Abstract: A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine. A first controller is in communication with a second controller that controls a second engine starting system of a second engine, the first controller being configured to intermittently direct power to the first engine starting system to alternately accelerate and decelerate the first engine during motoring with respect to the second engine.

Abstract: A system is provided for multi-engine coordination of gas turbine engine motoring in an aircraft. The system includes a controller operable to determine a motoring mode as a selection between a single engine dry motoring mode and a multi-engine dry motoring mode based on at least one temperature of a plurality of gas turbine engines and initiate dry motoring based on the motoring mode.

Abstract: A hybrid electric propulsion system includes a gas turbine engine having at least one compressor section and at least one turbine section operably coupled to a shaft. The hybrid electric propulsion system includes an electric motor configured to augment rotational power of the shaft of the gas turbine engine. A controller is operable to determine hybrid electric propulsion system parameters based on a composite system model and sensor data, determine a prediction based on the hybrid electric propulsion system parameters and the composite system model, determine a model predictive control optimization for a plurality of hybrid electric system control effectors based on the prediction using a plurality of reduced-order partitions of the composite system model, and actuate the hybrid electric system control effectors based on the model predictive control optimization.

Abstract: A hybrid electric propulsion system includes a gas turbine engine having at least one compressor section and at least one turbine section operably coupled to a shaft. The hybrid electric propulsion system includes an electric motor configured to augment rotational power of the shaft of the gas turbine engine. A controller is operable to determine an estimate of hybrid electric propulsion system parameters based on a composite system model and sensor data, determine a model predictive control state and a prediction based on the hybrid electric propulsion system parameters and the composite system model, determine a model predictive control optimization for a plurality of hybrid electric system control effectors based on the model predictive control state and the prediction using a plurality of reduced-order partitions of the composite system model, and actuate the hybrid electric system control effectors based on the model predictive control optimization.

Abstract: A system is provided for multi-engine coordination of gas turbine engine motoring in an aircraft. The system includes a controller operable to determine a motoring mode as a selection between a single engine dry motoring mode and a multi-engine dry motoring mode based on at least one temperature of a plurality of gas turbine engines and initiate dry motoring based on the motoring mode.

Abstract: A system is provided for multi-engine coordination of gas turbine engine motoring in an aircraft. The system includes a controller operable to determine a motoring mode as a selection between a single engine dry motoring mode and a multi-engine dry motoring mode based on at least one temperature of a plurality of gas turbine engines and initiate dry motoring based on the motoring mode.

Abstract: A hybrid electric propulsion system includes a gas turbine engine having at least one compressor section and at least one turbine section operably coupled to a shaft. The hybrid electric propulsion system includes an electric motor configured to augment rotational power of the shaft of the gas turbine engine. A controller is operable to determine an estimate of hybrid electric propulsion system parameters based on a composite system model and sensor data, determine a model predictive control state and a prediction based on the hybrid electric propulsion system parameters and the composite system model, determine a model predictive control optimization for a plurality of hybrid electric system control effectors based on the model predictive control state and the prediction using a plurality of reduced-order partitions of the composite system model, and actuate the hybrid electric system control effectors based on the model predictive control optimization.

Abstract: A system for gas turbine engine motoring includes an air turbine starter coupled to a gearbox of a gas turbine engine and a starter air valve in fluid communication with the air turbine starter to drive motoring of the gas turbine engine responsive to a regulated pressure from a compressed air source. A manual override of the starter air valve is adjustable to one or more predefined intermediate positions that partially open the starter air valve to limit a motoring speed of the gas turbine engine below a resonance speed of a starting spool of the gas turbine engine responsive to the regulated pressure.

Abstract: A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine. A first controller is in communication with a second controller that controls a second engine starting system of a second engine, the first controller being configured to intermittently direct power to the first engine starting system to alternately accelerate and decelerate the first engine during motoring with respect to the second engine.

Abstract: A system is provided comprising: a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source; a manual override operably connected to the starter air valve, the manual override is operable to open the starter air valve a select percentage by moving the manual override to a detent engaged position, wherein the select percentage is operable to allow enough airflow to achieve the maximum allowed motoring speed of the gas turbine engine; and a pressure regulating bleed valve in fluid communication with the starter air valve, the pressure regulating bleed valve operable to bleed a portion of the compressed air flow to regulate a motoring speed of the gas turbine engine in response to detection of the manual override in a detent engaged position.

Abstract: According to an aspect, a system includes a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source. The system also includes a variable-position electromechanical device operable to adjust positioning of the starter air valve and a discrete-position electromechanical device operable to adjust positioning of the starter air valve and limit a motoring speed of the gas turbine engine below a resonance speed of the gas turbine engine responsive to a pulse width modulation control based on a failure of the variable-position electromechanical device.

Abstract: A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to coordinate control of the first engine starting system to alternate use of power from a power source relative to use of the power by one or more other engine starting systems of the aircraft while maintaining a starting spool speed of the first engine below a resonance speed of the starting spool during motoring of the first engine.

Abstract: A system is provided for cross engine coordination during gas turbine engine motoring. The system includes a first gas turbine engine of a first engine system, a first air turbine starter of the first engine system, a first starter air valve of the first engine system, and a controller. The controller is operable to command the first starter air valve to control delivery of compressed air to the first air turbine starter during motoring of the first gas turbine engine, monitor cross engine data of a second gas turbine engine of a second engine system to detect a present condition or a commanded action that modifies an aspect of the compressed air received at the first starter air valve, and command an adjustment to the first engine system to compensate for the modified aspect of the compressed air based on the cross engine data.

Abstract: A system is provided for speed control during motoring of a gas turbine engine of an aircraft. The system includes an air turbine starter, a starter air valve operable to deliver compressed air to the air turbine starter, and a controller. The controller is operable to adjust the starter air valve to control motoring of the gas turbine engine based on measured feedback with lead compensation to reject disturbances attributable to dual to single or single to dual engine starting transitions.

Abstract: Systems and methods for rotating a gas turbine engine during a motoring cycle are provided. The system may comprise a controller in electronic communication with an auxiliary power unit (APU), a starter air valve, and a gas turbine engine. The APU may supply compressed air to the starter air valve which may supply the compressed air to an engine starter in mechanical communication with the engine. The rotational speed of the engine may be controlled by the engine starter based on the pressure of the compressed air received from the starter air valve. The controller may be configured to control airflow and air pressure through the system, by modulating the airflow from the APU and/or from the starter air valve.

Abstract: According to an aspect, a system includes a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source. The system also includes a variable-position electromechanical device operable to adjust positioning of the starter air valve and a discrete-position electromechanical device operable to adjust positioning of the starter air valve and limit a motoring speed of the gas turbine engine below a resonance speed of the gas turbine engine responsive to a pulse width modulation control based on a failure of the variable-position electromechanical device.

Abstract: A system is provided comprising: a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source; a manual override operably connected to the starter air valve, the manual override is operable to open the starter air valve a select percentage by moving the manual override to a detent engaged position, wherein the select percentage is operable to allow enough airflow to achieve the maximum allowed motoring speed of the gas turbine engine; and a pressure regulating bleed valve in fluid communication with the starter air valve, the pressure regulating bleed valve operable to bleed a portion of the compressed air flow to regulate a motoring speed of the gas turbine engine in response to detection of the manual override in a detent engaged position.

Abstract: A system for gas turbine engine motoring includes an air turbine starter coupled to a gearbox of a gas turbine engine and a starter air valve in fluid communication with the air turbine starter to drive motoring of the gas turbine engine responsive to a regulated pressure from a compressed air source. A manual override of the starter air valve is adjustable to one or more predefined intermediate positions that partially open the starter air valve to limit a motoring speed of the gas turbine engine below a resonance speed of a starting spool of the gas turbine engine responsive to the regulated pressure.

Abstract: A system is provided for multi-engine coordination of gas turbine engine motoring in an aircraft. The system includes a controller operable to determine a motoring mode as a selection between a single engine dry motoring mode and a multi-engine dry motoring mode based on at least one temperature of a plurality of gas turbine engines and initiate dry motoring based on the motoring mode.

Abstract: A system is provided for cross engine coordination during gas turbine engine motoring. The system includes a first gas turbine engine of a first engine system, a first air turbine starter of the first engine system, a first starter air valve of the first engine system, and a controller. The controller is operable to command the first starter air valve to control delivery of compressed air to the first air turbine starter during motoring of the first gas turbine engine, monitor cross engine data of a second gas turbine engine of a second engine system to detect a present condition or a commanded action that modifies an aspect of the compressed air received at the first starter air valve, and command an adjustment to the first engine system to compensate for the modified aspect of the compressed air based on the cross engine data.