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: A bowed rotor prevention system for a gas turbine engine includes a core turning motor operable to drive rotation of an engine core of the gas turbine engine. The bowed rotor prevention system also includes an auxiliary electric motor control operable to control the core turning motor to drive rotation of the engine core using electric power while a full authority digital engine control that controls operation of the gas turbine engine is either depowered or in a power state that is less than a power level used by the full authority digital engine control in flight operation.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a bowed rotor prevention motor. A motor shaft of the bowed rotor prevention motor is operable to drive rotation of the gas turbine engine through an engine accessory gearbox. The motor shaft interfaces with an air turbine operable to rotate an output shaft mechanically linked to the engine accessory gearbox. The bowed rotor prevention system also includes a controller operable to engage the bowed rotor prevention motor and drive rotation of the gas turbine engine below an engine starting speed until a bowed rotor prevention threshold condition is met.

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 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 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 for motoring a gas turbine engine of an aircraft is provided. 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 control motoring of the gas turbine engine, detect a fault condition that prevents the controller from maintaining a motoring speed below a threshold level, and command a mitigation action that reduces delivery of the compressed air to the air turbine starter based on detection of the fault condition.

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: A bowed rotor prevention system for a gas turbine engine includes a core turning motor operable to drive rotation of an engine core of the gas turbine engine. The bowed rotor prevention system also includes a full authority digital engine control (FADEC) that controls operation of the gas turbine engine in a full-power mode and controls operation of the core turning motor to drive rotation of the engine core using a reduced power draw when the FADEC is partially depowered in a low-power bowed rotor prevention mode.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a bowed rotor prevention motor operable to drive rotation of the gas turbine engine through an engine accessory gearbox. The bowed rotor prevention system also includes a controller operable to engage the bowed rotor prevention motor and drive rotation of the gas turbine engine below an engine starting speed until a bowed rotor prevention threshold condition is met.

Abstract: The present disclosure provides methods, systems, and computer-readable media for the detection of valve faults based on transient air pressure measurements. For example, a method for fault detection may comprise actuating a shut off valve to an open position, determining a first air pressure of air in an enclosed space at a first time, determining a second air pressure of the air in the enclosed space at a second time and in response to actuation of the shut off valve to an open position, subtracting the first air pressure and the second air pressure to obtain an actual pressure difference, comparing the actual pressure difference to a predetermined pressure difference, and determining, based on the transient comparison, whether at least one of the shut off valve and a check valve is in a failed state.

Abstract: The present disclosure provides methods, systems, and computer-readable media for the detection of valve faults based on transient air pressure measurements. For example, a method for fault detection may comprise actuating a shut off valve to an open position, determining a first air pressure of air in an enclosed space at a first time, determining a second air pressure of the air in the enclosed space at a second time and in response to actuation of the shut off valve to an open position, subtracting the first air pressure and the second air pressure to obtain an actual pressure difference, comparing the actual pressure difference to a predetermined pressure difference, and determining, based on the transient comparison, whether at least one of the shut off valve and a check valve is in a failed state.