scheduling valve disposed between the lubricant tank and the first engine component and between the lubricant tank and the second engine component, pumping a lubricant from the lubricant tank through a conduit to the scheduling valve using a pump, and controlling the position of the scheduling valve to vary a flow of the lubricant to two or more of the first engine component, the second engine component and the lubrication tank

Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed, where the controller modulates a duty cycle of the discrete starter valve via pulse width modulation.

Abstract: A lubrication system for a gas turbine engine according to an example of the present disclosure includes, among other things, a pump that moves a lubricant, a lubricant tank that stores the lubricant, a first engine component and a second engine component each requiring lubrication from the lubricant, a conduit between the lubricant tank and the first engine component and between the lubricant tank and the second engine component, a scheduling valve positioned in the conduit between the lubricant tank, and the first engine component and the second engine component, and a controller including a memory and a processor that controls the scheduling valve, wherein the memory includes an engine performance model, wherein the engine performance model includes stored relationship values between more than one condition experienced by the gas turbine engine during operation and a position of the scheduling valve, and wherein the scheduling valve varies a flow of the lubricant to the first engine component, the second e

Abstract: An aspect includes a system for pre-start motoring control for multiple engines of an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to control a motoring time of the first engine starting system relative to one or more other engine starting systems of one or more other engines of the aircraft by adjusting the motoring time of the first engine starting system within a tolerance of the motoring time of the one or more other engine starting systems in a pre-start motoring sequence.

Abstract: A system for controlling a start sequence of a gas turbine engine includes an electronic engine control system, a thermal model, memory, a model for determining a time period (tmotoring), and a controller. The thermal model synthesizes a heat state of the gas turbine engine. The memory records the current heat state at shutdown and a shutdown time of the gas turbine engine. The model for determining the time period is for motoring the gas turbine engine at a predetermined speed Ntarget that is less than a speed to start the gas turbine engine, where tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to a previous shutdown time. The controller modulates a starter valve to maintain the gas turbine engine within a predetermined speed range of NtargetMin to NtargetMax for homogenizing engine temperatures.

Abstract: An aspect includes a system for pre-start motoring synchronization for multiple engines of an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to synchronize a motoring time of the first engine starting system with one or more other engine starting systems of one or more other engines of the aircraft by extending the motoring time of the first engine starting system to match, within a synchronization tolerance, the motoring time of the one or more other engine starting systems in a pre-start motoring sequence.

Abstract: An example gas turbine engine compressor includes a first compressor section. The first compressor section includes a rotating stage that includes rotating blades and a stationary stage upstream thereof that includes stationary guide vanes. The stationary vanes controllably pivot about respective pivot axes for providing flow control into the rotating stage.

Abstract: An example variable vane scheduling method includes adjusting variable vanes from a position based on a first schedule to a position based on a different, second schedule in response to a control feature. An example method of controlling flow through a compressor of a turbomachine includes moving variable vanes to positions that allow more flow into the compressor in response to bleed air being communicated away from the compressor.

Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed, where the controller modulates a duty cycle of the discrete starter valve via pulse width modulation.

Abstract: A system for controlling a start sequence of a gas turbine engine includes an electronic engine control system, a thermal model, memory, a model for determining a time period (fmotoring), and a controller. The thermal model synthesizes a heat state of the gas turbine engine. The memory records the current heat state at shutdown and a shutdown time of the gas turbine engine. The model for determining the time period is for motoring the gas turbine engine at a predetermined speed Ntarget that is less than a speed to start the gas turbine engine, where tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to a previous shutdown time. The controller modulates a starter valve to maintain the gas turbine engine within a predetermined speed range of NtargetMin to NtargetMax for homogenizing engine temperatures.

Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed.

Abstract: A control system for a gas turbine engine includes a processing system operable to control a speed of the gas turbine engine and a memory system. The memory system is operable to store instructions executable by the processing system to determine at least one performance parameter associated with a stall condition of the gas turbine engine and to incrementally adjust an acceleration rate of the gas turbine engine based on detecting a degraded stall line limit according to the at least one performance parameter.

Abstract: A method of controlling lubrication flow to a first engine component, a second engine component and a lubrication tank of a gas turbine engine according to an example of the present disclosure includes, among other things, determining more than one condition experienced by the gas turbine engine, comparing with a processor on a controller the more than one condition against an engine performance model stored in memory on the controller, wherein the engine performance model includes stored relationship values between the more than one condition and a position of a scheduling valve, the scheduling valve disposed between the lubricant tank and the first engine component and between the lubricant tank and the second engine component, pumping a lubricant from the lubricant tank through a conduit to the scheduling valve using a pump, and controlling the position of the scheduling valve to vary a flow of the lubricant to two or more of the first engine component, the second engine component and the lubrication tank

Abstract: A lubrication system for a gas turbine engine according to an example of the present disclosure includes, among other things, a pump that moves a lubricant, a lubricant tank that stores the lubricant, a first engine component and a second engine component each requiring lubrication from the lubricant, a conduit between the lubricant tank and the first engine component and between the lubricant tank and the second engine component, a scheduling valve positioned in the conduit between the lubricant tank, and the first engine component and the second engine component, and a controller including a memory and a processor that controls the scheduling valve, wherein the memory includes an engine performance model, wherein the engine performance model includes stored relationship values between more than one condition experienced by the gas turbine engine during operation and a position of the scheduling valve, and wherein the scheduling valve varies a flow of the lubricant to the first engine component, the second e

Abstract: A control system for a gas turbine engine includes a processing system operable to control a speed of the gas turbine engine and a memory system. The memory system is operable to store instructions executable by the processing system to determine at least one performance parameter associated with a stall condition of the gas turbine engine and to incrementally adjust an acceleration rate of the gas turbine engine based on detecting a degraded stall line limit according to the at least one performance parameter.

Abstract: A method of protecting fuel hardware for a gas turbine engine in an aircraft is disclosed. The method may include determining a current altitude of the aircraft, and controlling a temperature of fuel for the gas turbine engine based at least in part on the current altitude. A thermal management system for a gas turbine engine in an aircraft is also disclosed. The thermal management system may include a sensor configured to detect a current altitude of the aircraft, and a controller in operative communication with the sensor. The controller may be configured to manage a fuel temperature for the gas turbine engine based at least in part on the current altitude detected by the sensor.