Abstract: Embodiments of systems and methods for air recovery are disclosed. The diverted pressurized air may be used to supply a hydrostatic purge to the unutilized portion of a turbine engine fuel manifold circuit to ensure that exhaust gases from the utilized side of the fuel manifold circuit do not enter the portion of the alternative fuel manifold circuit rack. The assembly used to remove compressor section pressurized air may include a flow control orifice, line pressure measuring instrumentation, non-return valves, isolation valves and hard stainless-steel tubing assemblies. In some embodiments, a turbine compressor section diverter system may include a small air receiver used to increase the volume of air supplying the manifold to aid in potential pressure and flow disruptions from a turbine engine compressor section.

Abstract: A fuel control system for a gas turbine engine includes a fuel metering valve, a pressure raising and shut-off valve (PRSOV), and a shutoff effector including a first stage unit that is electrically powered and a second stage unit that is controlled by the first stage unit. The second stage unit actuates a valve member of the PRSOV between an open position that allows supply of a fuel to burners of the gas turbine engine and a closed position that prevents supply of the fuel to the burners. Upon loss of electrical power to the first stage unit during operation of the gas turbine engine, the first stage unit is configured to: control the second stage unit to actuate the valve member of the PRSOV to the closed position after a predetermined time duration; or retain the valve member of the PRSOV in the open position.

Abstract: Disclosed herein are an apparatus and method fluid flow measurements which include a pressure transducer and a flexible tube. The pressure transducer is tuned to measure flow speeds having a Reynolds number less than 100 and include an inlet. The flexible tube has a first end fluidly coupled to the inlet and a second end positioned adjacent to and in fluid communication with a plurality of fluid outlets of a microchannel flow structure. Each of the plurality of fluid outlets has a cross section defining an outlet area. The second end has a cross section defining a flexible tube area that is larger than the outlet area.

Abstract: A fuel supply system includes a pump to be connected to a fuel tank. A metering valve is downstream of the pump. A control is programmed to control at least one of the pump and metering valve. The control is operable to take in a flow demand signal and a fuel pressure signal from a controller associated with a gas turbine engine. The flow demand signal is indicative of a desired flow volume and the fuel pressure signal is indicative of a desired fuel pressure. Operation conditions are identified for the at least one of said pump and the metering valve. A gas turbine engine and fuel supply system is also disclosed.

Abstract: A system for multiple burns from a solid fuel rocket motor may extinguish rocket fuel after the rocket has been ignited. The motor may be extinguished via rapid decompression of the combustion chamber. The fuel may then be reignited by a suitable igniter, and the process of extinguishing and reigniting may be repeated, enabling multi-burn maneuvers. A decompressive extinguishing plug nozzle may extinguish solid rocket fuel after the rocket has been ignited and/or keep a rocket in a disarmed (zero thrust) state until the rocket is to be armed. The nozzle may include a plug that mostly impedes the opening of the nozzle and an outer cowl that is movable to rapidly decompress the combustion chamber. This rapid decompression extinguishes the solid rocket fuel. In some aspects, the fuel can be reignited and extinguished multiple times.

Abstract: A fuel system for a turbomachine includes a fuel tank and a first fuel line in fluid communication with the fuel tank and one or more fuel injectors. The first fuel line includes a main fuel pump disposed on the first fuel line, and an electric metering system disposed on the first fuel line downstream of the main fuel pump configured for starting the turbomachine and metering fuel to the fuel injectors.

Abstract: A twin-flow, double body turbojet includes a fan that is positioned upstream from a gas generator and delimits primary and secondary flows. The gas generator is traversed by the primary flow and includes a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine. The low-pressure turbine is linked to the low-pressure compressor by a low-pressure rotating shaft, and the high-pressure turbine is linked to the high-pressure compressor by a high-pressure rotating shaft. The turbojet has an electric motor for injecting mechanical power into at least one of the rotating shafts. The turbojet also has a device for removing power from at least one of the rotating shafts and transforming the excess power into electrical energy. An electric storage means is positioned between the device for removing power and the electric motor.

Abstract: A gas turbine including a fuel gas supply system to supply fuel gas via a fuel piping to a gas turbine combustor, a pressure control valve installed halfway along the fuel piping, a flow control valve installed in the fuel piping at downstream of the pressure control valve, and a control device configured that in a case where a flow rate change occurs in the fuel gas flowing through the fuel gas supply system, along with a tendency of change in an opening degree of the pressure control valve or a pressure P1 at upstream of the pressure control valve, a command value of the flow rate of the fuel gas that is determined based on a demand value of a gas turbine load is adjusted so that the change is suppressed in the opening degree of the pressure control valve or the pressure P1.

Abstract: A flow metering system includes a pump configured to urge a fluid flow from a fluid source, and a recirculation line located at the pump. A pressure regulating valve is located along the recirculating line. One or more fluid delivery lines extend downstream of the pump to deliver the fluid flow to one or more fluid consumers. A flow control valve is located along each fluid delivery line of the one or more fluid delivery lines. A system controller is operably connected to the pressure regulating valve and the one or more flow control valves. The system controller is configured to maintain a selected delta pressure and a selected flow rate of the fluid flow by operation of the pressure regulating valve and the one or more flow control valves.

Abstract: A system comprises a variable displacement pump, a metering valve, a bypass line, a pressure regulating valve, a position sensor, and a control system. At least one fuel nozzle can be in fluid communication with the output line downstream of the metering valve, wherein the variable displacement pump is configured to supply fuel to the at least one fuel nozzle. The metering valve can be disposed in the output line for controlling outlet flow from the variable displacement pump. The system can also include an actuator line parallel to the variable displacement pump and connected to the output line to provide actuation pressure from pump output of the variable displacement pump.

Abstract: This disclosure provides an apparatus and method for harnessing machine learning and data analytics for a real-time predictive model for a FCC pre-treatment unit. The method includes collecting operating parameters of a pre-treatment unit and fluid catalytic cracking (FCC) unit; evaluating an independent variable of the operating parameters; and adjusting an input to the pre-treatment unit to control the independent variable within specifications in an output of the FCC unit.

Abstract: A system includes a thermal engine operatively connected to drive a propeller. An electric motor is operatively connected to the thermal engine to drive the propeller together with the thermal engine. An external input system is configured to accept input and output a thrust command. A protection function module is configured to enforce limits on the thermal engine, electric motor, and propeller. A low select module is operatively connected to receive input from the external input system and form the protection function module and to output the lower of input from the protection function module and external input system to the thermal engine, the electric motor, and the propeller.

Abstract: Techniques for determining a fan spool speed value associated with a hybrid electric gas engine (“engine”) are described herein. For example, a method includes generating a first fan spool speed value based on a base extraction amount. The method further includes generating a change in the first fan spool speed value based on a flight condition and a change in extraction amount. The method further includes generating a second fan spool speed value based on the extraction amount and an augmentation value for intersection of a combustion instability and burner pressure limit. The method further includes generating a second change in the second fan spool speed value based on the flight condition and the change in extraction amount. The method further includes determining a final fan spool speed value and operating the engine at the final fan spool speed value.

Abstract: A fuel control device includes a stem fuel valve opening degree determination unit, a branch line flow rate determination unit, and a correction value determination unit. The stem fuel valve opening degree determination unit is configured to determine an opening degree of a flow rate adjustment valve of a stem fuel supply line. The branch line flow rate determination unit is configured to determine an opening degree of a flow rate adjustment valve of at least one branch line. The correction value determination unit is configured to determine a correction value of the opening degree of the flow rate adjustment valve of the at least one branch line based on a value of a pressure difference between a fuel pressure upstream of a nozzle connected to the at least one branch line and a corrected fuel pressure for a fuel pressure at an outlet.

Abstract: A system includes a gas turbine engine having a low speed spool, a high speed spool, and a combustor. The system also includes a low spool motor configured to augment rotational power of the low speed spool. The system further includes a controller configured to cause fuel flow. The controller is operable to control the low spool motor to drive rotation of the low speed spool responsive to a thrust command while the controller does not command fuel flow to the combustor.

Abstract: A mounting member for a sensor for a turbomachine having an axis is disclosed. The mounting member includes a body configured to mount to a portion of a circumferential interior surface of a casing of the turbomachine. An opening extends through a radially inner surface of the body, and is configured to position the sensor facing radially inward relative to the axis. A passage in the body extends longitudinally through the body to route a communications lead of the sensor circumferentially relative to the circumferential interior surface of the casing.

Abstract: A method of delivering fuel to an engine during operation of the engine, that includes, sensing the speed of sound in the fuel, determining a density or property of the fuel, and based on that density or fuel property adjusting the flow rate of the fuel. Further, an established fuel profile or determined energy density value can also be used to adjust the flow rate of the fuel.

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: A gas turbine engine includes a compressor section and a turbine section. A first spool is rotatable with a first turbine of the turbine section and a first compressor of the compressor section. Additionally, a second spool is rotatable with a second turbine of the turbine section and a second compressor of the compressor section. An electric machine is positioned at least partially inward of the core air flowpath of the gas turbine engine along a radial direction of the gas turbine engine. Additionally, the exemplary gas turbine engine includes a gear assembly mechanically coupled to both the first spool and the second spool, such that the first and second spools may each drive the electric machine.

Abstract: The present disclosure relates to systems and methods that are useful in control of one or more aspects of a power production plant. More particularly, the disclosure relates to power production plants, methods of starting power production plants, and methods of generating power with a power production plant wherein one or more control paths are utilized for automated control of at least one action. The present disclosure more particularly relates to power production plants, control systems for power production plants, and methods for startup of a power production plant.

Abstract: A pumping system includes a pump array of multiple pump-engine assemblies. Each pump-engine assembly comprises a pump and a gas turbine engine driving the pump. A manifold is coupled to the pumps. A master controller is coupled to each of the pump-engine assemblies either directly or via one or more intermediate controllers. The master controller and any intermediate controllers are collectively programmed to respond to user input including a desired hydraulic output at the manifold by automatically calculating and applying inputs to the individual pump-engine assemblies to provide the desired hydraulic output.

Abstract: A method of deactivating a liquid distribution system of a gas turbine engine in the event of a fire condition includes introducing a quantity of air into the liquid distribution system at a location upstream of a liquid pump of the liquid distribution system. The quantity of air is greater than a liquid discharge capacity of the liquid pump, thereby starving the liquid pump.

Abstract: Device and method for regulating a flow rate of gas intended to supply a propulsion apparatus for a spacecraft comprising xenon tank, a circuit comprising a withdrawing pipe having an upstream end connected to the tank and a downstream end connected to a propulsion member, the withdrawing pipe comprising an isolation first valve, a regulating second valve and a member for measuring the pressure downstream of the regulating second valve. The regulating second valve regulates the flow rate and/or the determined pressure according to the pressure measured. The regulating second valve is a proportional valve of electrically operated variable throughout PCV type.

Abstract: A gas turbine engine includes a core having a compressor section with a first compressor and a second compressor, a turbine section with a first turbine and a second turbine, and a primary flowpath fluidly connecting the compressor section and the turbine section. The first compressor is connected to the first turbine via a first shaft, the second compressor is connected to the second turbine via a second shaft, and a motor is connected to the first shaft such that rotational energy generated by the motor is translated to the first shaft. The gas turbine engine includes a takeoff mode of operation, a top of climb mode of operation, and at least one additional mode of operation. The gas turbine engine is undersized relative to a thrust requirement in at least one of the takeoff mode of operation and the top of climb mode of operation, and a controller is configured to control the mode of operation of the gas turbine engine.

Abstract: Herein provided are methods and systems for a method for controlling autothrottle of an engine. A digital power request is obtained from an autothrottle controller, the digital power request based on an autothrottle input to the autothrottle controller. A manual input mode for the engine is terminated, the manual input mode based on a second power request obtained from a manual input associated with the engine. An autothrottle mode for the engine is engaged to control the engine based on the digital power request.

Abstract: A fuel metering circuit for a turbomachine includes: a meter; a pump; a control valve configured to return an excess flow of fuel delivered to the meter towards the pump on the basis of a fuel pressure differential at the terminals of the meter; a diaphragm; and a volumetric flow meter. The diaphragm and the volumetric flow meter are mounted parallel to the meter, downstream of the control valve, in order to determine a density of the fuel flowing in the metering circuit.

Abstract: Systems and methods for operating an engine of a rotorcraft are described herein. An engine parameter indicative of torque of the engine is obtained. A decrease of the torque of the engine is detected. At least one rotorcraft parameter indicative of at least one command to control the rotorcraft is obtained and evaluated to determine whether one of an autorotation mode and a powered flight mode of the rotorcraft has been commanded. When the powered flight mode of the rotorcraft has been commanded and the decrease of the torque has been detected, a shaft shear of the engine is detected and a signal indicative of the shaft shear is transmitted. When the autorotation mode of the rotorcraft has been commanded and the decrease of the torque has been detected, detection of the shaft shear is disabled during operation in the autorotation mode.

Abstract: A control system for limiting a power turbine torque of a gas turbine engine is disclosed. In various embodiments, the control system includes an engine control module configured to output an effector command signal to a gas generator of the gas turbine engine; a power turbine governor module configured to output to the engine control module a power turbine torque request signal; and a power turbine torque limiter module configured to output to the power turbine governor module a power turbine speed rate signal to limit a power turbine speed overshoot of the gas turbine engine.

Abstract: A method of monitoring bleed air provided from a first engine to a second engine of a multi-engine aircraft includes operating the first engine in a powered mode to provide motive power to the multi-engine aircraft; and when the first engine is in the powered mode: actuating an air valve to open an air flow path from a compressor section of the first engine to a plurality of parts of the second engine, after the step of actuating the air valve, determining a change in a temperature in a main gas path of the first engine at a location in the main gas path at or downstream of a combustor of the first engine, and in response to determining that the change is below a threshold, executing an action with respect to the first engine, the air valve, and/or the second engine.

Abstract: A compressor surge control system includes a rotor system with at least one compressor section and at least one turbine section operably coupled to a shaft. The compressor surge control system also includes one or more rotor system sensors configured to collect a plurality of sensor data from the rotor system, an electric motor operably coupled to the rotor system, and a controller. The controller is operable to monitor the one or more rotor system sensors while the rotor system is rotating. The controller determines whether the plurality of sensor data from the one or more rotor system sensors is indicative of an early-stage compressor surge oscillation. A surge control torque is determined to diminish the early-stage compressor surge oscillation of the rotor system. The electric motor is commanded to apply the surge control torque to the rotor system.

Abstract: An engine control system includes an electronic hardware engine controller in signal communication with at least one engine sensor, which measures an engine operating parameter (Ycrtr_t). The engine controller generates a synthesized engine operating parameter (Ycrtr) calculates an error (ERRcrtr) between the engine operating parameter (Ycrtr_t) and the synthesized engine operating parameter (Ycrtr). The engine controller further determines a corrector error parameter (Xcrtr) and determines a faulty sensor among the at least one engine sensor based on a comparison between the error value (ERRcrtr) and the corrector error parameter (Xcrtr).

Abstract: An engine system for an aircraft includes a first gas turbine engine, a second gas turbine engine, and a control system. The control system is configured to operate the first gas turbine engine with an idle fuel burn schedule in a taxi mode of the aircraft and operate the second gas turbine engine with a sub-idle fuel burn schedule in the taxi mode of the aircraft. The sub-idle fuel burn schedule includes a reduction of the idle fuel burn schedule. A fuel flow of the first gas turbine engine and the second gas turbine engine is increased above the idle fuel burn schedule prior to takeoff of the aircraft.

Abstract: The invention relates to a method for checking a measurement supplied by a sensor (2) of a turbine engine, said method being implemented by a computer (5) of the turbine engine. The method comprises the processing steps of: acquiring a first value of the measurement; comparing an increment with an increment threshold; and transmitting a measurement to be processed to the processing interface (6), said measurement being selected so as to be: equal to the value of an estimation model for the received measurement, if the increment is higher than the increment threshold, or equal to the acquired first value of the measurement if the increment is lower than the increment threshold, the method then comprising additional processing steps.

Abstract: A method of actively controlling torsional resonance of a rotating shaft of an engine is provided. The shaft has a rotational velocity characterised by a low frequency, rotational velocity term and a high frequency, oscillatory term superimposed on the low frequency term, the oscillatory term being caused by torsional resonance. The method including: measuring the rotational velocity of the shaft; extracting the oscillatory term from the measured rotational velocity; and on the basis of the extracted oscillatory term, applying a torque component to the shaft, the torque component being modulated at the same frequency as the torsional resonance to counteract the torsional resonance.

Abstract: A full authority digital engine controller (FADEC) based system is also disclosed. The system includes a processor, and a tangible, non-transitory memory configured to communicate with the processor, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the processor, cause the FADEC to perform operations. The operations may include measuring a first temperature at a first sensor disposed at a first known location of an engine, measuring a second temperature at a second sensor disposed at a second known location of the engine, and estimating at least one of a stress or a strain of a part or component in the engine based on the first temperature and the second temperature. The system may control fuel flow and/or other engine effectors during a thrust transient to limit the estimated stress or the estimated strain of the component from exceeding a predetermined threshold.

Abstract: A combustor system for a gas turbine engine includes a combustor case, a combustor liner disposed within the combustor case and defining a main combustion chamber, a dome defining an upstream end of the main combustion chamber, and at least one torch injector attached to the dome of the main combustion chamber configured to inject combustion gases into the main combustion chamber. Each torch injector includes a torch injector housing defining and surrounding a torch combustion chamber configured to house a combustion reaction, an outlet passage defined by the torch injector housing, an electrothermal ignition source extending at least partially into the torch combustion chamber, and a fuel injector configured to inject fuel into the torch combustion chamber to at least partially impinge on the electrothermal ignition source and generate the combustion gases. The outlet passage directly fluidly connects the torch combustion chamber to the main combustion chamber.

Abstract: A low-temperature turbocompressor structural arrangement for an internal combustion engine for using energy that is available but unused during operation to cool the air supplied to the engine by supercharging. The temperature of the air compressed by the compressor is reduced by a cooling system and the air is then conveyed to a further turbine actuated by the intake air flow of the engine. The structural arrangement may be mounted in full or in part, and also each component may be fitted into existing systems.

Abstract: A balancing system and method for an engine of an aircraft includes a housing retaining a magnetorheological fluid including magnetic particles within a carrier fluid. Electromagnets are coupled to the housing. The electromagnets are associated with fan blades of the engine. A balancing control unit is in communication with the electromagnets and sensors of the fan blades.

Abstract: An aircraft includes an engine, a thrust reverser, landing gear, a brake system, a pilot input device, and a control system. The engine is configured to generate thrust directed to move the aircraft in a forward direction. The landing gear includes wheels. The brake system is configured to generate a braking force on the wheels. The pilot input device is positioned for use by a pilot of the aircraft. The control system is programmed to: determine whether the taxi operations are allowed; receive a request to achieve and hold a taxi speed at a desired taxi speed from the pilot input device; and command the engine, the thrust reverser, and the brake system to achieve and maintain the desired taxi speed in response to receiving the request to hold taxi speed only when the taxi operations are allowed.

Abstract: A system for regulating a thermal parameter associated with a heat exchange assembly of a turbomachine includes at least one device for measuring or estimating the thermal parameter, a controlled valve acting on the flow rate of a fluid in the assembly, and a regulator including a comparator determining the sign of an error signal relating to the difference between the thermal parameter and a setpoint. The regulator further includes a switch configured to deliver, based on the sign, to a valve control system, a maximum control current switching the valve in a closed state or a minimum control current switching the valve in an open state, and a phase-shifter configured to apply on the error signal a phase advance determined from an estimate of a time constant of the control system.

Abstract: A fuel supply system for a gas turbine engine includes a fuel tank, a pumping unit downstream of the fuel tank and configured to receive fuel from the fuel tank, and a sharing valve downstream of the pumping unit and configured to receive fuel from the cruise pump of the pumping unit during a first operating condition. The pumping unit includes a boost pump, an actuation pump downstream of the boost pump and in fluid communication with at least one actuator of the gas turbine engine, and a cruise pump downstream of the boost pump and in fluid communication with nozzles of a gas generator of the gas turbine engine.

Abstract: A method of operating a rotary machine below a minimum emissions compliance load in a response mode includes reducing a fuel split to zero. The fuel split apportions a total flow of fuel to the combustor between a first combustion zone and a second combustion zone. The method also includes determining a current operating temperature of the first combustion zone using a digital simulation of the rotary machine. The method further includes determining a target operating temperature of the first combustion zone. The target operating temperature enables the rotary machine to operate below a traditional Minimum Emissions Compliance Load (MECL) while still in compliance with emissions standards. The method also includes channeling a first flow of fuel to the first combustion zone. The first flow of fuel decreases the temperature of the first combustion zone to the target operating temperature.

Abstract: Provided herein is a method for automated control of the gas turbine fuel composition through automated modification of the ratio of fuel gas from multiple sources. The method includes providing first and second fuel sources. The method further includes sensing the operational parameters of a turbine and determining whether the operational parameters are within preset operational limits. The method also adjusting the ration of the first fuel source to the second fuel source, based on whether the operational parameters are within the preset operational limits.

Abstract: An engine system for an aircraft includes a first gas turbine engine, a second gas turbine engine, and a control system. The control system is configured to operate the first gas turbine engine with an idle fuel burn schedule in a taxi mode of the aircraft and dry crank the second gas turbine engine in a first pre-takeoff portion of the taxi mode to cool the second gas turbine engine absent fuel burn by the second gas turbine engine. The control system operates the second gas turbine engine with a sub-idle fuel burn schedule in a second pre-takeoff portion of the taxi mode of the aircraft. The sub-idle fuel burn schedule includes a reduction of the idle fuel burn schedule. A fuel flow of the first gas turbine engine and the second gas turbine engine is increased above the idle fuel burn schedule prior to takeoff of the aircraft.

Abstract: A fuel system for a turbomachine includes a fuel tank and a first fuel line in fluid communication with the fuel tank and one or more fuel injectors. The first fuel line includes a main fuel pump disposed on the first fuel line, and an electric metering system disposed on the first fuel line downstream of the main fuel pump configured for starting the turbomachine and metering fuel to the fuel injectors.

Abstract: A gas turbine fuel supply system includes a fuel supply flow passage that includes a fuel gas heater which heats fuel and supplies the fuel heated by the fuel gas heater to a first nozzle and a second nozzle, a bypass flow passage that supplies the fuel to the first nozzle without passing through the fuel supply flow passage, and a bypass fuel flow rate adjusting valve that adjusts a flow rate of the fuel flowing in the bypass flow passage.

Abstract: The invention relates to an architecture of a propulsion system of a multi-engine helicopter comprising turboshaft engines connected to a power transmission gearbox, characterised in that it comprises: at least one hybrid turboshaft engine (20) capable of operating in at least one standby mode during a stable cruise flight of the helicopter; at least two systems (30; 40) for controlling each hybrid turboshaft engine (20), each system (30; 40) comprising an electric machine (31; 41) connected to the hybrid turboshaft engine (20) and suitable for rotating the gas generator thereof, and at least one source (33; 43) of electrical power for said electric machine (31; 41), each reactivation system (30; 40) being configured such that it can drive said turboshaft engine (20) in at least one operating mode among a plurality of predetermined modes.

Abstract: Methods and systems are provided for controlling a component of an aircraft engine by communicating data over an inner control loop portion of a distributed engine control network for an aircraft; and controlling an operation of the aircraft engine by communicating encrypted data over an outer control loop portion of the distributed engine control network, wherein the data communicated over the inner control loop portion is unencrypted or encrypted with weaker encryption than the data communicated over the outer control loop portion.

Abstract: Herein provided are methods and systems for setting an acceleration schedule for engine start of a gas turbine engine. A rotational acceleration measurement of the engine is obtained after the engine is energized in response to a start request. The rotational acceleration measurement of the engine is compared to a threshold value within an acceleration band having a maximum threshold and a minimum threshold. An acceleration schedule is determined based on a position of the rotational acceleration measurement of the engine in the acceleration band relative to the threshold value.

Abstract: Systems and methods for conditionally performing engine operational tests for a turbine engine are provided. A system comprising at least one processor can be configured to obtain sensor data associated with at least one sensor for a turbine engine. The sensor data identifies a current fuel flow associated with the turbine engine. The system can determine a predicted fuel flow of the turbine engine based at least in part on the current fuel flow and a fuel flow reduction associated with an engine operational test. The system can compare the predicted fuel flow to at least one threshold. The system can selectively initiate the engine operational test based on comparing the predicted fuel flow to the at least one threshold.