Abstract: The present disclosure provides methods and systems for determining a synthesized engine parameter of a gas turbine engine. An initial model parameter is obtained from an onboard model associated with the gas turbine engine. A correction factor for the onboard model is determined by modifying a difference between the onboard model and an aero-thermal model of the gas turbine engine using first and second engine parameters and first and second operating conditions, wherein the first and second engine parameters are independent from one another over an operating envelope of the gas turbine engine. The initial model parameter is scaled by applying the correction factor thereto to obtain a corrected model parameter. The corrected model parameter is output as the synthesized engine parameter.

Abstract: The present disclosure provides methods and systems for operating a multi-engine rotorcraft. The method comprises driving a rotor of the rotorcraft with a first engine while a second engine is de-clutched from a transmission clutch system that couples the rotor and the second engine, instructing the second engine to accelerate to a re-clutching speed, and controlling an output shaft speed of the second engine during acceleration of the second engine to the re-clutching speed by applying a damping function to a speed control loop of the second engine.

Abstract: Systems and method for filling a fuel manifold comprising at least a primary and a second manifold of a gas turbine engine are described. The method comprises providing fuel flow to the secondary manifold of the gas turbine engine, the secondary manifold being partly or completely empty; monitoring at least one engine operational parameter of the gas turbine engine as fuel fills the secondary manifold; and accelerating the engine when a transition threshold is reached, the transition threshold being associated with the engine operational parameter and indicative that fuel has reached the combustor.

Abstract: The present disclosure provides methods and systems for fault detection for a speed sensing system of a multi-engine rotorcraft. A shaft speed for a first engine and a rotor speed for at least one rotor of the multi-engine rotorcraft are obtained. The shaft speed is compared to the rotor speed. When the shaft speed is greater than the rotor speed, a first fault in the speed sensing system is detected and a first speed sensing system fault signal is issued. When the shaft speed is less than the rotor speed, a determination is made regarding whether the first engine is coupled the at least one rotor based on a fuel flow to the first engine. A second fault in the speed sensing system is detected and a second speed sensing system fault signal is issued responsive to determining that the first engine is coupled to the at least one rotor.

Abstract: Systems and methods for adjusting a variable geometry mechanism of an engine are described herein. An engine control request indicative of a desired output power for the engine is monitored. A rate of change of the engine control request is determined. The rate of change is compared to a threshold. Responsive to determining that the rate of change is beyond the threshold, a transient bias map is applied to a steady-state schedule to generate a variable geometry mechanism request indicative of a target position for the variable geometry mechanism. The variable geometry mechanism is adjusted toward the target position according to the variable geometry mechanism request.

Abstract: The present disclosure provides methods and systems for determining a synthesized engine parameter of a gas turbine engine. An initial model parameter is obtained from an onboard model associated with the gas turbine engine. A correction factor for the onboard model is determined by modifying a difference between the onboard model and an aero-thermal model of the gas turbine engine using first and second engine parameters and first and second operating conditions, wherein the first and second engine parameters are independent from one another over an operating envelope of the gas turbine engine. The initial model parameter is scaled by applying the correction factor thereto to obtain a corrected model parameter. The corrected model parameter is output as the synthesized engine parameter.

Abstract: The present disclosure provides methods and systems for fault detection for a speed sensing system of a multi-engine rotorcraft. A shaft speed for a first engine and a rotor speed for at least one rotor of the multi-engine rotorcraft are obtained. The shaft speed is compared to the rotor speed. When the shaft speed is greater than the rotor speed, a first fault in the speed sensing system is detected and a first speed sensing system fault signal is issued. When the shaft speed is less than the rotor speed, a determination is made regarding whether the first engine is coupled the at least one rotor based on a fuel flow to the first engine. A second fault in the speed sensing system is detected and a second speed sensing system fault signal is issued responsive to determining that the first engine is coupled to the at least one rotor.

Abstract: Herein provided is a signal processing device for use in an aircraft engine with a variable geometry mechanism (VGM) and associated systems and methods. The signal processing device comprises a processing unit and a non-transitory computer-readable memory communicatively coupled to the processing unit. The memory has stored thereon computer-readable program instructions executable by the processing unit for: obtaining a VGM position request signal; determining whether a variation of the VGM position request signal is within a predetermined range; when the variation of the VGM position request signal is within the predetermined range: filtering the VGM position request signal to reduce a level of noise in the VGM position request signal; and transmitting the filtered VGM position request signal; and when the variation of the VGM position request signal is not within the predetermined range, transmitting a processed signal, based on the VGM position request signal.

Abstract: Herein provided are methods and systems for controlling an engine having a variable geometry mechanism. A pressure ratio between a first pressure at an inlet of the engine and a predetermined reference pressure is determined. An output power for the engine is determined. The output power is adjusted based at least in part on the pressure ratio to obtain a corrected output power. A position control signal for a variable geometry mechanism of the engine is generated based on the corrected output power and the pressure ratio. The position control signal is output to a controller of the engine to control the variable geometry mechanism.

Abstract: There is described a shaft shear event detection method. The method comprises storing in memory a shaft oscillation signature determined as a function of known characteristics of the shaft and associated with a shaft shear event; monitoring a rotational speed of the shaft; detecting from the rotational speed an oscillation wave superimposed on the rotational speed by detecting a first period below a lower threshold and a second period above an upper threshold, and detecting a rate of occurrence of the first period and the second period, the oscillation wave having a wave modulation frequency corresponding to the rate of occurrence and a wave modulation amplitude; comparing the oscillation signature to the oscillation wave; and detecting the shaft shear event when the oscillation wave corresponds to the oscillation signature.

Abstract: Systems and method for filling a fuel manifold comprising at least a primary and a second manifold of a gas turbine engine are described. The method comprises providing fuel flow to the secondary manifold of the gas turbine engine, the secondary manifold being partly or completely empty; monitoring at least one engine operational parameter of the gas turbine engine as fuel fills the secondary manifold; and accelerating the engine when a transition threshold is reached, the transition threshold being associated with the engine operational parameter and indicative that fuel has reached the combustor.

Abstract: Herein provided are methods and systems for controlling an engine having a variable geometry mechanism. A pressure ratio between a first pressure at an inlet of the engine and a predetermined reference pressure is determined. An output power for the engine is determined. The output power is adjusted based at least in part on the pressure ratio to obtain a corrected output power. A position control signal for a variable geometry mechanism of the engine is generated based on the corrected output power and the pressure ratio. The position control signal is output to a controller of the engine to control the variable geometry mechanism.

Abstract: Systems and methods for controlling a gas turbine engine and a propeller are described herein. A target output power for the engine and a target speed for the propeller are received. A measurements of at least one engine parameter and a measurement of at least one propeller parameter are received. At least one engine control command is generated based on the target output power, the measurement of the at least one engine parameter and at least one model of the engine. At least one propeller control command is generated based on the target speed, the measurement of the at least one propeller parameter and the at least one model of the propeller. The at least one engine control command is output for controlling an operation of the engine accordingly and the at least one propeller control command is output for controlling an operation of the propeller accordingly.

Abstract: The present disclosure provides methods and systems for operating a multi-engine rotorcraft. The method comprises driving a rotor of the rotorcraft with a first engine while a second engine is de-clutched from a transmission clutch system that couples the rotor and the second engine, instructing the second engine to accelerate to a re-clutching speed, and controlling an output shaft speed of the second engine during acceleration of the second engine to the re-clutching speed by applying a damping function to a speed control loop of the second engine.

Abstract: Herein provided are methods and systems for controlling an engine having a variable geometry mechanism. A pressure ratio between a first pressure at an inlet of the engine and a predetermined reference pressure is determined. A fuel flow rate to the engine is determined. The fuel flow rate is adjusted based at least in part on the pressure ratio to obtain a corrected fuel flow rate. A position control signal for the variable geometry mechanism of the engine is generated based on the corrected fuel flow rate. The position control signal is output to a controller of the engine to control the variable geometry mechanism.

Abstract: Herein provided is a signal processing device for use in an aircraft engine with a variable geometry mechanism (VGM) and associated systems and methods. The signal processing device comprises a processing unit and a non-transitory computer-readable memory communicatively coupled to the processing unit. The memory has stored thereon computer-readable program instructions executable by the processing unit for: obtaining a VGM position request signal; determining whether a variation of the VGM position request signal is within a predetermined range; when the variation of the VGM position request signal is within the predetermined range: filtering the VGM position request signal to reduce a level of noise in the VGM position request signal; and transmitting the filtered VGM position request signal; and when the variation of the VGM position request signal is not within the predetermined range, transmitting a processed signal, based on the VGM position request signal.

Abstract: Systems and methods for adjusting a variable geometry mechanism of an engine are described herein. An engine control request indicative of a desired output power for the engine is monitored. A rate of change of the engine control request is determined. The rate of change is compared to a threshold. Responsive to determining that the rate of change is beyond the threshold, a transient bias map is applied to a steady-state schedule to generate a variable geometry mechanism request indicative of a target position for the variable geometry mechanism. The variable geometry mechanism is adjusted toward the target position according to the variable geometry mechanism request.

Abstract: Systems and methods for controlling a gas turbine engine and a propeller are described herein. A target output power for the engine and a target speed for the propeller are received. A measurements of at least one engine parameter and a measurement of at least one propeller parameter are received. At least one engine control command is generated based on the target output power, the measurement of the at least one engine parameter and at least one model of the engine. At least one propeller control command is generated based on the target speed, the measurement of the at least one propeller parameter and the at least one model of the propeller. The at least one engine control command is output for controlling an operation of the engine accordingly and the at least one propeller control command is output for controlling an operation of the propeller accordingly.

Abstract: Herein provided are methods and systems for detecting an uncommanded or uncontrollable high thrust (UHT) event in an aircraft, comprising arming a UHT function, comparing an engine fan speed to a reference target and detecting a first condition when a first threshold is exceeded, comparing a rate of change of a high pressure rotor speed to a reference deceleration schedule and detecting a second condition when a second threshold is exceeded, detecting a UHT event based on excess thrust when the first condition and the second condition are detected, and accommodating the UHT event.

Abstract: There is described a shaft shear event detection method. The method comprises storing in memory a shaft oscillation signature determined as a function of known characteristics of the shaft and associated with a shaft shear event; monitoring a rotational speed of the shaft; detecting from the rotational speed an oscillation wave superimposed on the rotational speed by detecting a first period below a lower threshold and a second period above an upper threshold, and detecting a rate of occurrence of the first period and the second period, the oscillation wave having a wave modulation frequency corresponding to the rate of occurrence and a wave modulation amplitude; comparing the oscillation signature to the oscillation wave; and detecting the shaft shear event when the oscillation wave corresponds to the oscillation signature.