Abstract: Methods and systems for starting an aircraft gas turbine engine are described. The method comprises, in a first phase of a startup upon receipt of a start request, modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor of the gas turbine engine.

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: Methods and systems for starting an aircraft gas turbine engine are described. The method comprises, in a first phase of a startup upon receipt of a start request, modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor of the gas turbine engine.

Abstract: There are described a system and method for operating a thrust reverser of an aircraft engine, the thrust reverser having a deployed state and a stowed state. The method comprises placing the thrust reverser in the stowed state when the thrust reverser is in the deployed state, a thrust lever associated with the engine is in a forward position, and the engine is rotating at a speed below an idle speed, wherein hydraulic pressure for stowing the thrust reverser is provided by a pump driven by the engine rotating at the speed below the idle speed.

Abstract: Methods and systems for starting an aircraft gas turbine engine are described. The method comprises, in a first phase of a startup upon receipt of a start request, modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor of the gas turbine engine.

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: There are described a system and method for operating a thrust reverser of an aircraft engine, the thrust reverser having a deployed state and a stowed state. The method comprises placing the thrust reverser in the stowed state when the thrust reverser is in the deployed state, a thrust lever associated with the engine is in a forward position, and the engine is rotating at a speed below an idle speed, wherein hydraulic pressure for stowing the thrust reverser is provided by a pump driven by the engine rotating at the speed below the idle speed.

Abstract: The present disclosure provides methods and systems for assessing a health state of an engine. During a fuel control failure event experienced by the engine, pressure data indicative of a pressure within a fuel combustor of the engine and acceleration data indicative of an acceleration of a shaft of the engine are obtained. The pressure data and acceleration data are compared to a predetermined limit associated with plastic deformation of the shaft of the engine. A maintenance issue for the engine is detected when the pressure data and the acceleration data are beyond the predetermined limit. An alert associated with a negative health state for the engine is issued responsive to detecting the maintenance issue.

Abstract: The present disclosure provides methods and systems for assessing a health state of an engine. During a fuel control failure event experienced by the engine, pressure data indicative of a pressure within a fuel combustor of the engine and acceleration data indicative of an acceleration of a shaft of the engine are obtained. The pressure data and acceleration data are compared to a predetermined limit associated with plastic deformation of the shaft of the engine. A maintenance issue for the engine is detected when the pressure data and the acceleration data are beyond the predetermined limit. An alert associated with a negative health state for the engine is issued responsive to detecting the maintenance issue.

Abstract: Methods and systems for starting an aircraft gas turbine engine are described. The method comprises, in a first phase of a startup upon receipt of a start request, modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor of the gas turbine engine.

Abstract: A system and method for rotor bow mitigation for a gas turbine engine are provided. An elapsed time since a shutdown of the engine and an idle operation time of the engine prior to the shutdown are determined. A rotor bow mitigation period is determined based on the elapsed time and the idle operation time and, prior to initiating a start sequence of the engine, the engine is motored for a duration of the rotor bow mitigation period.

Abstract: Methods and systems for detecting an uncommanded or uncontrollable high thrust (UHT) event in an aircraft are described. The method comprises detecting an abnormal engine response as a function of a fuel flow error, the fuel flow error indicative of a presence of excess thrust; in response to detecting the fuel flow error, detecting a UHT event based on the excess thrust and as a function of a threshold; and accommodating the UHT event when the UHT event is detected.

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, detecting a fuel flow error when an actual fuel flow minus a commanded fuel flow exceeds a first threshold, the fuel flow error indicative of a presence of excess thrust, detecting a UHT event based on excess thrust and as a function of a second threshold, upon detection of the fuel flow error, and accommodating the UHT event.

Abstract: A system and method for rotor bow mitigation for a gas turbine engine are provided. An elapsed time since a shutdown of the engine and an idle operation time of the engine prior to the shutdown are determined. A rotor bow mitigation period is determined based on the elapsed time and the idle operation time and, prior to initiating a start sequence of the engine, the engine is motored for a duration of the rotor bow mitigation period.

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, detecting a fuel flow error when an actual fuel flow minus a commanded fuel flow exceeds a first threshold, the fuel flow error indicative of a presence of excess thrust, detecting a UHT event based on excess thrust and as a function of a second threshold, upon detection of the fuel flow error, and accommodating the UHT event.

Abstract: The invention deals with increasing the quality of insulating mineral oil in transformers, by providing an isolating layer of flowing nitrogen over the oil's surface to keep ambient air from combining or absorbing with or in the oil, also providing a kidney or filter to remove undesirable contaminants such as water, oxygen, free radicals and debris from the oil, and providing a means of sensing trace gases produced in the oil responsive to transformer conditions and mixed with nitrogen flow to diagnose transformer conditions of interest such as hot-spots, short circuits, insulation failure or similar indicators of failure or incipient failure or need for service, the trace gas analysis being capable of remote monitoring and interpretation. The invention has application in the field of transformers where it is useful to provide self-sufficient and environmentally equipment and methods to prolong service life and reliability between service or inspection of medium, high, and extra-high voltage power.

Abstract: The invention deals with increasing the quality of insulating mineral oil in transformers, by providing an isolating layer of flowing nitrogen over the oil's surface to keep ambient air from combining or absorbing with or in the oil, also providing a kidney or filter to remove undesirable contaminants such as water, oxygen, free radicals and debris from the oil, and providing a means of sensing trace gases produced in the oil responsive to transformer conditions and mixed with nitrogen flow to diagnose transformer conditions of interest such as hot-spots, short circuits, insulation failure or similar indicators of failure or incipient failure or need for service, the trace gas analysis being capable of remote monitoring and interpretation. The invention has application in the field of transformers where it is useful to provide self-sufficient and environmentally equipment and methods to prolong service life and reliability between service or inspection of medium, high, and extra-high voltage power.

Abstract: The invention deals with increasing the quality of insulating mineral oil in transformers, by providing an isolating layer of flowing nitrogen over the oil's surface to keep ambient air from combining or absorbing with or in the oil, also providing a kidney or filter to remove undesirable contaminants such as water, oxygen, free radicals and debris from the oil, and providing a means of sensing trace gases produced in the oil responsive to transformer conditions and mixed with nitrogen flow to diagnose transformer conditions of interest such as hot-spots, short circuits, insulation failure or similar indicators of failure or incipient failure or need for service, the trace gas analysis being capable of remote monitoring and interpretation. The invention has application in the field of transformers where it is useful to provide self-sufficient and environmentally equipment and methods to prolong service life and reliability between service or inspection of medium, high, and extra-high voltage power.

Abstract: The invention deals with increasing the quality of insulating mineral oil in transformers, by providing an isolating layer of flowing nitrogen over the oil's surface to keep ambient air from combining or absorbing with or in the oil, also providing a kidney or filter to remove undesirable contaminants such as water, oxygen, free radicals and debris from the oil, and providing a means of sensing trace gases produced in the oil responsive to transformer conditions and mixed with nitrogen flow to diagnose transformer conditions of interest such as hot-spots, short circuits, insulation failure or similar indicators of failure or incipient failure or need for service, the trace gas analysis being capable of remote monitoring and interpretation.