Abstract: A bowed rotor start mitigation system for a gas turbine engine of an aircraft is provided. The bowed rotor start mitigation system includes a motoring system and a controller coupled to the motoring system and an aircraft communication bus. The controller is configured to determine at least one inferred engine operating thermal parameter based on at least one aircraft-based parameter received on the aircraft communication bus, where the at least one inferred engine operating thermal parameter is based on data describing a history of the aircraft before an engine shutdown. The motoring system is controlled to drive rotation of a starting spool of the gas turbine engine below an engine idle speed based on determining that the at least one inferred engine operating thermal parameter is within a preselected range.

Abstract: According to an aspect, a method includes predicting, by a processor, a projected oil-wetted metal temperature in a lubrication system of a gas turbine engine at shutdown based on one or more thermal models prior to shutdown of the gas turbine engine. The processor determines a coking index based on the projected oil-wetted metal temperature and a coking limit threshold associated with one or more engine components. An oil coking mitigation action is triggered as a shutdown management event of the gas turbine engine based on the coking index.

Abstract: A bowed rotor start mitigation system for a gas turbine engine of an aircraft is provided. The bowed rotor start mitigation system includes a motoring system and a controller coupled to the motoring system and an aircraft communication bus. The controller is configured to determine at least one inferred engine operating thermal parameter based on at least one aircraft-based parameter received on the aircraft communication bus, where the at least one inferred engine operating thermal parameter is based on data describing a history of the aircraft before an engine shutdown. The motoring system is controlled to drive rotation of a starting spool of the gas turbine engine below an engine idle speed based on determining that the at least one inferred engine operating thermal parameter is within a preselected range.

Abstract: A bowed rotor start mitigation system for a gas turbine engine of an aircraft is provided. The bowed rotor start mitigation system includes a motoring system and a controller coupled to the motoring system and an aircraft communication bus. The controller is configured to determine at least one inferred engine operating thermal parameter from at least one aircraft-based parameter received on the aircraft communication bus. The motoring system is controlled to drive rotation of a starting spool of the gas turbine engine below an engine idle speed based on determining that the at least one inferred engine operating thermal parameter is within a preselected threshold.

Abstract: A bowed rotor prevention system for a gas turbine engine of an aircraft is provided. The bowed rotor prevention system includes a bowed rotor prevention motor operable to drive rotation of a starting spool 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 starting spool until a bowed rotor prevention threshold condition is met or a bowed rotor prevention shutdown request to halt rotation of the starting spool is received.

Abstract: A bowed rotor start mitigation system for a gas turbine engine is provided. The bowed rotor start mitigation system includes a controller operable to receive a vibration input indicative of an actual vibration level of the gas turbine engine and a speed input indicative of a rotor speed of the gas turbine engine. The controller generates a bowed rotor start mitigation request based on comparing the actual vibration level to a modeled vibration level at the rotor speed.

Abstract: A fuel actuation system may comprise a servo valve (SV) including a torque motor and at least one screen, a metering valve (MV) fluidly connected to the SV, and an electronic engine control (EEC) operatively connected to the SV. The EEC may be configured and disposed to determine a travel time of the MV, a travel distance of the MV, a pressure of a fuel, and/or a temperature of the fuel, generate at least one of a travel time history, a travel distance history, a fuel temperature history, and a fuel pressure history, and determine a level of degradation of the fuel actuation system based on the at least one of the travel time history, the travel distance history, the fuel temperature history, or the fuel pressure history.

Abstract: A bowed rotor start mitigation system for a gas turbine engine is provided. The bowed rotor start mitigation system includes a controller operable to receive a vibration input indicative of an actual vibration level of the gas turbine engine and a speed input indicative of a rotor speed of the gas turbine engine. The controller generates a bowed rotor start mitigation request based on comparing the actual vibration level to a modeled vibration level at the rotor speed.

Abstract: A bowed rotor start mitigation system for a gas turbine engine is provided. The bow rotor start mitigation system includes a controller operable to receive a speed input indicative of a rotor speed of the gas turbine engine and a measured temperature of the gas turbine engine. The controller is further operable to drive motoring of the gas turbine engine by oscillating the rotor speed within a motoring band for a motoring time based on the measured temperature when a start sequence of the gas turbine engine is initiated.

Abstract: A fuel actuation system may comprise a servo valve (SV) including a torque motor and at least one screen, a metering valve (MV) fluidly connected to the SV, and an electronic engine control (EEC) operatively connected to the SV. The EEC may be configured and disposed to determine a travel time of the MV, a travel distance of the MV, a pressure of a fuel, and/or a temperature of the fuel, generate at least one of a travel time history, a travel distance history, a fuel temperature history, and a fuel pressure history, and determine a level of degradation of the fuel actuation system based on the at least one of the travel time history, the travel distance history, the fuel temperature history, or the fuel pressure history.

Abstract: Systems and methods for monitoring fuel actuation system health are described herein. A method for monitoring fuel actuation system health may comprise: moving a metering valve from a first position to a second position; detecting a first travel distance of the metering valve; storing the first travel distance of the metering valve to memory to generate a first travel distance history; and determining a level of degradation of the fuel actuation system based on at least the first travel distance history.

Abstract: According to an aspect, a method includes predicting, by a processor, a projected oil-wetted metal temperature in a lubrication system of a gas turbine engine at shutdown based on one or more thermal models prior to shutdown of the gas turbine engine. The processor determines a coking index based on the projected oil-wetted metal temperature and a coking limit threshold associated with one or more engine components. An oil coking mitigation action is triggered as a shutdown management event of the gas turbine engine based on the coking index.

Abstract: A bowed rotor start mitigation system for a gas turbine engine is provided. The bow rotor start mitigation system includes a controller operable to receive a speed input indicative of a rotor speed of the gas turbine engine and a measured temperature of the gas turbine engine. The controller is further operable to drive motoring of the gas turbine engine by oscillating the rotor speed within a motoring band for a motoring time based on the measured temperature when a start sequence of the gas turbine engine is initiated.

Abstract: A bowed rotor prevention system for a gas turbine engine of an aircraft is provided. The bowed rotor prevention system includes a bowed rotor prevention motor operable to drive rotation of a starting spool 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 starting spool until a bowed rotor prevention threshold condition is met or a bowed rotor prevention shutdown request to halt rotation of the starting spool is received.

Abstract: A bowed rotor start mitigation system for a gas turbine engine is provided. The bowed rotor start mitigation system includes a controller operable to receive a vibration input indicative of an actual vibration level of the gas turbine engine and a speed input indicative of a rotor speed of the gas turbine engine. The controller generates a bowed rotor start mitigation request based on comparing the actual vibration level to a modeled vibration level at the rotor speed.

Abstract: A bowed rotor start mitigation system for a gas turbine engine of an aircraft is provided. The bowed rotor start mitigation system includes a motoring system and a controller coupled to the motoring system and an aircraft communication bus. The controller is configured to determine at least one inferred engine operating thermal parameter from at least one aircraft-based parameter received on the aircraft communication bus. The motoring system is controlled to drive rotation of a starting spool of the gas turbine engine below an engine idle speed based on determining that the at least one inferred engine operating thermal parameter is within a preselected threshold.

Abstract: Systems and methods for monitoring fuel actuation system health are described herein. A method for monitoring fuel actuation system health may comprise: moving a metering valve from a first position to a second position; detecting a first travel distance of the metering valve; storing the first travel distance of the metering valve to memory to generate a first travel distance history; and determining a level of degradation of the fuel actuation system based on at least the first travel distance history.